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Supercharging a 944 - Why so hard?

Old 11-19-2017, 12:29 PM
  #16  
V2Rocket
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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.
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Old 11-19-2017, 01:11 PM
  #17  
MAGK944
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Originally Posted by slownrusty View Post
...At minimum, you need a larger engine displacement with at least 6 cylinders to drive a SC.
+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.

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Old 11-19-2017, 01:27 PM
  #18  
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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.
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Old 11-19-2017, 01:32 PM
  #19  
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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?
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Old 11-19-2017, 01:55 PM
  #20  
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Originally Posted by V2Rocket View Post
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.
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.

Originally Posted by MAGK944 View Post
+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.
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.
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Old 11-19-2017, 02:04 PM
  #21  
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Originally Posted by jderimig View Post
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?
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.

Originally Posted by slownrusty View Post
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.
what model? were you intercooled? did your turbo setup use an intercooler?
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Old 11-19-2017, 02:33 PM
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It was a IHI \ Hitachi model

And "Yes" both set-ups were intercooled.
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Old 11-19-2017, 05:10 PM
  #23  
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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
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Old 11-19-2017, 05:17 PM
  #24  
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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.
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Old 11-20-2017, 05:04 AM
  #25  
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I dont know why you bitch about space.
Here is a Honda CB550 with a SC, Micro squirt, higc comp engine.

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Old 11-20-2017, 08:05 AM
  #26  
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Originally Posted by slownrusty View Post
At minimum, you need a larger engine displacement with at least 6 cylinders to drive a SC.
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
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Old 11-20-2017, 11:07 PM
  #27  
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Originally Posted by Dubai944 View Post
. 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.
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.

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Old 11-21-2017, 12:52 PM
  #28  
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Originally Posted by Dubai944 View Post
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
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.
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Old 11-22-2017, 04:14 AM
  #29  
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Old 11-22-2017, 10:25 AM
  #30  
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I know that car well, I supplied VEMS PnP kit. He is from Hawaii.
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