I have this problem. My A/R is a .70 on a P trim. The turbo is a T04s at the time. I have a 60mm wastegate, a nicely built manifold which I am sure is not restricting at the time and an E-boost. It seems as no matter what I do to the E-boost, boost falls off with RPM. I can even get a spike to 20 messing with the sensitivity and boost setting and it still falls off to 11psi by redline. I have 10-11psi springs in it. The solenoid is connected to allow it to control both ports which means the spring shouldn't really matter.

Any ideas??

Its driving me mad, the power curve feels like a V8....

Thanks,

Chris

 

If its a rotary the AR is far to small and you are over spinning the turbo making it cut air instead of compressing it. Its pretty much running out of breath.

 

I see. I though that might be happening. I have a precision PT71mm GTQ turbo with a .96 A/R coming to me soon. This should take care of it. And yes it is a rotary.

Where in MN are u located? I live in Plymouth,MN even though my location says PR.

Anyone else have input?

Thanks,

Chris

 

I am down in Hastings. If you have porting you may still want to have a bigger AR I would want about a 1.06 or so. Some turbo gurru's will be able to tell you exaclly what you need with some details on your turbo.

 

The car is ported but its probably the equivalent of a medium street port on a REW, there isn't much to port on the RX-8 without breaking into the water jacket. I originally wanted a 1.06-1.15 on a P-trim but the turbo I bought is a Q-trim so I went with .96 to help out on the street where I drive the car the most. Hopefully it makes a difference....it might also be the boost controller....I will recheck all the hose connections but I am 99% sure everything is connected properly without boost/vacuum leaks. I might not know what I am doing programming it but I have followed the manual to the dot...how hard can it be to program 3 settings on a boost controller after I've redone the entire car?

do you have a rotary?

Chris

 

Yeah its quite possible its choking flow a bit. You can always just swap turbine housings and see what happens....if there's a flex joint in your down pipe more then likely you can swap in a larger one without any other changes.