SPRAYED 01

iTrader: (22)

Had the car on the dyno at speed inc today. With the boost controller at 80% duty (aem truboost) and an 11psi spring we are only getting 11psi. Just off the spring is about 7.5psi.

This is a forged 370 with stock intake and ported 241 heads,232/236 cam. Comp ball bearing,80/79 turbo with 1.32 ar and 3.5dp that goes to 3 then cutout.

Could this be back pressure, problem with controller?

Alex

SPRAYED 01

iTrader: (22)

Made about 600whp lock verter at 11psi. Thought that was kinda low for that turbo.

98Z28CobraKiller

iTrader: (17)

Torn diaphragm in wastegate

code4

iTrader: (30)

Wouldn't that give him more boost? I guess it depends on how his contoller is hooked up.

What did speed inc say? I would have had them try to trouble shoot it while there.

mike13

iTrader: (27)

From my own experience the duty cycle is deceiving, it might be at 80% but at 83% you might gain 2lb's. On my AEM I don't see a single lb of boost above the spring pressure until 70+ duty cycle

dudeman

iTrader: (43)

where is your boost/vac source for the boost solenoid? there isnt a check valve in your vacuum line anywhere is there?

eviltwin_1987

iTrader: (18)

What wastegate? What tranny?

MawneeC5

iTrader: (12)

I had a similar experience with the Tru Boost. Duty cucle seemed to give me about half that percent in boost percent increase(80% gave me 40% more boost) The controller worked fine, but the value wasnt a direct indicator.

SPRAYED 01

iTrader: (22)

Tial 38mm, flt level 7 65e with vig 3600 3 disc. No check valve, referenced from intake

dudeman

iTrader: (43)

what about a boost leak? check all of your connections and couplers. make sure they arent torn.

Slowhawk

iTrader: (12)

What catches me is the 7lbs on the 11lb spring. How is the controller hooked up?

mike13

iTrader: (27)

could be back pressure, also I wouldn't take anything for granted and would put low pressure and measure at what psi the valve opens. Could be as simple as a spring.

SPRAYED 01

iTrader: (22)

I've checked for leaks, could not find any. Is there any chance with a 1.32 going to a 3.5 dp but about 2 feet later going to 3 inch cause to much back pressure and stop it dead on making boost?

code4

iTrader: (30)

Although it is not an optimal set up I do not believe it would be the cause. I think you keep looking at the turbo as the problem but I think it is something else unless the turbo has damaged bearings.

rotary1307cc

iTrader: (5)

Something is goofy, that turbo should put the power down

eviltwin_1987

iTrader: (18)

If the vaccum lines on the controller are hooked up backwards, you will have these problems

compgto

iTrader: (7)

Hope you figure it out. This is the same turbo I have ordered.

SPRAYED 01

iTrader: (22)

Im going to have jim at speed inc try turning the controller up to 90%. If that doesn't work I was thinking of having him block off the waste gate referance, do a very quick run just to see if boost goes up.

SPRAYED 01

iTrader: (22)

Ok so from what I understand off the supposed 11lbs spring it only made 7lbs of boost but did 600whp.

So thats kinda good news but is really strange that it only made 7lbs with that spring.

blackmagicturbo

iTrader: (2)

Aircleaner? Seems some people are having problems with air cleaners being restrictive ?