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      06-06-2011, 09:46 PM   #1
saeedg48
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Question Complete Catless Exhaust - Increase HP vs Increase Volume

Complete Catless Exhaust - Increase HP vs Increase in Volume

hello. i have fabspeed xpipes connected to a megan racing exhaust system.
it's already hellah loud. it sounds great but i'd like to do a primary cat-delete to see more gains in hp and torque.

how much louder would it be compared to my current setup?
are the power gains significant?


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      06-07-2011, 12:14 AM   #2
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It will be to loud...and you will not like it, no matter the HP out come. It will collect the wrong attention bro..

Check out my thread.

http://www.m3post.com/forums/showthread.php?t=500855
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      06-07-2011, 01:14 AM   #3
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If you want to avoid the extreme sound gains, get a resonated X pipe.
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      06-07-2011, 02:05 AM   #4
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Primary cat deletes are the only thing that has gotten me a noticeable increase in power. Everything else was just noise.

I would run the Turner test pipes and put your stock secondaries back.
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      06-07-2011, 08:59 AM   #5
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Quote:
Originally Posted by kitw View Post
Primary cat deletes are the only thing that has gotten me a noticeable increase in power. Everything else was just noise.

I would run the Turner test pipes and put your stock secondaries back.
thanks for the replies -
so primary cat delete but secondary back to stock!? how would that sound?
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      06-07-2011, 09:41 AM   #6
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Probably very Raspy
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      06-07-2011, 11:59 AM   #7
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Quote:
Originally Posted by sbm3 View Post
Probably very Raspy
No.

It's only raspy if you end up with an exhaust that allows rasp through.

The stock exhaust, Innotech, and BMW performance do, the Akrapovic and Vanguard don't. Depends on the design of the muffler. I haven't heard the megan.

It will sound pretty similar to what you have, to be honest. The stock secondary cats flow well and the resonators keep rasp to a minimum.
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      06-07-2011, 02:14 PM   #8
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Why do you guys hate the rasp so much? I think it actually sounds kinda sexy on the M...almost exotic.
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      06-07-2011, 03:32 PM   #9
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should go with oem x pipe... sell the fabspeed and run turner test pipes....
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      06-07-2011, 03:48 PM   #10
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Quote:
Originally Posted by Dodge2Dub View Post
Why do you guys hate the rasp so much? I think it actually sounds kinda sexy on the M...almost exotic.
I actually like a little rasp, sounds more high tech. Its just when it gets to the level of a pissed off weed whacker is where I object to it.

Dave
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      06-07-2011, 04:10 PM   #11
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Quote:
Originally Posted by Dave07997S View Post
I actually like a little rasp, sounds more high tech. Its just when it gets to the level of a pissed off weed whacker is where I object to it.

Dave
I haven't heard a catless/resonator-less M3 with OEM mufflers in person. I was planning on going this route on Friday because I do like the sound from the YouTube videos. So the question, is this set-up a little raspy or the full blown P/O'd weed whacker?
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      06-07-2011, 04:18 PM   #12
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The majority of the tone of your exhaust will alwyas be determined by your muffler.....had the meisterschaft gt2 and fully catless it was too raspy, but with gintani sport its perfect.......might want to think of changing your muffler so you can run fully catless with a nice sound
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      06-07-2011, 08:09 PM   #13
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okay guys back on topic. deleting my primary cats will make the car louder. no questions asked. but how much louder!? is there anyway I could throw a custom resonator on where the primary cats are!?
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      06-07-2011, 08:15 PM   #14
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yeah if you take it to a muffler shop there should be no reason why they cant weld in an extra set of resonators
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      06-07-2011, 08:21 PM   #15
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Primary cats make a pretty big difference in volume. Resonators won't necessarily make it quieter but they should smooth the sound outa bit and make it sound better. Sound is very subjective though. Loud to you may be quiet to another
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      06-07-2011, 10:13 PM   #16
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Quote:
Originally Posted by saeedg48 View Post
okay guys back on topic. deleting my primary cats will make the car louder. no questions asked. but how much louder!? is there anyway I could throw a custom resonator on where the primary cats are!?
Sorry OP
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      06-07-2011, 11:01 PM   #17
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Quote:
Originally Posted by saeedg48 View Post
okay guys back on topic. deleting my primary cats will make the car louder. no questions asked. but how much louder!? is there anyway I could throw a custom resonator on where the primary cats are!?
The Turner test pipes with the stock secondaries are very similar in volume to the Fabspeed X pipe that I had. (mated with stock primaries)

The turner combo is raspier, if you have a muffler that allows it through, but less annoyingly bassy at low rpms.
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      06-07-2011, 11:08 PM   #18
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Quote:
Originally Posted by kitw View Post
The Turner test pipes with the stock secondaries are very similar in volume to the Fabspeed X pipe that I had. (mated with stock primaries)

The turner combo is raspier, if you have a muffler that allows it through, but less annoyingly bassy at low rpms.
this? http://www.turnermotorsport.com/p-13...at-delete.aspx
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      06-07-2011, 11:14 PM   #19
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Quote:
Originally Posted by saeedg48 View Post
yup!
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      06-08-2011, 10:45 AM   #20
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Quote:
Originally Posted by Dodge2Dub View Post
I haven't heard a catless/resonator-less M3 with OEM mufflers in person. I was planning on going this route on Friday because I do like the sound from the YouTube videos. So the question, is this set-up a little raspy or the full blown P/O'd weed whacker?
I have a Riss Racing xpipe with 200cpi cats that had no resonators on the car with the oem muffler. The car was in the pissed off weed whacker territory...I added 2 Magnaflow straight through resonators to the xpipe and it made a huge difference.

So the xpipe without the cats & resonators is going to be even worse.

Dave
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      06-08-2011, 01:28 PM   #21
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Take out the primary cats and replace them with two resonators.
Problem. Solved.
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      06-09-2011, 08:04 AM   #22
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Quote:
Originally Posted by Dodge2Dub View Post
I haven't heard a catless/resonator-less M3 with OEM mufflers in person. I was planning on going this route on Friday because I do like the sound from the YouTube videos. So the question, is this set-up a little raspy or the full blown P/O'd weed whacker?
I had my fabspeed HFCs with the stock rear section and the thing that drove me nuts is that the car sounded "farty" at around 2k RPM when accelerating from a stop. Think 2L engine - that is what it sounded like to me; it did not sound "raspy" to me like an E46 M3. Minor detail for some, but for me personally in the city, garages, etc. it was unacceptable.

As kitw mentions, the akra removed this from the exhaust note. It also restores some of the staccato that is lost on the OEM system when you fiddle with the cats/resonators/etc.
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