I have finally started working on my tune. I have been running on a tune that was originally done when I installed my first supercharger using stock heads and cam.
My current setup is a different supercharger (Vortech T-Trim) running about 1psi more boost, AFR 205 heads, and a Comp 220/224 .581/.581 115+2 cam with XER lobes. The car is a 2002 Corvette with a 6-speed and I am doing my tuning at an altitude of 7000 feet.
Before I first fired the car after the latest mods I upped the idle to 850 hoping that it would idle. It actually idles quite nice at that speed except that when I let off the throttle and let it return to idle the RPMS will sometimes drop to 500ish, recover, and then it will idle fine. I have no surging, it never stalls, and I have no cold start problems.
I did a bunch of reading on this forum. LS1Tuning, and LS1Tech to see what I should try to cure the problem. I tried the (nogo suggestions) VE 60/70/90 change, IAC Park Position 40C up to 21, Idle Air In Gear all points 60c up to 8.6. These changes induced surging, stalling, and hesitation so I put everything back to stock except the idle which I left at 850.
Does anyone have any ideas on what to try to get rid of the idle dropping (but never stalling or surging) and then recovering?
Thanks,
Mark Forbes