turbo ?

[chevyCowboy]

I have a gm-3 and for know i have it wired as tightly as i can shut. it dosent start to spool untill around 1600 to 1800 RPM. when crusing at 55 I get 2-3PSi and the most i have ever seen was around 13-14 and that was really laying on it going up hill.

My question is is that normal or It seems to me that i should see more boost at crusing speeds.

 

[Turbine Doc]

That is about normal, running wired shut isn't recommended, what kind of EGT are you seeing. later model GM turbos GM-8 would do better for you, best IMO would be ATT unless you can find a TM'd GM turbo dirt cheap.

New downpipe, 4" exhaust, and mandrel crossover would also benefit you, how many miles on your IP & injectors.

 

[chevyCowboy]

That is about normal, running wired shut isn't recommended, what kind of EGT are you seeing. later model GM turbos GM-8 would do better for you, best IMO would be ATT unless you can find a TM'd GM turbo dirt cheap.

New downpipe, 4" exhaust, and mandrel crossover would also benefit you, how many miles on your IP & injectors.

egts are normally around 800 or 900 IIRC ill watch tomorrow i have 4 inch exhaust and crosover. there is a muffler that came with the exhaust i am going to make a TM but have just never go around to doing it got all the stuff on my tool box at work just got to assemble

 

[Turbine Doc]

My boost with ATT runs 2-3 psi, but back pressure is about same close to the ideal 1:1 boost/bp ratio for max mpg we strive for, even at high boost 10+psi boost max BP is about 15-18 which is about 1/2 of when high boosting with the GM turbo where I've seen 45+ back pressure

 

[shadetree]

i have a gm 4 vacum and waste gate is frozen the gm 3 in the garage is the same way and i cant here the gm 4 spool up at all