No Boost????
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From: San Antonio, Tx
No Boost???? My dad and I just finished putting together twin rear mount turbo setup on his 8.1L 2500HD pickup with allison trans. The turbos are turbonetics t62-1 with a .81 exhaust housing and a 5 pound wastegate spring with front mount intercooler. Well once we finally got all the small pieces together we took it for run and well.. no boost. It does make a pound or two on the shift but then goes away. What could be the problem? Are the turbos the wrong size?
alot of things, start checking connections first off. Second you put the turbos in the wrong spot. They are supposed to be in the engine compartment.....j/k. All joking aside, also check your springs in the gates and make sure they are not a 3psi spring or something silly like that.
Well as far as turbo sizing goes that would be good for about 1000-1100fwhp on that motor in conventional setup. It should make a full 5psi by 3800-4200 even with a rear mount setup on those cubes. I image we are talking stock manifolds and 2.5" pipe to the turbos? Wrapped? That motor should kick those turbos like a mule on steroids really. There has to be a leak or a problem with the gage. Is it pulling good, AFR, ignition advance???
Joined: Jun 2004
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From: Ft. Irwin, California (But Virginia is home)
Where is the wastegate referenced to? If it's the turbine itself.....your lack of boost is the FMIC. Reference needs to be AFTER the intercooler when running a rear-mount setup. 
Also, ....have you checked the little things....like making sure there's not a kink in the boost gauge line?
Good luck.
Also, ....have you checked the little things....like making sure there's not a kink in the boost gauge line?
Good luck.
Thread Starter
11 Second Club
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Joined: Mar 2007
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From: San Antonio, Tx
Where is the wastegate referenced to? If it's the turbine itself.....your lack of boost is the FMIC. Reference needs to be AFTER the intercooler when running a rear-mount setup.
Also, ....have you checked the little things....like making sure there's not a kink in the boost gauge line?
Good luck.
Also, ....have you checked the little things....like making sure there's not a kink in the boost gauge line?
Good luck.
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11 Second Club
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From: San Antonio, Tx
Thread Starter
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From: San Antonio, Tx
Thanks that did it but still not making more than a pound in 1 first gear. In the upper gears at speed it pulls 4 to 5 psi. Thinking exhaust wrap or smaller housing on the exhaust side. Any suggestions?
Those turbos are not the correct size for making only 5psi and less then 450whp. Its going to be very laggy. You might have to drop down as far as a .58 hot side to make boost soon enough at lower power levels.
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From: San Antonio, Tx
My dad wants to know how much difference wraping the exhaust would help? Will boost hit sooner and by how much rpm? The truck has headers wondering if going back to stock manifolds will make a noticable difference on the truck like the cars do or should he put smaller exhaust housing? Any input suggestions or experiances would help, Thanks.
Joined: Jun 2004
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From: Ft. Irwin, California (But Virginia is home)
My dad wants to know how much difference wraping the exhaust would help? Will boost hit sooner and by how much rpm? The truck has headers wondering if going back to stock manifolds will make a noticable difference on the truck like the cars do or should he put smaller exhaust housing? Any input suggestions or experiances would help, Thanks.
Will probably take 2 50' rolls. My $0.02......wet the wrp before putting it on the car. It'll wrap better. Also wear gloves, as the fiberglass (or whatever gives it the heat resistance) will make your hands itch from handling it. Finally, spray the wrapped exhaust with DEI or similiar exhaust wrap paint. Seals the whole deal pretty well BTW, from what I've heard going back to stock manifolds makes a big difference (less surface area). Unfortunately my wife threw my stock manifolds/ y-pipe away while I was in Iraq
so I can't speak from experience........ Thread Starter
11 Second Club
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From: San Antonio, Tx
Wraped the exhaust from the turbos forward about 3 feet. Also we put the stock headers back in, and will test drive tomorrow to see what the results will be. The manifold question will be answered!
