Pettit says their upgraded ceramic coated stock turbos flows 15-20% more than stock. Has anyone seen this verified? If true which aftermarket turbo's would they be comparable to?

 

Some people say they are great, some people say they are worthless.

Here's a recent dyno with them:

https://www.rx7club.com/showthread.p...hreadid=268948

 

Spool-up is noticably faster. Maximum power output is probably limited by factors other than the turbos, since internal dimensions are nearly identical to stock and turbo fins are same as stock. Main advantage is the ceramic coating to minimize hot spots and limit cracks in the housing due to heat stress/contraction/expansion. I would probably go with M2 Garrett design if I were to replace again with a sequential twin - assuming M2 can get the order filled in a timely manner. My $0.02
Ron A.