I posted this here because it seems that 90% of people running a turbo are also EFI'd.

Let me set the stage:
We run an IH 1066 diesel pulling-tractor, stroked, bored, ported, cam, ect. (It's fun)
But there's a big stroker Ford that keeps out-dragging us. So we started playing with the turbo's exhaust-housing.

(Disclaimer-Previous information simply puts forth the situation that brought the question to my mind; any use of it to label the post as "bad content" is a complete misuse of the information.

I was doing a search here at the .org site, and ran across a statement the the exhaust housing of a turbo: "can see 45 psi, while the intake only sees 15 psi"
My understanding is that you want the pressure between the exhaust and intake housings to be as equal as possible. Correct?
I know that a great difference between pressures will make a turbo come apart. ( I know for a fact.... )
We had ours to about a 12 lb difference,...wasn't satisfied. A new housing later, it's down to about a 5 lb difference. Is this correct thinking behind the subject, that you want a nice, close pressure range between the two?

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225 Cubic Inches of Iron-Head American Muscle

225 bored .040 /.100 off block, Schneider Cam 224@.050~ .480 lift - Stock valves, blended bowls, Offenhauser intake with 500 Edelbrock carb

Most street cars/trucks, etc will run more turbine inlet pressure (exhaust backpressure) than boost pressure as they sacrifice a lot of power for low end response and mid-range. Lowering the turbine inlet pressure will increase power as there is less negative work being done pumping out the exhaust. Generally speaking this requires a larger turbine housing and will cost you low speed boost. If you can run more boost than turbine inlet pressure you can scavenge the combustion chamber really well and make a lot more power. If you can run a trick new variable geometry turbine you can have both response and top end power. http://www.holset.co.uk/files/2_5_1_5-VGT.php

I would not try to equalize your TIP and boost. If you run too large a turbine housing you may kill off boost and end up going slower.

Did the tractor do better or worse with the larger turbine housing?

Don't loose sight of the goal. If the change didn't make the competition vehicle faster or more reliable it wasn't a good change.

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Joshua

Thanks for the info! I guess we'll keep playing with housings, a VGT would be nice, but $$$!
The tractor has done better the closer we have gotten the pressure.
Remember though, Low-end is least important here, because it's full throttle right from the start(to get the wheels spinning). Were running about 60 lbs boost under full load. And only turning 2999 rpm. (Piping junctions use steel straps to stay together.)
Thanks again!

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225 Cubic Inches of Iron-Head American Muscle

225 bored .040 /.100 off block, Schneider Cam 224@.050~ .480 lift - Stock valves, blended bowls, Offenhauser intake with 500 Edelbrock carb