Supercharging a 944 - Why so hard?
 

So first. I will admit that SC on a 944 doesn't make a lot of sense $$$ wise, buying a turbo or an s2 is the best solution. So that should get "that" discussion out of the way. I have search this forum any many others on 944 SC threads. There are not many that end is great success or documented numbers. Many peter out before completion or do not end well. Why?

Also the target would be modest increase in HP and torque, not to create a fire-breathing 350rwhp monster. Maybe something in the 200-250 engine bhp range.

My understanding is to do this successfully you must:
1. Select the SC, match it to the flow and power you are targeting for the engine.
2. Design how to mount and drive it.
3. Size the pulley. Determine the rpm ratio (from 1) and necessary wrap needed to supply the SC required power (also available from 1 if you have the SC performance map).
4. Decide whether you are going to IC. Should be decided in step 1.
5. Design your plumping path. Get a local tube bender to fab a nice set of pipes
6. Plumb an oil supply and return line.
7. Provide a bypass.
8, Lower CR depending on 1.
9. Upgrade injectors and fuel supply depending on #1.
10. Install new engine management and tune. Don't fight with Motronic.

Have I left any "BIG" items out? Is so please add them. Of the list which are the most difficult/problematic?

-john

those are the basic steps but actually fitting them in the 944 bay is the hard part.
also, there are lots of little costs and details that pop up along the way and some people lose patience or $$ interest.

ive been chasing mine for 10 years but for most of the first 9 of those never had either money or time to dedicate more than a few hours per year working on it.
however...this past year has been different...big progress made for my SC setup so far, more to be made this weekend...

i will admit there have been a number of times i've thought just to quit while ahead and build a nice NA engine or stick turbo parts on it.
at this point i'm still doing it, just to say i finished it.

For some reason, which I do not understand, I am very tempted to try this, against my better judgement and the judgement of many others on this forum. Perhaps its insanity, but the engineer in me finds this appealing. I have wasted money is previous pursuits of less gratifying projects so that is nothing new for me.

If I do it, I would do most of the work on an engine out of the car, make the best CAD model I can of the engine bay and do the fitting on paper. Now I need to ask Santa for a spare 2.5L motor for Christmas....

this guy in ohio (mark, good guy) sells 2.5 engines for $500 or less.

https://plyhammersparts.com/

State of affairs as of right now... intend to swap the intake for a more attractive piece eventually (round plenum vs this box)

https://cimg3.ibsrv.net/gimg/rennlis...36e6a6e055.jpg

Where are you going to place the throttle? Is that an M90 (I assume from your previous threads).?

yes m90
currently aiming to stick the throttle on the end of that elbow next to the coolant tank.

I was admittedly doing this at one time, until Dimi ruined everything by sending me a ton of 951 gear for a price I couldn't say no to, so I built a 951 motor out of the donor NA block. And then I found a 951 in amazing condition (perfect 968 interior) for $2500 that needed a motor. 2 years later I honestly wish I had just stuck to my original plans. I love that 951 but it still has a ton of work left to go and I have no time. I would have had the '83 driving with a SC by now since it already has a standalone and I have a few friends who do fabrication/plumbing for a living. So don't assume that buying a 951 is always the preferred route.

I still consider a SC every now and then for my S. The plan is to build out a strong N/A 3.0 motor to swap in, but a supercharged 16V 2.5 would be a lot of fun too.

Augment is working on a similar concept. Low boost, good engine management and no IC at the moment. Still, should be safe as they made a turbod NA with 10,6:1 CR for drifting and it holds up! Obviously, it's not high priority for them either...
https://www.augmentautomotive.co.uk/...rger-dyno-run/

SFR
 

Interestingly enough I see this topic come up a bumch but never see much on the Speed Force Racing Solution. Why is That? Is it cost? Is it the different type of SC used? Or have not many people tried it....

here is the link to their solution:

http://speedforceracing.com/product-category/porsche/944/supercharger/

Find my old posts on the subject. I have posted plenty of info on it in the past.

Yeah they started a SC project 4 years ago !!

It should be a priority to sort as there is a market for such, it either illustrates how difficult it is to getting it working properly?, they take too much on and with little success, or both ?

R

^^^^ and complementary a rennlist posting dated 2002 --> https://rennlist.com/forums/968-foru...tml#post514556

I spent years and more money than I care to admit trying to perfect a SC on a 4 cylinder engine, granted this wasn't on a 944 but still an equally capable engine (twin cam 16V). After it was said and done, I was disappointed with the power even at 12psi, the 4 cylinder engine has to work extremely hard to turn the SC and overcome the parasitic drag of yet another pair of pulleys (SC pulley and tensioner) plus another belt. Performance was mediocre at best and reasonable only when you could wind it out on long stretches of road and pull it to redline, which was not ideal for everyday driving.

I eventually ended up pulling the entire SC setup with intercooler and custom piping and sold it, replacing it with a nice sized Garrett turbo and made more power at 5 psi of turbo induction vs a supercharger at 12 psi.

Thinking about it now, these are the same reasons Mercedes went away from their Kompressor 4 cylinder engines and now have turbo charged 4 cylinders in their place. In the mid 2000s, Mercedes had a Kompressor offering on their 4 cylinder, 6 cylinder and even V8s and it was somewhat short lived with the soon to come higher efficiency and more pragmatic turbos.

At minimum, you need a larger engine displacement with at least 6 cylinders to drive a SC.

few 944 owners have the $4-6k to throw at just the SC kit from SFR when they bought their whole car for $2k.

slownrusty...were you using a roots, or centrifugal type? by your description it sounds like centri.

+1, to make good power on a sc you need to start with a larger displacement so that parasitic losses are a small percentage of the additional power produced. My AMG 5.5L Kompressor puts out 620hp with minor tuning (500hp stock). The non supercharged version barely reaches 350hp.

https://cimg3.ibsrv.net/gimg/rennlis...a43c2a168.jpeg

I think MB went away from Kompressors on small engines because they had to meet l/km fuel regulations in Germany and the EU. Its very difficult to avoid the SC parasitic losses on the test driving cycle hence the appearance of clutches on their M62's,. That only helped them on small part of the efficiency test driving cycle but they included them anyways because they were desperate for every l/km they could squeeze out. I understand (not confirmed) that you can really minimize turbo boost on the test cycle, not as much on the Kompressors..

As far a SF goes, I think Spencer got it right. $5-6K sounds high especially considering the other options including dropping an S2 or 968 motor in there for competitive investment. However, going with the SF avoids 1200 or so hours you are going to spend DIY and when all is said and done, the SF would have been the way to go for some people.

I think alot of people (like me) are drawn to this type of project with the Siren call's of the $300 M62,M90 and Millenia SC's out there. Then we're trapped.

I looked at the performance map of the Lysholm LYS1200AX pump and for a modest boost project (~5psi) parasitic losses at 3000 RPM (engine) would be around 8hp. Which doesn't sound that bad. However the price of entry with this route is ~$2200 (maybe more) with a new Lysholm unit or $300 if you want to go the Mazda Millenia route which I think is fraught with unknown hazards.

Another question. What do people mean by "parasitic" loses? Are there losses OTHER than the power required to compress the air? What are those others and how much are they?

If its they are largely the former than those losses should linearly scale with engine size. The power to compress and move the air would be the same percentage on a 2.5L motor as a 6L motor for the same pressure ratio, no?

I was running a Roots unit, another notable mention is that regularly the SC outlet would see temps reaching 270F, so heat management is key.

I also own an E55 (2006 model) that I bought when it was just over 2 years old, so owned it now for 8 years. I have Kleemann's Stage 2 on it and it runs well but no where near the current and amazing M177 Bi-Turbo in the E63.

Packaging a SC under the hood of a 944 will be a challenge, bu the time you also include the piping and intercooler installation.

depends on the type of blower but yes it's power required from the crankshaft to compress the air. depending on the (in)efficiency of the blower that can be serious numbers, in actual HP, not percentage.
for example the M90 i've got going on my 944 at 10psi and ~12000rpm or so is supposed to require almost 50 (!) HP to run because that type of blower isn't great at making pressure, just moving air volume.
centrifugals and screw-types compress the air in a different, much more efficient way so they 1) make less heat and 2) take somewhat less power to run, but the tradeoff is they are much more expensive.

what model? were you intercooled? did your turbo setup use an intercooler?

It was a IHI \ Hitachi model

And "Yes" both set-ups were intercooled.

https://cimg9.ibsrv.net/gimg/rennlis...311b642864.jpg

A Friend of mine Supercharged a Vauxhall (GM) 2.0 Litre 16V engine with an Eaton Type and it produced 335bhp

Even if a Charger kit was produced and made 280bhp this would be a good upgrade on any 2.5 N/A,

You don't need to go for a huge capacity engine with the expense and downsides of the extra engine / drivetrain brakes and suspension weight etc...to have a quick car.


R

There was a guy on here who did it and it came out great. He never complained about performance but it ended up dead because of tuning issues.

I dont know why you bitch about space.
Here is a Honda CB550 with a SC, Micro squirt, higc comp engine.

https://cimg6.ibsrv.net/gimg/rennlis...1e57f4a209.jpg

Number of cylinders is irrelevant. Capacity does have something to do with it. A 3.0l 16v Porsche motor can run extremely well with a supercharger. I had great results with my setup years ago and we had a reliable 360hp+ at the wheels with barely 10psi of boost. Torque band was great, and no turbo lag made for a great race car engine. Would have been killer on the street. I didn't develop it any further but an aftermarket intercooler and a slightly bigger supercharger head unit would have pushed the output a long way higher. Like any power adder it depends on the whole engine package and tune working together. Results will be poor if you think you can just bolt one on. Most of the kits, including the SFR kit, are poorly engineered and will need to be modified to work well.

https://rennlist.com/forums/944-turb...o-musings.html

Very nice thread. For a modest street application I would like the torque you got at 4500rmp starting around 2500 rpm. 5-7# of boost is all I would need and don't care as much for top end. The centrifugal blowers seem easier for fabrication and space but probably not optimum for what I am looking for.

