Turbo Boost Creep Creeping T25 14B 16G [Merged]

[nek]

MBC is hooked up correctly, but I have it closed. And still some how some way im boost creeping almost 23-25 psi with T-25.

Hmm, Wierd that you can even make it to 23psi, I think I hit fuel cut at only 19-20.
But anyways, if your creeping on a t25 Id blame boost leak all the way( I know thats what everyone says but a leak causes so many problems)
Did you recently do any upgrades to the ic pipes or your bov or anything like that? Id run a blt and see what comes up. I know my system was leaking like crazy at the jpipe and a little at the bov.

 

[Mock]

Nope, all upgrades are stacking up in my room. And i did not think 23 psi with a stock fuel system was possbile. But when i am at WOB its hitting 23-25 on Autometer boost guage. Im letting off before fuel cut. I mean im htting this boost spike at 3500 rpm

 

[nek]

Nope, all upgrades are stacking up in my room. And i did not think 23 psi with a stock fuel system was possbile. But when i am at WOB its hitting 23-25 on Autometer boost guage. Im letting off before fuel cut. I mean im htting this boost spike at 3500 rpm

Pretty dumb question but is your mbc turned all the way down? A mbc fully turned down should only produce stock boost which should really not exceed 14lbs..
At what psi do you actually hit fuel cut?

 

[Blurred Talon]

If the MBC is all the way in/tight, I think that's your issue.

Also a 3" turbo back will cause creep, mine creeps to 18psi.

 

[c2ypt1c]

MBC is hooked up correctly, but I have it closed. And still some how some way im boost creeping almost 23-25 psi with T-25.

you want it to be "open" so it sends pressure to the actuator, which then opens your wastegate flapper. Well, assuming the MBC is not the problem - your actuator could be bad.

try connecting the line straight from the compressor housing to the actuator and see if that does anything...

 

[Mock]

you want it to be "open" so it sends pressure to the actuator, which then opens your wastegate flapper. Well, assuming the MBC is not the problem - your actuator could be bad.

try connecting the line straight from the compressor housing to the actuator and see if that does anything...

I believe it is the actuator, b.c. couple months ago i could open or close my MBC all the way and it wouldn't boost past 10 psi. Now out of the blue its hitting on average 20psi. I currently have a Turbo XS MBC, been on since i baught the car. I do have a brand new Hallman Pro MBC im going to put that on tomorrow and see if helps.

 

[c2ypt1c]

like i said above, an easy way to test the actuator is to connect it straight to the compressor, bypassing the boost controller all together...the actuator should kick in @ around 8 psi so you should only be able to boost that much. If it still shoots up to 23 then you know the actuator is bad...

it should take all of 5 mins to do

compressor------->MBC--------->actuator
(with boost controller)


compressor----------------------->actuator
(actuator test w/out boost controller)

 

[Mock]

like i said above, an easy way to test the actuator is to connect it straight to the compressor, bypassing the boost controller all together...the actuator should kick in @ around 8 psi so you should only be able to boost that much. If it still shoots up to 23 then you know the actuator is bad...

it should take all of 5 mins to do

compressor------->MBC--------->actuator
(with boost controller)


compressor----------------------->actuator
(actuator test w/out boost controller)

Great ill go do that now. Question though i have a room full of parts and had some questions. Im taking the car to the strip tomorrow night, have a bet with a friend and his 09 WRX. Would i be able to install my Walbro 255, New NGK Plugs and NGK BP7es,New MBC? I know BP7es are for higher boost applacations. I was thinking this might stop fuel cut?

 

[c2ypt1c]

fuel cut is dependent on the amount of air that the ecu sees. If you install new plugs, axles, a spoiler or whatever... it is not going to change the amount of air flowing into the engine. If you're going to race without control over your boost, all i can say is this doesn't sound very smart...

 

[TheOctane]

Check the vacuum line at the wastegate

 

[Mock]

Firgured i would need a tuning device. Thought it wouldnt hurt to ask. Well i just wait till i put my FP68HTA on before i throw the BP7es on.

Well the problem was the MBC, threw out the old in with the new. Hallman Pro holding 15psi. Can't wait to get this To-Slo25w off my car.

 

[pandagst]

my current set up is turbo back exhaust catles. o2 dump tube, garret big t28 turbo with an actuator, and greddy fmic.
should i be woried on geting any boost creep?

 

[dsmdeliveryboy]

my current set up is turbo back exhaust catles. o2 dump tube, garret big t28 turbo with an actuator, and greddy fmic.
should i be woried on geting any boost creep?

Depends how free flowing your exhaust is, with an o2 dump I don't think so though. Every car is different though.

 

[LiquidX]

I'd say you are fine.

