Tuning my 996tt

Vishnu Tuning · 2007-04-08 06:13:37

I posted this yesterday but the thread was deleted soon after. Someone didn't know that we just became site sponsors ;) ------------------------------ Hi guys, Managed to get basic control over fuel, timing and closed loop boost just this past week. Using our PROcede engine computer. Very similar to the one we've been using in the BMW 335s with good success. Still in the process of refining the tune, adding temporary overboost, sustained load boost decay, etc,. But so far, so good. Took the car to Full Function (union city, CA) and tested the car on their AWD Mustang Dyno. All results on 91oct. Stock, it baselined at a repeatable 325whp/353lbft of torque. Then I slowly enriched on-boost AFR form 12:1-12.9:1 to 11:1-12:1. Then gradually inched up boost while adjusting timing. Most knock prone are was right around 5k rpm. Required a bit extra fuel and little less timing. Seemed like the stock car is tuned pretty aggessively here to begin with. Boost eventually settled at 14.5psi peak, tapering down to 12-13psi by 6000rpm. Power gains were okay for starters. Peak power went from 325whp to 377whp. Torque went from 353lbft to 421lbft. Judging from today's tuning session, the car will make just as much torque as you want given octane constraints. I had torque as high as 450lbft but backed it off just to play it safe. It is my car after all But it's always fun to see the front end of the car lift up on the dyno. On the road, the car was surprisingly stable. Did some mild part throttle tweaking with good results. No hint of knock on the logs. No reduction of the knock-induced boost control coefficient. No measurable AFR lag during sudden on-boost transitions. Real nice. The only thing that I had to go back and tweak was the 4800-5100rpm range as the car transitioned from mild boost to full boost. 2 out of 5 times, it would induce knock retard. Fixed it by pulling back timing in the 5-10psi range and by adding a short term (0.5 sec) fuel enrichement. FWIW, this is a lowish reading dyno as far as Mustang dynos go. Last week it was dyno'd stock at 350whp/370lbft under virtually identical testing conditions at EIP's Mustang dyno (Santa Clara) . That's a pretty big difference from the 325whp/353lbft it put down on FF's heart-breaker dyno today. That said, I would expect the tuned numbers to be a bit higher on EIP's dyno. But that remains to be seen. Once I finish tuning this car, I'll take it around to different dynos just for fun. Maybe even to Sac Raceway to see what she runs. Next up: Going to install upgraded bypass valves and do some more tuning. Still working on a Sport Chrono-like temporary overboost feature as well as some other trickery that may be more trouble than its worth... lol. Cheers, shiv www.vishnutuning.com