Ahmet

Here's my mod list as of yesterday:
Chips, no cat. 18psi peak, about 12 by redline. I must note my engine is very tight with less than 2% leakdown across 4.

I'm running guru chips. The numbers from the dyno are obviously at the wheels. The power #s are nice but the air/fuel ratio is pretty ****ty, especially as the boost builds... Anyway, but that isn't where my headeaches come from, this is:

This is Randy's 944 turbo (the one I've been working on). It is not tuned at all, and is running 14 psi. The turbo in this thing is not running efficiently @14psi (running a vitesse 2 kit). Boost builds nicely however, and the car's easy to drive. It has full exhaust, intake, injectors, etc. etc. I will install the SMT6 on it this week, and hope to have a superior dyno sheet in a few weeks. Note that this car was tuned using a fuel pressure regulator only! I completed the driveline modifications at 4:30 am the day before...

Ian was there, hopefully he'll post some stuff too...
Ahmet

shaheed

those are nice numbers ahmet, i got pretty much the same numbers as you several years ago running pretty much the same setup except the chips were weltmeister. same boost bleed off etc.

NZ951

A Tial is your best investment!

danny951

So what's up with the A/F Ratio on the Guru chips? Why so low at the end?

eclou

If he's running a 26/6 I don't think the Tial will change the numbers too much. I had about the same numbers on mine before and after the Tial - the turbo just runs out of steam.

Ski

So what's the headache? Your chart vs. his? John at Vitesse has put together a very nice kit, which I guess you installed the chips in Randy's car that came with the kit? John has designed his chips so that the car will run without the SMT6 - it will run better and get dialed in with the SMT6 though. Jwl has a Vitesse STage II kit, after his break in miles from the rebuild at a boost reading of 15psi, he got 314 on rwhp and 308 torque. The car ran a bit rich and we found an exhaust leak. So I would say Randy's car is right there where it should be. You can tweak the fuel now to get the A/F dialed in.

Ahmet, you're running stock K26/6 and factory injectors?

Jake951

Ahmet: There's something a bit strange about both dyno charts. The max hp and torque numbers printed on the charts don't match what I read from the curves themselves. What's up with that?

ian

Jake,

The numbers printed on the chart are from the selected point on the graph, not the peak numbers, thats why they don't match the peak numbers.

Ahmet,

I still say your numbers are Head Gasket breaking numbers, those A/F's are not safe for the long term.

As I don't have the graph up loaded onto anything for my runs (Can you get that from them Ahmet?)

But I was running 17psi and the car was still rich at 11.5 to 12:1 accross the whole RPM band (while in boost) and put down 328 hp and 320 ft lbs of torque. There is more power to be had for sure, but it was a very hot afternoon and the dyno had less than perfect cooling so I'll save the aggressive tuning for another day.

Jake951

I'm looking at the max power and torque numbers printed on each chart and not not the selected points. Look at chart #1: max power is reported at 256.89 and max torque = 303.89. Then look at the curves. The max power never exceeds 250 hp and the torque never exceeds 300 ft-lb. There is a similar problem with the second chart. There is either a problem with the axis scaling in the Winpep viewing software or in the data itself.

Ahmet

The max figure printed on both charts does NOT match what the curves show, I'm not sure what caused the discrepency. I believe it might be the higest figures obtained, I will look into that. For now, I will only take into consideration what the chart shows.

I am ok with the power my car's making, the A/F is really ****ty, too lean around 3500rpm, and basically goes richer from there on... On the road it seems safe enough though, and I'm not concerned about that (however I have blown one headgasket on this a few months ago). I'm open to comments but doubt I'll do anything else to the car before selling it. Oh, does anybody want a 944 turbo with lots of small mods, perfect compression/leak down, turbo S transaxle etc. in fairly rough cosmetic shape for ~$5k?

Anyway, the main thing is, I'm fairly dissapointed in what Randy's car made. It's running a full vitesse stage II kit minus the SMT6 (which I will install this week). Looking at the chart, and not just the printed "max power" values, it's not ahead of my stock turboed car with stock intake and fairly restrictive exhaust (compared to his anyway), it's making no more torque, and only about 25hp more. His run was made at 14.5psi. The car's got open exhaust with one muffler and no cat. It's also got 55lbs injectors. It better make more in the future! Any input welcome on this.
Ahmet

ian

ahh, didn't notice that one, sorry. No explination for that one, I can only guess that the graphs don't include some correction factor that the peak numbers are including......

ian

Ahmet,

Randy's runs were @ 15.5 PSI, or that run was anyway.

Ahmet

The in car gauge showed 14psi according to the video Nick was taping. Randy apparently only grabbed one of the charts (real bright guy!), but yes I think the last run probably was a bit higher.

I scanned these charts, I do not have them in an electronic format, other than just the jpeg images. I can check to see if they're saved wednesday if you like.
Ahmet

Jake951

Ahmet: Danno can chime in here but he's said before that Guru chips are designed to run slightly lean in the boost ramp-up region for faster turbo spoolup but it does look like you are too lean there. As the turbo spools up, I've seen from my own dyno runs that 13:1 or maybe 13.5:1 is about right around 3000 rpm (with the K26/8). I found I actually lost about 20 hp there by going richer. Once you're into full boost, though, then you want to be richer. Is your car stock?

Ahmet

For the most part, yes. More open exhaust, no cat, cone filter, wires/colder plugs are the only engine mods. The car's got the 3 bar FPR that's supplied by guru also.
Ahmet