jeffro Posted October 4, 2010 Report Share Posted October 4, 2010 What causes this? i had my spring backed all the way down to 8psi about 3 weeks ago. recently, it wont go below 9.5, and creeps up till i hit boost cut at 10.5 psi. around 5500 rpm. the wastegate cant be adjust down anymore. what i do know is that im running an open downpipe, whereas before i was running a super restrictive exhaust. is this possibly weather related? or related to the open exhaust? i dont really want to buy an MBC. vacuum leaks, or exhaust leaks before the WG? Quote Link to comment Share on other sites More sharing options...
99FLHRCI Posted October 4, 2010 Report Share Posted October 4, 2010 I would think a open downpipe would lower boost as it would create less restriction. I know when I went to a larger diameter exhaust I "lost" 3 psi of boost. Quote Link to comment Share on other sites More sharing options...
DavidBaustert Posted October 4, 2010 Report Share Posted October 4, 2010 where is your boost reference for the WG? Quote Link to comment Share on other sites More sharing options...
jeffro Posted October 4, 2010 Author Report Share Posted October 4, 2010 intake manifold. im wondering if the hose isnt cut or something. Quote Link to comment Share on other sites More sharing options...
jeffro Posted October 4, 2010 Author Report Share Posted October 4, 2010 intake manifold. im wondering if the hose isnt cut or something. nope, all vacuum lines look good. i did take the vent nipple off the top of the wg, which opened the opening up by about 4 fold. i thought this was just a vent, but could this unrestricted flow be causing issues? Quote Link to comment Share on other sites More sharing options...
CRed05 Posted October 4, 2010 Report Share Posted October 4, 2010 Shitty turbo's are usually the problem. More specifically its the wastegate hole that isn't big enough. If you have an external wastegate, get a bigger one. Quote Link to comment Share on other sites More sharing options...
dover Posted October 4, 2010 Report Share Posted October 4, 2010 What boost controller are you using? I had a shitty manual on my WRX back in the day and it would be all over the place. I went to an electronic never had a problem again. I have a AEM tru-boost on my cobra and they bitch hits and stays at whatever I set it too. Quote Link to comment Share on other sites More sharing options...
dover Posted October 4, 2010 Report Share Posted October 4, 2010 Then again I also have a Turbonetics T-76 and Turbosmart Ultragate. Quote Link to comment Share on other sites More sharing options...
jeffro Posted October 4, 2010 Author Report Share Posted October 4, 2010 im running a garrett turbo with no MBC. could just be the shit wastegate. Quote Link to comment Share on other sites More sharing options...
DavidBaustert Posted October 4, 2010 Report Share Posted October 4, 2010 nope, all vacuum lines look good. i did take the vent nipple off the top of the wg, which opened the opening up by about 4 fold. i thought this was just a vent, but could this unrestricted flow be causing issues? No air should be coming out of that hole except the air being displaced by the diaphragm moving up and down. Try moving your boost reference to the outlet of the turbo, length of hose can have an effect on boost creep and WG response. Quote Link to comment Share on other sites More sharing options...
SRTurbo04 Posted October 4, 2010 Report Share Posted October 4, 2010 when i went from full exhaust to my open down pipe the boost would skyrocket... thats all the input i have Quote Link to comment Share on other sites More sharing options...
DavidBaustert Posted October 4, 2010 Report Share Posted October 4, 2010 im running a garrett turbo with no MBC. could just be the shit wastegate. FIAL? Quote Link to comment Share on other sites More sharing options...
jeffro Posted October 4, 2010 Author Report Share Posted October 4, 2010 FIAL? no, even more fail. the only thing i changed from my previous setup was my manifold and my downpipe. everything worked fine before. i had my vac source hooked up to the turbo outlet before and poor results. then i moved it to the mani and it worked well. my elbow going from my manifold to the wastegate has a crack in it i just noticed. im wondering if that doesnt have anything to do with it. pressure leaking out before the wg/turbo i wouldnt think would give boost creep. if anything, loss of pressure. Quote Link to comment Share on other sites More sharing options...
DavidBaustert Posted October 4, 2010 Report Share Posted October 4, 2010 FIAL as in fake tial, was wondering what WG you have? The change of turbo manifold can contribute to boost creep. Some manifolds are made with WG priority whereas others aren't. Quote Link to comment Share on other sites More sharing options...
jeffro Posted October 4, 2010 Author Report Share Posted October 4, 2010 this wg, http://members.shaw.ca/wyntonm/pic/WG38%20(B).jpg this manifold: http://img.auctiva.com/imgdata/6/2/1/6/4/5/webimg/293646757_o.jpg Quote Link to comment Share on other sites More sharing options...
DavidBaustert Posted October 4, 2010 Report Share Posted October 4, 2010 That looks like the same type of manifold I had on my car, never had any boost creep issues on the car. I'd get a new WG asap. Tial or turbosmart are great models. Stay away from synapse. Quote Link to comment Share on other sites More sharing options...