I have been looking at the Whipple W100AX which is a 1.6 l/rev unit. The performance map for the Lynsholm LYS1600 is below. Whipple says that map would be close to the W100AX. I calculated where we would be operating with the 2.5L engine at up to 7psi which is the blue line on the map. At 3K rpm the power to the SC is about 7-8 hp, at 6K it's about double at 16HP. At this boost level the motor should generate about 210HP at the flywheel. Seems like a reasonable solution.

Discharge temp from the SC would be around 70C. Don't what this would mean in terms of tuning to avoid detonation. I'd like to do phase 1 without an IC.

https://cimg7.ibsrv.net/gimg/rennlis...69643199ec.png

I am not sure if your reply was directed to me, but my set-up wasn't a bolt on. I spent several years and beaucoup bux playing with different engine compression ratios and custom pulleys to balance the drive ability and throttle response on and off boost, including several intercooler designs and piping layouts to minimize pressure drop and smooth flow.

Using a 3L engine is huge advantage over the smaller displacement 1.6L I was developing at the time, so your 3L volumetric efficiency is definitely at an advantage which is reflected in your stout WHP numbers.

R

I know that car well, I supplied VEMS PnP kit. He is from Hawaii.

Details..Intercoooled? Pulley ratio? How much boost intent?

Does anyone know how hot the case of a M90 or M62 at the input flange would get under "moderate" boost? I am thinking of 3D printing intake interface of the ductwork.

about as hot as the rest of the engine...likely cooler since it has all those strengthening ribs radiating heat off.
i have a pre-made intake "flange duct" for an 89-93 thunderbird M90 that i won't be using, it has a 2.5" pipe welded to it. ill sell it cheap, along with either/both of the "m90 outlet hats" pictured on the right side below.
it came from the godfather of all supercharged 944s, blown944's "lil mule" car if youve read about it.,

bottom middle...
https://rennlist.com/forums/attachme...820_144038.jpg

Dear Spencer..Have you considered using an Eaton blower off of a M-B C230? Looks like it could be adapted pretty easily with some ductwork/creative welding done. Looks small which would fit nicely in our 944 cars. Don't know about pressures/ pulley size, but might be a place to start..just thinking..

Rich - no, too small for our engines, IMO. The Ford M90 that I've been basing my stuff around moves 2x as much air per RPM.

Also, they have tended to be more expensive than the Ford M90.

I am taking a hard look at the MB M62 for my potential project. From rough calculations it would need a 3" pulley to get the 6-7psi boost I am targeting. Probably would need to take the clutch of the M62 for that size pulley. However this level of boost is probably the limit on a 2,5L with the M62 as it will probably be hard to get drive with smaller pulleys. The m90 would be more "scalable" but I like the M62 because I am after more low-end torque. The M62 would be spinning faster for the same boost as an M90 and should have less leakage at the lower rpms.

So far my concept has evolved to:
1. M62 with ~3" pulley
2. No intercooler, but may try water/meth injection just for safety and detonation margin.
3. Standalone ECU (10% of MS Black Friday sale....hmmm) (Also noticed prices are higher since a few weeks back....hmmm)
4. AC delete. (Initially. If I like it then I can figure out a scheme to save the AC later)

The Jaguar Eaton M90 short snout would be my first choice.

VEMS PnP systems were 15% off last week :P

So what would be the performance gain for 1/2 bar of pressure? Seems like it would be better if it were upped a bit more say about 10 inches..The junkyard C230's have an intercooler, and with the water, methanol injection, seems like the boost could be as much as 1 bar of overpressure. You have to look at performance gains of the turbo boys here...might need to add another headgasket though or a thick cometic one to lower the overall C/R. I don't have any pressure data to confirm the Eaton blowers on the M-B cars and what they yield. Where could I find such data? Does Eaton publish a list of blower #s and their pressures at certain RPMs?

yeah, i got one of those too, neat little package but i decided to continue with the brackets i had already to save another 5 years of development time, lol

any kind of mail-in rebate for previous customers? :p

Rich,
Eaton publishes a fair amount of info on the blowers but pressure doesn't depend on RPM.
Eaton blowers move a volume of air per revolution - the volume in cubic inches is the number after the "M" so my M90 supercharger is 90ci, some C230 use an M45, I think some use an M62.
GM 3.8 V6 came with either M62 or M90 depending on year, the Cobalt SS (the supercharger linked on the previous page of this thread) is an M62.

The blower itself doesn't make any pressure - but the spinning rotors forcing their displacement through every revolution and not allowing much "bleed back" is what creates pressure at the outlet side of the blower.
It's not quite linear due to thermal efficiency drop-off but in essence a 90ci SC at 1000rpm moves 90,000ci of air. At 5000 rpm it moves ~450,000ci of air, and so on.
The pressure only comes when the engine on the other side can't take in that much air on its own...but the blower is going to force that air in one way or another, the tradeoff is higher drive-power required by the SC, and HEAT.

Roots blowers are good for lower psi/lower rpm, you can run them harder but you really need to intercool, or run nitromethane.

With 6-7psi I have estimated 40% more torque across the rpm range with a little fall off at the high end due to advancing parasitic losses. So its modest but that is my Stage 1 target because I want to keep my NA transmission, clutch and brakes. That is a conservative estimate and may get that with less boost because tuning and cam offset has reportedly gotten conservatively 10% more by itself.

:corn:

Bare in mind the cam offset will help you out (higher VE at lower rpm = more useable airflow and less boost pressure) but the tuning will not be additive as far as power. You will be taking out timing versus putting it in, due to heat induction and so on. Obviously power will be up but it's not 10% gain from tuning plus 40% from the SC.

Michael, I agree. My point was that a 40% increase in torque would be conservative in that if I increase the VE of the engine then the SC boost pressure decreases at a given SC rpm. Less CS pressure = less heat = less parasitic losses = can be more aggressive on ignition timing. So it's not necessarily additive but it is synergistic.

Well I just bought a C230 M62 off ebay. Seller claims it may be a refurbished unit. We shall see. $150 gambled....

Maybe you can use V2's hacked up intake manifold for a start on the plumbing...just a thought.

that little guy is probably short enough to mount on top of the AC bracket.
with longer blowers (Jag M90 included) part of the problem is interference with the driver-side engine mount "arm" to the point I was considering making a whole new one.

there is tons of space in the 944 bay once the stock airbox and intake manifold come off but that arm cuts potential blower space down big time.

re: my manifold, i do intend to have a different intake manifold made so the ready-to-run box type i have will be for sale.
if anyone were interested in taking it off my hands that would speed up that process, lol.
nothing wrong with it, this box manifold was the one that blown944 used on his supercharged 944 drag car years ago, i just don't like the aesthetics of it :eek:

Perhaps but the MB SC uses a hexagonal hole for the output rather than the square one the American companies use. First thing is just to get the thing in my hands, see how the bearings are and grit blast it and make it purdy. Then this winter I will get under the hood and take off stuff to see how it might fit. I'd prefer to keep the existing stock manifold if possible.

]It looks like from rough eyeballing is I have about 13" from the accessory belts to the inside of the mount arm. I think I will be able to fit the MB C230 charger in that space because there is basically no snout on that unit. Then I plan to go straight up (sc upside down) and over to the existing stock throttle body. The intake side I haven't mapped out in my head yet.

you really want to put the TB ahead of the supercharger when using an eaton/roots, though i guess if you keep the clutched pulley on the MB blower you can put it after the SC...but that limits your boost options a lot for the future.

Yes I have seen it argued both ways on the endless "hot rodding" forums. I was hoping that I can use a bypass valve arrangement to get this to work with the TB after the SC. Could that work?


I do not plan to use the clutch. I will remove it and replace with a quick-change like pulley thingy.

Edit: After more research I will try and mount the TB before the SC.

In the bmw tuning World, rotrex is wery popular, they run With the sc And a bow.

Spencer, What were you planning to do about fuel? What injectors? Is there a higher (3bar) fuel pressure regulator for early 944's?

i have VEMS ECU so i can use whatever injector i want.
i have a set of 55lb/hr and a set of 72lb/hr on the shelf. i'm sure there's a 3 or 3.5 bar FPR that will fit the NA rail, haven't looked too much at it since these injectors are more than big enough to work at stock 2.5 bar.

I’ve been searching for the S2 with a 968 supercharged engine built by 9meister which put out 350hp and I found the old ad but not much more. Anyone have anymore info on that car?

9meister supercharged 944

I've been running a Rotrex supercharger on my S2 for 5 years now. I have been running it hard on the track for all of this time. You can find details in my thread. It's not hard, but takes a lot of time and thought to get it right.

I wouldn't run an Eaton.

I had superscharged (procharger C2) S2 and it was fun car to drive. Around 350hp with E85 it was quick enough. After that i couldn't even consider NA versions of 944. Now that engine is gone and there will be 1.8T in the engine bay before next season. I think any right sized supercharger will make 944's a lot more fun to drive. In case of self contained supercharger the installation is pretty straight forward.

I just read your thread. Very nice! That SC unit looks very easy (relatively) to package. Can you elaborate more on your thoughts about the Eaton?

no question the rotrex/etc are superior for higher-end HP. great choice for bigger engines like S2 (or all the common V6/v8 cars) that are fine down low but could use more top-end.

2.5 944 needs all the low-end help it can get, but no centri will give you that like the eaton will.

I don`t agree.

A racecar needs mid and top end power.

But for a daily cruiser, it might be the litle extra.

Not trying to be a wise guy, but how about a nice NOS kit? It installs in hours (not years), is priced more in line with the value of a typical 944 n/a, and can go from mild to wild depending on your risk appetite. :)

https://www.summitracing.com/parts/NEX-ML2000/

A SC can install in hours also. Its the optimization afterwards that can take a while.
I think to make a 944 NOS motor long-term reliable you would need to:
1. Upgrade the fuel system
2. Standalone ECU.
3. Water/meth injection if using stock compression ratio.

Now its no longer a few hours anymore.... :-)

But I thought about it.

Why would you need those things with N2O? The fuel pump, sure, if it cannot deliver the goods but the stock 944 pump seems pretty stout.

