Porschefile

As far as "modeling" software goes, take everything from the Engine Analyzer Pro with a grain of salt. Just FYI but, I've messed around with it a ton and have some friends far more educated than me that have as well and the EAP is incredibly innacurate at replicating forced induction. Well, at least turbochargers. I never really messed with the S/C stuff. It's much more accurate for an n/a application, however it's relatively old-tech software. The boost curves just aren't even remotely close to where they should be. With all of the specs for a K26/6 put in by myself, I think I was getting something like 8psi by ~4.2k. Anyone feel like donating some CFD software????? I'd sure love to hear about any other more modern programs if any of you happen to know of some.

Porschefile

Tommo951, I completely understand what you are saying. A broad torque band is preferrable and will lead to a faster car. HOWEVER, what I think people are getting blinded by here and in the past is substantial amounts of peak torque at a low rpm. This in and of itself doesn't mean anything, and it's the overall torque curve that is more important. I have no illusions about revving a 3.0L+ i4 to 7.5k+ rpm or anything. If you have a motor that only revs to 5k, of course you want your peak tq to come in low and stay as flat as possible and as high in the rpm as possible. Ignore Paul's peak tq number for a moment and simply look at the curve. He has peak torque at 3.5k. From 3.5k to 5k there is a ~60-70lb/ft torque drop and from 5k to 6k there is nearly a 100lb/ft torque drop. Now, you have quite a few variables to play around with here such as plenum size, runner length/diameter, TB size, exhaust/exhaust runner size, etc etc. What you can do is mess around with these components to mold the torque curve to your purposes. Sorry if I'm just reiterating the obvious. You can sacrifice a bit of peak torque, shift the peak torque rpm up a bit, and through modifying some other variables gain a wider torque band with more overall power which would result in a faster car. Afterall, HP = tq x rpm / 5252. More torque at higher rpm = more hp, which gets more work done. Anyways, the attached pics are an example of a more efficient torque curve (hope you don't mind me using these Russell).

Paul, please don't take any of this as bad mouthing your setup. The point of my post was just to explain simple/general physics. Your project is awesome, and extremely impressive considering all of the stock stuff you still have on the motor. That thing is going to be insane when/if you mod it some more! Keep up the great work.

Diver944

Don't worry Porschefile, I know you are trying to help us get the best out of this enigine and I have no plans to leave it as it currently is. We are merely at the point where we have the first stage completed, the engine is in and it's running. The fact that its running much better than I expected at this point is a massive bonus and it gives me real goosebumps to think what it will be like with just a little more work.

We already know that on boost the car is pulling a massive vacuum between the turbocharger and the AFM and that is the major bottleneck at the moment. It has a big ball race turbo with a 4" intake being powered by the gases from a 30% larger engine and its trying to suck it through a square hole of 2" by 1.5" that has a mechanical flap in the way. Once we remove that and get a proper 3.2 map in there we know that the torque curve will level out and the power curve will rise up to follow it closer

Guns951

Keep up the great work! Can't wait to see the final product, any idea when that might be (projected timeline for tuning etc)? It seems like the 951 is getting much love in many countries! Estonia, USA, Austraila, UK, Germany

333pg333

Don't forget our Svenska friends!
Paul, Jon can you tell us anything about the turbo on Lil? I know it's one of Simon's ball race turbos but what are some of the specifics? I'm sure you can tell us some details without giving any trade secrets away???

tommo951

4" Intake?? Paul that aint an intake its a black hole!!!!! Can't wait to see your car in the flesh! Still thinking of going the Vitesse Map?? I am staying Vitesse with mine once the 3.0l is installed.

Cheers
Tom

tommo951

Hi Porschefile,
I agree with you mate regarding the torque curve, I think this might be a communication problem. Maybe I was not crystal clear in what I was saying. The drop off of torque on Pauls figures is far from ideal, but we know why the figure drops away. The induction tract is so highly restricted for the flow. I was trying to make the point that you do not just sacrifice low end torque for high end RWHP maybe I did not make this clear enough. Have you ever driven in Uk? You will find most of the time on A roads you are travelling between 30- 70mph with occasional bursts up to about 120mph (No I was doing 60mph honestly constable!) Therefore low end torque is essential. I have driven across the US and we would love to have your roads but not your speed limit which needs some updating!!

Diver944

As requested I finally got round to uploading some in-car video taken on my private driveway This small clip is a 3rd gear pull from 1800rpm to 6200rpm which equates to about 30-100mph. I was going to do some through the gears footage to as high as I dare afterwards but it started to rain and I wimped out

RolexNJ

Paul: Nice short clip, thanks for sharing. And I saw the photo albulm pics too. Very nice my friend. I look forward to more things to come, and you still sorting out the car too. If you go to the track, see if you can make some more movie clips!!

Cheers

Diver944

Yes I have a couple of bulletcams connected front and rear for trackdays so should get some nice footage for you. If you're interested here are some clips from two years ago before the turbocharger went south:

http://www.pistonheads.tv/clip359

http://www.pistonheads.tv/clip177

RolexNJ

Nice footage Paul and track too! Damn I love Europe!! And this footage was when your car had the 2.5L in too? Do I assume correct?

UK952

Oooh im in one The car looks really smooth in the 3.2 vid - excellent Paul! and well down on the torquemeister crown (and to Jon and Simon)
Tony

UK952

That was when Pauls car was a 2.5 he was quicker than the GT3 through the corners but it wouldnt let him pass, He was quicker than me too, but I sneaked past the GT3 when an a ferrari 360 held it up
Tony

stv951

Ok. We need more info on that please. 951s quicker than a GT3 and a 360 Modena ? iam sure this has to do with driver skills mostly, but still quite difficult. i am glad to hear that though

UK952

Yes the 360 owner was an old boy, and probably not keen to throw his expensive pride and joy into the wall, the GT3 was not brilliantly driven though not bad, he had less torque than me though, Paul is very smooth and consistent - I think I was quicker than him on occasions but lack his consistency, some where I have some video of his car on the same day, will have to try and dig it out, but very busy at the moment and having PC issues,

Tony