LT1 MPH Shifting Points?
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Joined: May 2002
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From: Conway SC
LT1 MPH Shifting Points?
I have a 1994 LT1 Corvette Coupe with the LT4 cam and corresponding roller rockers and springs. The Corvette's computer presently has the stock MPH settings for shift points that correspond to the RPM ratings of 5700 RPM for the 1st to 2nd and 2nd to 3rd shifts under Wide Open Throttle conditions. I would like to know what the OEM MPH setting is in order to have a "baseline" from which to work on some different tuning adjustments and shift point changes. I have a GM chart for the LT1 motor that indicates for every 1 MPH adjustment to the shift point equals approximately 135 RPMs for the 1st to 2nd shift with a 3:45 rear end gear and 70 RPM for the 2nd to 3rd shift. According to the dyno tests my motor makes HP up to the 5700 RPM level but the HP gain per 100 RPM increase really levels off after 5400. The same is true for the 2nd to 3rd shift except the HP gain slows after reaching 5200 RPM's. I want to use the 5400 RPM level and the 5200 RPM level as the starting points for reprogramming the Corvette's shift points under Wide Open Throttle conditions. Knowing the exact "MPH starting point" before starting on these modifications will be helpful. Thanks for the information.
