Quote:
Originally Posted by cgeise
I have never run the car on the dyno with no booste - but I know it will run mid to high 9s with out the turbos working - dont ask how I know - the back pressure starts to creap up into the 2 to 1 range when it goes over 24- to 25 psi - and yes - the bigger turbos seam to have a better - more efficient turbine housing - but the whole turbo is so big it would take a major rework to make them fit -
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So If I read your reply correctly, you are saying that you have 24 psi of boost pressure in the Intake and 50 psi of exhaust pressure in the turbine housing inlet. Correct?
So how are you reading that pressure? A 3 BAR sensor can only read accurately to 43.5 PSI (1 bar is atmosphere - 2 additional BAR would be 43.5 psi. So how is that 2 to 1?
Last time I looked 24-25 psi at 2 to 1 was 48-50 psi of pressure.
Need a lot more actual info/ data. How you read the numbers, what instrumentation, etc.
Quote:
Originally Posted by taff2
Couldn't you bypass some of that backpressure through the wastegates? Back in the day,turbo drag racers used to use small turbine housings for quick boost response and then run a lot of the exhaust gases through the 'gates.
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That trick is still being done today Taff, except that the exhaust pressure acting on the turbine wheel(s) need to be high enough to support the horsepower required to drive the compressor wheel(s) at max boost.
A Guy named Danny Jones, who was the Indy Car Turbo Guy for Ford many years ago, told me you would like to be close on the intake and exhaust pressures at max boost with the waste gates open. You confirm this with pressure taps/ gages on the compressor and turbine flow paths.
Tom Vaught