Custom Exhaust Advice

N1KN4K · 05-02-2008, 06:46 PM

Hi all,

I'm brand new here and have owned my first subie for about 8 months now. It is a 2007 Impreza 2.5i. I've been lurking in the forums for quite a while but am not just beginning to post. The only mod currently on it my car Williaty's hybrid intake. I'm looking to put my next one on, and I would like that to be a custom exhaust.

I've got a reputable local shop that is able to fabricate one for me, but I wanted some advice on the specifics.
1. I've heard of two different suggested sizes for the NA motors 2.25 in and 2.5 in, what difference can I expect to see between the two? I've heard that the general consensus is 2.25 is better, why is this?
2. I want to put a high flow cat on and was wondering if there are any other specs that pertain to cats in relation to my car that I need to be aware of when discussing it with the shop. OR would I be better off going catless? Keep in mind I'm married and if the car is too loud my wife will go ape ****. Will a catless or a highflow cat cause problems with the noise issue.
3. Along the same lines, while I would like the small power gains out of the exhaust system, I also am doing it for sound. I'm not trying to be one of those people that asks "whats the best muffler," but ive been through the Exhaust/CAI thread with pics and vids and its all just overwhelming to me. Is there one or a couple relatively popular mufflers which you would suggest that I could research more in depth looking for the sound I want. I'm searching for more of a low rumble sound, but keep in mind as ive said above, I dont want something too loud, maybe a bit louder than stock.
4. Is there anything else I should keep in mind while going to talk to the tech which I haven't covered here? I can't guarentee they will be familiar enough with subies to catch something my inexperience misses.

Thanks all for your help!

* Registered users of the site do not see these ads.

nick516 · 05-02-2008, 07:04 PM

http://forums.nasioc.com/forums/showthread.php?t=533787

should find everything you are looking for there

rxer311 · 05-02-2008, 07:56 PM

post in n/a thread?

wrxguy02 · 05-02-2008, 08:22 PM

just buy one.

major companys spend ALOT of money in designing and testing exhausts for vehicles, your not going to get anywhere near the quality of a diy/custom made exhaust.
theres a reason why a exhaust has that little bend in it at that random spot, why you ask? well i have no clue cuz im not a exhaust fabricator for a major exhaust company, but they wouldnt put it there for no reason.

ive always heard this rule, for a 4 banger n/a motor...
2.0L and lower-2.25 inch exhaust
over 2.2L- 2.5 exhaust

why i dont know... im not a exhaust designer, i just trust companys hard work in designing and testing.

just my $0.02

05-02-2008, 06:46 PM	#1
N1KN4K Scooby Newbie Member#: 175832 Join Date: Mar 2008 Chapter/Region: MWSOC Location: Brandon, MI Vehicle: 2005 z51 Corvette LeMans Blue	Custom Exhaust Advice Hi all, I'm brand new here and have owned my first subie for about 8 months now. It is a 2007 Impreza 2.5i. I've been lurking in the forums for quite a while but am not just beginning to post. The only mod currently on it my car Williaty's hybrid intake. I'm looking to put my next one on, and I would like that to be a custom exhaust. I've got a reputable local shop that is able to fabricate one for me, but I wanted some advice on the specifics. 1. I've heard of two different suggested sizes for the NA motors 2.25 in and 2.5 in, what difference can I expect to see between the two? I've heard that the general consensus is 2.25 is better, why is this? 2. I want to put a high flow cat on and was wondering if there are any other specs that pertain to cats in relation to my car that I need to be aware of when discussing it with the shop. OR would I be better off going catless? Keep in mind I'm married and if the car is too loud my wife will go ape ***. Will a catless or a highflow cat cause problems with the noise issue. 3. Along the same lines, while I would like the small power gains out of the exhaust system, I also am doing it for sound. I'm not trying to be one of those people that asks "whats the best muffler," but ive been through the Exhaust/CAI thread with pics and vids and its all just overwhelming to me. Is there one or a couple relatively popular mufflers which you would suggest that I could research more in depth looking for the sound I want. I'm searching for more of a low rumble sound, but keep in mind as ive said above, I dont want something too loud, maybe a bit louder than stock. 4. Is there anything else I should keep in mind while going to talk to the tech which I haven't covered here? I can't guarentee they will be familiar enough with subies to catch something my inexperience misses. Thanks all for your help! Registered users of the site do not see these ads.

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
First log with my custom exhaust ADVICE	CenCali07sti	Open Source Reflashes	8	01-21-2008 12:24 AM
custom exhaust idea: need advice!	stealthWRX68	Factory 2.0L Turbo Powertrain	6	11-21-2007 06:49 AM
Looking for custom exhaust advice…	xcntrk75	Legacy Forum	19	04-12-2005 06:01 PM
Custom Exhaust - Skips Exhaust Plaistow NH	WRXBanish	New England Impreza Club Forum -- NESIC	3	11-14-2003 06:50 PM
Trade! my custom Exhaust on your RS Exhaust!	SONofSAM	Bay Area Impreza Club Forum -- BAIC	7	04-13-2002 02:15 PM

05-02-2008, 07:04 PM	#2
nick516 Scooby Specialist Member#: 178134 Join Date: Apr 2008 Location: Long Island New York Vehicle: 2004 jbp wrx wagon java black	http://forums.nasioc.com/forums/showthread.php?t=533787 should find everything you are looking for there

05-02-2008, 07:56 PM	#3
rxer311 Scooby Specialist Member#: 107099 Join Date: Feb 2006 Chapter/Region: Tri-State Location: Lancaster, PA Vehicle: '07 STI Satin White Pearl	post in n/a thread?

05-02-2008, 08:22 PM	#4
wrxguy02 Scooby Specialist Member#: 174672 Join Date: Mar 2008 Chapter/Region: South East Location: Greensboro, NC Vehicle: 02 AW WRX 02wrxX2,06sti,94wgn,04sti	just buy one. major companys spend ALOT of money in designing and testing exhausts for vehicles, your not going to get anywhere near the quality of a diy/custom made exhaust. theres a reason why a exhaust has that little bend in it at that random spot, why you ask? well i have no clue cuz im not a exhaust fabricator for a major exhaust company, but they wouldnt put it there for no reason. ive always heard this rule, for a 4 banger n/a motor... 2.0L and lower-2.25 inch exhaust over 2.2L- 2.5 exhaust why i dont know... im not a exhaust designer, i just trust companys hard work in designing and testing. just my $0.02