You need to inject more fuel to compensate the extra O2 you are getting from the NOS or you will be running destructively lean. The stock ECU and AFM does not know there is more O2 in the cylinders. You can inject fuel separately with the N2O but that is a very coarse approach because the system does not know what the MAF rate when you hit the bottle.

NOS is basically chemically supercharging. Still need to do it right either way or you kill your engine. Its easier to do it wrong with NOS in my opinion.

BTW I make N2O power rocket motors in my other hobby

I've run a lot of N2O, you can add fuel a couple different ways and it's not that difficult or dangerous as long as you have an adequate fuel system and a fuel pressure safety switch.
The WOT maps are not that sophisticated anyway and the 944 has no MAF, only an AFM. It'd be no big deal IMO to even run a dry kit for an old 5.0 Mustang on the 944.
Since you are not expecting to use more atmospheric O2 the temperature, pressure and humidity of the extra "air" is not a problem, it is a known quantity. Thus you just add a proportional amount of fuel. All you need is money! And extra bottles.

Cool, well you have much more experience that me on auto NOS, you alot, me zero. Perhaps we can start another different thread on NOS versus SC versus whatever on a 944. I'd like if possible to keep this thread on the topic of SC as that is what I want to learn more about.

Edit: Also I know that there is no MAF "sensor" on a 944, I was refering to Mass Air Flow rate in my post, abbreviated MAF rate. I think a dry NOS system on a 944 would burn the rings in short order. Especially on a later engine with high CR. But what do I know?:burnout:

https://cimg1.ibsrv.net/gimg/rennlis...acbceafbcd.jpg

My setup used an Eaton M90 from a 1990 Ford Thunderbird SC. It fit very nicely and lined up well with the stock pullies. Don't forget to run a bypass so the SC can freewheel when not inder load, helps with fuel economy. I was running 5.5 psi of boost and the car was fantastic. Loads of power from idle on. I never got it dynoed but I estimate it was making 180rwhp. I used Rogue's NA tune and the tunibility was amazing. I ran a front mount IC.

https://cimg0.ibsrv.net/gimg/rennlis...6af0b55e7f.jpg

Top view of where the SC was fit.

https://cimg4.ibsrv.net/gimg/rennlis...28cc18be78.jpg

View from under the car of the SC pulley location.

What did you use for the bypass valve? Is that it spliced in the intake pipe? How was it actuated?

I used the factory Bosch valve from the 944 turbo, it worked well. It's actuated when the motor is running in vacuum(cruising). That is it spliced into the intake.

What the thing in the intake with the wires running to it?

Eaton is not very thermally efficient (high temp), prone to heat soak and does not have a good top end. Ok for a street cruiser, bad for track use. Not really in keeping with the character of a Porsche in my view.

If you are tuned correctly, I think nitrous is more than doable. I forgot where I saw the video but a dude ran a 13 something in an otherwise mechanically stock 84 with a ton of nos. I would just be worried about the trans after the tuning is accounted for.

The Eaton is a tradeoff for sure. Typically the appeal of Eaton is the cheap (~$200) cost of admission. Perhaps its false economy.
Once you go to new centrifugals (not a lot of used centi's on ebay for sub $300) another whole world opens up. What about twin-screws? (Whipple).

twinscrew (whipple, etc) are almost "best of both worlds" but still crazy expensive, on par with or greater than centrifugals.

Seems very competitive with centrifugals. I have seen Whipple W100AX (97 ci/rev) discounted to ~$2100. Par with Rotrex, cheaper than ProCharger. Smaller than a M90 (maybe a little longer 14.6" with shortest stock snout) . Seems like the ideal unit for a 2.5L. What's the downside other than cost?

nothing, but do you want to spend $2100 on a blower for a $2100 car?

i bought My 951 for 14$
new engine And parts..15...

Still cheaper than a s2 motor swap. Isn't it about where you end not where you start?

Again I want to avoid a value discussion or else we will get the inevitable "just buy a turbo or s2 or 968 or Volvo S60" post.

Ok, with that in mind, no reason you couldn't/shouldn't use a twin-screw or centrifugal if that's what you want to use. They are definitely more efficient and probably easier to package.

For me, NFW I'm going to spend that $ on a single part, no matter how much I "want one"...I'll make do with something else at that point.
$2100 is almost as much as I paid for my 944 + Outback, combined... :)

No, don't get me wrong I would rather get my M62 or M90 working first.

If I had the choice of turning a fun $2100 944 into a REALLY fun $2700 944, or tuning a $2100 fun 944 into a REALLY REALLY fun $4500 944, I would try the first one first....

I am guessing your VEMS wasn't exactly cheap compared to the cost of you car? That was a single part.

However if you have a really nice 944 sample I could see someone using the Whipple for other subtle NVH considerations. There are quieter and not everyone loves the roots blower whine.

VEMS was $1200 or so I think, but I was able to sell my Rogue MAF+DME tuner setup to offset most of that so it was "OK" in my mind. Totally worth it.
..
Whipple being quiet...:roflmao:

That video was using a KB, probably a large one. They are known for screaming.

I haven't heard one in person but the consensus on the various forums is that the Whipple is significantly quieter than the the KB which in turn is quieter than the Eatons. All other things being equal, RPM, i/rpm etc etc. Some complain about the Whipple as they miss the Eaton or KB scream. But what do I know without hearing one in person.

So what caused the demise of your motor?

I had never checked the compression/health of my motor. It turns out somebody along the way had built my NA motor with very high compression and It also had a fair number of hard miles on it. I cracked the rings in 3 of the cylinders.

My brother has the setup now and has built a proper motor for it so it will live on.

I spent 2400$ canadian for my entire setup(Not including the previously purchased NA-Tune). The SC was $100. I spent a few bucks on a rebuild kit. The piping and materials were a few hundred dollars. It wasn't cheap, but the performance was amazing. I had a well know local mechanic/racer drive it and he was amazed. Loved the power, as well as the throttle response. It idled perfectly, cruised nicely., and would light up the tires in first at will. It was the perfect mod for an NA car, IMHO, how they should have come from the factory. I don't like my current turbo car nearly as much and have contemplated twin-charging it.

Darren, what compression ratio do you recommend for your level of boost?

some motivation for this thread
https://grassrootsmotorsports.com/fo.../131357/page1/

VE assumptions for pulley sizing
 

I received the MB M62 charger, it seems in excellent shape but the pulley was missing. Not a big deal because I would not be using the factory pulley as it is too large for the 944 motor. But I hoping to work the splined hub to accept new pulleys, oh well all projects have their challenges.

There is an outfit in Hungary who sells custom pulley conversions for the MB m62, but each pulley iteration will cost me $120 (including shipping) so I would like to get it close the first time.

There is a supercharging boost calculator here (http://performancetrends.com/Calcula...Calculator.php) that I would like to use to get into the ballpark with the initial pulley ratio. It needs an assumption of the engines and the blowers VE.

I think I can assume 90-95% for the engine VE, right? What about the blower. Eaton's data shows 62 ci/rev at a pressure ratio of 1 and it drops about 8% at 1.4. But this data is bare with no inlet losses. Any idea on what I should assume for the actual inlet ci/rev for this application?

ive seen that before, just used 80 for engine and 85 for blower.
just run the numbers at 62 ci/rev, no real reason to complicate things thinking about inlet efficiencies. just build the best (airflow-wise) inlet you can fit to the back of the blower.

Spencer, does VEMs give you flow rate in log anywhere? IT should be available and it can be used to estimate the VE of your motor at various RPMs (at WOT of course).

dunno, never looked for it.
but VEMS is tuned with assumed/calculated VEs based on AFR data from the O2 sensor, but i dont recall how high it goes.

If it uses a MAP and IAT then an airflow calculation is done somewhere, or can be done it you can get the MAP and IAT readings.

I estimate that with a standalone I will be able to dial in the pulley ratio in 2 interations. With the first one you determine the motors VE from the ECU data. With the flow and boost pressure measured the blower VE will be known. Then you will be able to calculate the pulley ratio for the boost and flow you want. I just want to get close on the first and avoid being too high. I would rather miss low than high but don't want to miss too low.

You can calculate airflow using VE logs, in fact most popular datalogging utilities do it for you. I use megalogviewer and I believe it tells you calculated airflow based on the measured sensor outputs during the log's duration.

I think 9:1 would be ideal. The turbo motor is close to 8:1. As long as you keep boost levels fairly low, run good fuel and the tune is solid, it should last and last. My brother built his motor at 9:1 so we'll see how that holds up next year.

I have an 84 motor which is 9.5 to 1. Do you think I can get a touch lower with a thicker head gasket (if there is one) or is that not recommended with a boosted engine? Or are piston mods the only way to go?

OK did a monte-carlo model which accounts for the uncertainty in the assumed VE of the engine and blower. Initially I do not want to end up over 7psi. Looks like I want to start with an 80mm pulley on the M62. Plots are the range of "what could happen"

https://cimg7.ibsrv.net/gimg/rennlis...00fc33ecf8.png

I wouldn't be afraid to run a slightly thicker head gasket as long as it's a quality brand.

I also wouldn't run your little M62 too hard. And I hope you are planning on intercooling?

I plan on water/meth injection, no intercooler.

Spencer, can the stock alternator fit in the power steering pump place? I see you moved it there but selected a different alternator.

Don't know, didn't try.
My arrangement as I showed off once upon a time was space-limited by an oil cooler line that is no longer there.
The GM alternator I had on there is MUCH smaller than the stock 944 unit.

I could throw it on there maybe tonight or later this week, but I doubt it'd be a good fit versus finding a more modern, more powerful, more compact unit.
Seriously, the early 944 alternator is 90 amps...modern 90 amp alternators are about 2/3 the size.

Thanks. Have you considered an electric PS pump so we can have the SC, AC and PS?

no, I haven't ever had functional PS on my car (12+ years) so it wasn't ever a consideration of mine.

I recently drove a 100% California smog legal LS3 996.
I'm told it's the first fully legal LS swapped Porsche.
Amazing, sorted swap.

I think that the tiny Nippendenso models that go on an early Honda FIT put out about 90 amps...They are only about 4 inches in diameter..might be a solution to tight quarters...jus sayin..

