Power loss at 8000rpm
 

I have a 2004 6 port built by Pettit, racing beat intake, exhaust and test pipe. runs great, starts great, and pulls hard, but falls flat on it's face / chokes out at around 8000rpm. Other people, who know much more about rotary than I, have suggested it may be the 5th/6th ports not opening, but I can't seem to find much info about this issue in the renesis motor. Any suggestions?

Do you have a check engine light at all?
There is a set of runners that opens at 7650 or so. This valve is called VDI and if the solenoid has failed, you could have such symptoms.

The only CELI have is P0420 because of the test pipe. Although it has thrown an air pump CEL before.

Here is some useful information about the S-DAIS system.
https://www.rx8club.com/rx-8-discuss...7/#post2303941

The car falling on its face at high RPM could be related to port opening, ignition components, failing catalytic converter...

As I recall the VDI solenoid code is manufacturer-specific, so a generic OBD scanner may not be picking it up.

good to know, thank you! But wouldn't it still throw a CEL?

Yes, but if you already have the CEL for your test pipe, you wouldn't know if there were others. If your code reader can't read manufacturer specific codes, it wouldn't show you that those other codes were present. I suppose you could clear the testpipe code, and see if the CEL goes out. If it doesn't, you have another code.

The other thing you could try is swap the SSV and VDI solenoids around, and see if the car chokes around 4000 rpm instead of 8000.

I know that DashCommand with the 2005 Mazda add-on can read MFR specific codes via a Kiwi3 (probably other ELM327 interfaces). Dunno, about any others.

Try replacing your air filter if you haven't done so in awhile. This happened to my 2007, sounded like it was dying 7500+ rpm. As soon as I replaced my air filter cartridge it ran perfectly again. A closer look at the cartridge and it was clogged with a thick layer of grease and dirt.

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