refresh951

Since it is so "been there, done that" do you have a link? The only guy that I know of that made such claims was Special Tool...

Thom

My professional experience with FEM and stress analysis taught me that altering minor details to a model will generate embarrassingly contrasting results.

I had the stock intake and some other aftermarket units on the flow bench, just showed what I experienced from the driver's seat with my 3.0 8V - the stock intake doesn't belong to a 3.0 engine.

A.Wayne

Never suggest it did, ( i said 2.5) you attacked me , not i to you...


I only asked where are the flow bench numbers and what are the targeted numbers, i would start there when comparing or discarding and yes to Sims , garbage in = garbage out, We are pretty please with the research work done with them over the decades and find sims with good data work goes along way .


Current day software gets pretty close when compared to Dyno numbers , especially in predicting gains and losses, as to 3L setup's are you running a stock 8V head and if doing so , why is the restrictions the intake manifold. The 3L stroke is an issue for me, if serious about racing i would lean towards the smaller engines, street use the extra piston speed and displacement is nicer ...


My 2c

A.Wayne

Hi Shawn ,

Not sure what you want me to link you to , most 951 stuff was done by many years ago, hop around the WWW , might turn up some archived stuff, remember the internet was nothing back then like it was today, most of us old timers are still struggling with it ...

blown 944

I can see 500 whp out of a 2.5 without issue (other th as n head gaskets). However, imo it would require an extended rpms range that would be more along the lines of a race car application.

I have no doubts it can be done with extensive port work, intake wotk and all the supporting hardware.


I imagine that even on a high strung 2.5 you would not choose the factory intake? AWayne....

A.Wayne

That racecar in question used the factory intake, there were no headgasket issues, car did 2 track seasons and won races and fast times as well as an SCCA auto-x championship. It was loaded with anti-lag, TC, Launch and boost power mapped for track control. The big issues with 951 is the old tub/ suspension geometry issues, traction is a problem on corner exit.


Engine VMax on that particular 951 was 7200 this was 10 years ago ....


What are you making out of yours Sid, about 480-500 whp ..?

blown 944

I'd say a bit more than that with a 130 trap speed in a 3000 pound car.

The general rule of thumb is that it takes 500 rwhp to go 125 in a 3000 pound car. I dynoed my last engine when it went 125 and it hit just over 500.

I've been using this since Bitd when I did a lot of engine water brake testing. Just subtract a set amount for drive train loss and yiu could pretty much kniw what it would run before putting it in the chassis.

Tbh, I prefer the trap speed over dyno numbers, as they can be all over the place.

333pg333

Agreed on capacity for a race car. If I were to get another motor it would be 16v and perhaps 2.2 - 2.6 ltrs with a bunch of custom supporting parts. Having a motor that would be built to rev out to over 8000rpm would help in terms of traction issues also. Although updating the suspension layout/components is another goal. There's a very high end 968 turbo down here being built with contemporary high end Porsche race suspension components. That will be interesting to witness. Obviously Duke also has similar in his car.

Back to intakes. Was never trying to say that what we've built is a 'cure all'. Appears to be an improvement for our application though. Not sure how apparent this will be tomorrow on the short, tight track but I shall report back.

333pg333

ps...what % do we think is fair to use for transmission losses? I've seen anything from 10% - to 33% used.

A.Wayne

Yeah , if 3000lbs it may require as much as 520, from experience 500 does about 129/130 in a 3000 lb car, the only reason it may require more is from heat soak losses ( 500 + represent your flash reading). So if you dynoed say 3 back to back runs and then avg, you will get a better idea of what is available to you for a full 1/4 pass and hence the calculated MPH would be closer, of course confounders (drag/gearing/etc) abound and will raise it's ugly head ...


anyway we dragging 333pg thread way out ....

A.Wayne

Rear transaxle 15 % , direct transaxle 12% ......

blown 944

I don't think pat cares, plus this forums been pretty boring lately.

I agree with 15% for these cars.

I'd venture to say it'd dyno closer to 600 than 500. One thing to remember is that I'm not getting the initial mph to build a pin like a normal car due to easy take off. Also, since my 130 runs, I've ran faster half track passes that if ran our the back door should run 134-135. I've been shutting it down to keep from being booted.

It's running good and I'm just going to stick with lower boost for awhile.

333pg333

I guess until we run at the Drags we won't be able to compare directly (recognising that we're closer to Sea Level than Sid). It would take us probably 30psi to hit 600whp at the dyno we use at a guess. I think Sid is running what, 19psi or less? Our motors can't be that much different so that's why I don't worry about comparing dyno figures. I know we're not running as much ign as some others but I don't think we're going to find another 100whp with more timing.

Anyway, we're packed and ready for tomorrow.

333pg333

Found this from earlier this year if it's relevant to anyone.

Dougs951S

Anybody ever see these? I might do something like this with my intake and just build a decent sized plenum for them. It would be neat if I could figure out the cable and linkages. They are 45mm butterflies designed to be welded to 45mm tapered bellmouths and 90* elbows. I think they would suit the tapered 48mm S2 runners well.