TonyG had a 100% legal swap before the LS3 even debuted, lol

^ Like. I will search.

Last I removed the airbox to survey the room I have, I have plenty.

Spencer: Do you know if an alternator can be driven with a single v-belt? Thinking ahead of moving the alternator to the PS place but still use the PS crank pulley.

that's how i was going to do it, using the PS pump drive pulley and a v-belt pulley from an old volvo or something on the alternator.

"serpentine multi-rib" belts only really came about in the late 1970s...before that everything was "single V belt", alternators, mech fans, AC compressor, power steering, etc.

So I put together a rough budget for this project. Prolly left a few things out which I will compensate for by adding 50% to my estimate which may not be enough. But here goes.

ECU $609
MS3 $409
Other sensors $50
Wideband O2 $150

SC $690
MB M62 $170
Custom Pulley Set $270
Water Inj $150
Tube Fab $100

Alternator Relocation $150
Smaller Alt $100
Bracketry $25
Pulley Mods $25

Electric PS conversion $135
Volvo S40 PS Pump junkyard $50
Fittings $25
Elect $35
Mounting $25

Total $1584

Probably in the ballpark, but IMO designing in a proper intercooler is a better idea than water inj.
It's a cool idea, and it definitely works, but having to refill a tank and having another semi-complex system of switches and pump(s) sounds like a PITA.

Check out these guys for a pulley, I sent them a stock Ford SC pulley to get dimensions from, and had them make me a custom larger (to get underdrive) lower-boost pulley for ~$160 shipped.
I bet if you sent them your MB pulley they could whip up a solid (non clutch) version to fit your needs.

http://www.southfloridapulleyhq.com/

The shaft on the MB M62 is splined which is a deal breaker for many of these after market companies. I'll send them an email though and ask if they can do one.

then perhaps the solution is to have the MB nose shaft turned on a lathe to remove the splines, and make it (if possible) the same OD as the GM-style pressfit pulleys.

More on the pulley cost
The $269 includes 2 pieces. The splined hub that mounts on the shaft, and the pulley that mounts to the hub in a "quick change" arrangement. New pulleys after that are less than $100 (from Hungary.....)

https://cimg1.ibsrv.net/gimg/rennlis...4caffe9231.png

You are probably right but I want to avoid the ducting and fabbing. Running a 1/8" nylon tube from the washer fluid tank to the SC output sounds easier to me fab wise. At the boost levels I am targeting I probably do not need IC so this is just R&D and play for me. I would be running the injection off MS3.

Now for fun project afterwards I was thinking of using the AC (its right there) to do the intercooling. Fashion up a small evaporator and expansion valve right at the SC output and pump the refrigerant up there. With a 40F evaporator you do not need a very big heat exchanger. Have a valve actuated by the ECU or vacuum to direct the refrigerant to the cabin evaporator when off boost. Should work right?

Ford tried that on the Lightning as an optional extra.
They use the AC to passively cool the water in the air-water intercooler system while driving around so it gets super cold. Then when you actually go into boost the water is at 35 degrees or whatever rather than roughly ambient which helps a LOT in cooling efficiency.

You could do similar with your to-be-injected water.

If you want to directly "air condition" your boost, not gonna work.
The 944's AC system takes 8-10hp to cool ~300 cfm from the blower fan from 100 degrees down to 65 or so in the cabin.
Air coming out of the blower will be 250+ degrees, lol, and the compressor turns off when you got WOT :p

Good to know, saves me some work.

Why dont you guys just use a stock 951 cooler? It fits right in the nose, and will do the job for your SC engines :)

We have a manufacturer in the UK called BRISE who do smaller Alternators....

http://www.brise.co.uk/Alternators/

I fitted one on my 924 to lose weight over the large heavy stock one and bracket, but it also free's
up the space around this area..

https://cimg9.ibsrv.net/gimg/rennlis...d1becacdfa.jpg


R

^^ Those are nice alts, but I'd prefer search for a cheaper solution firstly....

Edit: This one looks good and its chromed!
http://www.topstreetperformance.com/...BoCoCQQAvD_BwE

there are plenty of compact, OEM-type alternators available here with a little bit of leg work available new from our auto supply stores for the equivalent of ~50 GBP.
i do fully agree that the 944 could use an "alternator diet" as the stock unit is an underperforming, oversized monster compared to more modern units.

i will be using a modified 951 unit.

Thats what I would have done, but my car was an 84 so access to that area was zero.

If anybody wants to give this a shot, my Jaguar XJR "short-snout" M90 is not going to be needed so it is up for sale.
This one is rarer than the Ford version I am using, it is about 2.5" shorter overall so will be easier to package.

Good used condition, ready to bolt on and go (could use a cleaning though).
I need $300 to break even (that's what I paid the dismantler who removed it from the running but wrecked Jaguar)

https://cimg2.ibsrv.net/gimg/rennlis...30385e22f9.jpg

Interesting thread. While I am not Supercharging a Porsche. I have done a good amount of work on doing the same to Honda 1976 GL1000 Goldwing motorcycle. That project is ‘sorta’ stalled right now, but that is only from my own laziness. I went out to my shop today and looked at all the parts I have collected to date, and my build binder. This thread may help get me back on the road to finishing that project, I really do hope so. I noted a few posters mentioned the Rotrex brand. That is the S/C brand I went with on my project, a C15-60 to be exact. Its sweet ‘spot’ is in the 90 - 240 HP range. I was going for 100 - 125 HP, low RPMs on the actual S/C, so well within its limits. I won’t post any data here, I think that is a little off topic for this thread. However, a book I would highly recommend for anyone wanting to do such a S/C project is ‘Supercharged’ by Corky Bell. I will be following this thread and I may interject if I feel I can add something technical to the conversation.

An idea I had a few years ago was to run the blower off the balance shaft cog. Machine a balance shaft pulley to fit the shaft of the blower. 2:1 cogged ratio, no slip. My car has the balance shafts deleted so it seemed viable in my case.

Here is my friend Harald`s ch550sc
Running microsquirt ++++

https://cimg3.ibsrv.net/gimg/rennlis...e6ecfff340.jpg

Looking into intercooling options. Looking at these a2w barrel units. Seems appealing to me from the space saving and possibly simpler air ducting. The water loop part doesn't bother me. For the power and boost I am looking for these compact units might work. Any comments on this approach?

Pictures is 4" diameter total length around 11". From frozenboost.com I think I could fab this to fit in the space that the j-boot and throttle body now occupy.


https://cimg2.ibsrv.net/gimg/rennlis...2b76879f35.png

Thaose are really nice looking units. I presume that the inlet and outlets are about 2" since the total diameter is only 4"..Keep us posted! Thanks!

When you go to start fabbing stuff up you'll realize how little space there really is under a 944 hood.
I've looked long and hard at those AWICs, barrel types, the boxy types, even thought about making my own. It'd package so much better without all the air piping.
But those things sure seem bigger than they really are when you try to stuff them into a car.. :)

I think you could fit one of those if you designed the entire system around fitting it, if that makes sense.

You can use a BMW Water IC. ( 13717575406/405 )
Water cooler where the oem ic is placed.

https://s3-us-west-2.amazonaws.com/u..._196628_04.jpg

You are so right. I have taken stuff off and laying in parts.

I am going to print a model of the barrel unit and see where it can go under the hood.

BTW I have my aluminum "foundry" going and plan on casting custom pieces to get things to fit.

ive seen those.
if someone were clever they could fit one of those bricks sort of next to the AOS/brake booster.


there's no point to use an AWIC if you're going to put it where an A/A would fit, because you still have to run pipes.
the point of AWIC is to have a direct connection between SC->IC->intake runners, potentially even in one single unit.

Sorry bad writing.
The water cooler for the awic can be placed where the oem is.
This cooler is not huge, and will wit in tight places, its the size of the oem airfilter box.

The hot setup would be individual a2w cores in each runner of a custom intake manifold. There is alot of space now between and below the current intake runners.

one big core would be easier to make and probably superior to 4 individual ones.
if you wanted to go down that path i have the AWIC from a supercharged Jaguar with the Jag runners cut off, ready to clean up (cut a little more off the outlet side) and weld to your 944 runners.
it's a beast (very large) and the oil filler cap would need to be relocated (Lindsey sells a kit to do that).
when the jag owners turn up the power this AWIC has proven to be good past 400hp as long as the secondary heat exchanger is up to par.
i'll sell you this AWIC as-is for $75 plus shipping.

https://rennlist.com/forums/attachme...wic-cooler.jpg

I want to go back to CAD and see if I design one that sits on the MB M62 outlet. Bare cores on that that expensive so fabbing a custom A2W IC doesn't seem that intimidating to me yet. I am thinking a 4.5" x 4.5" by 2" core might do it thermally. Pics to come tomorrow I hope.

So here is the "stack" concept. With the alt relocated I 'think' I can get the SC low enough for the IC stack to fit under the hood. Of course the lower tank casting needs to be tweaked a little because as shown it can't be assembled.

https://cimg8.ibsrv.net/gimg/rennlis...c095aa9e36.png

Do we know how much heat is produced in the SC?
I've got some experience in water-cooling PCs (GPUs as of late) and got an idea. As long as we don't need to remove much more than 1000 watts of heat...

That is what I should have done for my turbo swap. Hindsight is 20/20.

At full tilt for this project = 1.5 pressure ratio, 300 cfm and 83C temp drop, I am calculating around 20000 watts of cooling required. (with a roots blower).

guessing you're looking at PC radiators...
they are a very nice size and shape and very inexpensive - looked at them too.

they might work if you can get enough water flow and a big enough heat exchanger at the front of the car.

depending which SC you use and boost levels, could be 150C coming out the blower.

Its relatively easy to get good heat transfer. Its also relatively easy to get low pressure drop. It's relatively difficult to get both at the same time.

Yeah, I was thinking that radiators and fittings are available in all sizes and pumps operate on 12 volts. The ducting for water/coolant is also much simpler to package than for air since you don't need the constant big diameter. However, the tube will not tolerate temps above 60 Celsius and removing 20 KW heat? I mean, that's a lot of wasted HP right there.

