ATP GTX3076R vs CBRD BBK-B BB
#106
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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.
Last edited by sparky; Apr 10, 2014 at 09:21 AM.
#108
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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
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
#109
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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.
Last edited by sparky; Apr 10, 2014 at 11:04 AM.
#110
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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.
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.
#117
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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
https://www.evolutionm.net/forums/ev...vs-7670-a.html
#118
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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.
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.