What is the exhaust A/R on this turbo. I'm scared to see what the BP is going to be on my PT88 with the .96 ar. I am sure its gonna be as bad if not worse. This is a great write up by the way thanks.

 

Whats the turbine size on that pt88?

 

Mine is a .96, but I'm sure that pt88 has something near 80 or larger on the exducer turbine side. You should be fine unless your north of 400 cubes.

 

Well that dose help to explane the "law of deminninshing returns" To some.... It's truly a hard concept to grasp.

But I have to say I dont think you have enough air fresheners.

 

Looking for the specs, cant find them. na its just a 370 10:1 compression.
Should be getting tuned on the 25th of next month.

 

Well knowing that, I guess it is safe to say that these turbos are OK. Definitely not GREAT. Atleast they are good for anyone who isnt wanting to run a great amount of boost pressure. Like you said, seems the magical number with these will be no more than 14-18psi depending on exact engine setup.

Great info and thanks for taking the time to do it for everyone's benefit

 

Cool test Foose. Thanks for posting it. So were you saying oem's like to keep backpressure at 2.5-3:1 for driveability? Less backpressure produces more power but hurts driveability?

 

PT88 has a 94mm turbine inducer IIRC.

 

Good test!
What where your test port locations?

 

I was gonna ask the same question.

Edit: i see that's a pic of the crossover tube.

What about just before the T4 flange?

Don't forget, you're also trying to push all that pressure from one side of the engine to the other, then thru just one log.
The old GN's were this way, there is an upgrade for those cars; it allows both sides to transition into a y pipe design, merging just before or at the T4 flange; which helps lower back pressure.