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Discussion Starter #1
During my up-pipe install I happend to look at the wastegate arm. I noticed that its basicly the same set-up as the TDO5 12a on the Mitsu Starion/Chrysler Conquest. Back in my SQ days we would losen that 10mm nut and twist the eye bolt all the way in (toward wastegate). That would raise the boost to 14psi. Then I remembered that the WRX has a factory boost controller and it probably wouldnt alow it. So if we took the T section out of the wastegate hoses and replaced it with a union (like the 3/16th mod part) then it shouldnt be a problem. This way we could get all the benefits of more boost w/o the PTFB of a MBC.

Has anyone tried this?

Also after the up-pipe I noticed my boost falls off after about 5k rpm. It will be at about .9 then fall to as low as .5. I never noticed this before but we all know how we pay more attention after mods. I used to have the MBC on but removed it so maybe I am just used to the way it would hold the boost?


Steven
 

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BVM said:
During my up-pipe install I happend to look at the wastegate arm. I noticed that its basicly the same set-up as the TDO5 12a on the Mitsu Starion/Chrysler Conquest. Back in my SQ days we would losen that 10mm nut and twist the eye bolt all the way in (toward wastegate). That would raise the boost to 14psi. Then I remembered that the WRX has a factory boost controller and it probably wouldnt alow it. So if we took the T section out of the wastegate hoses and replaced it with a union (like the 3/16th mod part) then it shouldnt be a problem. This way we could get all the benefits of more boost w/o the PTFB of a MBC.

Has anyone tried this?

Also after the up-pipe I noticed my boost falls off after about 5k rpm. It will be at about .9 then fall to as low as .5. I never noticed this before but we all know how we pay more attention after mods. I used to have the MBC on but removed it so maybe I am just used to the way it would hold the boost?


Steven
I am thinking that not too many do this because there is also the fueling and timing issues that need to be addressed when upping the boost on the car. By the time you do that, you already have an engine mangement system that can be used to up the boost safely.:)
 

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not to highjack this thread, but i have a stock boost gauge, and when im in 3rd gear it goes all the way to .1 and then falls to like .09 at the most. the only mods i have are a perrin DIF, TXS BOV, and delete elbow, what im getting at is people always say their boost drops a lot but i dont experience this, am i just a lucky one. oh its a 2004 with almost 3k miles.. thanx
 

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My 04 is the same way. The Boost will go up to 14.5 and settle just above 13.7 and it may drop to 13.0 by the time I hit about 6500 rpm.
 

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Discussion Starter #5
I am going to give it a try today. I'll post my results.

The boost issue bothers me alot. I remember the boost falling off somewhat w/o the MBC (pre up-pipe) on but I didnt remember it falling off that much. Guess I will pull the MBC off the Skyline and reinstall it on the WRX before and after my boost mod idea.
 

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all wrx's boost drops i think. its something subaru set up so that you don't blow your engine. your right though, the MBC will help hold boost all the way to redline because it and not the boost solenoid is controlling the boost
 

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BVM said:
During my up-pipe install I happend to look at the wastegate arm. I noticed that its basicly the same set-up as the TDO5 12a on the Mitsu Starion/Chrysler Conquest. Back in my SQ days we would losen that 10mm nut and twist the eye bolt all the way in (toward wastegate). That would raise the boost to 14psi. Then I remembered that the WRX has a factory boost controller and it probably wouldnt alow it. So if we took the T section out of the wastegate hoses and replaced it with a union (like the 3/16th mod part) then it shouldnt be a problem. This way we could get all the benefits of more boost w/o the PTFB of a MBC.

Has anyone tried this?
Steven
Yes, my car is running this wastegate actuator arm adjustment. Not just 14, more like 20. Is very like a MBC setup, just even cheaper, holds the wastegate well shut and no temptation on playing with the boost setting.
Not bad, is a common mod here (Argentina). You still get PTFB at high loads but not really bad EGTs.
 

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Rancid said:
The TD04-13G can't flow all that air all the way to redline. It s less a safety feature and more the ineeficiency of the stock turbo.
Pretty much this is the case.... And Hernan, I hope you are planning on getting a new turbo soon unless they run a different turbo overseas that is.
 

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Re: Re: boost idea

Chunks said:
What's that mean? pain in the ****ing balls?
partial throttle full boost
 

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Re: Re: Re: boost idea

Originally posted by Chunks
What's that mean? pain in the ****ing balls?

AIRBORNEGUYWRX said:
partial throttle full boost
Pretty much the same thing no?

Sorry for the thread hijack

Back on topic..

You mean just adjust the wastegate arm so it doesn't open as easy and bypass the factory boost controller

Free mod?
 

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Discussion Starter #13
Yeah, thats the plan and so far its working VERY well! I run Shell Optimax 98ron fuel in here and I cant see a down side yet. I have the boost set to 15psi with the stock boost controller by-passed and the wastegate eye bolt twisted in (toward front of car).
It is just like having an MBC installed!

FREE MOD FREE MOD!

Steven
 
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