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Discussion Starter #1
I been reading these forums and alot of ppl have boost creep with a tbe. I called a shop around here in dallas called wasabe racing and they said i will not have that problem, they are sell me a aps turbo back exhaust. I was wondering who has a turbo back exhaust with no boost creep problem, since alot of ppl have.
 

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I'd really like to know this as well. I didnt experience boost creep before, but I got my turbo ported anyways to keep from having problems for when I get the nurspec back.

Robert~
 

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avo turbo inlet question

ya :( unfortunately sti is right. I believe a full port job will fix it, but it sucks that it has to come to that.

Robert~
 

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Discussion Starter #5
I called another shop here in dallas that does mainly wrx/evo and shyt and they said i shouldnt have boost creep with a full tbe. I told them that alot of people get it and they said they never had, and looking at the topic i post so far no one in this forum has a tbe with no boost creep. damm shops!
 

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you WILL get boost creep with a turbo back exhaust...no matter who makes it. from what i've read aps makes some really nice stuff...but boost creep will occur when you remove the two cats in your stock down-pipe....to combat this problem staticx has an electronic boost controller...and had the wastegate of his turbo ported...this seems to be the cure...we shall see...i intend on running the god sped dp soon and we'll see...it's not the end of the world either....it wont make you lose a race..just make you back off the throttle a bit...but i still cant be beat...even with a little creepin.... 8)
 

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I have a little creep but I have never had a fuel cut. My MAX boost is under 17 PSI. I have run it @ 15 degrees F with zero problems. I have a TXS TBE with high flow cat. My only problem was a little discolor and melting of the bumper. TXS has corrected the design and it should not be a problem now.

I am also CEL free {running the TBE for 6 months}.

EDIT 1-6-04
I had a fuel cut yesterday with a boost spike of 18 psi in 4th gear at approx 6k rpm. It was 9F with a windchill of -7F{Does the windchill matter?}.
 

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i spoke to a gentleman @ flat 4 and he said the same thing hummer said.
his peaked @ about 17 psi. definitely had creep, but never encountered fuel cut probs.
 

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New Take Off STI Seats

Installed TBE on sat Perrin with o2 sim. Boost creep and fuel cut fist run. Removed exhaust and brought turbo exhaust housing to Petit racing mazda specialist in Fl. Stated common problem with Mazdas took two hrs to port wastegate and 70 dollar charge problem fixed. Wish after market sellers would tell the truth about their products. Would have saved me 4 hrs work.
 

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I wrote APS directly about this. They gave me a perfectly honest reply, stating I would have boost creep and the only way to solve it correctly is either a new turbo or wastegate porting. A boost controller will help, but it's an artificial fix, the problem still exists and you will not reap the full advantage of a TBE. Sounds like someone is eager to make a sale to me.
 

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The reason is simple, the stock wastegate is too small to remove enough air to slow the turbine down so since it cant slow the turbine down the car builds more boost. Stock you have cats and your exhaust that all causes backpressure, since the exhaust gasses cannot leave fast enough you dont overboost, its all backed up and your exhaust turbine has to cut through all this "extra" air its basically slowing down. With a TBE or DP etc you are letting all the "built up" air evacuate faster so now your exhaust turbine doesnt have to cut through backed up air, its moving faster making more boost, its working better but now the stock wastegate cannot keep up, it is too small to let the excess air leave. IE overboosting, thats why a port and polish (read cleaning and making the wastegate larger) works. Nothing but a larger wastegate will solve this although a boost controller may help somewhat it is not a "fix" and if you wait until the temp gets colder you will overboost even more.
Hope that helped.

*edit* oh some exhaust cause higher spikes than others, thats because some breathe better than others, been discussed 1000x's before but exhaust with some backpressure on a turbo will increase low end torque more than another that flows better (higher top end) since "no exhaust" on a turbo is the best exhaust, or so the large discussion goes :D but that doesnt mean you should get the largest exhaust you can since the more an exhaust expands the slower the exhaust gases go (expanding gasses are cooling off faster and moving slower) so dont get a large 10' full turbo back exhaust :D most agree that a 2.5' exhaust is not a restriction on turbocars up to 450-500hp (cant remember I should read "Maximum boost" again :)) while a 3' is best for higher hp applications although I dont belive the difference whould be noticed by most.

Again I hope that helps :wink:
 

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sti_187 said:
I was wondering who has a turbo back exhaust with no boost creep problem, since alot of ppl have.
I ran into a guy, w/ an STI who had it but supposedly curtailed it w/ a controller, as I was getting my exhaust installed.

He did a full Invidia turbo back and did get creep, all the way to fuel cut. But, he then added a Greddy electronic boost controller set at 15. He says the car runs perfectly now and he hasn't hit fuel cut since??? Take it for what it's worth.

--EDIT--
Post ECU reset, w/ the TXS stealthback, operating under reasonable outside temperatures, boost creep is not an issue.
 

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I'm crutching my wrx with a MBC for now but did notice some serious creep today 18 degrees out.

Question: Can I install my WRXs Perrin up/downpipes on an STi (WHen I get one this spring?)

Also, do you guys know any links that have good pictures of the do it yourself wastegate port job.

I knife edged my throttle body intake and butterfly, and ported my intercooler inlet elbows so I now have the correct dremel bits to port.

Hopefully the tungsten carbide bits are hard enough to port cast iron?? Anyone know?
 

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I have been running with a RFL BOV and never had a problem. put my stock one back on because everyone says it is better . I have deltadash and was loggin when it hit 18.4 psi. fuel cut and ecu started blinking. I am going back to my RFL. i do have the logs if anyone is interested.
 

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As you just explained it, your stock BOV hold boost pretty good! :lol:

Really though they should both let you hit equal amounts of boost, maybe your RFL is not tight enough? They are pretty good BOV's from what I understand so maybe you need some spacers (or something) in there? I believe they are adjusted with washers?
Sorry If I mistyped about the RFL and its adjustment, although I know you can adjust them somehow.
 

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it seems to me that if you leave that last oem cat on you will not have boost creep.a gt spec header and a bosal downpipe with the last cat,
and stock cat back no boost creep.--we will be trying a twin tip bosal cat back and then a sti genome muffler....which sounds great.

dave
 
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