Boost Creap Help
12-20-2012, 06:22 AM
#1
Boost Creap Help
So I just got done doing a custom build. I have a OBX manifold with a custom 3in down pipe I made, 3in straight pipe exhaust with one OBX resonator into a tip with open dump off the wastegate.
Today I went to go tune for the bigger exhaust. Its been months since iv hit boost. First pull 4th gear I did my car felt like it boost spiked I looked at my gauge and was boosting 15psi with a 10psi spring. I drove home and swaped out my tail knock off wastegate because I thought it might have been stuck closed, for my turbonetics wastegate aslo with a 10psi spring. I did another 4th gear pull car boosted 10psi held for a few sec then just started creaping up once it hit 14psi I stopped!
Aslo my open dump used to be super loud and raspy when I did my WOT pulls today with the new setup I couldnt hear it?
What do you think is making these happen?
Today I went to go tune for the bigger exhaust. Its been months since iv hit boost. First pull 4th gear I did my car felt like it boost spiked I looked at my gauge and was boosting 15psi with a 10psi spring. I drove home and swaped out my tail knock off wastegate because I thought it might have been stuck closed, for my turbonetics wastegate aslo with a 10psi spring. I did another 4th gear pull car boosted 10psi held for a few sec then just started creaping up once it hit 14psi I stopped!
Aslo my open dump used to be super loud and raspy when I did my WOT pulls today with the new setup I couldnt hear it?
What do you think is making these happen?
12-20-2012, 05:33 PM
#6
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If Manifold and Downpipe are the only things you've changed, it's got to be one of those 2 most likely. If it is 1 of these, it's likely the manifold. What kind of manifold were you running before? If you've gone bigger w/your new downpipe that shouldn't make you spike boost, that should help eliminate it to an extent. Do some research on the manifold and see if anyone else has had spike issues. GL
12-20-2012, 07:06 PM
#7
If Manifold and Downpipe are the only things you've changed, it's got to be one of those 2 most likely. If it is 1 of these, it's likely the manifold. What kind of manifold were you running before? If you've gone bigger w/your new downpipe that shouldn't make you spike boost, that should help eliminate it to an extent. Do some research on the manifold and see if anyone else has had spike issues. GL
12-21-2012, 04:17 PM
#11
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It could be the fact that the exhaust gas has to go "uphill" to the wastegate itself. It could be building pressure in that pipe and could cause the wastegate spring to not respond accurately because of the length of tubing between the manifold and the wastegate. You could take the manifold off and have the wastegate routed from the side or bottom of the manifold if there's room. The shorter the path to the wastegate the better. GL
12-21-2012, 07:28 PM
#12
It could be the fact that the exhaust gas has to go "uphill" to the wastegate itself. It could be building pressure in that pipe and could cause the wastegate spring to not respond accurately because of the length of tubing between the manifold and the wastegate. You could take the manifold off and have the wastegate routed from the side or bottom of the manifold if there's room. The shorter the path to the wastegate the better. GL
12-21-2012, 08:02 PM
#13
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Honestly it looks like you could have the wastegate pipe cut off and welded shut and move it to the opposite side of the flange, with a good dump routing it shouldn't get in the way of coolant lines or radiator or other things. Def. worth looking into. GL
01-16-2013, 01:07 AM
#14
Hey i had a question about running dual gates with these manifold. Iv decided to add another runner from the bottom collector. Im just going to use a extra wastegate to cap the top original runner. my question is should I run a vacuum line to the top wasegate and run two wastegates? I know thats a lot of waste dose anyone know if that will work?
01-16-2013, 03:19 PM
#17
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I think by adding another wastegate it'll just give you more of a problem and make the setup more complicated then it needs to be. The manifold isn't a divided twin scroll so there really isn't a point of running 2 wastegates. IMO the reason for the boost spike is because of where the wastegate is positioned. The gases have to travel way too far in the position where its at now. It would be ideal to have pipe coming from the collector cut shorter and placed closer to the collector so that the wastegate can work more efficiently.
01-16-2013, 05:50 PM
#19
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If you're putting the wastegate port in a different spot (bottom of merge collector) then you need to close the original opening for sure. Even if you cap it off or put another wastegate on there it would still give you issues. However you get to close the original port for the wastegate has to do a REAL good job because if not done properly the flow will be off going into the merge collector.