No Boost - Turbo
10-12-2009, 07:41 PM
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No Boost - Turbo My car is only making 3psi on a 7lb wastegate spring. We have checks all vacuum lines and checked for exhaust leaks and nothing. The turbo will not boost more than 3 psi. Its a single front mount turbo kit. I used OFI's hot parts. What could it be? Its currently at the dyno and would really like to get this thing to 7psi...
Last edited by JerikSS; 10-12-2009 at 07:53 PM.
10-12-2009, 09:17 PM
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sounds like a wastegate problem. Double check your vacuum line to the gate and check the gate so that its seal is good. make sure its not leaking from the side when you changed springs
10-13-2009, 03:03 AM
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Out of all of the cases I have seen where people were encountering over or underboosting situations they were almost always directly attributed to wastegate or BOV issues, whether that be the part itself or improper installation if boost/vac lines going to it. Even doing a free-rev while looking at the BOV will indicate if it is at least somewhat working properly. Recheck it all and if you still have problems then cap both ends of the cold-side and do a pressure test of the system. Chances are likely that it is something simple that was just overlooked.
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10-19-2009, 09:14 PM
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what kind of gate are you using? I had the same problem with my jgs 50mm. turns out it was my "7psi" spring was not enough. I went with a double spring set-up and now I'm making 6.5-7 on gate.
10-19-2009, 10:04 PM
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If your exhaust system is restrictive it can cause issues makeing spring pressure rated boost due to back pressure.
have seen a setup need 16psi worth of spring to make 8 psi boost, went from a 3" to 3 1/2" exhaust and instantly would make 16psi boost (no other changes)
Also if your boost reference is from the turbo and you have a restrictive intercooler/intake you won't see wastegate spring rated boost at manifold, move the wastegate boost ref to manifold and you will.
have seen a setup need 16psi worth of spring to make 8 psi boost, went from a 3" to 3 1/2" exhaust and instantly would make 16psi boost (no other changes)
Also if your boost reference is from the turbo and you have a restrictive intercooler/intake you won't see wastegate spring rated boost at manifold, move the wastegate boost ref to manifold and you will.
10-19-2009, 11:47 PM
#13
If your exhaust system is restrictive it can cause issues makeing spring pressure rated boost due to back pressure.
have seen a setup need 16psi worth of spring to make 8 psi boost, went from a 3" to 3 1/2" exhaust and instantly would make 16psi boost (no other changes)
Also if your boost reference is from the turbo and you have a restrictive intercooler/intake you won't see wastegate spring rated boost at manifold, move the wastegate boost ref to manifold and you will.
have seen a setup need 16psi worth of spring to make 8 psi boost, went from a 3" to 3 1/2" exhaust and instantly would make 16psi boost (no other changes)
Also if your boost reference is from the turbo and you have a restrictive intercooler/intake you won't see wastegate spring rated boost at manifold, move the wastegate boost ref to manifold and you will.
10-20-2009, 02:59 AM
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If you have a 7lb spring and want to see 7 psi at the manifold, reference the gate at the manifold. If you ref at the turbo there will be some pressure drop between turbo and maifold due to intercooler and intake pipes.
10-20-2009, 07:23 AM
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mine would make 2.5-3 psi, my dp ends about 6-8 inches after it goes through the k-member. after talking with the guy who designed the wastegate (very nice guy from jgs) he explanied that there using the same springs as that from a very well known and trusted wastegate company. that company rates there springs off the back pressure most 4cly. produce. when you get into the bigger cibes engines all that changes. thats why the big boys dont even mess around with changing springs all the damn time, they just run co2 to control everything. at first I thought he was just trying to sell me some 20 dollar spring, he sent out 2 different springs for me to try. (think I paid $12 with shipping for them). tried the "big" spring and the car would lag, then just jump to 10+psi. put in the "med." spring and the one I already had car now makes 6.5-7 psi by 3000 or so. jgs gates are made so you can run 2 springs if you wish/need.
I'm running a mp76 with a q trim, I vac. ref. right off the turbo housing to the wastegate (about 4-5 inches away from each other).
op have you tried pressure testing your cold side?
I'm running a mp76 with a q trim, I vac. ref. right off the turbo housing to the wastegate (about 4-5 inches away from each other).
op have you tried pressure testing your cold side?
10-21-2009, 01:03 AM
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If you grab the shaft of the turbo does it seem to spin freely? Also if the "budget kit" comes with a tial 44mm gate, then perhaps you did not install the fire ring. Hope that helps good luck and it'll be interesting to see what the problem is.
