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Old 12-01-2005, 10:39 PM   #1
dchampagne
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Question 06 WRX, stage 2 COBB TBE: is 3" too loud?

I've been researching on how to mod a WRX (or maybe an MY06 9-2x, also 2.5L). Both MY06s' potential looks nice. Cobb's stage 2 dyno results show a very nice flat torque curve after 3,000 rpm.

I'll mostly use my wagon in and around town so low and midrange power will be my concern.

I know you might say the 9-2x has extra sound deadening (Aha!), but I am worried about how loud it sounds to others (including popos here in Quebec).

In that respect, I'm wondering if Cobb's 3" TBE might be a bit too loud for me.

Hypothetically, how can I speed up spool time with a lesser diameter exhaust line? I know the STi is a 2.25".

Is a 2.5" still that much noisier?

(How do you like my writting btw?)
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Old 12-01-2005, 11:55 PM   #2
gjhsu
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I thought STis were 2.5" piping.

The Cobb catback, IMO, is just right in terms of volume, and I'm fairly particular in car loudness. The only other one I would prefer in terms of tone and volume would be the Prodrive muffler. The downpipe will make it a bit more whistly, but I don't think the 3" would bother you.
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Old 12-01-2005, 11:59 PM   #3
Amplified2000
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The muffler style will have far more impact on the sound level than the piping size. I run a Helix catted downpipe (3") into a Borla Hush cat back. The Borla Hush is a 3" exhaust but comes with a 2.5" stock style adapter so that it will mate to the factory downpipe/midpipe.. I replaced that with a true 3" flat flange adapter from MadDad that makes it a full 3" exhaust all the way back. Because of the design of the Borla Hush muffler it is actually pretty quiet untill you romp on it, then it growls a little bit but overall is a very quiet exhaust. If you go catless it will be a bit louder and make a bit more power, but I couldn't escape my inner tree hugging hippy so I went for a catted system.
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Old 12-02-2005, 03:34 AM   #4
02WHITEDUB
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I've got a Cobb catted DP mated to a stock catback. With a gutted OEM UP it's virtually the same volume as stock. If you didn't own and know the car, you'd never guess there's a high-flow system in there. The ONLY noticable difference is at WOT the note is a little bit different, and you hear a bit more 'whoosh' from the UP.

I understand that the Cobb is the quietest DP (Cast head and cat) I think I'll end up putting the Prodrive axleback on my stock resonator for a deep, burbly, but quiet exhaust note.
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Old 12-02-2005, 08:49 AM   #5
migs76
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once you are catless, it's all loud. and you will experience even more droning in a wagon. 2.5 vs. 3in will always be an issue. unless you're planning to make big power numbers the 3in piping is really unnecessary.

want to speed up spool? get rid of the cat in the uppipe and get some aftermarket hoses (i.e. samco/perrin).

i've sat in cars with both set-ups. catless 2.5 and 3in/sedans and wagons. the difference is negligible. as other posters have said, it does boil down to the axleback. take note tho, catless + oval prodrive (1 on the quieter mufflers) is still "loud".

get to some meets. listen to other ppl's set-ups. hopefully, you'll have a better idea of what you're looking for then.
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Old 12-02-2005, 09:52 AM   #6
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With a wagon you need to be concerned with droning. I went with a Stromung intermediate pipe mated to an STi axleback. It is a little louder then stock but not by much, but I do still have all my cats in place. It gave the car a nice subtle boxer growl. I will be getting a catless STi uppipe soon and I will keep you posted if it gets louder.
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Old 12-02-2005, 10:01 AM   #7
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My advise would be to go with the infamous Ebay SS Autochrome TBE as I did. With fully catless 3" Piping and a 4" Grapefruit Launcher tip, you're ears will be ringing after even the shortest of trips.

Seriously though...I had a few cops following me with this thing and my state allows NO EXHAUST MODIFICATIONS and they never pulled me over...but I did keep it under 3k RPMs
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Old 12-02-2005, 10:12 AM   #8
hondaeater69
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Quote:
Originally Posted by migs76
once you are catless, it's all loud. .

Um, no it's not. I"m completely catless with an STi OEM muffler, and if you didn't know any better you'd think my car was completely stock (it's a stage 4 protuned car). THe muffler has 95% to do with the sound coming from the back of your car.

Quote:
Originally Posted by migs76
want to speed up spool? get rid of the cat in the uppipe .

