Size of STi axleback inlet?

[ScoobySubyDoo]

Is it 2.25 or 2.5? I have searched a lot and have found mixed responses. Please don't tell me to go out and measure it, I won't see my car for a few days.

The reason I ask is because my wrx has an Invidia v2 catless DP, stock wrx midpipe with a resonater, and a 2004 STi axleback exhaust. I want a non-resonated midpipe just to have a throatier, maybe louder sound.

The invidia DP is a 3 inch outlet (right?) so I will need a midpipe that goes from 3 inches to 2.25 or 2.5 inches I am guessing. Any info would be appreciated.

Thanks

[WMCCook29]

Here's what you're looking for: http://www.daddysscp.com/product_p/hb.htm

[ScoobySubyDoo]

Ok thanks, seems a bit pricey so maybe I will look into custom making one. So basically the answer to my question is, the STi axleback inlet is 2.5 inches? So I need to make a mid pipe that goes from 3 inch inlet to a 2.5 inch outlet, right?

[rocketperson7]

Originally Posted by ScoobySubyDoo

the STi axleback inlet is 2.5 inches?

yes

personally, I would run with out the muffler and only the resonator before I would run muffler and no resonator

resonator-less does not mean "throaty"

but it's your car

[ScoobySubyDoo]

So you would keep the resonater and just buy a different muffler? I like the stock sorta look to the STi exhaust. So deleting the resonator won't change the sound at all?

[tomacGTi]

Resonator-less and cat-less STi axlebacks sound very tinny and gruff for lack of a better word.

I spent alot of time on YouTube looking before I pulled the trigger on my setup. The most I would do with the STi axleback is a catless downpipe. It just sounds really unrefined once you pull the remaining resonator and cat out of the equation.

[rocketperson7]

Originally Posted by tomacGTi

It just sounds really unrefined once you pull the remaining resonator and cat out of the equation.

Um..there isn't another catalytic converter after the one in the downpipe, but ok

OP, you need to think about what each part in the exhaust does

Resonator- think of this as a sound frequency filter, this does not really affect volume, but will filter out any "tinny"-ness to the exhaust, it's going to keep all of the lower frequencies

Muffler- this absorbs sound. Mufflers that absorb mostly higher frequencies are mufflers that people say aren't tinny without a resonator. These mufflers are also going to be cocked sideways, be obnoxiously loud, and be mad tyte br0.

again, it's your car, do a youtube search, waste lots of money on an exhaust you don't need, end up hating it..repeat

[ScoobySubyDoo]

Ok well I already have a catless DP. I will look up a bunch of sound clips to see what I like.

[D-Rodman]

The sti inlet is a bit smaller than 2.5" but interfaces and bolts together fine to a legit 2.5" exhaust flange.
I've had a cobb down pipe mated to a stromung straight thru intermediate to an sti axleback. There was nothing unrefined about it, just to quiet and mellow for my taste. You have to try different types of exhaust to find what you like.

[ScoobySubyDoo]

So basically, the only way to get a louder exhaust is to change out the STi axleback? Changing to a straight midpipe won't do anything?

[ScoobySubyDoo]

Haha I'm g00d br0. I will probably just stick with the catless downpipe and STi axleback then. I can spend the money on other useful things

[rocketperson7]

good choice, that's what I've done as well

[ScoobySubyDoo]

It is just a big change I will have to get used to. My last car was obnoxiously loud when you were on the throttle but quiet when cruising. I liked it a lot. But, maybe my new quieter subaru is a good change

[tomacGTi]

http://www.track-tek.co.uk/images/wr...w-text-600.jpg

Factory cat/exhaust layout. Three cats.

[ScoobySubyDoo]

Idk why that diagram is like that because I have no cats. My exhaust system is stock besides the catless DP. No cats after the DP here...

[jospgut]

^^ the downpipe has 2 cats and the uppipe has one.

[ScoobySubyDoo]

Ok well I have a catless up-pipe as well, forgot to mention that. His diagram says the mid-pipe has a cat though

[jospgut]

Originally Posted by ScoobySubyDoo

Ok well I have a catless up-pipe as well, forgot to mention that. His diagram says the mid-pipe has a cat though

The stock downpipe has two parts, they are referring as the mid pipe the end part of the down pipe

[ScoobySubyDoo]

oh alrighty.

[Vlad]

The diameter questions always come up, I took some measurements and posted them here.

http://forums.nasioc.com/forums/show....php?t=2416743