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Discussion Starter · #1 · (Edited)
Im looking into getting an APS exhaust system because it looks more like stock. I would like to know how you can tell the difference between the full 3" exhaust and the one the tapers down to 2.5". where exactly does it neck down? anyone know? thanks!


Look like full 3 inches?
 

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The taper is at the back of the downpipe. Also referred to as a "donut" gasket. See my ongoing thread in this sub-forum for details.
 

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Discussion Starter · #3 ·
ender18d said:
The taper is at the back of the downpipe. Also referred to as a "donut" gasket. See my ongoing thread in this sub-forum for details.

then this is a full 3 inch correct. this is the DP/midpipe connection
 

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Looks like it.
 

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ender18d said:
The taper is at the back of the downpipe. Also referred to as a "donut" gasket. See my ongoing thread in this sub-forum for details.
Are you sure about this?!

I have an APS full 3". Nhluhr has the 2.5". IIRC, the taper is actually in the axleback. The downpipe, catpipe, and midpipe on the APS are the same for BOTH systems. In fact, you should be able to convert an APS 3" to the APS 2.5" by simply replacing the axleback portion of the APS. Nhluhr and I discussed this awhile ago and I remember what I just stated above as being the facts.

t
 

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I don't see why you would want to have a 3" go into anything smaller. Why buy an exhaust that has a bottle-neck.
 

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Blais, I have the APS full 3" catted if you want me to stop by ader's (spelling?) place for sound.

also, look at nhluhr's car. He has the 3-2.5 APS system and he loves it. there is virtually no difference at stock turbo power between the full 3, and 2.5 system. plus, it's much quieter. I know you want a bigger turbo though. I'd personally go 3" (obviously, and i did). South Coast Subaru has the best price for APS.
 

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I'm pretty sure Wolf is right that the taper down is where the midpipe and axleback meet. That seems to be how most 3" to 2.5" systems work.

With a quick look around I found this:



Looks like that axle-back piping is 2.5" and that's where it tapers down. That's a pretty nice design actually, letting you go to 3" if you want with just a new axle-back. I thought they might have done something like the old TXS midpipe which starts as 3" but then quickly shrinks down to 2.5" when it gets to the axle-back flange.
 

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jsmsustudent said:
would there be any advantages to getting the 3.5" if you have the stock turbo or is 3" plenty? I might upgrade turbos but it will be a long time before i do.

the 3"-2.5" would be plenty, but if you are going to upgrade turbos i would go with the 3". APS doesn't sell axlebacks seperately. If you don't care about the loudness a 3.5" system would produce, then the 3.5" is the way to go.
 

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^^^Backpressure an issue with 3.5" and stock turbo? :confused: (I have no idea, but the thought came to mind).

I'd go 3" regardless...I can't imagine that the 2.5" is THAT much quieter. :notsure: (Cobb is quiet and it's a 3" system with a pinch at the donut gasket)
 

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nandanrp said:
^^^Backpressure an issue with 3.5" and stock turbo? :confused: (I have no idea, but the thought came to mind).

I'd go 3" regardless...I can't imagine that the 2.5" is THAT much quieter. :notsure: (Cobb is quiet and it's a 3" system with a pinch at the donut gasket)

according to nhulhr, his roomate IIRC, had the R1 (full 3"). nhulhr had the R2(3"-2.5"). He said there was a big difference. I'm sure he'll see this thread and chime in.
 

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Discussion Starter · #14 ·


im buying a used one, and i want to make sure its the 3inch, the guy doesnt know (it came with his car)

this look right?
 

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hard to tell what size it is.

From that angle, it looks like the tip is flared, but again it's hard to tell. You need more pics. Preferably at the axle back midpipe connection. Also see if you are getting a cat. It's in the downpipe.

FYI APS' tip isnt flared at the end.
 

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^^^looks like a greddy
 

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Discussion Starter · #19 ·
well the downpipe has the removable catless pipe part, i can see that in more pics he sent, i dont know any other exhaust system that does that.
 

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Blaiser said:
well the downpipe has the removable catless pipe part, i can see that in more pics he sent, i dont know any other exhaust system that does that.

ok. the removable cat/test pipe should be in the Down of the "down pipe", lol if that makes sense.

^^I posted the pic. mine looks like it has a flare too...
 
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