Andy

Are you bringing that pretty engine to Sharktoberfest? We'd love to see it in person and pick your brain (especially since I take some credit for starting the "supercharging on the cheap" thread). I'm still exactly where I was on the car when I started the thread - five projects behind (and now I'm a monthly LA house payment poorer, so not likely to be pouring any money into the shark and have even less time to play with it).

Don't forget me when you're looking for an 85/86 to experiment with - I'm local and don't need my shark to commute in so it can be down for a few weeks if need be...

 

Go Ride Sno,

You should get serious with this kit for an 86.5 and sell a couple to the rennlisters here. So can you get 6-7 psi for $3600? I think thats what most people want to know. The other thing is: how much more power can you get from changing pulleys?
Do you have the kits ready, if not when will they be ready TO SELL? Get the pictures of the installed kit together for us all to drool over. How many others have done an S/C like yours?

Ive got an AT in mine and the flatter power curve sounds good.

 

Uh oh! The answer varies, and can be quite a bit as it's one mod the Cobra Mustang guys do and pump out 430 rwhp.

However, that road is fraught with peril.

Let’s say for the sake of argument that one has a 5-6-7psi roots setup with no intercooler on a S4.

Corky Bell has a rule of 1,075 absolute. This 1,075 number is the resultant combustion chamber temperature when first, the blower compresses and heats up the air charge, and secondly, the compression ratio squeezes that, and heats up the charge yet again.

This process obeys Boyle’s Law which in a nutshell states that a gas which is compressed will heat up.

If one obeys this rule and stays reasonably close to this number, the promise is that an engine will not detonate, the true enemy of a forced induction engine. It is detonation which destroys ring lands and blows out head gaskets, not boost itself.

Of course, the above statement assumes proper air/fuel management.

So we have an engine with a 10:1 compression ratio running a roots at 5 psi non-intercooled. What is the resultant combustion chamber temp of this combination, and how close is it to Corky’s ‘magic number’ of 1,075?

10.0:1 cr at 5psi = 1210.79 absolute
10.0:1 cr at 6psi = 1239.66 absolute
10.0:1 cr at 7psi = 1267.55 absolute

Not good.

As one can see, even at 5psi, the resultant temp is 135.79 degrees over Corky’s 1,075, which does not look promising, and why earlier in this thread I exhorted people to save up and purchase the intercooled version.

What kind of temps are we looking at with an 85% efficient inter/after cooler affixed onto the same engine setup?

10.0:1 cr at 5psi = 1072.42 absolute
10.0:1 cr at 6psi = 1076.75 absolute
10.0:1 cr at 7psi = 1080.93 absolute

Whew, those numbers look MUCH better! And not only that, the horsepower numbers are much better too; at 7psi it’s worth nearly an additional 60 hp, a nice gain for sure.

So getting back to the original question, if a smaller supercharger pulley were installed to increase boost, one would get more horsepower providing it already has an intercooler.

Otherwise, on a non-intercooled setup, the blower will be spinning faster, creating more heat, making the charge less dense. The end result would more than likely be no horsepower gain. And to make matters worse, one will enter into detonation, destroying the engine shortly thereafter.

Summing up, spend the extra bucks on the intercooled version; you'll be happy that you did.

 

Lagavulin,

Thanks for writing all the math down, but I bet there's still folks out there who think you don't have to intercool a pressurized car. Especially important as most of these folks are boosting a 10:1 comp car.

Oh well, they will learn when things melt I guess.

Greg

 

Is the difference in the Euro's compression ratio based on the cylinder head shape/size, or the piston shape/size?

 

bc,

As I recall, mainly piston, but I haven't got a euro head around to cc right now, so don't quote me.

The head is slightly different as the valves and ports are slightly larger.

Greg

 

Just checking in here......... By the poll it looks like 80% of potential installers would go intercooled.

Jim,
I can't wait to get started on your car!!!!!!! I already have some ideas.

Lagavulin,


You shall see things.....wonderful to tell.....A superbike in the rearview mirror..and oooooh so many horsepower...............though the road may wind, and yet your clutch grows weary...Still shal ye follow the way....even onto 1000HP.

Thanks all that contributed.

I'll be back to try to answer the new questions later. Until then here is some more food for thought.
Below are the graphs for the MP112. I placed a diamond there to show about where 4psi would fall. Max blower RPM would be about 10400, Max drive power would be around 22hp, Max discharge temp would be less than 100 degrees F (similar to running hot air from under the hood with a NA or other setup?).



