Twin Turbo Setup

[Lextreme II]

Hey Gang,

While i am gathering forged internal parts for my future project. I am thinking about putting a set of either Garrett GT28R or GT30R in the position of A/C Compressor and the Alternator position. The power steering pump will be eliminated and relocate the alternator in the space. Therefore, there will be two nice size slot available. I was thinking to make the twin sits in there.

The turbos will sit in the position of north to south. The compressor will be facing the front of the car and turbine will be oppisite.

The drawback is no ac and no ps. However, the turbos will have great spooling due to the proximity from the exhaust and the compactness.

Secondly, from this design i would run it without wastegates and boost will be control by a wastegate located in the inlet pipe. What do u think of the whole system?

 

[acmtt]

Would you run both compressor outlets into one FMIC inlet, or run the split intercooler with opposeing outlets?
Twin GT28's MMMM tasty!

 

[mycarhasposessedme]

Forget the inlet pipe relief valve and use internal wastegates.
One of the best benefits of twin is that 2 small internal gates can cope easily, otherwise you will be spooling the turbos up past their efficiency range and gennerating to much heat. This is exactly why exhaust wastegates were invented. Other than that it sounds great.
P.S What are you going to do without PS pump, maybe convert to a manual rack?

 

[JBrady]

David, I agree with MCHPM, run internal wastegates, no wastegate is a major loss of efficiency. I am allways impressed with your ambition and persistance to build these systems but you do understand that very few will want to eliminate A/C let alone power steering.

Be less concerned with placing the turbos close to the ports and more concerned with maximizing the manifold shape and size as that will contribute to spooling.

Another very cool consideration would be to source a pair of VNT turbos.

You have also abandoned low mounting due to oil control but this CAN be dealt with and leaves a very good turbo location available.

 

[JustenGT8]

Definitely run a wastegate of some fashion as boost control using a relief valve is very very inefficient and also quite difficult to control well.

You seriously want to check what style rack you have as no PS can = imminent death. I think (but i am not sure) that the toyota racks of your vintage don't use a solid shaft but smaller shaft that controls the racks hydraulic valves. This shaft isn't very strong as it only needs to control the valves which then handle the steering pressure....it can snap if used without the PS pump!!! leaving you with no steering.



Subaru racks use this design as i found out on my setup in the GT4 Celica and i quickly installed the PS pump.