Boost creep will usually happen on very free flowing exhaust setups and the other major factor is with internal gate turbos. With the internal gate, if the wastegate entrance is the least resistance between itself and the turbine then you will not creep. Once you exceed the maximum amount of flow the wastegate is capable of or too much back pressure is produced (turbulence) then the turbine can become the least resistant and cause boost creep.

The Evo3 16g is notorious for boost creep mainly due to turbine housing design.

 

[Sandman817]

Whats up guys, a couple months ago my turbo was boost creeping to 20+ pounds and would fuel cut,and finally my motor went on me. I have decided i am going to pick up another motor in the next couple weeks and i would like to fix my boost creep problem before i get the new motor running. I have read that porting the exhaust manifold and the waste gate on the turbo will pretty much eliminate the boost creep. I am going to be running a big 16g turbo, obx o2 housing w/ external dump tube, and a 2.75" to 3" downpipe. Since i was planning on upgrading my exhaust manifold to a tubular one, would i still need to port this to reduce creep, or are they pretty good as is? Let me know what you guys think about me going with a tubular manifold instead of porting my stock mani. Thanks

 

[purewake07]

Yes, should fix your issue if you port your exhaust mani and your o2 housing.
But if your going tubular setup then you need not worry about boost creeping

 

[LiquidX]

Boost creep occurs because the exhaust flow post turbine is very free flowing. That is a good thing, however, that free flowing exhaust is most likely choosing the turbine instead of the wastegate port for it's exit.

You need to port the inlet of the wastegate or go external to rid your creep.

 

[Sandman817]

i am getting mixed responses from everyone. people say if you port your wastegate then it gets rid of creep, but going tubular will get rid of any creep also. ive also read that people running a new o2 housing with a dump tube helps with creep.

If i just follow this tutorial and run a tubular manifold. Will this eliminate my creep problem?

 

[toyotagt1]

Ok i have a 1990 eagle talon tsi awd running the stock 14b turbo with a 3in exhaust system from the back of the turbo with a test pipe and a front mount intercooler with a hks bov and i have been reading up on boost creep alot and have not found a answer so that is why im making a new post about it. My car before i installed the fmic was running a steady 8psi but when i installed the fmic i would peak at 17psi at 5,500rpm when my car would start to hit fuel cut and i havent been able to solve this problem since. i have already check for boost leaks and have found none and i checked my waste gate actuator and it seems to be working just fine so idk what to do

 

[BMPer4manceDSM]

Maybe get a minor tune?

 

[HIGHPSI4]

Recheck your boost lines. Sounds like you hook one back up wrong.

 

[toyotagt1]

Maybe get a minor tune?

i did get a full tune from my dsm mechanic and it helped some but not alot he said i needed a header but iv never heard of a header fixing boost creep?

Recheck your boost lines. Sounds like you hook one back up wrong.

i checked them all and replaced the one from my waste gate to my boost control solenoid. when i installed the FMIC i did eliminate the boost line that came off the stock j-pipe and teed into the waste gate line could that be a problem?

 

[ryan90tsiawd]

.... a header? If anything getting a header that flows better will make it even worse.... Boost creep is from getting too much exhaust flow... so much that the wastegate flapper can not bypass the needed amount of exhaust flow to the turbine wheel. There are a couple of tricks that you can try to help out. You can pull off the o2 housing, and grind out the divider that separates the wastegate flapper and turbine wheel... Only do it on the o2 housing.. not the turbine housing... this will help out some for sure.

 

[toyotagt1]

.... a header? If anything getting a header that flows better will make it even worse.... Boost creep is from getting too much exhaust flow... so much that the wastegate flapper can not bypass the needed amount of exhaust flow to the turbine wheel. There are a couple of tricks that you can try to help out. You can pull off the o2 housing, and grind out the divider that separates the wastegate flapper and turbine wheel... Only do it on the o2 housing.. not the turbine housing... this will help out some for sure.

i have a tubular o2 housing so i cant cut out the middle or i would but thanks tho i appreciate it

 

[U8NTRDY]

.... a header? If anything getting a header that flows better will make it even worse.... Boost creep is from getting too much exhaust flow... so much that the wastegate flapper can not bypass the needed amount of exhaust flow to the turbine wheel. There are a couple of tricks that you can try to help out. You can pull off the o2 housing, and grind out the divider that separates the wastegate flapper and turbine wheel... Only do it on the o2 housing.. not the turbine housing... this will help out some for sure.

Agreed, just a better header would make it worse, but if he got a manifold flanged for an exeternal wastegate and got either a 38 or 44mm external w/g, it should help control the boost greatly... might be a little overkill for his current setup though