Bigbird Posted October 4, 2010 Report Share Posted October 4, 2010 when i went from full exhaust to my open down pipe the boost would skyrocket... thats all the input i have I know Paul and I don't drive Hondas, but I do know that even just adding a downpipe WITH an exhaust on my car can cause boost creep. Paul saw boost creep with an open DP setup, and you are too. Get an exhaust.... Oh and that wastegate looks craptacular...no offense. Quote Link to comment Share on other sites More sharing options...
CRed05 Posted October 4, 2010 Report Share Posted October 4, 2010 i've never heard of downpipes and exhaust causing boost creep. Boost creep happens when exhaust gas is unable to bypass the turbine because of the wastegate. Change your wastegate. Quote Link to comment Share on other sites More sharing options...
jeffro Posted October 4, 2010 Author Report Share Posted October 4, 2010 i've never heard of downpipes and exhaust causing boost creep. Boost creep happens when exhaust gas is unable to bypass the turbine because of the waste gate. Change your waste gate. i read that with the open down pipe, there is zero to little back pressure within the turbine housing. since there is no back pressure, the turbine can over spin because there is nothing limiting how fast the turbine can freely spin. but at the same time how can the turbine spin faster than the pressure of the exhaust. i think i'm going in the wrong direction here. could the cracked elbow possible create a micro vacuum within the tube, pulling the waste gate towards the closed position? Quote Link to comment Share on other sites More sharing options...
CRed05 Posted October 4, 2010 Report Share Posted October 4, 2010 No man, turbo's dont want back pressure, the less the better it uses the pressure from the exhaust manifold, that's where you want pressure/velocity. You have a crack between the wastegate and the manifold? That should just cause it to spool slower and possibly build less boost I would assume. Quote Link to comment Share on other sites More sharing options...
Smokey Posted October 4, 2010 Report Share Posted October 4, 2010 The times that I've seen a downpipe "cause" boost creep it's because the exhaust without restriction is now the least path of resistance. The point of the wastegate is to divert exhaust gasses from going thru the turbine. What is likely happening here is that the new exhaust has little enough restriction that the path of least resistance has changed from being the wastegate to being out the turbine and thru the exhaust....so now even when the wastegate is open wide, it cannot pull enough of that flow away from the turbine, so the turbo keeps spinning faster and making more boost. So I would say that your new exhaust is too big for the wastegate you have. Possible solutions would be to revise/replace the wastegate so that it can now out-flow the exhaust under all circumstances or place a restriction in the exhaust. I've seen people use metal plates with smaller diameter holes (2.5" small plate put inbetween sections of a 3" pipe for instance) to restrict flow in the exhaust to put things back in balance. Quote Link to comment Share on other sites More sharing options...
jeffro Posted October 4, 2010 Author Report Share Posted October 4, 2010 The times that I've seen a downpipe "cause" boost creep it's because the exhaust without restriction is now the least path of resistance. The point of the wastegate is to divert exhaust gasses from going thru the turbine. What is likely happening here is that the new exhaust has little enough restriction that the path of least resistance has changed from being the wastegate to being out the turbine and thru the exhaust....so now even when the wastegate is open wide, it cannot pull enough of that flow away from the turbine, so the turbo keeps spinning faster and making more boost. So I would say that your new exhaust is too big for the wastegate you have. Possible solutions would be to revise/replace the wastegate so that it can now out-flow the exhaust under all circumstances or place a restriction in the exhaust. I've seen people use metal plates with smaller diameter holes (2.5" small plate put inbetween sections of a 3" pipe for instance) to restrict flow in the exhaust to put things back in balance. ive got a 3" to 2.5" reducer coupler i could clamp on the end. i bet that'd fix it. edit, no clamping, blew my last one apart from clamps haha Quote Link to comment Share on other sites More sharing options...
DavidBaustert Posted October 4, 2010 Report Share Posted October 4, 2010 ive got a 3" to 2.5" reducer coupler i could clamp on the end. i bet that'd fix it. edit, no clamping, blew my last one apart from clamps haha He's speaking on the exhaust side, not intake. He is suggesting that you're dp/exhaust isn't restrictive enough and the exhaust it not flowing through the WG as it should and is causing the boost creep. Quote Link to comment Share on other sites More sharing options...
BIGGU Posted October 4, 2010 Report Share Posted October 4, 2010 ebay setup = ebay performance. replace all ebay items and youll be fine. david, Why stay away from synapse? Quote Link to comment Share on other sites More sharing options...
Smokey Posted October 4, 2010 Report Share Posted October 4, 2010 He's speaking on the exhaust side, not intake. He is suggesting that you're dp/exhaust isn't restrictive enough and the exhaust it not flowing through the WG as it should and is causing the boost creep. This. Quote Link to comment Share on other sites More sharing options...
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