black-sinner

So my pt88 seized up after being installed new and with about 10 dyno pulls and 4 highways pulls... Sent it to PTE and they claim it's a BP issue....!!!
Made 904whp/840wtq @18psi with clutch slipping, graph shoots up after 3700rpm and level then drops a little at 6000rpm

It's a t4 .96 a/r turbine... I haven't measured bp but i thought lots of guys are using this setup on their 370s ...
Has anyone experienced bp issues with it?

Old Geezer

iTrader: (3)

How about some details as to how the hot side, and the exh is laid out, engine specs, etc.

Hank Peabody

iTrader: (2)

I have a 6.0 with a PT7675 running max 15psi a little over 6000rpm, I should have alot more back pressure than you, my turbine is alot smaller.

stock48

iTrader: (17)

Ran a PT88/T4 on my old 370 at 20~22 psi with no problems. Twisted ~6800 rpm thru traps. What size oil line are you running?

LosLs1's

iTrader: (21)

@stock48 how what numbers did you make with that set up?? I also have a turbonetics 88mm mid-frame setup coming soon...

black-sinner

Truck manifold d.side+ custom manifold p side, 2.5" pipes to a t4 flang,then 4" down pipe through the bumper ... Engine is a 370ci , l92 heads and tu1 cam..

black-sinner

What does your dyno graph look like?

black-sinner

Did you measure BP? Is the power falling off after 6000rpm? Why is pte saying that i have a BP issue?

L92 fox

iTrader: (2)

I have seen a lot of people run a pt88 with a 364-370 ci motor. Mightymouse went deep into the 8s with his. Something else must have happened.

Great numbers btw, my lsa headed 370 with a modified pt88 will be up and running this week. Gives me hope for some good numbers

Atomic

iTrader: (37)

Probably close to 2:1 at that level, which is not enough to damage the turbo, IMO.

black-sinner

Thanks, need to get a clutch that could handle the power and not kill my leg...

stock48

iTrader: (17)

Never ran it on the dyno went 9.6 and 145 mph with a smoked trans with that combo. Current combo in sig has been 9.73/139.xx at 22~23 psi, and dynoed 906 sae RWHP@20 psi so prob 1030~1050 or so with pt88.

What inside turbo failed? I never checked back psi but It couldn't have been too low lol My cam was only 215@.050 so power pk is early but power never fell off. Shifted at 6k and hit traps at ~6800. Also ran thru 3.5'' muffler. The GT91's have same turbine and housing if in T4. The tc78/68's have tons of back psi and seem to live. I would guess there was a oil issue, or problem with turbo.

black-sinner

-4 oil feed going in and -6 going out , PTE. Said the backing plate was damaged due to excessive BP

Nitroused383

iTrader: (10)

Found your problem, get a -10 on there and make sure it's draining properly (no kinks and a straight down hill path).

black-sinner

If there was a drainage issue wouldn't the turbo smoke?

stock48

iTrader: (17)

-6 is too small for drain but yea I would think it would smoke.. Was thrust knocked out, or journal bearings? I don't see how backing plate could be damaged from back pressure. The thrust bearings on those are really temperamental, if bov is too small, or air filter is restrictive the thrust can go out.

black-sinner

Bov is a procharger Q trim unit and i run a metal mesh infront, pte said nothing about thrust or journal bearings upon inspection, and i suspect power drop up top is more due to clutch slipping than BP... I've seen the exact same turbo be used with 383ci engine making 950+whp @ 19-20psi with a clean graph up to 7k rpm....

My question is has any one faced BP issues with the PT88?

9sectruck

iTrader: (9)

I had mesh on my pt88 and gained 5psi when it was removed nothing else was changed besides the mesh being removed.
I would say it created suction on the impeller which in return looks like alot of back pressure pushing on the turbine.

black-sinner

WTF!! If mesh can do that then how do you keep crap out of your turbo?! Then i guess an air filter would be even worse?!

RedRocketZ28

iTrader: (19)

Everything I have seen indicates that mesh is worse for flow than an air filter.