boost creep or no?
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12 Second Truck Club
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From: Jacksonville FL.
boost creep or no? I'm having a problem where boost won't stop rising. i can hear the wastegate (open atmosphere) wasting like crazy but boost still rises. this is at half throttle. haven't went full throttle yet. with the old turbo i never had this issue. after i got the slight exhaust leak at the gate it raised the pressure about 1psi for both high and low. now with the new turbo it won't stay down.
the old turbo was basically a t67 with a .81 exhuast housing. the new one is a tc78 with a bigger exhaust wheel and a .96 housing. the wastegate is a 38mm on the crossover pipe.
the old turbo was basically a t67 with a .81 exhuast housing. the new one is a tc78 with a bigger exhaust wheel and a .96 housing. the wastegate is a 38mm on the crossover pipe.
Like I said on PT, you have two problems. One the gate being to small, and the other large problem is the gate in the cross over. You are only evacuating exhaust from one bank and doing so about 4-5ft away from the turbo. Show a pic of your kit and any one with knowledge of turbo systems on here will tell you the same thing.
You might be able to band aid it by installing a larger gate, or by having a small turbine housing/wheel to back it up and force it out the gate.
You might be able to band aid it by installing a larger gate, or by having a small turbine housing/wheel to back it up and force it out the gate.
Thread Starter
12 Second Truck Club
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From: Jacksonville FL.
just looking for more opinions is all. i don't know of one truck turbo setup that uses both banks out the wastegate. i wouldn't say 4-5 feet. more like 3 but i can take a pic. it just seems to me that if it takes pressure to spin the turbine and you have any leak (wastegate)in the pressure side it would slow spool or limit boost. i understand that if it can't leak fast enough then it will continue to spool.
Exactly that is why you want the stiffest spring you can get to hold the boost you want. This is one way to come into boost faster. Putting a smaller spring in it is just a band aid.
Also every setup I have ever built, truck or car has both banks feeding the gate. Any other way is not correct. If it does work its because of other problems in the system (high back pressure).
Also every setup I have ever built, truck or car has both banks feeding the gate. Any other way is not correct. If it does work its because of other problems in the system (high back pressure).
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From: Savannah, TN
That was a big increase in turbo size. What spring do you have in the gate and what do you see at half throttle. That is a small gate for that size turbo. make sure you have full stroke on the valve. Also where is the outlet going is it long if it is very long a increase in size may help but i doudt it a way to check that is it possible to dump it out of the gate if it helps . Not to get in this argument but pressure does not cause the turbin to spin . it is gases going thru the housing, only time pressure is present is when the housing is under sized are the a/r is undersized to allow boost at a lower RPM .so in turn it is undersized for wide open throttle.
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Thread Starter
12 Second Truck Club
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From: Jacksonville FL.
this is all being done at half throttle. i didn't want to go wot until i made sure the tune was up to par. the wastegate just has a small 2" dump on the end of it. i think it was a yellow turbonetics spring. it made 7psi on a honda accord with a t04b turbo.
hellbents10, how do you gate both sides? do you put the turbo in the middle? just trying to think of a way to do it with the gate down there.
hellbents10, how do you gate both sides? do you put the turbo in the middle? just trying to think of a way to do it with the gate down there.
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From: Savannah, TN
If the gate is fine why is he seeing creep? Do you think the gate is to small? what is the largest gate you can bolt up to his system without changing the flange. The lower the exhaust pressure the harder it is to controlle in my experance.
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12 Second Truck Club
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From: Jacksonville FL.
i found out the evolution gate is only a 35mm gate. i have a 38mm tial here i'm going to try. also found out that 1800 WE TURBO. is not sts's phone number
