The "let's brainstorm how to make a piggyback work" thread

[eTiMaGo]

Originally Posted by largeorangefont

Why do you guys want to do closed loop fueling adjustments? They are not needed. The car is self adjusting (to a point) in closed loop.

well yes but it tries to stay at 14.7 AFR no matter what. And from looking at the data that Pavel posted, the car can stay in closed loop mode even up to quite high RPMs, as long as the gas pedal is not being mashed down.

On the other hand, it is something I am not so sure about in the first place, at three quarters throttle, 4000RPM, for example, is there enough pressure from a SC/turbo that it would require fuel enrichment? Or am I barking up the wrong tree?

[largeorangefont]

Originally Posted by eTiMaGo

well yes but it tries to stay at 14.7 AFR no matter what. And from looking at the data that Pavel posted, the car can stay in closed loop mode even up to quite high RPMs, as long as the gas pedal is not being mashed down.

On the other hand, it is something I am not so sure about in the first place, at three quarters throttle, 4000RPM, for example, is there enough pressure from a SC/turbo that it would require fuel enrichment? Or am I barking up the wrong tree?

That log has great info, but he is just putting around. Have him datalog a pull in a gear. Do one in 2nd from 2000 RPM and full throttle to redline, and the same in third gear. What is done to the car?

You are thinking correctly. Generally forced induction cars go into open loop sooner than NA cars. Some NA cars don't hit open loop until you go WOT. My guess is that this is one reason the Blitz SC is clutch driven, so you are not getting boost at lower load areas.

We can't see the actual AFR, but we can see his timing, which will be helpful.
Can he graph injector latency or duty cycle too? If so get that on there.

You can't hope to tune closed loop, no piggyback I have ever seen can do it. It just causes problems.

[largeorangefont]

Originally Posted by PK198105

LOF i got no engine mods so far and i need a longer straight with no one in front of me to do it safely and properly. ill try and do a run like you said from 2000k and up in each gear.

That would be great. Even seeing what a stock car does will be very helpful. Is there anything on the PID list relating to the fuel injectors?

Your list for that other pull had all the stuff we need, except for injector duty cycle or pulse width.