NEED HELP! boost spikes to 16 psi on stock settings

[Ademy08]

I just installed my boost gauge recently and I noticed that my boost goes to around 12 psi and then spikes up to around 16. Sometimes the boost stays at 16 and other times it will go back down to 12. What can cause this? I am currently stock except for intake, Type RS BOV, and 3" Megan Racing Cat-back exhaust. And as for a boost leak test, I would have performed one but jaredgsx (a member from this site) ripped me off and charged me $20.00 and won't return my e-mails or to the paypal claim that I filed . He is a fraud and should be kicked off dsmtuners.

Adam

 

[Ademy08]

Any Ideas At All? Wtf

 

[duck95]

3 inch exhaust without supporting mods on your turbo and wastegate flapper will cause boost creep.

http://www.dsmtuners.com/forums/showthread.php?t=96678

 

[forcefed 95]

i know it sucks having that spike and creep but you dont really have to wory about fuel cut or anything your stock fuel system can handle 16psi jsut fine. if anything think of as free hp w/o having to buy a mbc

joe

 

[Ademy08]

I actually have a MBC sitting right next to me I just didn't put it in because of the spike. I didn't want to increase the boost and have it spike to where it could be harmful. So do you think I should put it on?

 

[Ademy08]

What do you recommend that I do to my turbo and wastegate flapper?

thanks

 

[forcefed 95]

heres a link that will better help you understand porting your turbo and o2 housing, hope this helps and keep us posted http://www.vfaq.com/mods/porting-O2.html

joe

 

[dj_justice]

Im just curious, why would putting a larger exhaust on cause boost creep? Is it because the larger exhaust slows down the flow of exhaust gasses?

 

[brandonzero0]

Boost creep is caused by a fully opened Wastegates not being able to flow enough exhaust to bypass the housing via the Wastegates itself. For example, if your boost is set to 12psi, and you go into full boost, you will see a quick rise to 12 or 13psi, but as the rpm's increase, the boost levels also increase beyond what the boost controller or stock settings were. Boost creep is typically more pronounced at higher rpm's since there is more exhaust flow present for the Wastegates to bypass.
Effectivve methods of avoidng or eliminating boost creep include porting the internal Wastegates opening to allow more airflow out of the turbine, or to use an external Wastegates.

 

[MelloEclipse]

not so much 'slows down' the flow, instead it lowers the pressure on the exhaust side of the turbo...so it doesn't have to work as hard...without the other mods to counter this it can come off as a bad thing.

i still say stick to the steps in the tech/diy and problems similiar to these can be prevented.

 

[brandonzero0]

Or buy a 34mm flapper.

 

[Ademy08]

If I would take my o2 housing to a local machine shop would they know exactly what to do and not make a hack job out of it?

 

[MelloEclipse]

most likely you'll be ok taking it to a local shop...but you'd be better off to ask before hand if they have experience with DSMs..and if not..find someone close who is...it'll save you alot of trouble in the end.

 

[forcefed 95]

also though with a stock turbo and 3in exhaut its kinda hard not to get creep or spike seein as the turbo breaths so much better, as the respone of the turbo increase. meanin you will feel the turbo spool alot faster than with a stock exhaust and the quicker spool is what gives you that spike in psi casue it happens so fast that the wastegate cant keep up

joe

 

[Ademy08]

alright guys, new update. I just got my car back from the garage today, it went in for something simple, but when i got it back and drove it I'm now spiking to 20 PSI!!! isn't that a dangerous level for stock fuel system? what should I do?

 

[TURBOCASS]

yes! Are you venting the bov? Are you running a blow thru setup?

 

[Ademy08]

Yes, I am currently venting the blow off. how would that effect the boost spiking/creeping?

 

[delta448]

First off, put the recirculation tube back on your BOV and compressor intake pipe.

Second, check your wastegate actuator, make sure the boost/vac line doesn't have any holes in it and is still connected to the WG actuator. Make sure the line is only attached between the WG actuator and a pre-throttle-body-post-compressor intake pipe, or the compressor housing itself. Do not "T" into the WG vac line anywhere. Now check your flapper arm to make sure it opens and closes the WG without much resistance. If everything else checks out, use compressed air to verify the WG actuator is working.

You should not have boost creep if you still have your catylytic convertor and stock downpipe. Make sure the downpipe is connected securely and there are no large exhaust leaks in it or the cat. If you have a gutted cat or a bad dp, you very well may have boost creep. You will need to port the turbine housing to cure boost creep, not just the O2 housing. Boost creep occurs because there is a large difference in pressure between the exhaust mani and the turbine outlet. Decreasing the exhaust resistance post turbine creates faster spool and a higher chance of creep.

 

[Ademy08]

the recirculation tube is now back on and it only spikes to around 16 again. But while I was driving around one of my friends told me that black smoke was coming out of my exhaust? do you think the spike/creep has anything to do with the black smoke?

 

[delta448]

Black smoke usually means you're either burning oil or running really rich. You may have damaged your pistons or their rings by running lean with as much boost as you had without the proper supporting fuel mods. You also may have tricked the ECU into adjusting the timing/adjusting fuel trims by venting your BOV, if you did it for awhile. The settings that made the car run acceptably before in the incorrect configuration could be now causing you issues since the turbo system was returned to the way it should have been.

Have you checked your wastegate yet? If the wastegate isn't functioning, you'll have overboosting and surging problems, your turbo will leak/burn oil and soon crap out.

Pull the battery ground cable, reset the ECU and check your wastegate!

 

[Ademy08]

don't you need the code for the cd player if you reset the ECU? I don't have the code to reset it.

 

[nad1]

I'm having a similar problem on my T25 with full 3" turbo-back exhaust. How exactly do you go about checking your wastegate? And to reset the ECU, all you have to do is disconnect the ground to the battery, correct?

 

[delta448]

If you have the upgraded factory Infinity CD player, you will need the code, otherwise there isn't a code programmed into it.

I believe there is a way to retrieve the Infinity unit's code while it is hooked up, however I don't remember it. I am pretty sure it's in either the Haynes or Chilton's manuals. If you can't find it in your owners manual or in either of those two, you can get the serial # off of the back of it and the dealer can look up the code for you. They usually charge a small fee for that though.

 

[delta448]

I'm having a similar problem on my T25 with full 3" turbo-back exhaust. How exactly do you go about checking your wastegate? And to reset the ECU, all you have to do is disconnect the ground to the battery, correct?

If you have a 3" turboback, you most likely are experiencing boost creep. Especially with the T25. Time to get out the die grinder and do some porting or buy an external WG.

To answer your question, yes, -to reset the ECU all you have to do is pull the ground off the battery and let it sit for about a half hour.

 

[nad1]

It creeps from like 10-12 at WOT, but spikes to 15 or so after shifts. I was told there was nothing I could do other than porting, and I don't feel like taking all that stuff off if I'm not replacing it with something better.

I was told an O2 dump and manifold won't help either.