Greddy Profec B Spec II Controller Question

[Mayolives]

Is anyone here using a Greddy Profec B Spec II boost controller on their L28 ? I'm searching for answers concerning the controller's tuning. I'm using it on a new engine with many bells and whistles including an Electromotive Tec 3R ignition system, GT35r turbo and a Tial waste gate that currently has a 14.5 lb spring installed. I'm running a conservative lo boost setting of about 14 psi with my gain set around 50%. This produces lots of hp and torque but the engine has a little stumble around 4200 rpm and then makes steady boost to the shift point. I have tried a high boost setting of 20psi with the gain set at 45% and still have the same little engine stumble. My questions is, what gain settings are other user's running on this engine. We spent a lot of time on the dyno and have really tuned this thing to the max but I still have the little stumble. I'm convinced that it is boost controller, waste gate problem that produces the stumble. Any suggestions?

[jgkurz]

including an Electromotive Tec 3R ignition system

 

Mayolives, I assume you mean Tec3R engine management system and not just the ignition. I also have a Tec3. What I'd suggest is data logging a run that includes the hesitation. That way we could get the big picture of what the car is doing including the MAP readings. Your EBC is a great unit and should be problem free. Can you send me a log?

[Mayolives]

John,

Yes, I am using the tec 3R engine mgmt sys. I don't have any of the data logs. They are stored on the Electromotive guy's lap top. He mapped and remapped but could not get the hesitation to stop. We have decided to go back to th dyno this Saturday to give it another try. After reading post at other forums, I think we need to lower the gain settings. The Evo guys use this EBC but run lower settings for the gain. I'll keep you posted.

[jgkurz]

Mayolives, The dyno is such an expensive way to tune your car. For the cost of some dyno tuning sessions you could buy a cheap laptop and tune yourself. In my opinion, it's nearly impossible to tune all aspects of a standalone EFI just on the dyno. One benefit of most dyno's is they have a wideband sensor to give you much more accurate AFR readings. This is just a educated guess, but I would bet the problem with the hesitation is not your Profec B but the tuning on your Tec3. There are many people with Electromotive systems on this forum that should be able to provide a wealth of information to help you tune yourself. There are several people on this forum that I how huge thanks to for helping me get my car running well.

 

I would be happy to help. Ideally we need the Tec3 .dat log file, dyno file, dyno graph and the Tec3 bin file.

[Mayolives]

John,

Thanks again for your input. I have a laptop but used the tuner's computer when we tested. I should have downloaded the files to my machine and will do so asap. Yes, the dyno is an expensive place to work to bugs out of my car, but I have little choice in the matter. My car is a dedicated race can, full cage, no headlights, turn signals, tags, state inspection, insurance etc. There is really no place to "road" test it.

[Mayolives]

For those who are interested, we found our problem when testing at the dyno this past Saturday. I am using 55 lb Seimens fuel injectors and theie duty cycle was maxed out when attempting to run boost pressure above 20 psi. and we were able to tune out a little lean area that apparently was causing a slight hesitation around 4200 rpm. The Profec B Spec 2 worked best on low boost setting using 30 % gain, and on hi boost a 15% gain. Out final boost settings create 14 psi on lo and 19 psi on hi. The car now pulls hard and make gobs of hp and torque.