What's the size of the oem IC's core? That would be an indicator. My idea was to place radiators where the turbo oil cooler is mounted but on both sides. The pumps could be operated off of the fog light cables or something. Even standard PC fans could be used to aid air flow in stop and go traffic.

Just thinking out loud...

Corky Bell recommends 7 sqin of air charge flow area per 100 HP for a liquid to air IC.

Wow, if I calculated correctly and this is true, then a single triple 140 mm radiator I was thinking about would be good for a mere 1300 HP. And I wanted to use 2 of them! :D
Oh, and these are available in 1, 1.5, 2 and 3 inch thicknesses. :)

I'll use same one as V2 has. It will replace plenum, and the only thing between it and turbo outlet will be factory TB.

Will need to get creative to shoehorn it in though.

https://cimg3.ibsrv.net/gimg/rennlis...0178804ab1.jpg

The capacity doesn't add linearly if you stack them. If its 140mm square you have about 25 sqin. You would need then to subtract out the structure, I think the area is actually where air can flow. So I am guessing that is good for 350 to 400 HP. To get more you would need to run them in parrallel not series.

You also have to consider the pressure drop accross each cell. Those may not optimized for that as that is not a concern with processor cooling.

Please post a picture of what you are thinking about.

it's not quite that easy... :)
AWIC cores need to be BIG to work. remember that on say a 944 at 5000rpm it's got to flow ~220cfm @ whatever pressure ratio the blower is pushing out, all heated to 150C and trying to get it to 50C on the other side.

that jaguar IC pictured above (factory rated at 325hp, good at 400hp) is about 4.5" high, 16" long, and about 7" thick.
the weak spot is the stock Jag front heat exchanger, rejecting the heat from the warmed up water back to atmosphere.

needs more heat exchanger and more coolant flow.

another example, this is the intercooler core for the supercharged 6.2L camaro/Cadillac, about 600hp.
https://www.dedicatedmotorsports.com...-p/ribctsv.htm

Just got off the phone with Bell Intercoolers. For my application he suggested a core size of 4.2 x 6 x 3" core thickness which would be conservatively rated good for 230 rwhp. Since I am looking for ~225 bhp at the crank he said I could even go smaller than that. Reducing the core thickness to 2" would only have a small effect on efficiency. This setup would need 5 gpm of coolant flow.

if that size would work, take a look at Setrab "type 6" 13-row oil coolers.
i looked at making my own AWIC using one of those...core is 9.5x4x2 thick.

For the charge cooler or the coolant cooler? The above is a little long for what I would like to try which is to "stack" the IC right on top of the blower outlet and be within the envelope of the MB M62 blower.

for the charge cooler between SC and cylinder head.

if thats too big, then go to your local auto supply store and ask to snoop around their collection of heater cores... :)

Yes my friend had an Opel Ascona Fully restored and Modified with a 2.0 GM Engine and Eaton Supercharger, using an Oil Cooler
for a Chargecooler... the last I heard it was pushing about 320bhp

https://cimg3.ibsrv.net/gimg/rennlis...60ecd43b1c.jpg


See Build link


R

I meant these radiators and for cooling the coolant, not the charge.
http://www.frozencpu.com/products/18794/ex-rad-491/Alphacool_NexXxoS_Monsta_Triple_140mm_Radiator_-_80mm_Thick.html?tl=g30c95s931&id=teHpSQTV

With these, core and total area are practically identical. I don't think pressure drop is an issue at the coolant side. Those pipe-looking intercoolers are really nice and could be a great combination!
Moreover, PC pumps can do 300-400 gpm (1200-1500 liters per hour).

Ish - to cool the coolant you want as big (surface area, not thickness) an exchanger as you can physically fit.
On a 944 chassis, you could get a cooler about 600mm wide by 350mm tall in front of/in place of the AC condenser...

The other thing to consider for the coolant radiator is you can have a smaller coolant radiator if you have a larger coolant tank and play the duty cycle game. For a track car where you are on the boost alot then you certainly need the radiator capacity. But for a street car not so much.

Latest CAD work on the stacked intercooler idea. Using the recommended core size from Bell Intercoolers (4.1 x 6 x 3" core thickness) I can fab (I think) a stack like this. Will need 6.7" of vertical space on top of the SC too fit. I was going to pull the alternator to see how much depth I would have but it 15F outside and my garage heater won't make it warm enough for me to work. So it will have to wait a few days. I worry about the sharp turn in air flow at the top, don't know if this a big concern or not (even if I have the space).

https://cimg8.ibsrv.net/gimg/rennlis...d5b45655a8.png

the ford 3.8 SC had a similar sharp-turn outlet and they put some guide vanes on the underside of the outlet "hat" to direct the flow towards the exit.
i can take a photo later if interested.

So the vanes were "inside" the casting cavity? Yes a pic would be handy.

not my photo but you get the idea.
to clear the thunderbird hood this "hat" is only maybe 1.5" high but the pipe connection is 70mm OD, all the flow gets squeezed thru a ~1.5x2.5" slot that the vanes are pointing at.
interestingly the Tbird SC guys have a product called a "raised top" that is this thing but 3/4" or 1" taller to nominally make that "slot" less restrictive - but it doesn't actually seem to change anything.
people have tapped this hat pre and post-slot and found like 5 extra PSI on the SC side of the slot vs the discharge pipe but it doesn't seem to cause any noticeable power loss. that air is getting out...

https://cimg4.ibsrv.net/gimg/rennlis...91ad59a271.jpg

Spencer, thanks for the pic. Those would be easy to add. I was picturing the vanes differently like trying to bend the flow. But that would be a manufacturing nightmare.

But you are right it all has to come out, positive displacement is positive displacement.....just makes the sc work a little harder.
I updated the config a little, increased the flow area of the core (5.3x6 instead of 4.1 x 6) and reduced the core thickness to 2.25". The lower piece with the original dimensions wasn't easily castable anyways. Making it bigger makes proper draft on the pattern possible. That brings the total stack height just under 6 inches. Still too cold in the garage to work today though.

that's RL user"mattipuh"s car.
with mild head work and hot cam and some other pretty easy stuff they made like 190hp out of a 2.5 8v, that was before the SC and that crazy billet plenum came along.

The feed line to the Injectors looks to be a single S/S tube, with four outlets feeding the top (inlets) of the four Injectors. The actual Throttle Bodies are black, which is a standard colour for some of the JENVEY DCOE Style replacements that they make. The angle of the Injectors and the location of the Throttle Plates makes me think they might indeed be a JENVEY product? JENVEY is UK based, and very popular in the European aftermarket world, they also do some OEM stuff for the EU Big Boys.

I am not a 944 guy, but this is a fun thread to follow.

It looks like a very clever "averaging" system for MAP. With ITBs it's hard to get a steady MAP signal. Many turn to alpha-N tuning (using TPS and RPM instead of MAP and RPM). He's referencing all 4 cyls to get an average signal.

i would guess based on the suspicious reservoir, foam-wrapped pump looking thing and pressure regulator on the firewall that it's a water/alcohol injection system.
if so, cleverly done using the stock rail.

also just noticed where the oil filler is... LOL

The blue lines appear to be going to vacuum related components... MAP sensor, bypass valve, FPR

Did anybody read the GRM article on supercharging their Miata (not the one they blew up)? They said they did it for under $200, although that didn't include already-installed engine management, parts they had laying around, or labor. Their setup seemed pretty simple for modest gains. It piqued my interest and has me asking "how hard could it be?"

When I looked at using a Eaton m62 or m90 I found I was going to have to cut the snout almost to the bearings just to have enough room to bring the inlet elbow around. Plus the throttle would need to be on the elbow and near the front. Creating a super long path which may hurt response. Now mounting the "to the side" and not directly to the intake would make plumbing a bit more complicated but allows an intercooler and the throttle response should be like factory.

this was how the thunderbirds were set up.

Hi, I'm that Hawaii guy. Figure I join in and see what you guys are up to. I have about 2-3k miles on this set-up, tuned up to 5500 rpm @ 6psi....still working on the knock sense config/tune.

I've done all the work myself other than the PNP VEMs from Raceboy (Peep). Basic tools + a cheap MIG welder, all steel work, minimal aluminum.
This is a learning experience for me, while I use the car for SCCA Solo only. Running total is about 3,000usd, this includes the VEMs.

Car is running pretty good at the moment, had to remove the throttle cam...it made it super annoying to drive...super responsive.

Willing to help folks with what I went through.....lots of research...TONs.

Current pulley ratio is 2.09 with the Sable 6.5" to the 3.11" SC
Eventually I hope to get a 2.8" SC pulley to try a 2.32 ratio. Guessing 10psi.....but I'm parting together a pre-sc water injection set-up for under $200 to be controlled by VEMs.
My IATs are +23 from ambient 30 at peak (uphill climbing with moderate acceleration, 60-70mph)
The 951 IC can probably do better, just need to get it better airflow as the early 944 was not meant to house the IC in that stock location.

1983 944 Forged/Sintered bottom end (early engine oem)
AFM, DME, with on/off TPS delete
Radiator mounted lower, recreated front cowl frame, alternator moved to lower location.
Currently modifying Air dam to better isolate the air flow and feed the IC better.
VEMs ECU v3 MAP IAT Bosch OBD2WB integrated + Bluetooth
Eaton m62 GenV from a GM Cobalt SS, inlet cut shorter and rerouted
Bosch Knock Sensor integrated for logging (adde 4k crystal to board)
OEM Crank position/speed sensors used
OEM head temp sensor Bosch e30 IAC
OEM fans are controlled by VEMs 1 stage, both fans.
2x Audi 1.8T aftermarket diverter valves
OEM 944 Turbo Intercooler
4-1 Headers, no cat, 2.5" primary pipes, Dansk Sport Exhaust
High Imp.Deka 80# Injectors (left in batch fire) 3 bar saab fpr
OEM Astra coil twin coil pack for wasted spark/no distributor Audi/Vw 5k type spark plug wires
Audi TPS (direct replacement) Removed aftermarket throttle cam (back to oem with less response)
2000 Dodge Caravan lower radiator hose cut in two for upper hose modification.
Running a Sable crank pulley that I drilled out to fit. OEM is 5", this Sable one is 6.5"
2005 Honda fit belt :)

People have been picking up Nissan Quest Alternators, compact, higher output and very similar mount.

