boost creep tial 44 help

[osirisk8er10]

hey guys i have been having huge issues with creep for over a year now i have tried absolutley everything i know and everything i have read searching about it and cant figure it out i have tried two diffrent wastegate springs the 11psi spring and the 7psi spring and i aslo tried just running the pressure source from the compressor housing to the wastegate and it hits 10psi and just creeps all the way to redline i have a ported head with +1 over intake and exhaust valves 288 cams a dnp manifold with tial 44mm wastegate and a 35r i aslo have a hallman mbc its hooked up correctly and draws pressure from the compressor housing to the lower diaphram of the gate the top of the wastegate is vta if i leave the mbc hooked up i hit 15psi and just creep until i hit boost cut i am also using aem and i have the boost cut at 18.12psi i raised it to 19psi for the cut to see what would happen and it just hits that to it never wants to level off it sits at 15psi for around 400 to 500rpms then starts creeping any help would be much appreciated thanks

 

[EclipticalGS]

well youve got a pretty big turbo for only running 15psi. usually ppl use those turbos for like 22psi+. I understand your'e using a externally gated 44mm but the reason for youre creep is because when you hit your full boost (15psi) at like what 3500rpm's? so then your gate opens up fully and then you've still got 3500-7000 rpms of exhaust that has to flow out your gate bcuz you dont want to make any more boost. You can port the hell out of your gate flange, or get a better flowing manifold, or run an open dump with a bigger and less restricting tube. You will always have creep when you use a huge turbo with tons of power making capabilites and run low boost.

Just imagine how much exhaust would flow through a wastegate if i ran 7 psi on a 35r...

that is if im even talking about the right turbo, GT3582R right.. heres this post....

"The 600hp capability of the dual ball-bearing GT3582R turbo has made it one of the most popular choices for the 2.5L WRX & STi. The 35R turbo tends to be too big for 2.0L cars, so we reccomend it for the 2.5 only. Choose the .82 AR for maximum performance, or the .63 for improved spool. The 35R features a T31 turbine housing will bolt directly to the Turbo XS rotated mount upipe & downpipe and attach to the intake."

that turbo is meant for BIG power man.

turn up the boost or deal with the creep.

You know what you should do, wherever it creeps to at redline, say it hits 18.22 psi at redline, then jsut start running 18 psi boost!! and tune for that, not a big difference.

 

[osirisk8er10]

yes i understand everything of wich you are saying and i appreciate all of the info but i have tuned for 18.22 psi and also for 19.00 psi because of the creep it doesnt level off there either but it is still creeping up there also and im only running pump gas right now and it comes in at around 4500 and redline is 8500 my main concern about running that much boost is mainly detonation i have got way more than enough fuel im running conservitive with timing im at about 17.8-18.9 degrees how much knock is everyone allowing on the 1g knock sensor i read on the aem forum to switch to a 2g knock sensor?? because they are more accurate?pump here is 93 octane and sorry for posting in this forum but i cant post any of this in the correct forum not enough posts thanks and my dump is 1.5in and vta. exhaust is 3in right off the hot side

 

[tenn-gsx]

I ran my 3575 at 12psi no problem during break in. No creep or anything like that. I realize that your turbo may flow a little bit more than a 3575 but it should still be able to hold the boost as low as 15 psi with a 44mm wg. Your problem may be the placement of the wg. Mine was directly on the turbine housing FP style. This means that the exhaust from all 4 cyl has to go past the w/g regardless of wether its open or closed. If yours is on the # 1 runner It may just be too much to ask of the exhaust to turn arround and go back up the #1 runner rather than just passing through the turbo. It will always take the path of least resistance and asking the exhaust to change directions that much probably causes alot of turbulence and resistance at the collector.

 

[osirisk8er10]

very true that is why im confused as to why im getting so much creep it doesnt really matter where the boost level is set because it always creeps and my gate placement should be fine im coming off the number 2 runner and it sees a little bit from the number one also i should be seeing enough exhuast flow i think what is happening is that im flowing so much air at such i high velocity that im pretty much just by passing my wastegate all together did you run a 2.5" 02 housing or anything of that nature? i think that my 3in is just to efficient and thats why my wastegate isnt seeing enough gases i noticed that alot of people are using aftermarket 02 housings and such but im just using my own custom 3in with an 02 bung in it.i have practically no back pressure at all

 

[EclipticalGS]

agreed, like i said, a better flowing manifold

 

[tenn-gsx]

I was running a 2.5 tubular v-band o2 housing. That very well could be the problem. Just fyi It has been proven that 2.5 vs 3.0 is unnessicary until you get over something like 700hp. Even then the gains are minimal because the exhaust gases are so hot and velocity is so high that close to the turbine outlet. I dont have the links that support what I just said but I have seen dyno results on a thread somewhere on here. I think it was on a Bushur Evo if I remember correctly.

 

[osirisk8er10]

i agree also but i am trying to avoid that because the only thing i would buy is a tub manifold using twin gates to make sure that i fix the problem however that would cost me alot of money seeing as how i would hafta buy another manifold and another wastegate so that i am trying to avoid.. and when i built the 3in exhaust because my turbo outlet is 3in and didnt really think much into know it kinda sucks ha. i de tuned the car a little so the creep has gone away its just really rich but as soon as i start taking out fuel and giving a little timing i would just smack boost cut at 19psi so any ideas as to what i could do. maybe a exhaust silincer to ad a little back pressure that should give me control back? or would i be to restrictive?