Car and Driver MP112 Z06 article.
Car and Driver.com article about the Lingfelter Eaton MP112 roots supercharged Corvette Z06.
530 HP (125 hp gain)
5.5 psi
No Intercooling
Cast Pistons
10.5:1 compression ratio
3.7 sec 0-60
11.7 1/4 mi
197 mph estimated top speed

"The $185,000 Porsche 911 GT2 trails it to 60 mph by 0.1 second and to 100 by 0.6 second and does the quarter-mile in 12.0 seconds at 121 mph."


Gbyron,
What is Lingenfelter thinking by selling this setup. Why the heck would a guy who has built 250mph street twin turbo waste his time with such technology. Maybe he did it just to make the engineers at Porsche feel bad.

Andy K

 

Here are answers to the questions in the post that inquire about the systems.

Q13:Yes, the Eaton is the most optimized Roots blower ever, but so what?
A: Regardless of the premise that it is old technology it is widely used and wouldn’t be if it didn’t deserve some merit. Just because it is not the newest and best technology doesn’t mean it is not good enough, as shown, IMHO, by the use on the Z06. Most of our cars are 17+ yrs old yet we haven’t sent them to the scrap yard.

Q14: Are you bringing that pretty engine to Sharktoberfest?
A: I plan to be there with the car and blower in place. I wouldn’t call it pretty though. At best it is photogenic. There are some pretty ugly hand made pieces under the hood. It looks like there will also be an “89 S4 running an IC3 setup there.

Q15: So can you get 6-7 psi for $3600?
A: I am afraid not. At this point I have to say the limit is 4psi for the $3600 N1 system. This is all I have experienced my N1 with and can’t comment on anything higher.

Q16: The other thing is: how much more power can you get from changing pulleys?
A: See Lagavulin’s post on that matter. I would say at this point it is not safe to just swap pulleys and get more psi/power without intercooling with the N1. If we take the example of the Z06 we may reason that we could do this. But it has not been done so I can’t endorse it. Add an intercooler to the N1, and then swap to the IC1 pulleys (you’ll then have the IC1).

Q17: Do you have the kits ready, if not when will they be ready TO SELL?
A: They are not ready yet. I see no reason why I couldn’t have them ready by mid to late October. Given the replies, I have commissioned the tooling for the manifolds and now it’s just a matter of time.

Q18: How many others have done an S/C like yours?
A: As far as I know mine is the only 32 valve in the universe to have a positive displacement blower. There was an old-school roots on an 85 or 86 car once. I believe Steve C, who posted above about the AMG SC, bought the setup and has yet to install it. There were also 2 old school roots blowers on an Old Booger, yep 2 on 1 engine.

I am having a lot of fun with this and hope everyone is enjoying reading and contributing. Keep the questions and comments coming.

I thank all that have contributed so far. Special thanks go out to those contributors who think positively about positive displacement. In a Jamacian voice "Ya got ta think positive, positive, povitive......"

Andy K

 

Actually that would be at a little over 100 degrees where the diamond is in the Delta Temperature chart. That wouldn't be the discharge temperature. That would be the increase in the temperature of the discharge temperature over whatever the intake temperature into the blower is. Some temperature measurements at the airbox were done and the results posted a while back that showed about a 30F increase in the temperature in the airbox with the stock setup over ambient temperature. If the increase in air temperature was about the same by the time it gets to the inlet of the blower as it was for the air by the time it got to the stock airbox, you'd be getting ambient temperature plus 30F degrees, plus over another 100F degrees for the air temperature coming out of the supercharger discharge at 4 psi of boost. In other words, on a 70F degree day you'd be getting over 200F discharge temperatures out of the supercharger at 4psi of boost.

 

Just thought I'd add something to mess with people's minds. Remember, you can have a supercharger AND a turbocharger on the same engine. Hahaha. Think about that.
It's been so long, I can't remember is there's even an advantage to it. But I've seen it done.
Ok, you can go back to what you were doing, now.

 

Thanks Z. You are correct I forgot to say increase, should have said "max discharge temperature increase". It is just as Z explanis it. I'll go back and edit to avoid confusion. I also should do the math to find the exact temp increase at 4psi.

