Crazy Boost Creep @5K

[neuralracing]

I bought a ported SBR Mani and B16G (supposedly with the upgraded wastegate). I have a ported Evo III O2 housing as well. I am using the AEM EMS to control boost (also tried a Hallman MBC). My problem is that at about 5K revs the boost just jumps... I have to let off the gas as it goes up to 25 psi and climbing. I have set the wastegate duty cycle to the max at that RPM range with no success. Should I contact SBR... my buddies tell me to go with a Tial 44mm external, but if I paid extra for porting an the WG from SBR I shouldnt be seeing this. Any ideas?

 

[DSMvroom]

Well you have lots of exhaust flow to spool that turbo, so it wants to keep going and going.

The trick to porting exhaust pieces is to at the same time make sure you are making the path of resistance less through the wastegate. If not, then the air will just keep going right over that exhaust wheel and spin spin spin. The ported exhaust manifold only helps the turbo spool more as it expels the gasses better. The secret in preventing creep lies in porting the turbo's exhaust housing as well as the o2 wastegate path.

An external wastegate may help depending on the wastegate path. I think an external wastegate dump would be helpful also.

Your cheapest resolution for now I think would be to see what you can do about porting that o2 housing "better."

 

[oldman]

http://www.dsmtuners.com/forums/showthread.php?t=183108&page=1&pp=25

Before you say the turbo is vendor ported, so was the author of that thread as well as majority of people who has this issue.

 

[neuralracing]

OK... so my options are to Port the turbo more... or is it to port the O2 housing more? A local guy is selling me a Tial WG (44mm) brand new for $300. Should I go that route instea din case I decide to go with a bigger turbo down the road? If so... does someone have some pics of how to route the WG dump so it doesn't go straight to the FMIC piping and the radiator fans?

 

[Turbo Talon 111]

you would have to port the wastegate portion of the turbo and O2 housing. if you do the compressor side of both then you are working against it. just make sure you don't over port and put a hole in anything or keep the wastegate from sealing. have a reputable shop help you if you are concerned with it.

an external WG would be better than the internal but it has to be done right. i don't have experience with that though. good luck.