Supercharging a 944 - Why so hard?
#16
Rainman
Rennlist Member
Rennlist Member
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.
slownrusty...were you using a roots, or centrifugal type? by your description it sounds like centri.
#17
Nordschleife Master
#18
Racer
Thread Starter
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.
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.
#19
Racer
Thread Starter
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?
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?
#20
Rennlist Member
+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.
Packaging a SC under the hood of a 944 will be a challenge, bu the time you also include the piping and intercooler installation.
#21
Rainman
Rennlist Member
Rennlist Member
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?
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?
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?
#22
Rennlist Member
It was a IHI \ Hitachi model
And "Yes" both set-ups were intercooled.
And "Yes" both set-ups were intercooled.
#23
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
#26
Rennlist Member
https://rennlist.com/forums/944-turb...o-musings.html
#27
Racer
Thread Starter
. 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
https://rennlist.com/forums/944-turb...o-musings.html
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.
#28
Rennlist Member
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
https://rennlist.com/forums/944-turb...o-musings.html
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.