[Ilma]

Originally Posted by shiv@vishnu

I'm also well versed on the mechanism the JB3 uses to control boost. It pulls the signal to ground which means that it extends the ground pulse of the wastegate signal. This means that not only does it rely on the factory PID closed loop boost control system, it is also only capable of increasing wastegate DC, not decreasing it. And from my research on this subject, that will prevent it from solving this issue. Also, Terry has publicly stated (many times) that this throttle closure problem isn't even a problem. in fact, he describes it as desired behavior.

Regards,
shiv

So in layman' terms......is this saying that the wastegate DC is producing too much torque and then the ECU is attempting to limit it via throttle plate closure to achieve the inherent torque target?

Is that why being able to REDUCE the duty cycle is desirable.......to prevent exceeding torque values that the ECU will then try to negate?

[33llipsi5]

Originally Posted by scalbert

I should have some hard data on a stock vehicle, JB3 1.2F and a PROcede vehicle concerning the actual throttle plate position under normal driving. Once the data is presented, people can judge for themselves. I have no clue what the outcome will be but true throttle plate position voltage versus throttle pedal voltage versus RPM should be a telling tale; if there is a tale to tell.

Perhaps you can simulate WOT in all forward gears?
(by varying the ramp rate of the simulated RPMs correlated back to time in each gear)

The reason that I'm suggesting this is to see if the piggybacks are 'up to the challenge' so to speak of completing their algorithms in a timely fashion. Generally speaking, a control system that applies outputs to stale inputs is undesirable at best, dangerous at worst...

[scalbert]

Originally Posted by 33llipsi5

Perhaps you can simulate WOT in all forward gears?
(by varying the ramp rate of the simulated RPMs correlated back to time in each gear)

The reason that I'm suggesting this is to see if the piggybacks are 'up to the challenge' so to speak of completing their algorithms in a timely fashion. Generally speaking, a control system that applies outputs to stale inputs is undesirable at best, dangerous at worst...

Yes, it could be done but not sure it would be worth the effort. We'll be logging the actual analog signals with external data acquisition equipment while driving which is probably the most important enviorment.

But IMO, since the DME uses RMS filtering of its analog inputs, the piggybacks are able to see and react to changes in a timely manner.

[33llipsi5]

Originally Posted by scalbert

Yes, it could be done but not sure it would be worth the effort. We'll be logging the actual analog signals with external data acquisition equipment while driving which is probably the most important enviorment.

But IMO, since the DME uses RMS filtering of its analog inputs, the piggybacks are able to see and react to changes in a timely manner.

Might be fun to see how and where things correlate in the real world compared to what you see on the bench... (Might also be fun to push each of them to their limits - whatever they are - to see how they deal with 'adversity' [so to speak])

[scalbert]

Originally Posted by 33llipsi5

Might be fun to see how and where things correlate in the real world compared to what you see on the bench... (Might also be fun to push each of them to their limits - whatever they are - to see how they deal with 'adversity' [so to speak])

We may be doing a bit of this bench work this upcoming week. And yes, some "curve balls" will be thrown at them.

[x-noize]

running jb3 1.1 no issues at all oh and i raped a 350z turbo today,thats all =cD

[dtg]

Well, since I'm the OP I guess I have some say...

I did speak with Shiv and he has been unbiased and helpful without any information that leads me one way or another. I also worked with Terry alot on this issue and needless to say Terry did everything he could to remedy my perceived problem and it turns out that it's not really a "problem" or a defect in the tune. The conclusion was that the partial TB closure is designed into the JB3 software as a backstop in the case of a boost spike. The "hesitation" is something that some cars experience more than others and some drivers are more aware of it than others.

I posted here not to in any way trash the JB3 because I cannot do that... it's a great tune and Terry is a stand-up and honest man. I just felt that there is something (hesitation) that I'm feeling that I'm not really 100% happy with and wanted to post my experience here to see if anyone could shed some light.

So, thanks all for the feedback and I hope I did not cause any trouble... I certainly did not intend for the thread to head in that direction.

[Ilma]

Originally Posted by dtg

Well, since I'm the OP I guess I have some say...

The conclusion was that the partial TB closure is designed into the JB3 software as a backstop in the case of a boost spike. The "hesitation" is something that some cars experience more than others and some drivers are more aware of it than others.

Not bashing - but you state that TB closure is "designed into" the JB3??

Would it not be more accurate to say that it is designed into the stock ECU and the JB3 does not modulate it?

I didn't think that JB could actually control the throttle plate closure.......correct me if I am wrong please.