Quote:
Originally Posted by Bob Cosby
Your optimum shift point will be several hundred rpm above peak HP. The idea is to get the maximum average HP in each gear. For most cars, this is typically 400-800 rpm above peak, and varies with each gear change because of the different rpm drop going from 1/2 vs 2/3 vs 3/4 (and 4/5 in the 5.0).
This is one area in which the LS3 in the SS has a distinct advantage over the 5.0, and why it will run pretty much the same ETs as the 5.0 - even though they both put about the same power to the ground with the 5.0 being ~250 lbs lighter. Why? The LS3's rev limiter is ~600 rpm above peak HP. The 5.0's is only ~250 rpm above peak HP, thus the LS3 is making more AVERAGE power in each gear.
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I have to disagree based on actual races. This is a heavy car and torque moves heavy vehicles. The LS3 has a higher rev limiter because it's cam peaks at a higher RPM. A shift in the l99 above 6K is beyond peak HP as well as peak torque (after shift completion). I've got about 250 1320's and another 200 or so logging runs to base this on. GM put the shift at 6k for a reason. Change the cam, tire size, stall etc and this all goes out the window. I can actually feel the car loose steam as I exceed 6k. Peak HP in the L99 occurs around 5800-5900, therefore a shift at 6000-6100 would be optimum. Anything more than this puts you on the wrong side of the torque curve in the L99. I've ran 5900,6000,6100,6200,6300 and 6400 shift points. I've hot lapped the car at least 30 times on multiple occasions while lowering shift points. At each interval the car gets faster while lowering shift points. My car is just as fast letting it shift into 5th at 6000 as it is letting it trap at 6450 in 4th. Why, because the added torque from the lower RPM negates the time it takes to shift.