I believe the FAST kits actually drew in hot air from under the hood and ran 5 psi, no intercooling. At least that's what it says and shows on the F-A-S-T website

I am guessing that to raise the temp of intake air by 30 degrees as the measurements have shown the under hood temp must be at least 4x that or 120 degrees above ambient.

Let's see... at 5 psi a centrifugal blower raises the temp by about 62 degrees F so that would mean the outlet temp would actually be around 180 degrees above ambient for the F-A-S-T car or on a 100 degree day or 280 degrees total.

Let’s assume that the N1 setup is using the cool air intake that would be provided with it. We’ll use 110 degrees F as the increase in discharge temp for the M112. Add 30 degrees for increase as the air heats due to under hood temps. We’re up to 140 degrees above ambient. On a 100 degree F day the discharger temp would be 240 degrees total.
That’s 30 degrees less than the FAST setup.
Even if the under hood temperature was only 90 degrees above ambient they would come out equal.


Can someone explain the whole Z06 thing for everyone?

Andy K

 

The under hood temperatures were 85F-90F above ambient in those measurements. That was with the stock radiator flap system working, and with the car at a few different driving speeds.

You kind of lost me above. I'll use numbers for the temperature increases at the boost levels mentioned from above. On a 100F ambient day, the underhood temperature would be 190F based on those measurements I mentioned being taken. On the F-A-S-T setup with the underhood air intake, the supercharger intake would then be that 190F. If the centrifugal supercharger increased that by 62 degrees, that would bring the temperature up to 252F. Since the supercharger is compressing the air at the front of the engine, and the outlet air is higher than the under hood temperature, there wouldn't be any additional heating of that air by the time it got back to the engine air intake. There might be a temperature drop by the time it got back there, but it probably wouldn't be too much if any, so we'll say 252F as the engine intake temperature.

On the same 100F ambient day, the cold air intake with the N1 setup would be 100F. Since the under hood temperature would be the same 190F as with the above setup, the air would be heated 30F by the time it got to the back of the engine, where the supercharger intake is. That would make the supercharger intake temperature 130F. If the M112 then heats that air an additional 110F at 4psi of boost, it makes the supercharger output 240F. The discharge from the supercharger is the same as the intake to the engine, so the final intake temperature for the engine would be 240F, or about 12F lower with 4psi of boost than the F-A-S-T setup at 5psi of boost.

 

Andy,

I have no idea what John Lingenfelter was thinking - other than "damn, I'm gonna make some cash off those Vette guys". I'm sure he knows better, so that's all I can guess.

Have you actually seen a stage 1 or 2 (twin turbo) setup?. It is a POS, low cost (theoretically) high profit deal. Might not have been so high-profit after he started rebuilding them when they fragged...

I have not seen the Eaton version yet, but with no intercooling, it is hard to imagine any better results unless it has almost no boost - which begs the question- why bother? No, I'm not talking 15 PSI either.

Buy one, drive it hard, listen for the noise of the engine shooting craps. I have one friend and one acquaintance who would be happy to sell you their twice rebuilt (twin turbo) C-5 "Lingrenades". That system is for folks who want that extra "oomph" to show off once a year, and to brag to their friends about. Not for even semi-semi-serious driving.

Go out and run one hard for any period of time (like a minute or two) and the combination of non-intercooled air and lean fuel mixture will probably make you wish you bought that Turbo Porsche - or at least spent the money to get intercoolers, correct fuel enrichment, lower compression, and a proper set-up.

I have watched this slap-on stuff for over 25 years - it's really neat on a cool day, when you punch it for 10 seconds, feel the rush, then go back to driving like a responsible citizen. And almost any car, can take boost (even a lot of boost) for a very short amount of time. But put it on a track, or try to run that guy next to you for an extended period of time on a 100F day. When they get done sweeping up the remains of the motor, then the ideas of "cool air, plenty of fuel, and no detonation" may become a little more valid to the unbeliever.

Greg

 

Richard at Whipple Industries confirmed today that the Whipple 2.3L will support 650HP. He also confirmed that the 2.3 has made over 740hp (this was spinning it beyond it's limit though.) There is a 1.6L that will support 450HP and is $200 Less. Pricing on the 2.3AX from Superchargers4Less is around $2k including snout and pulley. Thanks Chris!

Andy K

 

Andy

Glad to be of help.

Hopefully we will have two versions running and tested by Sharktoberfest.

Chris W