I know, I know.. what do you want from such a weeny turbo right? https://www.nopistons.com/forums/pub...#>/biggrin.png Right now the turbo is straight as it comes from HKS, .84 Ptrim - .60 57trim. To be honest I love this setup, it is very fun to drive on the street especially in LA where first and second gear are actually useful. But when the road does open up I can literally picture the power curve in my head, and feel it flatten out around 5500rpm and stay there. Would bumping up the compressor side to a 60trim and a .70 housing do much for me on the top end?



Matt

You would want to bump up the exhaust side to a .96/1.00. The compressor side won't effect it that much. Upgrading to 1.0 is going to give you a nice punch on top end and you won't suffer from much lag either.

Three of us have three different setups.I had TO4 non-ported, Mark had T66,Fast Freddy had stock twins non sequentail. My TO4 is a cartech .81 "P" Trim while mark's is .96. Both Freddy and I get it on much faster than Mark due to spool up sooner and he Mark)has the new ballbearing turbo. Based on the many runs we do as a group Freddyand I are thinking about two smaller turbos producing the same volume as a larger turbo...maybe a T88 but it would spool up so much sooner so the power and torque is really in driving RPM.

Mark dyno'd at ARI's RX7.Com and had 420 at the wheels at 16lbs. Its fast but it comes on around hard at 5,000.Shift,5,000,shift.

As of today mark has sent ot Back to tubonetics to get the housing changed to a .81 but keeping the compressor side as is.

Just out of curiosity, what does Mark rev to,and is his motor ported?

Cool I think I'll give that option a shot, very easy for me to swap the exhaust housings. In studying the compressor maps for a TO4 57 vs 60 the 60 clearly flows a little more air with better efficiency at like boost levels.. maybe I'll explore that option when I need a rebuild/streetport.