Gear Calculations and Rev Limits

[daj349]

Everywhere I've read on the forum owners regurgitate the statement that power drops after 7 or 7.5k rpm. Yes, it does. But just because you're losing power doesn't mean you're going to make more power when you shift to the next gear. The area under the curve per rev is what is important here and it seems many tuners do not realize this.

We're looking to maximize the integral of the horsepower curve between the gear changes. Also, the drop after the OEM rev limit is going to depend upon your mods and tune. I based my gearing calculations on stock sport tires btw. It's attached to this post.

Let's look at an example of Mike's dyno

N/A HP BRAG thread



(red) Shifting from 2nd to 3rd at 7500 rpm and 338 hp brings us down to 5250 rpm and 270 hp.

(blue) Shifting from 2nd to 3rd at 8k rpm and 325 hp brings us down to about 5550 rpm and 285 hp.



It's clear to see that the average power produced per rev when shifting at 8k rpm is much larger than at 7.5k

When we are reving that high, oil starvation has been the main issue. This is further exasperated by lateral acceleration. Do we have evidence of how this engine holds up at 8k every once in a while? Please post references or first hand experience and not just what you've heard. That's how misinformation occurs. What's a happy medium between 7.5k and 8k? I know we have a wet sump and the the old GTM brand was looking into putting baffles in the oil pan to help. Also do we have more reference N/A dyno graphs going above 7.5k? I've only found 2.