Strange boost problem
Strange boost problem this is wierd hope you guys can understand what im trying to explain, if im cruising at 50mph and just jump on the gas wot there is no boost- vaccum stays at 18-20 . if im crusing at 50 and i apply slight throttle pressure watch boost guage needle move just a litte from 20-18 then jump on gas wot boost goes to 5 psi . any idea what is going on??? 
Originally Posted by bboyferal
Sucks, that rules out what would have been a not-so-bad problem... 
See if there are any leaks in your WG or BOV..Maybe even in your piping.
TECH Resident
Joined: Jan 2004
Posts: 832
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From: Castro Valley, CA
Is there a boost controller on your setup? It almost sounds like the wastegate spring is sticking a bit... and when you give it a little mild acceleration prior to the punch you might be supplying the topside of the wastegate with a little push to "unstick" the spring and allow it to close properly? But at only 5 psi I'm guessing you're just running against the spring...
So, really: you punch it at 50 mph, and see no boost at all even as the car (presumably) kicks down a couple of gears? And no boost builds at all as you keep going?
So, really: you punch it at 50 mph, and see no boost at all even as the car (presumably) kicks down a couple of gears? And no boost builds at all as you keep going?
[QUOTE] that is exactly what it does . no i dont have a boost controller. it is just a 5psi system, we dont get 5psi out of the system only 4 but the needle jumpst around. we sealed the exhaust yesterday no change, any ideas on how to check the charge pipe fittings for leakage???
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Sounds like a defective wastegate. My old set-up had a "Turbonetics Delta Gate Mark II"(set-up for 10psi) and it was doing all kinds of weird stuff, like...if i go wot from a roll the boost gauge would go to 5-6psi and then as the rpm climbs boost would also climb to 7-8psi, it was acting like a centrifugal supercharger set-up like rpm related, and once in a while the gauge's needle would kinda fluctuate, I bought a new Turbosmart 38mm and it fixed all the problem, boost jumps right to 10psi as soon as i go wot.
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Verdad Gallardo TECH Resident
Joined: Jan 2004
Posts: 832
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From: Castro Valley, CA
It seems to me that boost leakage would affect your setup at all times, and not give you the funky on/off behavior you're experiencing now.
I agree with the above post; sounds like a defective/sticking wastegate. One method of testing would be to substitute in a higher boost spring (e.g. 7 or 10 psi) and see if you suddenly start to see boost in a *brief* application of WOT.
I agree with the above post; sounds like a defective/sticking wastegate. One method of testing would be to substitute in a higher boost spring (e.g. 7 or 10 psi) and see if you suddenly start to see boost in a *brief* application of WOT.
My guess would still be your wastegate, is it an old/used unit? it might have a tear in the diaphragm or a crack on the shell/body itself. It would be nice if you know anybody in your area that would let you try their unit just to see for sure, but keep in mind that wastegates has to put up w/ a lot of abuse from extreme heat which a lot of times get overlooked when diagnosing these kind of problem.
brand new system , installed two weeks ago. im going to so a leak test on the charge pipes to see if any leaks, maybe that is what the problem is. hell i dont know i just know ive got to try something.
Originally Posted by BUYAMERICAN
SmokeN20
I look forward to seeing your results solving the no boost issue with STS setup. Keep us updated.
TIA
I look forward to seeing your results solving the no boost issue with STS setup. Keep us updated.
TIA
Last edited by smoke20; May 29, 2006 at 05:03 PM.
hey im having the same issue just got the kit done,but i do have an adjustable boost controller now i turned that thing all the way up and only seeing like 2 pounds of boost,how do you test if its the wastegate not working?
