Power loss at high RPM
 

Trying to diagnose power loss. New engine rebuild with exhaust porting. Just done 1000 km so I lifted the rev limiter to see how reacts to the higher RPM however, it was a bit underwhelming.

I have lightweight flywheel so it revs quickly to 8000km however, it struggles to go to 9000 and beyond. I have not driven the car for 2 years however, I do not recall having similar issues before as i recall hearing the buzzer all the time.

My cat is currently gutted so cat is not the issue. I still suspect exhaust restriction as it could be collapsed resonators or catback restriction.

Coils are almost new and plugs have done less then 5000km

Any other suggestions?

Engine Power Loss
• chokes as revs increase
o O2 sensor failure (too rich)
o MAF failure
o MAF disconnected
o e-shaft sensor fouled
o accessory belt fraying
• high end power loss (hard fuel cut)
o Rev limit reached
• high end power loss (jerky and stumbling)
o Ignition failure
o fuel pressure loss
o e-shaft sensor fouled
• high end power loss (smooth)
o Catalytic converter clog
o air filter clog
• low end power loss (smooth)
o Engine compression loss
• low end power loss (stumbles)
o Ignition failure
o front O2 sensor failure
• revs slowly but smoothly
o O2 sensor failure (too lean)
o catalytic converter clog
o air filter clog
• sudden power drop at a specific rpm
o Intake valving actuation problem
• trouble getting to redline
o Ignition failure
o front O2 sensor failure
o catalytic converter clog
o air filter clog
o e-shaft sensor fouled
o fuel pressure loss
o MAF failure

I will begin with checking exhaust. The resonators are hanging low and scraping on speed bumps and it has been dented. I also suspect it may have have collapsed causing restriction.

Its a new rebuild so I will assess if its not resolved

I'd start with a simple compression test to see what the max psi is in each rotor housing.

What ignition dwell settings are you using?