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2007 FSTI and X 6 MT
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22,330 Posts
Discussion Starter #1
I have been rocking the stock FXT rear muffler section for a few weeks and I really like it nice and quiet. With this thought, my exhaust set up is

TXS 4" dp, high flow cat, 3" cat back with RFL muffler(straight thru design)

I would keep the dp and cat in place, add a 3" electric cut out and go with it, but im concerned that it will sound like crap and I will loose some hp.

So, does anyone have an electric cut out on their forester?
 

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2008 FSXT M/T
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4,170 Posts
youd probably need a seperate tune for it and it def wont sound good though(on a v8 it does), ever hear just a dp? not to mention to really take advantage youd want to be catless, the cat would still be a restriction...

a lot of these cutouts dont last long either, being under the car exposed to the elements they take a beating.
 

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2004 forester xt
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293 Posts
i ran with mine for about a week with no axel back just a 3" catless down pipe and 3" mid pipe and it turned heads left and right and it sounded sweet! bad thing is its a cop catcher.... i rolled past a cop who was 4 lames away going the opposite way i was in 4th gear doing 35 which is about as quiet as i could get it and he whipped around after me so quick!

luckily i dodged him and lost him in a neighbor hood lol
 

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2014 CVT
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826 Posts
you just have to make sure you use them......otherwise they seize up, there was a guy at my school that run them on his STI, but he graduated so i cant help much past that
 

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2007 XT - 5MT ELH, EWG, E85, Kinugawa TD06SL 20G 8cm
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1,589 Posts
Just get a Forester specific MadDad Whisper back-box, I am running an STi one (shorter canister) and its rather civilized under most rpm, once you gun it, you get a sweet boxer rumble, look for my snow-drifting vid, you can hear the exhaust.
 

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2005 Legacy GT
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3,726 Posts
i ran with mine for about a week with no axel back just a 3" catless down pipe and 3" mid pipe and it turned heads left and right and it sounded sweet! bad thing is its a cop catcher.... i rolled past a cop who was 4 lames away going the opposite way i was in 4th gear doing 35 which is about as quiet as i could get it and he whipped around after me so quick!

luckily i dodged him and lost him in a neighbor hood lol

:shake:
 

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none none
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9,011 Posts
When I broke my axle back bolts, I ran "open cat" for a few days. It thundered down the road, but nothing like a straight pipe muscle car. The turbo ends up quieting it down a bit, I'd say the sti around here with a nur spec exhaust is louder than mine was with open cat (hes catless though). I think one of the cutouts that just has a blank plate that can be removed is usually a better way to go. If they use salt on the roads by you, the motor will most likely seize up, especially on any of the cheaper cutouts.
 

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2016 Outback and WRX CVT
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2,589 Posts
AFAIK, electronic ones still have a rather high rate of failure. Mechanical ones, like FPT said, you'll want to use it enough that it doesn't just seize up on you.

Depending on where you go in your exhaust tract, you may or may not pass emissions inspections, if that's a concern. Pre-cat will be what you're looking for, in terms of getting power out of it, but in all honesty, with your post-turbo pipework, if you simply removed that last cat, you'd likely see just as much power gain as you would with the cut-out. Yes, you'll likely lose a bit from the stock muffler still being in-place, but it's give-or-take.

A long time ago, Team23Jordan on LGT.com did a back-to-back run with his 3" turbo-back, with the cut-out open and then closed. The difference was easily within margin-of-error for the dyno, itself.

The crucial pieces to your project would be if you were going to put the cut-out before the cat. or after (in which case you'd likely not see much gains, at all) and similarly, if you were going to go with a CBE (since you've got the DP already), whether or not the cut-out would make any difference, at all, in terms of power gain.

For the aural mod, though, that's definitely one that's variable according to individual tastes. :smile:
 

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2007 FSTI and X 6 MT
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22,330 Posts
Discussion Starter #11
If I were to do this, which im thinking I wont, but IF I were, I would add a 3" section to the rear where the axle back mates, then put the cut out infront of the stock muffler. Basically it would neck down after the cut out to 2.25 but still retain the 3" cut out.

Several of the locals run the DHM's with no issues.

Edit above, I meant DHM.

Welcome to DMH Performance!

3 year warranty too!
 

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2007 FSTI and X 6 MT
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22,330 Posts
Discussion Starter #13
Could you possibly run a cut out with a extension/ resonator on the end. Though that just sounds like a lot un-necessary-ness!
My thoughts exactly. I think I will just buy/make a silencer for the RFL.
 

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05 FXT
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1,540 Posts
I've got a wild idea that I have yet to test out. Maybe I'll try it in the next few weeks, but I think it'd fit the bill perfectly for both of us. I'm in the same boat as you.
 

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05 FXT
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1,540 Posts
Will do. I've got a spring based valve I'd like to try out in the exhaust. I have 2 concerns at this time...

1: The spring pressure may not be enough to keep the valve shut as much as I'd like. But that could be resolved by adding a helper spring.

2: Based on my logs w/ the axleback on and off, it seems the bottle neck is not the STi muffler, therefore I'm guessing it's the resonator in the stock mid-pipe which for some reason I keep running. Should I continue to run it, my valve would need to be branch out for the valve will need to be pre-resonator creating concerns on where the valve will be and where will all of my nasty exhaust gases go flying. I haven't had the car on a lift or crawled under in a while now, so I haven't sniffed out if a good route is possible or if I'm just going to say heck w/ it and let it dump.
 
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