I drove my modified Bonneville today. I mean really hard . I was checking all the mods .
I did them all in one swoop. It was reasonably fast. Keep in mind this is the first time I've really drove the car.
I did notice a ... step like progression in the acceleration. Is this the PCM ramping up timing or the boost bypass kicking in ?
I do have a smaller SC pulley. I put in 92 octane and a full bottle of octane boost so I wouldn't think it was the timing.

Does anyone else have this sensation with a modified car ?

JLathem

Not a fair comparison, since I'm chipped, but forget the bottle of octane boost. That only took you to 92.1 octane.

Do you think the chip is causing the progression ? I can accept the octane boost idea.
I just didn't want any degrade in performance due to KR.

JLathem

MIne frequently does a similar action. I haven't figured it out.

EDIT: I do know it'* not the boost bypass. Mine'* disabled.

It must be the PCM programming. Maybe GM held back a little or a lot as it seems. I guess my mods just make the progression more pronounced.

JLathem

GM did hold back a little in the PCM to protect the 4T60 against the L67 power. That may be why I don't see it, with the aftermarket PCM installed.

I think you are correct Sir. I sent an e-mail to Jet today. I have a nearly new
GM remanned transaxle. Dealer replaced at 80k so it has about 40k on it now.
I hope it holds cause I can't stand that feeling. You can really tell the PCM is holding back
in the lower RPM.*

JLathem

Lower RPM'* is where I'd expect that to hold back. Our torque peaks very low in the band.

Mine does it with and without the Hypertech chip, BTW.

Ok ... anyone have any ideas ? Maybe the Jet Chip removes this ?
It is a real and tangible stepping up of power. It feels like maybe the PCM is pulling timing or fuel and then applies the subtracted amount in three steps.
It does it at the same RPM'* each time.

JLathem