Removing Secondary Cats - BMW 3-Series (E90 E92) Forum

Fraggy · 02-14-2008, 01:26 PM

If I were to remove the secondary cats, what effect on sound should I expect to get? Will it be louder? Will there be drone? Will the sound have a "sharper' edge? Sorry to sound like an idiot, but Ive never removed those parts before.

jjhan85 · 02-14-2008, 02:04 PM

yes it will sound louder...but i dunno if its a good thing... =\

not too sure

Gen_E92 · 02-14-2008, 02:24 PM

i recall ur current set up already has some drone, so I wouldn't recommend doing that.

Fraggy · 02-14-2008, 02:32 PM

Hmmm, I see. Whats happened is that over the last 500 miles or so, the exhaust is getting quieter

Sometimes I cant even hear it anymore except under hard acceleration. The drone is still there, maybe not as pronounced as before, but the nice sounds are getting quieter as well.

arabbmw · 02-14-2008, 06:10 PM

what kind of piping do you have now?

I was told by a guy who is really good with exhausts that removing the secondary cats and putting in x pipes is the way to go. Also seen it backed up here on the forums.

Fraggy · 02-14-2008, 06:13 PM

Piping is stock now...

cn555ic · 02-14-2008, 09:17 PM

Thats the first I have heard a exhaust getting quieter as it gets broken in!! Maybe you are just getting used to it...I also feel that my CP-E exhaust is getting quieter also...I think its me being adapted and used to the noise now after 2 weeks since the install...

Panoz · 02-19-2008, 02:31 AM

The change of sound is not really that big. There is a "metalic" baritone sound at 2000-3000 (as westwest888 mentioned).

There are some annoying sounds at cold start ,but when you reach the appropriate temperatures its fine.

In general , i would propose you not to delete the secondary ones but replacing them with HFC instead (100s maybe?).

Fraggy · 02-19-2008, 10:52 AM

Thanks guys, I will leave them in. Ive already replaced the Corsa with the fake Eisenmann for now.

02-14-2008, 01:26 PM	#1
Fraggy Brigadier General Drives: 2007 e90 Join Date: Jun 2005 Location: San Diego Posts: 3,236 iTrader: (11)	Removing Secondary Cats If I were to remove the secondary cats, what effect on sound should I expect to get? Will it be louder? Will there be drone? Will the sound have a "sharper' edge? Sorry to sound like an idiot, but Ive never removed those parts before. __________________ Step--Premium--Sport--Nav--20% Tint--Blacklines--18" Beyern Mesh--Michelin Super Sports--Bastuck Exhaust--M3 Steering Wheel--BMW Performance Springs--Koni--M3 Front/Rear Sways--
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02-14-2008, 02:04 PM	#2
jjhan85 J-Han Drives: BMW E90 325i jetblack Join Date: Mar 2006 Location: Maryland Posts: 398 iTrader: (0) Garage List 2006 325i Sport Pac ... [0.00]	yes it will sound louder...but i dunno if its a good thing... =\ not too sure __________________ 325i // Sport Package // 6 speed manual // AFE intake // Resonator + Muffler Delete // 20% tints//

02-14-2008, 02:32 PM	#4
Fraggy Brigadier General Drives: 2007 e90 Join Date: Jun 2005 Location: San Diego Posts: 3,236 iTrader: (11)	Hmmm, I see. Whats happened is that over the last 500 miles or so, the exhaust is getting quieter Sometimes I cant even hear it anymore except under hard acceleration. The drone is still there, maybe not as pronounced as before, but the nice sounds are getting quieter as well. __________________ Step--Premium--Sport--Nav--20% Tint--Blacklines--18" Beyern Mesh--Michelin Super Sports--Bastuck Exhaust--M3 Steering Wheel--BMW Performance Springs--Koni--M3 Front/Rear Sways--

02-14-2008, 06:13 PM	#6
Fraggy Brigadier General Drives: 2007 e90 Join Date: Jun 2005 Location: San Diego Posts: 3,236 iTrader: (11)	Piping is stock now... __________________ Step--Premium--Sport--Nav--20% Tint--Blacklines--18" Beyern Mesh--Michelin Super Sports--Bastuck Exhaust--M3 Steering Wheel--BMW Performance Springs--Koni--M3 Front/Rear Sways--

02-19-2008, 02:31 AM	#8
Panoz Lieutenant Colonel Drives: E92 Space Grey 335i ,Aero Kit Join Date: Nov 2006 Location: EU Posts: 1,563 iTrader: (0)	The change of sound is not really that big. There is a "metalic" baritone sound at 2000-3000 (as westwest888 mentioned). There are some annoying sounds at cold start ,but when you reach the appropriate temperatures its fine. In general , i would propose you not to delete the secondary ones but replacing them with HFC instead (100s maybe?). __________________ Procede V4 , Catless DPs, Forge FMIC, Injen Intake, VK Oilcooler, Hartge Quads Exhaust, Modded CDV, Synapse BOV Kit, BMW Performance 335i SSK Kit, P3 vent boost gauge Space Grey 335i -> See more pics HERE

02-14-2008, 02:24 PM	#3
Gen_E92 Brigadier General Drives: slow Join Date: Oct 2006 Location: Vancouver Posts: 3,383 iTrader: (17) Garage List 2007 335i [3.88]	i recall ur current set up already has some drone, so I wouldn't recommend doing that.

02-14-2008, 06:10 PM	#5
arabbmw Lieutenant Drives: 335i coupe Join Date: Nov 2007 Location: G hills Posts: 552 iTrader: (2)	what kind of piping do you have now? I was told by a guy who is really good with exhausts that removing the secondary cats and putting in x pipes is the way to go. Also seen it backed up here on the forums.

02-14-2008, 09:17 PM	#7
cn555ic The Coding Guy Drives: FBO 335i Vert meth/nitrous Join Date: Jun 2007 Location: Brooklyn, New York Posts: 17,872 iTrader: (5)	Thats the first I have heard a exhaust getting quieter as it gets broken in!! Maybe you are just getting used to it...I also feel that my CP-E exhaust is getting quieter also...I think its me being adapted and used to the noise now after 2 weeks since the install...

02-19-2008, 10:52 AM	#9
Fraggy Brigadier General Drives: 2007 e90 Join Date: Jun 2005 Location: San Diego Posts: 3,236 iTrader: (11)	Thanks guys, I will leave them in. Ive already replaced the Corsa with the fake Eisenmann for now. __________________ Step--Premium--Sport--Nav--20% Tint--Blacklines--18" Beyern Mesh--Michelin Super Sports--Bastuck Exhaust--M3 Steering Wheel--BMW Performance Springs--Koni--M3 Front/Rear Sways--

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