[dradernh]

Originally Posted by ScottSinger

I agree, as long as u stay above the rpm for maximum torque ( or near ) then shift halfway between that and the rpm for maximum horsepower.

Right. Using Dinan's results for the stock engine output, there's a negligible decrease in HP when dropping from 6K to 5K during a 4-5 shift, but there's an 18% increase in torque. That seems significant to me. It does look like spinning the engine up to 6500K makes sense for the 3-4 shift, as that would be necessary to be at 5K after the shift.

I was at another race shop yesterday (i.e., not the one with the shift-at-6K recommendation). Over the years, this shop has built quite a number of sports cars for IMSA/Grand Am/World Challenge and done very well at it (e.g., landing sponsors as major as McDonald's for its Daytona Prototypes). I now wish I'd brought this question to them, because I'm certain they'd take one look at the data and say "This RPM is where you want to shift." And the recommendation would have come with a good bit of insight, which with this hobby is something I always feel that I need.

I think I'll try them and see what they say, especially in terms of providing context.