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Old 10-12-2006, 08:40 PM   #1
2006-2.5i
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Default What can i do to my 2006 2.5i to increase HP?

I was wondering if anyone with a 2.5i has any ideas of parts like an exhaust or intake that will bolt up to the 2.5i to bost performance with minimal work? i've been looking for parts all over the place and none of them seem to fit the 2.5i only the WRX or STI .
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Old 10-12-2006, 08:45 PM   #2
FalconRS
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I'll assume you're talking Impreza 2.5i:

Headers: 98-05 2.5RS OBX, Rallitek, Cobb
Catbacks: Any 98-01 or 02-05 2.5RS catback
Intakes: Injen RD1222 (with one minor change)
Lightweight Pulleys: Any for EJ2x subaru engines
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Old 10-12-2006, 11:33 PM   #3
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Quote:
Originally Posted by FalconRS View Post
I'll assume you're talking Impreza 2.5i:

Headers: 98-05 2.5RS OBX, Rallitek, Cobb
Do these headers fit the 2.5i without modification to the exhaust/oil pan, etc?
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Old 10-12-2006, 11:51 PM   #4
FalconRS
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Quote:
Originally Posted by semaj View Post
Do these headers fit the 2.5i without modification to the exhaust/oil pan, etc?
Yep. Only the Borla and Borla-replica UEL headers don't fit. Haven't heard of anybody test fitting the TWE headers though.
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Old 10-12-2006, 11:57 PM   #5
schooby
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Quote:
Originally Posted by FalconRS View Post
I'll assume you're talking Impreza 2.5i:

Headers: 98-05 2.5RS OBX, Rallitek, Cobb
Catbacks: Any 98-01 or 02-05 2.5RS catback
Intakes: Injen RD1222 (with one minor change)
Lightweight Pulleys: Any for EJ2x subaru engines
98 header and catback fit the 05-06? You've tried it?

Intake for weight reasons, and everyone on in this section raves about lightweight pullyeys.
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Old 10-13-2006, 12:13 AM   #6
FalconRS
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Quote:
Originally Posted by schooby View Post
98 header and catback fit the 05-06? You've tried it?

Intake for weight reasons, and everyone on in this section raves about lightweight pullyeys.
Running the Borla 14885 catback (for 98-01 cars) on my 05, and the Borla-replica header (also for 98-01) as well. As for the rest, Rallitek lists one header for 98-06, and one catback for 98-06. The Borla- and Borla-replica headers DO NOT fit 06+.

Any questions?
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Old 10-13-2006, 12:20 AM   #7
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Quote:
Originally Posted by FalconRS View Post
Running the Borla 14885 catback (for 98-01 cars) on my 05, and the Borla-replica header (also for 98-01) as well. As for the rest, Rallitek lists one header for 98-06, and one catback for 98-06. The Borla- and Borla-replica headers DO NOT fit 06+.

Any questions?
care to explain why it wouldnt fit? i was planning on a Borla setup on my 07. If thats the case.. does that mean 02-05 headers would not fit the 06+?
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Old 10-13-2006, 12:31 AM   #8
FalconRS
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Quote:
Originally Posted by JoeyW View Post
care to explain why it wouldnt fit? i was planning on a Borla setup on my 07. If thats the case.. does that mean 02-05 headers would not fit the 06+?
Didn't really read the rest of the thread did you? Only the Borla-style headers don't fit, due to a different oil pan design. If you wanted to use the Borla-style headers, you'd need an older oil pan along with either a stock or aftermarket 98-05 catpipe. The Cobb/OBX/Rallitek headers all fit fine on the 06+.
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Old 10-12-2006, 08:46 PM   #9
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how about trading it in for a wrx/sti?
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Old 10-12-2006, 08:49 PM   #10
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Quote:
Originally Posted by nicmowrx View Post
how about trading it in for a wrx/sti?
Sad little people.
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Old 10-13-2006, 12:51 AM   #11
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Fact remains, they do gain power on 05 and previous cars, and nobody's proven yet that they lose power vs. the 06 stockers...lots of people have jumped on the assumption due to the true-EL nature of the 06 stockers.
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Old 10-13-2006, 01:01 AM   #12
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Quote:
Originally Posted by FalconRS View Post
Fact remains, they do gain power on 05 and previous cars, and nobody's proven yet that they lose power vs. the 06 stockers...lots of people have jumped on the assumption due to the true-EL nature of the 06 stockers.
Worth a dyno comparison for someone!
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Old 10-13-2006, 01:13 AM   #13
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Worth a dyno comparison for someone!
Couldn't agree more!
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Old 10-13-2006, 02:07 AM   #14
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I was under an 06 examining the exhaust for awhile last night...

The stock exhaust is 2.25" from the header back (although it was a legacy not a Impreza, so i'm not sure about the axleback on the Impreza) and the only way I can see to "improve" it would be to run a better muffler or just run a track pipe from the header back eliminating the 2nd cat and resonator. Its a really nice design now, and I want to convert to it if I can

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Old 10-13-2006, 02:33 AM   #15
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:do it do it:
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Old 10-13-2006, 02:35 AM   #16
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:do it do it:
Bacardi and Cola?
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Old 10-13-2006, 03:17 AM   #17
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:do it do it:
Have to find someone selling the stock 06 headers/cat section... I'm sure not going to buy them new
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Old 10-13-2006, 09:42 AM   #18
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Dude, if you get ahold of that thing and an oil pan, something to try might be hollowing out the cat in the header itself to get the restriction further away from the primaries. I think this would have a bigger effect than deleting the cat in the cat section.
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Old 10-13-2006, 01:24 PM   #19
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Quote:
Originally Posted by FalconRS View Post
Dude, if you get ahold of that thing and an oil pan, something to try might be hollowing out the cat in the header itself to get the restriction further away from the primaries. I think this would have a bigger effect than deleting the cat in the cat section.
Ya, I might actually be able to get a dead-cat header sometime anyway, since we just toss them out here at work (IE free stuff!). However, with the cat being so close to the engine, it makes it actually significantly better for emissions and doesnt really worsen the flow that much compaired to the old header/cats (which suck in terms of flow)
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