Thom

Coming from me that may sound a bit strong, but do you have a dyno chart with the GTX3582R?

Dutch944

That sound.. 😊 you guys are making me jealous all the time.. I wist i had more time to finish my car!!

Paulyy

We're all waiting on this

333pg333

Sure. I thought it was posted elsewhere. Unfortunately the dyno chart isn't of much help as it was done on a different ramp rate according to the operator.
I don't quite understand but from what he said (briefly) he loaded it up really slowly to get a better tune. Said he got more timing into it as well. The chart looks slower than the previous turbo which doesn't make sense as I know it's more responsive.

1st one was the BW hybrid. 2nd is the Garrett.

964-C2

+1
Keep it coming! You are a big inspiration for me, love reading about your car!

Paulyy

Well it does look like the turbo is an improvement. you're getting more power from 6500-7000

Doesn't Sean have an aftermarket intake of some sort laying around so you could try?

Thom

Odd that the new turbo brought a slight improvement beyond 6000 rpm since you said the previous one felt "larger", but I guess that adding a bit more timing up there helped too.

Paulyy

I think he means more lag and less linear as imposed to feeling 'larger'

ausgeflippt951

This is a joy to see, Patrick. You're very deserving mate!

Very excited to see you employing the services of an aerodynamicist. Surprised to see so much rear aero balance, but hey: thats the end of the car you want it on -- not the other way around!

Tell me, will you be evaluating dive planes? I'd really like to install a pair on my car and would like a 944 case study. Unfortunately, dive planes are some of the most sensitive aero parts on the front of a car and when improperly sized/angled/shaped, it can actually be detrimental to the car's performance. But there aren't many better ways to help shift that aero balance towards the front.

Were your initial front-lift numbers WITH that giant splitter installed? Curious.

333pg333

I wish I could get more info out of the tuner but I can't ask him everyday for the maps/charts. He's a really nice guy when I see him but just seems to be super busy and often working well into the night so it is what it is. As mentioned, I don't think we can compare the charts completely apples for apples due to different ramp rates and possibly temps. He also said we had problems with wheelspin due to the slicks turning to mush at some stage this time around.
I guess apart from the coolant issue, we have a great motor for the time being and the bottom line is laptimes. Having the fastest RWD T.A. car at the shorter track is a sign of things to come. We've got more improvement to come which is exciting.

Colin, the calcs were done on the car as it was in 2013. With the splitter and dive planes. I was amazed and couldn't believe with our fairly significant dive plane 'extravaganza' that we were still showing lift!
From what I've heard, read and seen, Diveplanes/Canards etc are not what they appear. Unless you did some pretty significant aero work yourself, I'd not go there. At best you'll get some downforce but with that will always come drag. At worst, just drag and possibly lift. Perhaps those really small ones that Tony G had on his Red car might be worth a shot. I think they were off a Cup Car. I've seen a lot of people removing their Diveplanes so it's not all as obvious as it would seem.

964-C2

Am I reading the dyno shart correct, you have about 8 psi boost pressure at 4000 rpm?

333pg333

Ok, finally some more info. Interestingly the boost comes on much earlier when comparing these two pulls.
Here’s a bit of an explanation from the dyno operator:

“I have attached 2 files. The 1st is boost. 2nd is torque. These overlays are at different ramp rates. This shows the problem we are faced with turbo cars & ramp rates.

The higher horsepower reading is in shootout mode which is the correct ramp rate to show the correct horsepower/ torque readings. Unfortunately this does not allow the turbo to spool so therefore shows the boost coming in later. The slower ramp rate also overheats the tyres causing wheel slip. “

So this makes a lot more sense in terms of what we’ve been ‘feeling’ by the seat of our pants. Very different curves and response rates. Going to get the Ign map too.

refresh951

Amazing power Patrick. The loading definitely effects the boost curve. Here is a chart from my car. The blue line is at the dyno and the gray line is a street pull (more load).

333pg333

Ahh, that's good to see Shawn. Shows just how much dyno charts can be misleading. Thanks!

Thom

The "ramp rate" is I suppose the Proportional and Derivative gains of the PID settings controlling the boost delivery in closed loop. They can be a pain to get right when using a wastegate spring that is "too stiff", against which the solenoid won't be able to work with enough finesse to smoothen the boost curve to just let the PWM algorithm to work as it should.

Since loading a turbo on a dyno will never put as much load on the turbo as it would on the road, at least during the boost build-up rpm range, it's going to be difficult to get the "best" PID settings on the dyno, and even when using a MAP-driven ECU it's possible you might also run slightly lean on the road where the turbo spools before reaching peak boost, if you tuned for a targeted AFR on the dyno.

An ECU log from the track will be far more accurate than a dyno run to show how a turbo spools in real driving conditions, if you have any to show.

In my experience at least.