We have an Evo 5 project with a slightly warmed 4G63 combination.

Oliver H beam rods, GSC Stage I cams/GSC springs/retainers, Evo 9 Turbo, and good intake/exhaust along with 23 psi/Link ECU.

This GSR car has seemingly short gearing with ~80 mph = 4000 rpm.

Finally took it to the rev limit in 5th gear on the autobahn...160 mph at 8000 rpm. It seemed like it would go another 10 mph if we upped the limit, but wary of throwing a rod, etc.

How high can we rev these engines to assuming decent condition, etc?

Video for interest:

 

Check out GSC recommendations for max RPM with the particular valvetrain you have, assuming your motor is a standard 2.0.

Rods/Crank/Valvetrain and quality of tune are all things running through my brain if I were to try to sing it to 8k+rpm in 5th

 

The engine can be revved much higher but the problem is the turbocharger.
It cannot get the air out and back pressure is high. Imagine running a sprint with a straw in your mouth.

 

Abacus: Makes sense. Figured the Evo 9 turbo would run out of breath. The gearing seemed to help as it zipped up there pretty quick and felt it would go more...

 

25m/s average piston speed is a typical ceiling for reliability. This applied to all motorsport, F1 etc.
4G63 with 88mm stroke is 8500rpm @ 25m/s.
4G63 with 100mm stroke is 7500rpm @ 25m/s.

Can you rev higher than this? Yes.
Should you? Probably not.

 

I wouldn't and haven't thought twice about revving a 4g63 to 9500 with the right setup. Piston speed is my last concern. Backpressure is a concern.

Any 88/94mm engines will live a while going to 9000-9500. Some even go to 10K. Its just one of those things where if you've got that much turbo to support it , something else will wear out or break beforehand. 250/350hp a hole is hard on things.

I own a unicorn 94/150mm engine that lived 800-1100hp to 9000/9500 for 26K hard miles and 13-14 years. It had a week cylinder for over a decade and leak down was 30-50% . We tore the engine down this year and it was clearly time . Bearings were almost toast and it would foul one spark plug.

 

Great posts - thanks! I believe I followed Abacus rebuild on youtube...

 

Get the HKS taller Final Drive.

 

Yeah a lot of high revs has to do with more with the valvetrain and how good it actually is. I agree with you about how the engine is built as well. I know I accidently saw 10500 on my engine by accident the first time I made a full boost pass at 60 plus psi. I didn't have the rev limiter set where I needed to and over reved the engine. Thankfully everything lived, but again good valve train and thankfully it didn't get hurt. Even with a 162mm engine not something I really wanna do all the time.