.
there is no UP cat in the 06's
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Old 12-02-2005, 10:36 AM   #9
EDM
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Quote:
Originally Posted by hondaeater69
there is no UP cat in the 06's

On the WRX too or just on the STi?
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Old 12-02-2005, 10:49 AM   #10
migs76
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Quote:
Originally Posted by hondaeater69
Um, no it's not. I"m completely catless with an STi OEM muffler, and if you didn't know any better you'd think my car was completely stock (it's a stage 4 protuned car). THe muffler has 95% to do with the sound coming from the back of your car.



there is no UP cat in the 06's
if you cared to read my post carefully, you would have seen that i agreed with some of the other posters that it is ultimately up to the axleback. and no where in his post did he mention that he is getting an sti.

reading is fundamental. you need to get more for your money at state college. deak.
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Old 12-02-2005, 10:53 AM   #11
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Quote:
Originally Posted by migs76
if you cared to read my post carefully, you would have seen that i agreed with some of the other posters that it is ultimately up to the axleback. and no where in his post did he mention that he is getting an sti.

reading is fundamental. you need to get more for your money at state college. deak.

i read your whole post jackass. However, your comment that "it's all loud if catless" is NOT correct. The STi i mentioned is an STi axleback (which is still a muffler last time i checked) mated with a catless exhaust, and it is NOT loud.
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Old 12-02-2005, 10:54 AM   #12
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Quote:
Originally Posted by EDM
On the WRX too or just on the STi?

only my 06wrx +, never on the STi.
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Old 12-02-2005, 11:18 AM   #13
tenth
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Quote:
Originally Posted by migs76
and no where in his post did he mention that he is getting an sti.
In case you haven't figured it out yet (hard to tell), the 06 WRX doesn't have a cat in the up-pipe. It's not just the STi anymore.
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Old 12-02-2005, 11:28 AM   #14
migs76
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2006 saab 92-x does not have the new 2.5 blocks like the my06 wrxs. still has cat in the up.

the term "loud" is relative.

Last edited by migs76; 12-02-2005 at 11:41 AM.
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Old 12-02-2005, 11:36 AM   #15
Scooby921
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I personally have a Cobb "Street" TBE, with the high-flow cat. It is not at all loud. It has some grunt when you get on the throttle, but is not nearly as loud as any truck with straight-pipes. I would call it a mid-range exhaust when comparing dB levels.

I wrote a review on it here:
http://forums.nasioc.com/forums/show...3#post11859373

There are several other reviews of the Cobb system floating around the review area.
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Old 12-02-2005, 01:51 PM   #16
Shinobi_30000
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I heard that the '06 doesn't have a cat in the uppipe before they started to sell them, but thank you for clarifying that, nice to know

-'06 owner
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Old 12-02-2005, 02:12 PM   #17
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Quote:
Originally Posted by Shinobi_30000
I heard that the '06 doesn't have a cat in the uppipe before they started to sell them, but thank you for clarifying that, nice to know

-'06 owner
how about the 05s anyone??

<----------
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Old 12-02-2005, 09:12 PM   #18
tenth
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Quote:
Originally Posted by migs76
2006 saab 92-x does not have the new 2.5 blocks like the my06 wrxs. still has cat in the up.
The 2006 isn't out yet, and from what I've read, the 06 will be out in the new year with the 2.5.

EDIT: Definitely getting the 2.5

http://www.autoblog.com/entry/1234000993053927/
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Old 12-02-2005, 10:01 PM   #19
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Quote:
Originally Posted by boostinscooby
how about the 05s anyone??

<----------

The 05 WRX do, but the STi don't that's why I am putting in an STi uppipe.
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Old 12-03-2005, 05:30 AM   #20
DeeBoy
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if noise is a problem better check out the MadDad Whisper, apparaently it doesn't even drone in a wagon.

http://www.daddysscp.com/dcart4/prod...1&cat=3&page=1
http://forums.nasioc.com/forums/showthread.php?t=882976
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Old 12-03-2005, 11:13 AM   #21
Pete Holt
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As far as aftermarket exhaust systems go, the Cobb is pretty tame in terms of noise. You don't have to worry about sounding like some obnoxious Civic with a grapefruit shooter muffler on the back with 103hp. The Cobb is quieter than the Stromung unit which I really liked on my old Suby. It will have a mellow rumble at idle and then it will come to life when you get into the throttle. I have had the Cobb exhaust on my car with the stage 2 accessport for about a year and a half and it sounds nice. No complaints about the noise, but a lot of people say it sounds like a V8 with the nice low mellow boxer rumble.
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Old 12-03-2005, 11:17 AM   #22
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..I really like my Stromung 3" single......it is 3" all the way back but I have a catted DP so it mellows it a bit....over ~4k it clears its throat...but NO fart pipe sound
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Old 12-03-2005, 01:01 PM   #23
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I like the SPT cat back, 3" back from the cat, 3.5" tip I think. Very throaty, with a beautiful idle growl, but quiet compared to ricey (IMO) exhaust like the super loud GREDDY ones.
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Old 12-03-2005, 01:58 PM   #24
Scooby921
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Another comparison for the Cobb...

I parked my car next to my friend's '04 WRX. We turned them both on and let them idle. His BPM is loud enough you can't tell my car is on. The BPM is supposedly more quiet than a Blitz, Perrin, TurboXS RFL, and several others.
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Old 12-03-2005, 04:12 PM   #25
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I'm about to get an HKS cat-back and a cobb downpipe, how does that sound? Is it too loud? Should I get the silencer for the HKS?
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