Trying to help my friend with his 2017 Silverado fitted with an On3 turbo kit. I thought we had the street tune pretty well sorted out on 12 psi boost, but at the track we data logged a stubborn RPM "bobble" in first gear. Somewhere between 4,100 to 5,100 RPM (depending on how much boost he leaves on) the RPM takes a brief 600 to 800 drop. I do not see any change in ignition timing, injector pulse, throttle position, torque management advance - but yet there is a 600 to 800 RPM drop during first gear launching from a stop. I would love it if anyone cares to take a look at the attached log from a dragstrip pull (note the RPM drop at time 31.780 sec). This truck runs in the 7.7 to 7.8 second range in the 1/8th with lots of promise for better ET if we could get a clean pull. I should probably ease back on shift TM to help with the RPM recovery after shifts. The tight converter is dropping over 2,000 rpm on shifts.
Any suggestions on the attached tune would also be welcome. The truck put down 550 rwhp - stock 5.3 with just the On3 turbo kit around 12 psi if I remember correctly.17 Silverado turbo 27a.hpttrack 4.hpl
Reply With Quote
