Hi guys,
Managed to get basic control over fuel, timing and closed loop boost just this past week. Still in the process of refining things, 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

 

Nice job Shiv. Is your airfilter and/or exhaust stock? Please keep posting.

 

roadsterdoc-- thanks for the kind words. And yes, everything is stock (stock exhaust, stock air filter, stock bypass valves, etc,.) The only work I've done is install new plugs (FR6s). The Berus that came with the car couldn't support anything over stock boost.

I do have a question for you though... The factory bypass valves are feed a boost/vacuum signal. In most applications I've seen, the signal comes from the intake manifold. In this car, the signal lines go to a valve. One side of the valve goes to a vacuum tank. The other side goes to the manifold (with a one way check valve that only allows air/boost to the top of the bypass valves. So my question is, why is this so? Does the factory ECU induce some sort of open system "pre-spool" by opening the bypass valves and allowing the turbos to spin up (without pressurizing the intake tract?) It would be nice to know what the engineers had in mind when designing it this way.

-shiv

 

No, I doubt it is anything that sophisticated. I could be wrong, but I think German engineers just love to use vacuum solenoids and accumulators. They're freaking everywhere in these cars. PM'd you a diagram.

 

Great work Shiv!

 

Thanks for the diagram. Although I already had that handly. Alldata is a wonderful thing! Yes, solenoids and accumulators are everywhere in this car. But i gotta think there is a reason for the bypass valve plumbing that we're no aware of. Oh well

Cheers
shiv

 

Shiv, is your car a k16 or a k24?
thanks
Joe W.

 

Hi Joe-- It's a totolly stock 2001 996tt with original k16s. The car has 49k miles on the clock.

-shiv

 

Excellent (from a greedy point of view ). That's what I have,
so it sounds like your work may help me ASAP. I'm local (94556)
so I would come visit some time.
thanks
Joe

 

No problem. Our new dyno shop (in livermore) should be up and running in a couple of weeks. We had to move it out of Blackhawk due to noise complaints... grrr.

 

k. What's the new address? Will BlackHawk be open till then?

 

Why not tune partial throttle on the dyno?

 

Better to do it in a real world environment?

 

Because with a car in this power level doesn't meet max torque at every throttle angle. So, in effect, partial throttle tuning is mostly subjective. You end up caring more about how the car transitions from partial load to max load. And how it goes the other way. And how knock resistant it is during these dynamic conditions. A lot of this can, in fact, be done on the dyno. And a lot of it was. But the final step in tuning is always seeing how it feels because sometimes you don't know what you want (or don't want) until you feel it.

Shiv

 

Shiv !!!!! Very informative thread. I wish you the best in finding more usable power for the TT. Count me in !!!!!
Divi