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2004 Forester XT
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26 Posts
Discussion Starter #1
I was wondering if anybody knows if the sti intake manifold is any different to the 2004 xt. Any advantage to upgrading it? Which years sti will it fit? Plus it looks cool when you open the hood with the red intakes. Any feed back would be awesome
 

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2006 Forester XT A/T
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8 Posts
I was also thinking of fitting one to my car, but I'm not sure it is worth the effort, if it is only a cosmetic upgrade...
 

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2004 Subaru FXT MT
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1,841 Posts
It's the same aside from the red paint.
This. I'm don't think its worth many hours of labor for a red manifold. If you have to take it apart for other reasons, go for it. Thats my opinion anyway.
 

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As others have said, color is the only difference. The intake manifold and tgv's are one of the biggest PITA jobs to do on the car. All of the fuel lines, engine harness etc are bolted to the bottom of the intake manifold, and there are tons of things to disconnect (and then getting it back in is NOT fun).

The only time I'd swap the intake manifold is if you're already swapping fuel rails or injectors or putting on tgv deletes.
 

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2006 Forester XT 4EAT
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362 Posts
I believe the 2.5i manifold is the only one that would flow more air.

I also believe you would need a tune to accomodate for it.
 

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04 Forester XT MT
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269 Posts
I believe the 2.5i manifold is the only one that would flow more air.
I read that a couple weeks ago and was wondering if there was any truth to it since I haven't seen alot of people talking about swapping to that manifold
 

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2004 fxt A/T
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2,567 Posts
I read that a couple weeks ago and was wondering if there was any truth to it since I haven't seen alot of people talking about swapping to that manifold
It requires a FMIC since the plenum is larger on the N/A and would make fitting a TMIC impossible.
 

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2005 FXT 5-spd
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278 Posts
How do the intake runner diameters/lengths on the 2.5i compare to the FXT/STI manifold? Generally, a larger plenum volume = better highend power. The same is true of larger diameter shorter runners. I've always thought the STI/FXT could gain some decent upper range power by going to a manifold with a larger intake plenum and shorter runners especially with larger turbo setups. The STI manifold has a very small plenum with long runners which probably helps considerably in the great low end/mid range of these cars. However the small plenum could have been a compromise in the design in order fit a TMIC rather than a design for better lowend power.
 

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07 fxt
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396 Posts
the stock sti/fxt manifold doesnt really choke until you get around 600whp.
the 2.5i mani is nice becuase it bolts directly to the head and has no tgvs. it does flow more too but the dbw throttle body doesnt bolt to it.
dominic of maxwell power services runs the new plastic lgt manifold on his car (07sti). the runners on it i think are bigger and they look like they would flow better as well.
 

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2005 FXT 5-spd
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278 Posts
the stock sti/fxt manifold doesnt really choke until you get around 600whp.
the 2.5i mani is nice becuase it bolts directly to the head and has no tgvs. it does flow more too but the dbw throttle body doesnt bolt to it.
dominic of maxwell power services runs the new plastic lgt manifold on his car (07sti). the runners on it i think are bigger and they look like they would flow better as well.
Well the fact that it doesn't "choke" isn't really what I was refering to. A good amount of the powerband characteristics are determined by intake design. Or put another way, when designing an engine, an engineer will design the intake manidold with the type of powerband they want in mind. It has to do with more than how much it "flows".

I like the no TGVs part!
 

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2007 Forester XT
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119 Posts
So a 2012 sti intake manifold will fit a 2007 fxt? I'll be doing a stage 2 install soon and since intake manis are cheap I figure I might as well.
 
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