Cxracing turbo problem
 

I have a Cxracing turbo kit (t3 6063) on my brz rated for 8 psi, when I went to go get it tuned it was only pushing 6.6 psi boost. I asked the tuner why and he said it has to do with the elevation here in utah and that the turbo can make that power, just not on the fa20. But I think it has to do with wastgate. Can someone help?

Yes, your wastegate spring rate could be set low and be bleeding off any excess pressure greater than 6.6lbs. Whether yours is doing that, without a video and documentation, I can't answer that. If you are reading a pressure (boost) gauge from inside the cabin of the car, it could be leaking out some pressure (air) before it gets to the gauge, causing the gauge to read low.

With that being said, at higher altitude, the air is thinner and it takes more pressure (more boost) to make the same amount of power. So, it may be possible that the turbo kit can flow 8 psi at high elevation, but it will be making less power than it would be if it would flowing 8psi at sea level where are is more dense

I just noticed when i get on the gas you can hear exhaust coming out the dump pipe. It does that From 4000-7000 rpms the reason I was wondering if it was my engine being able to make that power or not, is because I was planning getting a boost controller instead and boosting it to 12 psi. Is that possible for my turbo setup?

I have no idea. sorry. I'm not familiar with cxracing or the kit you have, or what turbo it is.

Who did you get it from? Have you contacted the manufacturer?

If your tuner did not set boost to 12 psi, there is likely a reason for that.

I don't know much about turbo issues but 8 psi is 8 psi right? I don't see that changing at higher altitude. I thought that was why turbo cars fair well in altitude.

Boost is not power. It results in power. How does what engine it is on effect how much boost it can make? If the turbo is rated at 8 PSI how are you going to get 12 out of it?

Sorry I meant the external wastgate is set to that.

I had the cxracing kit before I scrapped it and fixed it. I ran 10 psi without issue. But I swapped to a tial gate with a 10 psi spring. I'm willing to bet the stock on needs a controller to hit 8.

Maybe the wastegate spring is inaccurate?

Boost leak. Elevation won't matter at all on a turbo unless it was at the very end of it's compressor map. 8psi is 8psi at sea level or mountain top (though you'll get more lag), that's why they used turbos on piston driven aircraft...and then moved to jets that are basically turbos that are combusting fuel themselves, but I digress... The wastegate doesn't open all at once, so you'll hear it before you hit max boost, so that's normal.

Also, CXRacing has a bad reputation for subpar parts... So it wouldn't surprise me if the wastegate spring was weak or there were leak sources.

OK the way you said it confused the hell outta me. I looked it up and if you have the turbo I think you do it's operating pressure is 20psi. You should be able to get 12 out of it with some work. I wouldn't recommend it though since you are starting to play with fire at that sort of boost on a budget turbo. The less expensive kits such as this are fine for what they are but you can't expect top level performance for a rock bottom price.
I will throw in with Poodles that you likely have a leak or weak spring.