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Looking for some advice. I just picked up a used Cobb turbo back exhaust for my '04 FXT. I'm going to get my mechanic to put it on this week but I figured I should replace the up pipe at the same time to free up the restriction from the cat and to prevent any chance of the honeycomb in the cat from breaking off and killing my turbo and possible my engine.

Now my question is since Cobb no longer makes up pipes what pipe should I go with? Do I need the flex joint in the up pipe? Will the uppipe be compatible with the standard stag 2 maps in my AP2?

Thanks for any help!
 

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Official sf.org decal guy
2006 FXT
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12,367 Posts
Looking for some advice. I just picked up a used Cobb turbo back exhaust for my '04 FXT. I'm going to get my mechanic to put it on this week but I figured I should replace the up pipe at the same time to free up the restriction from the cat and to prevent any chance of the honeycomb in the cat from breaking off and killing my turbo and possible my engine.

Now my question is since Cobb no longer makes up pipes what pipe should I go with? Do I need the flex joint in the up pipe? Will the uppipe be compatible with the standard stag 2 maps in my AP2?

Thanks for any help!
Just go with an OEM one. You could pick one up pretty cheap on NASIOC. Unless you go with some aftermarket headers you probably won't see any difference between OEM and aftermarket uppipes.
 

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2004 Forester XT 5spd
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I installed an OEM catless up pipe and it decreased my turbo lag by at least 500rpm. It's a worthy upgrade.

Also....do the DP install yourself. Get some PB Breaker (it's like WD-40 only WAY more effective. Trust me, I didn't believe it until I tried it. It's practically a necessity.) and a breaker bar and go to town.

I had never done much mechanic work before. I pulled the headers off my old 98 Forester and I've done oil changes. Do the DP and UP install yourself and you'll become a pro.

Make sure you have extra bolts because if you're still running stock and the hardware hasn't been replaced....you WILL break, strip, destroy bolts. A hair dryer or heat gun is also helpful for putting the intercooler hoses back on. (I did it at 3am in my cold garage...it took me 2 hours until I tried heating up the hoses and BAM they went on.)

For instructions, search NASIOC and You Tube for wrx downpipe and up pipe install.
 

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2004 Forester XT 5spd
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Also, the AP maps should be fine with the up pipe. It doesn't really give you any horsepower or torque, it reduces turbo lag.

Turbo lag explained: It takes time for your engine to build up enough exhaust pressure to spin the turbo enough to produce boost (compressed air that is sent through the intercooler and into your engine which makes it "go vrooom moar"). The catalytic converter in the stock 04 pipe restricts the flow of exhaust from the engine to the turbo which delays the spinning of the turbo even more.

You COULD remove the cat from the up pipe yourself...but I'm told it's a pretty big hassle and an OEM catless up pipe is worth the $30 shipped.

Again....do the install yourself. I did this weekend. I learned so much from the process and I have that satisfying feeling that I DID THIS when I blow past people on the highway.
 
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