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2008 Forester XT Auto
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148 Posts
Discussion Starter · #1 ·
Sti tmic, 255 walbro, vf-43, invidia DP, access pro with cobb vf-43 map installed.
Stock intake and fxt exhaust. Car is an auto.

K guys, I monitor boost and I get 12 psi peak in first gear and ~13.5 in all the other gears. Peak is supposed to be 15.5! Cobb says it's a boost leak. My turbo is only at 11,000 miles, and I used all new gaskets on the turbo install. Using the stock restrictor pill as cobb requires in the notes. My boost controller is stock, and held boost perfectly fine when I was at stage 2. I've checked all hose connections and made sure everything is super tight! I didn't replace the gaskets at the y pipe connecting to the intercooler. But the connections are very tight. What do you guys think?
 

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2005 Forester XT 4eat
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4,581 Posts
It definitely could be the intercooler gaskets. Also, 13.5 psi isn't necessarily bad for a boost target of 15.5. Stock FXT exhaust could also be holding you back. Is the invidia dp catted or catless? What's your altitude?
 

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2008 Forester XT Auto
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148 Posts
Discussion Starter · #3 ·
It's catted. Altitude is 2200 feet. Think there might not be a leak? The tune calls for a free flowing turbo back exhaust, which I don't have cause the fxt exhaust goes down to 2.25" before the muffler.... I don't want a loud obnauxious exhaust though. And I can't afford $600 for a maddad axle cat back. Think I should install a sti axle back? I hear they arnt too loud and flow much better....
 

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2005 Forester XT 4eat
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Not hitting boost target is safer than over boosting. As long as the car drives well, I'd leave it as is. High altitude + cat + FXT catback sounds like a combination that would limit boost safely.
 

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2008 Forester XT Auto
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148 Posts
Discussion Starter · #5 ·
I'm in the process in buying a sti Catt back. Is that going to help at all or am I wasting $150? I'll go from 2.25" to 2.5" and the muffler apparently flows better...

I kinda wanna hire this Clark guy who sells maps online to install in my car. He says with my combo, his map will run 18psi. I've read a lot of guys run psi at that level with a vf-43. I still want more power, and 12-14 psi won't cut it! What do u think?
 

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2008 Forester XT Auto
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148 Posts
Discussion Starter · #7 ·
Is that a boost controller? I read a thread that somebody had my problem and his boost controller was acting up. What's the difference in a manual and non manual? E tuners seem pretty good... I'm thinking of doing that..
 

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2005 Forester XT 4eat
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Your stock BCS might be fine. First decide who you want to tune your car, then ask them which BCS they prefer. There are a lot of reasons why tuners prefer a 3 port BCS to the factory one. They only run around $100.

There isn't much difference between the FXT catback and the STI catback, but the STI one should flow more, and should allow higher boost. It's worth replacing if the one you are replacing it with less rusted than your current one and you can rustproof it.
 

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2017 VW Golf SportWagen 5MT
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Okay. If you want more power, swap that turbo for a 20G to begin with and don't waste your time. If you want to stay concervative and quiet, you are there minus a GOOD professional tune at a local dyno (altitude, fuel, etc). $150 for an STi catback is $80 too much, but it's alright -- just don't expect a power change.

Stan
 

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2011 turbotek tuned fxt 4eat paddle shift
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When you say you are using the stock pill are you refering to the pill for the vf43 or the pill for the td04? Did you buy the turbo new or used? If you are using the pill and lines that you had on your td04 then that is your problem the pill for the vf43 has a smaller opening to allow it to build more boost. If you dont have the vf43 pill you can get them at your local dealer for under $10.
 

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2008 Forester XT Auto
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148 Posts
Discussion Starter · #11 ·
It's the stock pill for the Td-04. Do you think that's it? I'm going to a dealer to buy a 2007 sti vf-43 pill and try that. Wish me luck!
 

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2011 turbotek tuned fxt 4eat paddle shift
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Yeah I prefer a 3 port as well but you can't use cobbs ots tune you will need a custom tune or etune. You can email my tuner if you want he tunes a lot of guys on here you can pm me if interested. Another thing you can do is take out your td04 pill and fill in the hole a little bit with super glue or jb weld. Just fill it in a tiny bit and repeat if needed until you hit your desired boost level.
 

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2008 Forester XT Auto
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148 Posts
Discussion Starter · #16 ·
Is that what an electronic boost controller does? You can get rid of the pill problem? But then I need a etune or pro tune... Why does some controllers have 3 ports? My stock one only looks like it has 2...
 

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2011 turbotek tuned fxt 4eat paddle shift
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Yes a aftermarket ebcs or eletronic boost control selonoid is a 3 port designed to block airflow while your stocker is a 2 port designed to bleed it off. The 3 port will eliminate the pill and you will need to replace all your vac lines on the turbo but its very easy. Yes you will need a pro tune but i suggest one anyway as cobbs maps suck and are generic. If you want to go the 3 port route email me and i can give you my tuners email and he can send you a 3 port for cheap and etune you as well. If you would rather go the cheap route then try my suggestion of filling in the pill you have until you hit your target.
 

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2008 Forester XT Auto
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148 Posts
Discussion Starter · #18 ·
I would like to buy the vf43 pill and hit target boost with my vf43 which is 15.5 pounds before I get an etune. It's good insurance my system isn't leaking and everything works safely. Then I wanna get a good etune, I'm texting a guy who I met on nasioc and has a decent rep doing etunes. Goes by Clark tuning. He says his tune for my setup runs 18 psi. That sounds pretty intense compared to the dismal 13 I make now! Think this route is good?
 

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2008 Forester XT Auto
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148 Posts
Discussion Starter · #19 ·
A new boost controller isn't exactly needed is it? My stocker works fine... And I haven't heard of any major advantages to a new one unless you're running bigger psi than I will be
 
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