It is some work to cut out the NA guts under the nose, but yes it is the most inexpensive solution if you are willing to cut and fab a bit.

When I cut the m62 from the GM Cobalt to fit a 90 cast elbow on it, it was about 1 inch from the needle bearings. Given this is one of the longer SC, I'd say any other should fit unless we are trying to fit a m112 with a long pulley nose.

My TB is still in between the plenum and IC, the only draw back I found was the larger diverter valve needed when you are off-throttle and in gear at a high rpm. People said it would create more heat due to the SC....have not noticed it. I may move it to see, but it's doable without moving it for low boost set ups. The bypass is a must tho.....

I used a Bosch 3bar FPR for a turbo Saab, inexpensive and it bolts right on....looks identical...other than the part # and pressure.

Second that, I'm using 2 Bosch style diverter valves for a vw/audi. Metal housing ones can come with different spring rates.

Could you post a link to it?

Which fuel rail do you have? One of the 2 early styles?

That's why the GM LSJ m62 or 5th gen is not a bad one to use. It's a more efficient roots, kind of under the twin screw...but much less costly.

Uh...the one that the fuel line runs my the brake booster?

https://www.ebay.com/itm/BOSCH-02801...72.m2749.l2649

Do you have a pic that shows the fit of the Cobalt M62 in your engine bay?

A basic question on SC ratings. Roots blowers are volumetric devices. An M62 gives about 62 CI of air per revolution. But is this rating based on the input air temperature or the outlet air temperature for the purpose of calculating the mass flow?

John, it moves 62 ci (volume) per revolution, period.

Mass flow will vary based on inlet temperature and outlet restriction.

62ci at 0*C is still 62ci at 100*C... :)
But those 62ci weigh less at 100*C.

I really don't think you need to waste time calculating that stuff - the SC will be pulling in ambient air from the air filter just like an NA car, so inlet temp should be the same.
The blower is going to move the air, no matter what - you need to focus on cooling the air down AFTER the SC.

Ok, to make sure I understand... Assuming no inlet restriction I get 62CI of air at inlet density per revolution. Assuming no leaks we then will get that equivalent 62CI inlet conditions forced into the cylinders.

Then all intercooler does (on a positive displacement blower) is to reduce air intake temps to prevent detonation? In other words, hypothetically, if I am not detonating without an IC, then adding the IC has no other effect?

https://cimg8.ibsrv.net/gimg/rennlis...aa94ad7895.jpg

Initial cut before figuring out how to better shape and cap the end.
https://cimg9.ibsrv.net/gimg/rennlis...4588be9073.jpg

The oem bracket for the alt and ac was completely removed and I reused the mounts replacing it with a steel tube frame to lower the alt and let the SC sit as low as possible.
https://cimg0.ibsrv.net/gimg/rennlis...50927c9043.jpg

Fitting with TB in front of SC. Eventually moved it back between the plenum and IC for other reasons.....i think both can work if the bypass flow is big enough.
https://cimg1.ibsrv.net/gimg/rennlis...e1cbe86e1a.jpg

About to cut out the NA nose to fit IC
https://cimg3.ibsrv.net/gimg/rennlis...280ff0ab48.jpg

The framing was way to narrow to fit the piping I wanted, so the radiator had to move down a bit.
https://cimg2.ibsrv.net/gimg/rennlis...ccd0a85c7f.jpg

Lowered radiator mount extension with aluminum bolted to welded extensions. Top angle bar to protect the radiator and stiffen the sub frame.
https://cimg6.ibsrv.net/gimg/rennlis...f833386dcb.jpg

How it is now.
https://cimg7.ibsrv.net/gimg/rennlis...a1e4db9d42.jpg

Another angle. double diverters...not recirculated.
https://cimg8.ibsrv.net/gimg/rennlis...718bce1589.jpg

Top view to see the orientation.

Well in the end you should be able to produce more power by being able to run a higher ratio pulley set up (that will increase the air temp) and add back timing that will produce much more power......kind of a big difference.

looks awesome!

Thanks, hoping this will help others to get motivated that when certain aspects are carefully understood..it can be a stable set-up.....take advantage of that VEMs so we can figure out how to best tune and mod the config.

Yes I understand that.

The reason I ask is that Corky Bell in his book Supercharged (Ch 5, page54-56) talks about the IC increasing charge density and thus HP (with a roots blower) over the same non-IC configuration. I can't get my head around this if you are getting 62CI of inlet air per rev regardless.

that's all an IC does in any setup, takes the HOT HOT HOT air coming out of the supercharger (or turbocharger) and reduces that temperature as much as possible, making it cooler/denser as it goes into the cylinders.

the key is that cooling the air down so much lets you run more aggressive spark timing which makes the difference in power.

https://cimg0.ibsrv.net/gimg/rennlis...f9001a3cb8.png

the 62 CI is a measurement of volume, eventual pressure factors in density that is affected by the temperature of the air.

the blower is stuffing 62ci of air thru per rev. doesn't care what temperature the inlet air is - volume is independent of temperature.

the air is only compressed into boost once it's on the outlet side of the blower, being forced into a "room" (manifold) with all the air that has come thru the blower previously and not been ingested by the engine.
if the air has been intercooled before entering that room, mass X of air will take up less space (volume) than it would have if it weren't intercooled. mass per volume = density.

so if the room is a given size, and the intercooled air takes up less volume for a given mass, there's now more room for the blower to pack in even more air.
blower doesn't have to work as hard to blow this extra air into the room = less parasitic drive losses = more hp at the flywheel end instead of being used up at the crank pulley end.

the difference in parasitic loss isn't a whole lot though - as i said before the key is the ability to run more aggressive spark timing.

Corky's calculations show with IC you can achieve the same power at a lower pressure ratio than an non-IC system. This is just based on the amount of air entering the cylinders. Does not take into consideration tuning advantages that can be exploited with cooler air charges. He also shows an IC system requires less SC CFM than an non-IC system. Again this is without tuning exploits.

I am not arguing with you, I am just pointing out Bell's inconsistencies with (everyone) here is saying....

I will see if I can post a snippet of his calculations if you don't have access to Bell's book. Has anyone here read this book and comment on these calcs in Ch 5?

ive read that book a few times.

one thing that can be confusing is that in a piston engine with boost (either turbo or SC) CFM into the blower does not equal CFM out.
the engine will only ever ingest it's own displacement VOLUME, regardless of temperature, density or pressure.
when the intake valve opens (on a 2.5L 944) a given cylinder is going to pull in ~38 ci worth of air volume.
the CFM difference between what the blower will pull in per rev, versus what the engine will consume per rev, makes the pressure ratio.
a 500hp, 5.0L SC engine is pulling 750cfm at the blower inlet but only 450cfm is going thru the manifold, just much denser cfm's.

because the SC makes the charge air so hot, it is not very dense (low mass per unit volume).
38ci at 100*C is still 38ci, but has much less air mass in it than 38ci at 40*C.
more air mass + corresponding fuel mass = horsepower.

increasing the supercharger output pressure (drive ratio/pressure ratio) is one way of increasing the density of the air in the manifold - simply forcing even more air into the same size container, at an even higher temperature, will still pack more density (therefore mass) into a given volume.
however it is easier (less supercharger work) to get the air denser for more power by intercooling it, dropping the temperature which naturally makes the air molecules stick closer together (denser) to get more mass into the same 38ci cylinder.

Yes but conservation of mass still has to apply... the mass flow rate at SC input has to be equal to the mass flow rate through the engine....And as I understand it HP is directly proportional to air mass flow rate. (All other tuning being equal).

Again the genesis of my original question... Is SC 62 CI per revolution based on the inlet conditions, outlet or something in between? If its the last 2 then I can understand how IC can affect mass flow rate.

When I get home from work I will post the sections I am questioning and see if you agree.

are you looking at the equations like these?
http://www.lextreme.com/icvsnic.htm

i believe what happens is that not all of the air actually makes it out of the blower case because it's being pushed back by the compressed air already in the manifold.
so the rotors scoop up 62ci of air at the entrance but only push out into the manifold say 2/3 of that air.
the rest gets carried back around by the rotors which then displaces new air that would've come in.

higher pressures/temperatures exacerbate the "blow back" because the rotors don't have a very good seal between lobes (like a screw compressor does)

https://hydemotorworks.com/2015/10/1...gain-formulas/

Another write up of the power potential to gain.

That site is blocked by my company's firewall.


Then its not positive displacement. That effect should be accounted for in the VE spec for the blower. I can see cetri's having this effect.

Not to throw everyone off...but you could just go with a standalone and do a proven air to air IC with https://www.ebay.com/itm/HX35-HX35W-...4383.l4275.c10

The main reason I went with a roots SC is...Hawaii's SCCA tracks are in a small area. I wanted the most immediate and low rpm boost possible for the tight course.

I will try and make a post showing Corky's formula chain without violating copyright laws.

His chain is HP based not "boost" based. Mass flow rate is the objective. (in his calc chain). "Boost" is an outcome of increased mass flow rate and the engine cfm.

that term's a little misleading but still generally correct.
remember that a Roots supercharger is an ancient device originally designed for blowing air into steel furnaces.
in the 1850's when it was invented it was not really a pressure-creating device, just a simple air mover "blower" that might've been barely above atmospheric output pressure.

the first major, widespread use of the roots blower in ICE design was the detroit diesel industrial (later automotive) engines from the 1930s.
2-stroke diesels can't aspirate from the crankcase like a gas engine so they used a roots blower on top to blow air into the chamber thru ports (no intake valves). even this was barely above atmospheric pressure - just enough to get roughly atmospheric pressure into the cylinder and account for flow losses caused by the complicated path the air had to take to get there.

in these simple air-moving applications they are truly "positive displacement" moving a fixed amount of air per revolution. there's no pressure on the outlet side of the rotors pushing back.

when the roots blower got borrowed for hotrodding purposes in the '40s and onwards was the first time this design was really making "boost".
the design has been heavily refined in the last 150+ years, adding more lobes to rotors and twisting them a little bit (GMC/DD), then a little more (1990s Eaton), then adding another lobe and twisting it further (Eaton TVS) to minimize the effect of "blowback".

