RPM shift point for '08 C2 @ DE?
#1
Instructor
Thread Starter
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I want to shift up at the peak horsepower on my '08 C2, where can I obtain the RPM shift point? I'm hopeful this is where I need to shift up at a DE. I don't believe I should go to the red line.
Thanks
Thanks
Last edited by Harvey in FL; 08-07-2012 at 11:59 AM. Reason: word edit
#5
Nordschleife Master
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On pretty much any factory geared gearbox, including your 997, because of the mechanical advantage of the gearing and the fact that you reduce that advantage every time you shift, even though redline is past peak horsepower, shifting at redline will provide for the quickest acceleration. This is because the differential in the multiplier of the gearing is big enough that you are putting more power to the ground in the shorter gear than you are in the next gear up, even though the next gear up has you starting to create more engine power due to where you fall in the powerband after the shift.
We frequently build gearboxes with gearing where, for example, the power to the ground in 4th gear after a shift is equal to or even slightly greater than the power to the ground in 3rd gear. But those are really close ratio gearboxes and for high level racing. There's not an OEM on the planet that I know of that gears a car that way straight from the factory.
That said, for a DE, where those final 10ths/lap don't matter as much, at least to me and in my own DE vehicles, as much as getting a reasonable lifespan out of my motor, I pretty much shift all my cars 300-500rpm short of the factory redline except in the rare instance where I get blinded by the red mist because I think I'm running a lap that is going to win me the DE Cup.![hiha](https://rennlist.com/forums/graemlins/roflmao.gif)
IBK...
We frequently build gearboxes with gearing where, for example, the power to the ground in 4th gear after a shift is equal to or even slightly greater than the power to the ground in 3rd gear. But those are really close ratio gearboxes and for high level racing. There's not an OEM on the planet that I know of that gears a car that way straight from the factory.
That said, for a DE, where those final 10ths/lap don't matter as much, at least to me and in my own DE vehicles, as much as getting a reasonable lifespan out of my motor, I pretty much shift all my cars 300-500rpm short of the factory redline except in the rare instance where I get blinded by the red mist because I think I'm running a lap that is going to win me the DE Cup.
![hiha](https://rennlist.com/forums/graemlins/roflmao.gif)
IBK...