Twin Turbo Upgrade time, I need sizeing help.

[QuadCamSix]

Heres the problem. Im currently running twin TDO4-HL turbochargers on my 5VZ-FETT. While the compressors flow enough for the power I want to make the turbine housing is WAY too small. The turbos move serious air at idel!!!! (Think of a hair dryer at full blast) With the wastegates closed the car falls on its face around 5k rpm's With them open the car pulls better and the turbos still spool!!! That means the turbine housing AND wastegate port are both whoefuly small.

I built the system to be scailed up for more boost so I have a choice in the new turbochargers. I can move up to a pair of TDO5 turbos or even the TDO6's but I dont want to overdo it because the low redline on this motor may make the turbos available power range unuseable.
Here are the stats:
Semi log manifolds each feeding from 1 bank of the V6
Total dissplacement of the engine is 3.4L
Compression ratio 9.6:1
Redline 6800

Any help on calculating the actuall flow requirements per bank would be appriciated.

Jim

[quigon]

Wouldnt ct26s do the job ? I dont think they would spool at idle

[QuadCamSix]

Originally Posted by quigon

Wouldnt ct26s do the job ? I dont think they would spool at idle

With the MR2 housings they probably would however those turbos are realatively large for the power they make. I chose the mitsubisi turbochargers because the flanges are all the same and can be easily swapped out. I would love to have all toyota parts in there but I just dont think there is enough room.

[bgrieger]

TD05's will be too large for you. On 3L motors, they really don't even start to hit the sweet spot until after 4500RPM, and on the high revving nissan and mitsubishi 3L motors come into their own up in the 7000-8000 RPM range. Are there other turbine options available to you for the TD04? Perhaps external wastegated models have more to offer, but your manifolds become an issue to go that route...

[QuadCamSix]

True the TDo5's are a bit larger but the static compression ratio of this motor is 9.6:1. That translates to a lot of exhaust gasses vs the DSM motors with compression ratios in the 7's

BTW im talking about the TDO5 14B mitsubishi turbo not the T-O5 big mamma jamma, also im considering the TDO6 16G for each manifold but im having some trouble calculating the flow i will need and most maps are for compressor flow not turbine flow. The motor is choked off badly, I have never seen a turbo spooling at idle like this, supposedly the 13G turbos im using flow to around 220hp per unit but the internal wastegates cannot support the amount of exhaust flow and no ammount of turbine clipping will solve this either.

Basically I need a list of the turbine flow limitations for a bunch of different turbines and housings. That way, if i have to build new manifolds I will know bassed on my projected horsepower and V.E. what turbines will match the motor best. Compressor flow maps are well documented so choosing a specific trim wont really be a problem, im just trying to find exactly the right size turbine and housing for my application.