Here is a summary of Corky Bell's calculation chain.

Desired Power = stock power x pressure ratio x density ratio x VE ratio x drive power efficiency.
For his example he assumed: Stock engine: 302 CID, 220hp at 5500rpm, VE 80%, Objective: 320hp @5500 rpm
He assumes a VE ratio of 115% and a 90% drive efficiency for his sample calculation.

Solving the top equation for pressure ratio:
Intercooled 85% efficiency: density ratio = 0.97, pressure ratio = 1.45 or 6.6psi boost
Non-intercooled, temperature gain 180F: density ratio drops to 0.75, solving for pressure ratio = 1.87 or 12.8psi

For blower CFM required. Basic engine airflow rate = (cid x rpm x 0.5 x VE)/1728 = 384 cfm (assuming stock engine assumptions above)
Blower CFM required = stock engine CFM x Pressure ratio
Non-intercooled: 384 cfm x 1.87 = 718 cfm
Intercooled: 384 cfm x 1.45 = 557 cfm

So what is wrong with Corky's model?

nothing's wrong with it, it's just not covering the reasoning behind why IC vs non-IC need different pressure levels to get the same air mass into the cylinders.
it does seem to be modeled around achieving an arbitrary temperature in the cylinder though.

you might find this interesting:

https://docs.lib.purdue.edu/cgi/viewcontent.cgi?article=1126&context=icec

Can you summarize the link for me? :-)
The only temperature calculation involved is using the gas law to compute the charge temperature rise for the non-IC case.
The calculation also implies you need a smaller blower with IC to get the same HP as a non-IC setup. As far as reasoning, there is no reasoning other that the first HP equation, its valid or its not. To me its a simple conservation of mass equation which is hard to argue against. The rest is gas law (which is also hard to argue against).

Its the blower "CFM" thing I am still hung up on. If that CFM is input CFM then the mass flow rate into the cylinders should be the same with IC and non-IC, the only difference will be the plenum pressure. That's is where I am 'stuck'.

I wonder if Corky will take my phone call?

Corky is supposed to be very good about tech help, please share what he tells you.

the link is an investigation into the effect of pressure ratio and rpm on volumetric efficiency of a roots blower.
goes into explanation about the clearances between rotor lobes and between rotors and casing causing boost leak-back which lowers the VE of the blower as pressure ratio goes up.
boost/hot air gets caught by the rotors on their "Downswing" and that mixes with the incoming air in effect diluting the new intake air with hot air (raises charge temp/lowers density).

basically the pressure on the outlet side of the blower finds its way back to the inlet side and partially displaces the incoming "cfm" - the blower is fighting itself re-compressing a portion of the same air over and over reducing effective CFM output.

I created a SC design spreadsheet based on Corky's Chapter5 root's blower application chapter.
Put in your engine specs and desired HP it will calculate the rest including supercharger sizing and pulley ratios for both IC and non-IC configs. I still want to tweak it a little, consider it a work in progress.

Updated the spreadsheet.
Added calculations to size fuel injectors
Added estimation of thermal load for the intercooler

bumping this up for anyone interested in trying their own 944 Sc project...these two aluminum parts are for sale.
left is the inlet to an early (oval port) Ford Eaton M90 supercharger with a 2.5" inlet tube.
right is the top "outlet hat" for any year Ford Thunderbird SC M90 (89-95) also with a 2.5" tube.

$75 shipped for the pair, will sell individually if desired.
i also have a disassembled early model M90, ready for rebuild, to match these parts if interested.

https://cimg2.ibsrv.net/gimg/rennlis...d6f5daa405.jpg

Just an update:
VE tables are dialed in and smoothed by hand a bit.
Timing has been put back while monitoring knock, knock action is now enabled.
Boost is 6psi, peak power is 2500-5200, I have a pulley upgrade coming in, expect 10psi soon.
MAT are very good now, only +3 to 6 above ambient after improving the air flow to the 951 IC
I did a recent compression test and scoped the cylinders, all good after about 5,000 miles.
Target Lambda was reduced to .86 and re-tuning the VE really brought it to life.
I have no clue to how much more power is being produced, but it feels like a 75 NOS shot.

What I am learning is the real squeezing of the power is the full control from a standalone...hands down the best part of the entire set-up.

After I get the pulley in, I might be forced to really put in the water/meth injection. Looking at the numbers on a 9.5 CR it might be required.

Awesome.

I am curious if you tried my spreadsheet and plugged your numbers in to see if its close to predicting what you are seeing?

I tried but the goal of the sheet seems to be more meant to estimate thermo. Including the efficiency percentages greatly impact the calculations......those are assumed. The PSI is not a real great indicator of gain. I was getting the same amount of of boost through my tuning and that meant really nothing other than I did not have a major leak and the SC was in the general ballpark of being sized right.

My two cents is....correcting the air temp is critical, being able to add fuel on boost and retard timing only on boost/rpm is as important as the air temp.
ON top of all that, being able to monitor and review the data as you tweak and drive it harder is what will keep you out of trouble. I reviewed the drive data as I increased the rpm soft limiter, it took two weeks before even WOT and a month before I hit above 4500 rpm. I was overly cautious, but this was a learning experience for me....watched and read tons of tuning tips and articles.

I am suggesting putting in numbers for your situation (efficiency is a guess but a starting numbers) and see what HP gain it predicts. Then estimate your HP by the quarter mile or time to 60mph dyno....then compare the prediction to your 'measured' hp.

I agree that boost pressure is not important, is how much fuel you are using per rev at WOT that matters.

Still going well
 

I ended up replacing the crank pulley with a small block ford aluminum pulley (same crank bcd) to get 6 ribs, swapped out the alt pulley for a 6 rib and upgraded the SC pulley to a custom 2.7" for $50. Found a Honda S2000 Gates RPM Racing belt that fit. Getting roughly 8psi, had to back down on the timing of course, but it feels fantastic. Cannot wait for the SCCA season to start. Currently waiting for some upgraded boost hose clamps as the cheap T-bolt clamps are not holding up and starting to deform and strip since I used a cheap ebay universal pipe kit. I did not know that well made hi-torque worm clamps actually do a better job and only $3 a clamp that are SS, lined and hold up to 150lbs. I expect the boost to rise a bit as there are leaks at the hose clamps. Also the air dam adjustments to improve the air flow to the IC have fixed the air temp creep. About 10k miles so far.

Details on that Ford pulley?
By same BCD you mean the Ford pulley matches the bolt holes on the balance shaft gear, that the 944 accessory pulley bolts to?

Yes the BCD is the same, the difference is the 4 bolts or fastener diameter bore for each, the ford ones are larger. I searched out steel sleeve spacers to fill the gap and used longer grade8 metric bolts. The advantages are low cost aluminum crank pulleys that are bigger in diameter as the 5" oem crank is way to small to match up with the smaller SC pulleys.....if you want to max. the SC potential and not run into belt grip issues. I would get a 7" if I was to buy another one.

This is the 6" one I got, next step up is the 7"
Sorry I forgot it is a 10rib, so it gives you the option of running another belt or shifting the alignment :)
https://www.summitracing.com/parts/v...-041/overview/
https://www.summitracing.com/parts/v...-051/overview/

cool!

good Idea. Are you running power steering? It looks like the 10 rib pulley might hang over power steering pulley.

My '83 is a manual rack so I do not know if it will line up to the stock PS pulley. You can always look into what it will take to shift the PS pump if it does not line up.

Just an update, on the grid while waiting to run on the past events...the IC heat soaks with MAT rise from 35c to 61c! It does not cool down in the runs either...just not enough time moving. I'm in the middle of installing a on-demand low pressure Water Injection pre SC and another on-boost only high pressure post IC injection with 50/50 water/meth. The low pressure is a DIY with Mcmaster car nozzles, the high pressure is a Snow Performance. Initially I will use the hobbs switch to ON the pump and solenoid (ebay) with just pure water to witness the temp drop. In the end I hope I can tune a second VE table and IGN table to kick in when the standalone sees the high-pressure pump running. The 50/50 tank will have a low sensor to trip the fail-safe so I don't run the leaner tables on empty....I hope. Plan to pick up the rest of the fittings I need today and try it with pure water.

You could also spray water on the intercooler to bring the temps down. that way you can control the temp without affecting the mixture...jus sayin..thanks.

Given the higher CR and the event runs being so short 35-50 secs per run. I need the air charge to be cooler immediately along with the knock suppression. In testing today I watched the MAT go from 45c to 27c in one quick 2nd gear 2-4500rpm. I came to complete stop at a light and noticed the MAT remained at 29-31 for sometime. The 50/50 makes a huge difference in comparing 100% water too.

Thats basically the same MAT I get with my NA. What psi do you run?

27C is a GREAT IAT number....must be working :p

I thought you should avoid running water pre-IC to avoid condensation/pooling issues?
If you look at current OEM Ford turbo stuff their IC's actually have a drain plug for pooled condensate just pulled from the charge air.

Yea seeing the temp drop to 27c that quick made me happy. The pre sc actually doesn't seem to help at all. I tested it separately with the car heat soaked, not a change in temp at all....shot variations of amounts too....maybe it did pool idk.

7-9psi

Winter is coming and its time to get back to my SC project. Ordering a VEMs pnp from Peep shortly.

My goal is to find a way to keep the AC. If there is room (and there might be with my MB M62), what is the downside of fabbing a double pulley on the alternator and sistering a belt drive to the SC? I am thinking that would be too much load on the pulley and the belt would slip?

pulleys need maximum belt wrap which can be provided by really tight idlers or a larger pulley.
more ribs is even better but you're limited by the stock accessories to a 5 or 6 rib belt depending on MY of your car.

since the beginning my project has been designed around keeping the AC but TBH it would be WAY easier to do this without AC installed.

