Compressor Cover ID

[Freebaggin]

For a while I've had a the following turbo:

- CHRA GT30/40 (61/82mm "600HP" comp wheel and 60/55mm exhaust)

- Machined out 0.60A/R comp cover (don't know which type, as in T04E etc etc)

- 0.63A/R "Cosworth" internal gate turbine housing

I'd like help with identifying my comp cover (pic attached). Thanks in advance.

[discopotato03]

Its a T04B probably .60 ARR compressor cover . Way way too small for a GT40 compressor wheel . I'd like to see the "Cosworth .63 AR "Turbine housing . If its off the TA34 (wrongly called T3/T04E hybrid , a phrase coined by turbonetics) fitted std to the RS500 sierra , it can't work properly . The TA34 turbines had much less tip height than GT BB anything . If it was re-profiled (the turbine housing ) it is now junk . Why anyone would want to use these housings on a GT3040R CHRA is beyond me .

Firstly the GT3040R is not an ideal match .

Secondly the GARRETT integral gate exhaust housing kills the efficiency of the UHP GT30 turbine , leading to excessive turbine inlet or back pressure .

Thirdly the T04B compressor cover kills the efficiency and chokes to death the GT40 compressor .

You must remember that Area to Radius Ratios (ARR's) for turbine and compressor housings is worked out based on the original (native) wheels diameter . GT40 compressor wheels (82 or 88mm) generally use T04S comp covers which are huge compared to T04B's .

The individual who built that turbo has little idea or respect for how turbochargers work . Smaller GT30R's with the correct housings could make more power and have far better transient response than that thing .

Also note that the RS500 Sierras were a dog on the road and track , they had all or nothing power delivery and plenty of cheat components . For starters the turbine housings were extrude honed which enlarged the volute and ARR ratio . There were some illegal (larger) turbine housings as well . In a vain effort to chase RB26DETT power they were allowed external gates to control boost . No way the integral could bypass enough gass to allow 500hp from 2L (122 Cu in .) .

Do not attempt to emulate this turbo as a well set up GT30R is better all round .

The TA34's were the end of the road for bush bearing turbos , the GT's eat them .

[Freebaggin]

Apart from that you think it's great..... Seriously, thanks for the input.

Photo of turbine end attached. I had the dodgy looking turbine back plate machined flush so that at least the turbine and wastegate flow was unrestricted.