Originally Posted by cjg454ss

arguments? I call them constructive conversation:d

Originally Posted by cjg454ss

yea the pt88 would be laggy. here is why, its going on a truck. the turbo was intended for grandnation v6s(according to precision), leaving on a transbreak and 2 step. much different than a street truck.

when you see a dyno pull with the torque higher than the horsepower...you know the turbo was choking. an example was with my pt88, i make 800rwhp and 820rwtq. thats a T4 flange on 22psi. on a t6 S91, 988rwhp, 850rwtq on 17psi.

if turbos have low backpressure they will really start to shine uptop. a choked turbo will go flat. my setup went flat and the new setup pulls an extra 200hp. thats a lot more power for only 3mm more tubine and less boost.

additionaly, the physical size of the pt88 is little compared to a t6 S series turbo. personally i went through 3 pt88s and wouldnt put another on my lawnmower. there are much better turbos to chose from, a T6 S76 will blow a t4 pt88 out of the water, but some people just want to say "its an 88mm"

Originally Posted by Atomic

Where did you find a compressor map for the PT88? I never could find one.

Originally Posted by DoubleTrouble

forcedinductions.com

Go down to the left tab that says, "Turbos, Turbo Selection 101"

Originally Posted by JimS

Thanks for that.

Originally Posted by DoubleTrouble

Thanks that makes sense now that you explained why. But I have a question about your dyno pulls.

Which turbo had more power under the curve and not just peak power? Do you have any dyno graphs to post?

Originally Posted by cjg454ss

i have some graphs ill dig up. the pt88 was slow to spool on my 365cu. a 76gts would of been just as fast if not faster.

my s91 400cu spools at 3500, full boost by 4500. entirely different animal. power goes up and never falls to 7200rpm.

here is a video of the spool

this was a z06 making 760-780rwhp. he got the first move and is supercharged. your tune can help a little with spool also.
additionally i was 12psi of boost.

http://www.youtube.com/watch?v=Il6u2vAgCFQ


personally the pt88 is a poor turbo for out ls1. personally id would do a 76gts, it will make 750rwhp. if you want to go higher than that, get a T6 80mm, on these trucks you would never need anything bigger unless you want to put 1100+ hp to the ground.

Originally Posted by cjg454ss

thats kinda funny because 2 years about i had a pt88 on a 365cu ls1 and i kept breaking the journal bearing and precision said that the turbo was seeing excessive backpressure and that i needed a larger hot side for the cube motor. it was nothing crazy either, stock 317 heads and 20psi of boost reving to 6500rpm of so.

precision said the pt88 was built for the grand national guys for a particular class. it likes less cubes and the hot side a/r is limited to .96 i believe.

Originally Posted by stock48

Wow I wonder how much the PT88/T4 is holding me back.