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Old 09-10-2010, 11:55 AM   #1
RaineMan
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Default 2.5i Stock Exhaust Diameter?

Hey all.

Wondering about the size of the stock 2.5i exhaust. Can someone post measurements? I'm looking to get a little more sound out of the car and replace my plain (and slightly rusty) stock muffler. don't really feel like shelling out mega bucks for a full cat-back. Was gonna order a muffler and tips online then go down to a local shop and have them welded up... just need to know what the inlet size should be.

Thanks!
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Old 09-10-2010, 12:34 PM   #2
chuds
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Not sure of exact diameter. If your buying a muffler and having them weld it they 'should' be able to make just about anything work. Muffler inlet 2.25 or 2.5 is good.

I put a wrx (2.5'' pipe) stromung axel back on my 2.5i with no issue. Flanges will match up perfect. I got mine used here for a fraction of the price. Check local classifieds section here for a great deal on an axel back.
Still might have to torch off the old bolts, mine were beyond rusty and a new gasket.
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Old 09-10-2010, 12:37 PM   #3
iRazor
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my muffler place said i have 1.75 on my 10' impreza sedan. im looking to replace mine as well but im not sure if the wrx catback i was looking at would bolt up directly to my headers
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Old 09-10-2010, 12:57 PM   #4
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Quote:
Originally Posted by iRazor View Post
my muffler place said i have 1.75 on my 10' impreza sedan. im looking to replace mine as well but im not sure if the wrx catback i was looking at would bolt up directly to my headers
on my 08 2.5i Legacy i have a 2.25" mid pipe with 1 7/8" splits to each muffler
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Old 09-10-2010, 12:58 PM   #5
RaineMan
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Quote:
Originally Posted by chuds View Post
Not sure of exact diameter. If your buying a muffler and having them weld it they 'should' be able to make just about anything work.
True... however restriction is still in the back of my mind. If the stock exhaust is smaller than 2" I may lean more towards buying a full cat-back.

For you guys with dual mufflers I'd say the mid-pipe diameter is what I'm after... since the pipes would be smaller after the split b/c they only have to carry 2 cylinders worth of exhaust.
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Old 09-10-2010, 02:53 PM   #6
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Quote:
Originally Posted by RaineMan View Post
True... however restriction is still in the back of my mind. If the stock exhaust is smaller than 2" I may lean more towards buying a full cat-back.

For you guys with dual mufflers I'd say the mid-pipe diameter is what I'm after... since the pipes would be smaller after the split b/c they only have to carry 2 cylinders worth of exhaust.
You have a Ej253 there are no restrictions in the exhaust! The mid pipe on a 08+ Impreza Sedan is 2.25 inches more than enough to flow the output of the heads. I would go no larger than 2.5 I would stick to 2.25 esp if you have a stock motor
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Old 09-10-2010, 03:20 PM   #7
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Quote:
Originally Posted by GEE-OTTO View Post
You have a Ej253 there are no restrictions in the exhaust! The mid pipe on a 08+ Impreza Sedan is 2.25 inches more than enough to flow the output of the heads. I would go no larger than 2.5 I would stick to 2.25 esp if you have a stock motor
I've got an 07... single exhaust.

But yes, if it is really 2.25" I will be replacing the muffler and that is it. I was hoping it didn't have some pea-shooter 1.5" system on it. It looks like 2" or 2.25" to me... was just seeking confirmation from someone before I start buying parts.
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Old 09-12-2010, 08:45 PM   #8
Sir-Knight
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I have my whole stock exhaust off the car... it's 2.25" Just measured with my digital caliper.
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Old 09-14-2010, 12:31 AM   #9
bmobs06
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Quote:
Originally Posted by Sir-Knight View Post
I have my whole stock exhaust off the car... it's 2.25" Just measured with my digital caliper.

depends, are you measuring outer diameter or inner? i'm pretty sure the inner is 1 7/8ths or something. i measured mine when i did the full sti catback but cant find the pictures. the sti is a 2 1/2 outer diameter but a 2 1/4 inner.
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Old 05-10-2012, 12:19 AM   #10
grungeman
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I am also looking to put a muffler on my 07 impreza would a new one make a ok sound?
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Old 05-10-2012, 10:40 PM   #11
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id is 1 7/8ths i switch mine to a complete sti cat back, wasn't hard.
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Old 05-10-2012, 10:51 PM   #12
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Like everyone is saying 2.25inch
I went with a magnaflow 2.5 inch straight through muffler and love it, in my opinion it's equivalent in sound to the spt(I do have uel headers on so that will make a decent change it how its going to sound on your car) the magnaflow only set me back $70 with a tip and new hangers when all was said and done
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Old 05-17-2013, 10:24 PM   #13
cmarco98
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Default 07 impreza 2.5i sedan

Soooooo what's the actual pipe inside size for the 07 2.5i and what size to go to for catback? Cause I seen different answers on the thread. And best axle back for my car? What size muffler inlet and outlet? Sorry for alot of q's but please and thanks!
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Old 05-18-2013, 10:39 AM   #14
subbyxinxdistress
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it is actually a 2" pipe. i just did the wrx modded header install and the 2.25 piping i bought literally slid over my stock piping. so i had to cut a slit and hammer in the gap.
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