tre3478

Is there anyone successfully doing this? Or is it all Theory?

I am looking at doing a fully built 2.2 motor...and just wondering if I can take it to 9000 rpm safely....

I am supercharged and all of that as well... so ... just curious if people are doing it or everyone just sticks with the 8600 RPM rule?

thanks

Gregg Lee

How many times?

afzan

I believe people have done used oil analysis on stock ap2 motors and there was a significant increase in wear when they revved up to 8400-8500 range vs the stock limiter (8200). This was based on street+ HPDE track days I believe

I'm not sure how a built motor would compare, but just some food for thought

Slowcrash_101

Think about it like this, an F20C has a stroke of 84mm, which means that the mean piston speed is ~ 56.37mph @ 9,000rpm, the F22C has a stroke of 90.7mm, if you do the math at 8,400rpm your mean piston speed is ~ 56.81mph so you actually have a higher piston speed at a lower rpm because of the longer stroke. This is partly the reason the F22 uses lighter pistons, the other reason is that it has less material in order to have the same compression.

For poops and giggles a 2.4 stroker kit would have your mean piston speed at ~ 71.8mph @ 9,000 rpm. At that engine speed an AP2 piston which weighs 346 grams has ~ 45% more kinetic energy than an F20 piston(355g) at the same speed with an F20 crank.

The crankshaft main journals are the same diameter on the F20 and F22 cranks, but the offsets are different, so the crank rotates at the same speed but on the F22 the piston has to travel a grater distance per crank revolution, greater distance in the same amount of time = higher piston speed for any given RPM. This is why the F22 has lower rev limit but makes the same amount of peak power but more torque under the curve than the F20.