Of course.. Gates has a pretty comprehensive belt design guide. Since my project is going for only low levels of boost I was hoping that my drive requirements are modest. Issue is that alternators typically have small pulleys (2") which do not have a lot of drive potential. If I put a 3" pulley there to give more drive capacity will the lower rpm of the alt be an issue I wonder?

yes, 3" for example is a huge difference in RPM (50% slower), it'd be ok moving but you'd really struggle with lights/fans/etc while idling at a stoplight.

on mine the only way i figured to make AC stay was to put the alternator on the other side, where the PS pump used to go.
however, 15 years ago Huntley Racing hung their SC from their intake manifold which cleared the stock 944 alternator/AC setup, so it is doable.
i think if you could really get creative designing an SC mount bracket you could hang it off the side of the engine, above the stock AC/alt, it's just you start to get limited in room for plumbing to/from the SC as space is limited on that side by the fender and brake cylinder.

see my work-in-progress (this picture is from 2011, lol) :

https://rennlist.com/forums/attachme...-belt-path.jpg

33% slower, maybe I can set idle at 1000 instead of 800 and get 25% of that back....

I want to keep PS also.... :-)

nowadays there are lots of options for electric PS pumps, or electric-assisted racks....something to consider.

there are even electric AC compressors but those tend to need much higher power capacity (48V or LOTS of amps) to run.

[QUOTE=jderimig;15382814]3" might be too big with the relatively low output oem Bosch.
Also having the engine running well and solid with VEMs prior to adding boost reduces a ton of risk.
In reading some MB230 specs, the crank pulley might be 6.1" Isn't the 2.58v's crank a 5"? Do the math, I don't think the existing pulley will drive it hard enough.

Yes, I do have a Volvo C40 PS pump. Trying to figure how to mount that. That was my first idea on how to keep AC.

[QUOTE=mdnt08;15382873]Yes I will need a custom M62 pulley around 80mm for the modest boost level I am going for. There is a gentleman in Hungary who makes those.

I took a look at my Volvo ps pump for fit again. If I cut off some mounting ears it may fit where where the stock PS reservoir goes. However the pumps reservoir is too tall. If I 3D print a shallow custom reservoir it might work.

The only question is how much fluid do I need in the reservoir? Do I only need enough that fluid stays above the intake at all times?

My brother is looking to sell my entire Supercharger setup if anybody is interested. It is not a kit but comes with everything you need to supercharge a 944(with some minor/major mods)

Comes with DME(Rogue) with tuner and logger.
Rogue NA-Tune with custom stainless MAF tube
Eaton M90
https://cimg2.ibsrv.net/gimg/rennlis...ac74574546.jpg
https://cimg0.ibsrv.net/gimg/rennlis...6af0b55e7f.jpg
Top view of where the SC was fit.
https://cimg1.ibsrv.net/gimg/rennlis...e363920050.jpg
https://cimg4.ibsrv.net/gimg/rennlis...fd9f11e2cb.jpg
https://cimg1.ibsrv.net/gimg/rennlis...5e5ea6f077.jpg

SC Mounting bracket
Intercooler and piping
and much much more.

Its a great way to get started, most of the hard work is done. around the $1700 range for everything.

That is a deal DarrenD.
Beautiful fabrication!!!

Would you consider selling that without the NA-tune and rogue gear?

​​​​​​​Facebook post about Sc kit for NA's
 

https://cimg0.ibsrv.net/gimg/rennlis...451d5e9161.jpg
From facebook

https://scontent.fsan1-1.fna.fbcdn.n...92&oe=5CA807D8

Aaron Hafer

New Member · November 20 at 6:41 PMWhat kind of interest would there be for a bolt on roots / twin screw type supercharger kit for the Porsche 944? Pricing starting probably somewhere around $1800 without engine management.

Facebook post about Sc kit for NA's

Nice, it claims to keep the AC also. His later post shows he is using the MB62 roots.

That image is of a TPC SC kit for a 996

And yet there seems to be a long line of people wanting to fork over $1500 to $1800 on vaporware. I am in the wrong business.

And so it begins...
https://cimg0.ibsrv.net/gimg/rennlis...0b49d5b003.jpg

Look what I pulled! I may have started a hoarding problem.
https://cimg7.ibsrv.net/gimg/rennlis...90037eafb6.jpg
https://cimg9.ibsrv.net/gimg/rennlis...6a080fbe51.jpg
Thinking about using one of these IHI twin screws vs. an M90.

Advantages:
Higher boost potential (I need that at 7000 feet)
More efficiency (~64% adiabatic efficiency at 1.8-1.9, vs 62% at 1.4 for the M90)
Less heat
Cool factor
Thinner form factor may fit better
Sound?

Disadvantages
Harder to find refurb parts
Less volume per Rev (~73ci)
Has to be plummed to oil supply

Given the potential to drive it harder, I'm no too concerned about the volume defficiency. Tapping the engine for oil shouldn't be too hard, but mating it up to the supercharger may require some creativity. Do you think I could turn it into a sealed unit?

Lachlan - still digging for those parts I owe you.

Those Mazda units are super cool, I thought about those once (I also owned a Millenia 10 years ago) but the lack of parts was my concern.
Millenia S owners have to buy new ones at $3k apiece if their original one pops, but you might be able to scavenge parts from multiple units to make a solid one.
73ci per rev is still plenty for a 944 motor that takes 75ci/rev at 100% VE...just add overdrive to the blower.

The skinnier case will be a huge help in packaging.

Here is the bottom of the IHI S/C.
https://cimg2.ibsrv.net/gimg/rennlis...c0020abe9a.jpg

There are two oil compartments for the front bearings/gears and rear bearings each with a feed and return hole. On the mazda, these are fed by thin engine oil, and those guys complain about it leaking out of seals and getting gunked up. Whether I plumb to engine oil or seal off and make an internal bath of S/C oil, I need to figure out what fittings I can shove in here. I didn't grab the lower bracket from the junkyard, but here's what it looks like (the IHI just sits on top)
https://cimg3.ibsrv.net/gimg/rennlis...8e6fe39456.jpg
Here are some up close pictures of the holes:
https://cimg7.ibsrv.net/gimg/rennlis...46a82ce2f0.jpg
https://cimg0.ibsrv.net/gimg/rennlis...fed5106924.jpg
https://cimg4.ibsrv.net/gimg/rennlis...b872281b0b.jpg
https://cimg6.ibsrv.net/gimg/rennlis...0498ab0293.jpg
https://cimg7.ibsrv.net/gimg/rennlis...4946ed5ae8.jpg
Can any of you identify what fittings I need to plumb or seal these, and where I might find them?

first thought would be to yank out the brass tubes and see about tapping the case for NPT brass.

...or get somebody to braze some fittings onto those existing nubs.

VEMS + SC + Nitrous
 

So I just go my VEMS PNP from Peep, and it got me thinking again (dangerous).

How about low boost SC + low shot N2O + no intercooler? As I get older complexity of projects is a turn-off. Was thinking of a low shot Wet N2O system instead of the SC initially.

do some research if pre-SC or post-SC injection is better.
that stuff comes out cold and does some "intercooling" on its own. pre might keep the rotors cooler which might help general efficiency? but post would help take the heat out of the charge.

both :evilgrin:

update i guess...
last weekend i finished welding my intake manifold and primed it.
yes, it's got stacks inside, about 10" from stack entrance to valve seat, and the D plenum is big enough to roll a tennis ball through. about 0.75x displacement for plenum volume.

https://cimg6.ibsrv.net/gimg/rennlis...fe1c71c64a.jpg
..
..
yesterday i was making new brackets to mount my AC condenser and intercooler, so i can then start "laying pipe" (plumbing the IC).
light at the end of the tunnel...

thanks for the update!

Looking good Spencer!

My current plan, in order to avoid yet another custom elbow and vacuum connections, has the supercharger going pretty far back. It fits ok, except it's going right through where the dipstick needs to go. Has anyone had any success bending or otherwise relocating the dipstick?
https://cimg7.ibsrv.net/gimg/rennlis...8554afe685.jpg

Thought I might show some progress photos of my S2 SC build, I'm using a Rotrex C30-94, with 100mm pulley, giving about 5-6PSI, No intercooler but a modified oil coole cylinder tyo cool down the Bypassed air which gets heated by the SC then gets diverted to in front of the SC, therefore a potential builup of heat can occur,
https://cimg7.ibsrv.net/gimg/rennlis...0ad2d43c70.jpg
The SC ann Nissan Quest alternator are coupled together and both hang off the factory alternator mounting points, the SC has a front and back mounting brackets made out of 6mm Aluminium (tried to find Aluminum here in Oz but couldn't find it) the effect is a rock solid setup
https://cimg8.ibsrv.net/gimg/rennlis...fa687dcd2e.jpg
Stock alternator
https://cimg0.ibsrv.net/gimg/rennlis...a255d006e8.jpg
Space
https://cimg1.ibsrv.net/gimg/rennlis...8cde1e7b78.jpg
Some shaving of the alternator was needed
https://cimg2.ibsrv.net/gimg/rennlis...736f83e734.jpg
With the AFM in place

very clever!

Can you put a turbo in a 1983 Porsche 944
 

Can you do this to a regular 944, and what would it cost?

Yes, I would personally get all 944T factory parts as it would be the simplest method. 944T rods, pistons, crossover, headers, downpipe, exhaust, turbocharger, wastegate, oil drain mount, oil pan, intercooler, pipes, injectors, intake, wireharness, both ecu’s, diverter valve, and a few other components. Getting all that you used will cost you... more than you want but honestly around 3-4k with you doing the work and mostly stock used parts. You also need to consider power goals and if you want low boost like 7psi or want mid around 15-18psi, which would make a difference in cost of what you may want to get. Then you would want to upgrade brakes and suspension as more power shows other weaknesses in the driveline. This is a dangerous slope, hence why the supercharger and the v8 swaps are tempting. I believe the supercharger can be done cheaper and are good for someone wanting insta power but looking for a little more thrill. The v8 can be the same cost or more depending on the level you want to go and quality of the build.