I would like to know how the following turbos compare in size to say a GT4202 T4 1.28, mainly on overall length and the dia of the turbine housing. This turbo would be on a 355ci V8 revving to 6500-7000rpm Max.

- S400 80mm with 83mm Turbine wheel and T4 Turbine Housing (Same as ST80?)
-PT8047 with T4 Turbine (is the std PT88 Same length?) This turbo appears to be using GT4708 Wheels ?

- GT-80 with T4 Turbine

I'm currently running a Garrett T51R 76mm Comp wheel with 1.22ar T4 exhaust, the turbine wheel is a bit smaller than a GT4202. I have run 9.14 at 149mph at 3400lb, but back pressure is killing th power on pump fuel. So i want to step up to something that with make a little more power, free up the exhaust but not loose too much spool. But i am very room limited, so i need something not too big either. The T51R is probably the size of a PT76GTS.

 

I can tell you are looking for the 'sleeper' turbo... so I would stay away from the borgs in that case. It is a bit hard to run a big borg turbo and keep the cover small and sleeper looking... although they may have come out with some 400 frame covers that appear to look like 300 frame covers.

the PT should be a good little turbo, but will for sure be limited by the T4 housing. Would be a good time to consider the advantages of going T6.

Due to the fact I dont like garrett exhaust wheel design, I would say that if you are dead set on T4, I would go borg for max power, as I believe they have the best flowing/spooling T4 exhaust sides on the market right now, and garrett wheels are among the worst.

 

I can fit a big comp cover like a S400/GT42, just don't have the room for a T6 Turbine, plus i would have to re do the piping, i'm not chasing a huge amount more power, just want to free up the exhaust a bit pre turbine.

 

 

Go borg then... You should gain a bit of power, and you might even pick up spool going to a giant T4 setup.

 

The exhaust wheel from the GT47 Garrett (92.7mm) must flow heaps better than the little 83mm in the T4 Borg Warner S400's, just interested to see what effect the big wheel would have on spool up ?