How high can a HKS 272 rev?

 

If you're still on the stock valvetrain, the highest you should rev is 8 thousand but if you're on a stock sized turbo it doesn't really matter since it will run out of breath way before then.

 

this is just as dependent on the springs, retainers, and the inner workings of the motor as well

stock retainers and springs I would not rev any higher than 7,800 rpm

upgraded I would say for the motor's sake cap it at 8,000 rpm

 

so if i upgrade to GSC S2s or Jun 272 high do those REV? 9k? more?

I just love a rev happy motor and cams extend out your gear and give a bigger advantage road racing

 

I went up to 8100-8200 once and it hit the rev limiter/fuel cut. I have the basic bolt ons and 264/264 cams.

It's not about which cams you choose that will allow you to rev higher, it's about the motor. Did you not read the previous posts?

 

I'm not sure driving a stock turbo at 8000 rpm is gonna help you road racing. I could be wrong, but I think ur making so much less torque at that point in the power band that it would always be advisable to shift rather than ring out the motor.

 

well i meant upgrade to those cams when i upgrade to GT35R

 

Depending what TURBO you have, you shouldnt be going past 7600 with the stock turbo. If you have a GT35R or something like that, then to go reliably to around 8500 Id get some springs/retainers.

 

Oversquare (bore is greater than stroke) motors will rev easier and have less stress on the rods. With the right bore:stroke you can rev the bottom end to the moon.

Undersquare (stroke is greater than bore) motors will produce more torque and higher VEs due to the longer stroke relative to bore. But the piston head speed coming off TDC produces forces that will tear rods apart.

But at the end of the day, the limiting factor to high reving engines is the valve train. Springs can't keep up. Which is why F1 went with pneumatically actuated valve trains with pneumatic springs = 18,000 RPMs.