czwalga00gt

iTrader: (3)

Just for fun, who wants to guess my backpressure. I'll be testing it tonight.

My dyno flatlines at 4500 rpms at around 550rwhp. I thought I bought at turbo with a .96 housing. Later I found out that my housing was .81


Parts:

Built LS2
Ported Heads
Turbo Cam
T76 @ 15 psi
.81 Housing
Front mount


I'm going with 51 psi.

qqwqeqwrqwqtq

I'll go with 44psi

TracyRR

iTrader: (8)

I say 48#.... Good luck

SincalT/A

iTrader: (16)

What size is the wastegate?

Where in the system you gonna measure from?

czwalga00gt

iTrader: (3)

I have two 38mm wastegates. It's measured in the one bank about a foot from the header collector. I have an extra o2 bung there.

czwalga00gt

iTrader: (3)

Welp, you guys were close I overshot. 43 psi.

I only ran out 2nd gear though, not sure if it would be more in 3rd/4th with a longer sustained load. Wonder how much power i'm losing because of it.

Phil99vette

iTrader: (11)

So at 15psi your seeing 43psi of backpressure? *****! 1:1 is awesome, 2:1 is good, 3:1 is a power robber

czwalga00gt

iTrader: (3)

Yep, well after the dyno i did more research and my turbo wasn't what I thought it was. After I found the .81 AR ratio I had a good feeling it was my problem.

Phil99vette

iTrader: (11)

Whats behind the .81, dual or single wastegates, dumped to the atmosphere? What size downpipe?

czwalga00gt

iTrader: (3)

Duals dumped to atmostphere, 3" DP for about 3 feet then it goes to 3.5"

Tiago

iTrader: (27)

you need bigger than a 0.96 I would say 1.08 would be a nice compromise...

DrTurbo

iTrader: (3)

What turbine wheel???

czwalga00gt

iTrader: (3)

F1-68? I think. Can you maybe PM me with what I need to buy. I was going to email you guys here in a little after I figure that out.


Definatly looking for a 1.08/1.15 ratio depending on what is available.



Heres my description for the turbo I have:

60SE-SB-H76-D-D-68-OCO_81

mike13

iTrader: (27)

That sounds familiar, my motor did the same thing with a .96a/r on a TC76, I ended up stepping up to a ST80
383 (stroked ls)
ported heads, cam

DrTurbo

iTrader: (3)

ST80 will do it, also you can go with some other units. Just give us a shout....we can narrow the choices down.

czwalga00gt

iTrader: (3)

I'm not looking for another turbo... just a housing. I dont have any room to add anything bigger. The turbo sits millimeters away from the crank and radiator.


I'm leaving for vegas tonight, so let me know what you think and ill get back to you next week.

350SS

iTrader: (38)

Are you using a mecahnical or electrical gauge to measure? Datalogging or just watching the gauge?

Gabbiani

iTrader: (20)

Space is limited but that 3" isn't helping either. I think my mp70 was more like 4:1.

DrTurbo

iTrader: (3)

The MP units will be well into the 4:1 ratios as the turbine wheels in their 70 and their 76 flow much less.

DrTurbo

iTrader: (3)

Ok...just let us know.