I think that we can all basically agree on the benefits of the pulsed TS concept in theory. No one is arguing about the improvements in spool offered by a TS housing vs an open housing.

I tend to agree with you in general terms that a TS configuration might be advantageous in certain competition scenarios as well, given the right combination of track layout, driving style, driver experience, and engine displacement in an Evo platform.

At the same time, it is a generally held view that the MHI turbine housing castings, in spite of offering relatively fast spool (i.e. 9.0, 9.8, 10.5 single puck & 10.5 dual puck) are restrictive, high back pressure, inadequate bypass flow designs. These deficiencies are accentuated on increased displacement track Evos.

The F.P. non-divided housing attempts to address the drawbacks and compromises in the MHI castings whose deficiencies to a considerable extent suffer due to the very nature of the beast. I wouldn't recommend a standard MHI turbine housing casting for an increased displacement Evo(2.3L, or 2.4L) mill used for Time Attack or road racing. You differ on this issue apparently.

 

Has anyone maxed out a 8374 ts .94 t4 on a 2L car yet? Kinda curious how it compares to the turbos in this thread.

 

Another fun fact.
BBK-B Inducer size of compressor is 57mm.
ATP GTX3076R Inducer size of compressor is 58mm.

BBK-B Turbine wheel diam is 56mm. <--not 100% this number is correct.
GTX3076R Turbine wheel diam is 60mm.

BBK-B is 57lb/min wheel
GTX3076R is 63lb/min wheel

 

I like the .92 integrally gated TS T4 housing for an 8374 on a 2L displacement motor. For a competition driven stroker, I like the 1.05 externally gated, T4 TS housing. Nice turbo.

 

Might be a bit late, however just backing Razor's comments, the ATP rear Garrett turbos are the last place I would look at for a track car.
Just looking at it screams 'heat and backpressure' at the boost level you're going to have to run to be happy.

It has to be either a T3 frame Garrett kit or a EFR IMO.

 

I guess I am gonna have to save up $5500 for that BW EFR 7670 for next year...

 

Y no 8374?

 

because that is way too big for my uses.

 

Trust me - its not too big. The 8374 on a 2.3L has better transient response than a 3B on a 2.0L, and if you want low exhaust back pressure, a big turbo is the way to do it.

 

R/T Ernie is running an 8374/1.05 on a destroked 4G64 for road course duty, isn't he? Or maybe I am mistaken.

 

He has a 8374 that will be replacing the 7670 he currently has in the car.

 

I think RT has something in his setup that is holding it back. should have spooled faster and made more power. but I do think either the 7670 or 8374 in the 94 t4 housing is the hot ticket for time attack. look at geoffs 8374 numbers on 2.0. imagine larger displacement.
https://www.evolutionm.net/forums/ev...vs-7670-a.html

 

I agree with you '94 that the 250(minimum)RPM loss in spool on the FP housing is pretty lame. In fact, I am depressed because my 3B has the ported anti-surge compressor cover and that reputedly robs another couple hundred RPM in spool.

I am either gonna order a stock MHI comp cover from CBRD cut for the BBK wheel(damn the surge!), or I'll weld up(fill) the surge ports and retaper the compressor inlet area removing the step down transition making it conical internally.

 

you can fill the ports with jb weld. plenty strong for the application. and can be burned back out if you wanted to reverse what you did.

 

Yup, thanks, JB Weld it is