Dennis Wilson

Since you are putting more air into the engine at 2800-3000 rpm and higher, you need more fuel than the stock WUR is designed for. The last thing you want to do is run lean under boost. You may be able to tweak the A/F mixture or standard WUR but that would also affect the low rpm (non-boost) running.

Dennis

SMTCapeCod

Programmable wur- one version is at Unwired Tools (.com). I think I've only read of two installs, requires a laptop and wideband 02 sensor to really dial in properly....yes, just like the rice tuners have been doing for a decade or more....

CAShark

Very interesting, thanks for the info. Makes total sense now.

hacker-pschorr

Sure it is, 17psi on my bone stock L-Jet 81 is making as much power as a stage 1 S4. Total cost? Less then most pay for a sorted out S4 5-speed.

This April wil be year three for my car with boost. You can ask anyone who has experienced my car, I don't baby it, ever

Then you have Jean-Louis, This will be his third season running a supercharged EuroS with 10.4:1 compression. His first season was without an intercooler!!!
Ask any of the racers around here about his driving skill's, he is no slouch.
On top of that, his car see's double duty almost every track event with his wife driving the car in a seperate class. So on average is eight track sessions per day.

Roy928tt

Question to "toofast928" what is the weakness with 4.5 pistons ? how much boost is to much ?

I'm intending pushing 10 psi into my LPG powered 4.5 litre, with the intention of finding 400 flywheel hp, should I be afraid and why ?

I figure that with the high octane fuel,LPG, I should be able to achieve this, and I really don't see why the low comp. 4.5 should have an issue with this,

Thanks in advance, Cheers Roy

Rick Carter

I don't know of anyone that has done this. There are quite a few 85/86 around 300 rwhp with the S3 intake, mine was 291 prior to the SC.

toofast928

Roy,
The 4.5 USA piston compared to the 5.0L:
4.5L has top ring land closer to the piston crown and the crown is not as thick. I cracked 3 piston ring lands at 8 psi.

But I was not using LPG. Headers play a big role as to get the exhaust out of the cylinder soon as possible. The cast iron manifolds cause such a restriction in a blown 4.5 that the head is left to absorb the extra heat. Contributing to detonation.
Tony

Roy928tt

Tony,

Thanks for your answer.

I am backing the exhaust gasses up in the head with a couple of turbochargers, but you then go on to mention detonation, which I am expecting to avoid. Thanks for the insight into 4.5 pistons, it is unfortunate that the piston is not ideal for boosted engines. I will persist none the less, and be very carefull to avoid detonation.

Thanks Cheers Roy

largecar379

I just pulled my 4.5L Euro down (over Christmas holiday) to find 7 out of 8 pistons with busted ringlands. This is a 10.5:1 motor with no blower of any kind.

Detonation? Maybe.....Can't say how it was set up before I got it, or what gas was put in it, but from when I bought it up to teardown--the car always had premium gas and no knocking.

Go figure.






--Russ

SharkSkin

I had heard this was not possible. Do you know of anyone who has done it?

dprantl

I was thinking of doing that myself a couple of years back. There was more than one person on this list at that time that had an S4 intake fitted to an S3. The guy was using some black box to activate the flappy when he wanted to. I don't recall who it was, but he even had a picture of the engine bay in his avatar.

Dan
'91 928GT S/C 475hp/460lb.ft

Lance J

1) I'm going to start with euro heads, TB.
2) Headers or 85.5 manifolds

5.0 liter bottom end swap
Can you use 944 turbo pistons in the 5.0 liter bottom swap? What is needed to do the swap on MY79

hacker-pschorr

Todd is using stock 951 pistons in his car:

https://rennlist.com/forums/928-foru...ler-30psi.html

They are not ideal since they do not come all the way up to the top of the cylinder.

Lance J

bump

Tony

is the intercooler new in your Avatar Erik?
engine looks sharp!