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Discussion Starter #1
I currently have a 2.75'' pipe starting at the axle back (stock downpipe, stockmidpipe, 2.75'' straight pipe where the muffler was with a cute tip on the end)

anyone ever replace the midpipe with another straight pipe ... basically meaning stock down pipe, then straight pipe all the way back? (eliminating the resonator)

I'm wondering if it'll sound crappy or not before I pay a shop to bend some pipe for me... probably a 3'' or 4'' midpipe...
 

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The way it sounds is subjective of course,

But I have run an RS with borla headers and stock cat without a catback at all (so basically the same sound as a straight pipe) and it sounded mean as hell, although pretty loud.

It could be too harsh for some though.
 

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Discussion Starter #3
I'm hoping for something that sounds like this:



with the diesel-esque whistle from the turbo... but I think he has straight pipe from the turbo back. ie; no cats. so I might not get the whistle unless I go for a different downpipe with some high-flow cats.... or no cats at all.

I want to run cats still, just no resonator or muffler.

so if I do this and it's TOO loud, I can still weld in a muffler in my rear pipe (plenty of room for a normal size straight-through muffler)...

I still need to get an accessport and tune though...
 

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Discussion Starter #5
well right now I DO have a straight pipe from the axle back... and it doesn't sound like that. here's my car, "muffler delete" (straight pipe from the axle back. has a pretty tip on the end to look stock)


(I can't hear the turbo at all) -- so I'm hoping getting rid of the resonator will bring out more sound, including the turbo whistle... however, like I said, I might have to go catless to get that.
 

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My fault, i totally wrote the wrong thing, i meant CATBACK. Sorry saturn :) I think you'd get what you want with a straight pipe catback....i believe adding an intake will also allow you to hear the turbo more, but then you'd probably want to get a tune.

You are right, you will probably hear even more turbo with a catless downpipe
 

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Discussion Starter #7
right.

and for what I do mostly (rallying/dirt) I probably want to keep the stock air box -- it isn't even that restrictive with a K&N drop-in filter.
 

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right.

and for what I do mostly (rallying/dirt) I probably want to keep the stock air box -- it isn't even that restrictive with a K&N drop-in filter.
Yeah, our stock intake is pretty good as OEM intakes go....and you are correct in that certain rally rules dictate that you keep the cat, exhaust manifold, and airbox stock anyway. (at least some of the classes in SCCA rally are like that).

That and you probably want the anti-water ingestion properties of the stock intake :)
 

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Discussion Starter #10
yep

I'm assuming the resonator is what hides most of the good sounding stuff

I would go fully catless straight pipe from the turbo back, but I don't want to destroy my car (no tune + true straight pipes + boost creep)
 

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My brother's 05 makes that whistling noise as well, very much like in the video. He has a catted DP w/ STi axleback. I doubt it's the resonator thats keeping the sound away as the SPT exhaust and aftermarket catbacks remove the resonator but do not produce that whistle.
 

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Discussion Starter #12
but the SPT exhaust is still pretty restrictive

maybe it's the cats :(

oh well I want to get rid of the resonator anyway, if it's too loud I'll get a muffler
 

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It should be the cats. When installing the SPT exhaust, I unhooked my mid pipe, and started the car......... still didnt hear the whistle.
 

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Discussion Starter #14
yeah just talked to someone

they said the resonator is basically a straight pipe with some holes around it, it isn't restrictive... to get the whistle I need a DP with high-flow cats

and DP means I need a tune... so $$$$
 

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I have been running a catted DP for 6 months now without a tune and haven't run into any issues. No spike or creep. I am sure I would have more HP with a tune but the car is just fine without it.
 

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I am running it exactly the way you describe. 3" resonator-less midpipe is the only change to the exhaust system. sounds the same only louder. No raspinesss or droning. SPT and most other companies remove the resonator as all it does is add a lower tone and volume to the system. However since we have boxer engines, the tone note actually sounds very similar with or without resonator.
 

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Discussion Starter #19
the "rumble" sound is from the unequal length factory headers and the timing of the boxer engine

equal length headers, found on hondas, etc... are what porsche use... plus some porsches DO rumble... just depends

there are subarus with equal length headers that don't rumble
 

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i was under the impression that it was the unequal length headers that produce the sound. not the boxer engine. How come porsches dont sound like subies then?
ehh, it's what ppl are used to. Boxer motors dont rumble sound wise..... they make the car shake side to side sometimes. Youre right, it's the unequal length header design that gives the car its sound. The 2.0L GRB STi does not sound like the 2.5L STi we have here, also due to header design.
Aside from Porsche, Ferrari had a flat cylinder designed engine..... flat 12!!!!
 
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