E92 335i Exhaust noise on start up

cbmotorsport · 10-03-2015, 07:27 AM

Hi guys,

Having owned my 335i for a couple of weeks now, I'm over the moon with it.

One thing that I have notice is that on start up when cold, the exhaust note is quite a bit louder / deeper, then after a couple of minutes it quietens down. I have done a bit of research and discovered (like my e46 330ci had) that there is a butterfly valve in one of the tail pipes.

I discovered on another page that disconnecting the connector by the N/S tail light stops the valve from closing. Went out this afternoon to look at it and it has already been disconnected, so I guess this doesn't work?

It does sound nice on cold start up, wanted to see what it sounds like all the time. Was hoping this connector was the solution - if it was too noisy for everyday use then I could just plug it back in and go back to normal!

Anybody shed any light?

Thanks

Chris

pmmcbl · 10-03-2015, 08:44 AM

To my knowledge what that plug does is allowing both tail pipes to let smoke out. By default the near side one won't come into action until you get to certain rev ranges or speeds. I guess it was designed like this for a reason which at the moment can't remember in detail.
I have a e91 335i and I love the noise in the morning. Difficult to compete with my next door neighbour with the rs6.

pmmcbl · 10-03-2015, 08:47 AM

Meant to say that it's normal to the exhaust to sound louder at the start then within 20 seconds it calms down once the revs drop. I will go for longer when the winter kicks in.

RajB · 10-03-2015, 10:01 AM

Yup totally normal. Mines decatted and got the Akrapovic system too so it's proper loud on first start up. I love it lol.

Sparky68 · 10-03-2015, 10:03 AM

Mine isnt overly loud, not sure next door agree though!

old grey steve · 10-03-2015, 10:29 AM

As the others have said perfectly normal mines got a primary de cat and on start up does sound a little louder(it was louder with the BMW PE Exhaust mind)and thst sounded the nuts but sadly not to the wife's liking.

pmmcbl · 10-03-2015, 03:28 PM

I would love to change my system with a Remus performance but the noise would kill my neighbours and my kids would kill me.

RajB · 10-03-2015, 03:44 PM

Quote:

Originally Posted by pmmcbl

I would love to change my system with a Remus performance but the noise would kill my neighbours and my kids would kill me.

Shouldn't let that stop you. I leave the house at 6am and the start up is wonderful......LOL

Sparky68 · 10-03-2015, 03:50 PM

Quote:

Originally Posted by pmmcbl

I would love to change my system with a Remus performance but the noise would kill my neighbours and my kids would kill me.

Fcuk it, if i am up so should everyone else be

RajB · 10-03-2015, 04:17 PM

Quote:

Originally Posted by Sparky68

Fcuk it, if i am up so should everyone else be

Agreed. Mines an alarm clock for everyone else.

pmmcbl · 10-03-2015, 04:35 PM

You guys kill me! I can't justify spending big money on a car which I don't do many miles and don't plan to keep it for years. But ohh my they sound amazing with a decent system.

Dann · 10-04-2015, 03:10 AM

The flap closes at idle and opens at about 3000rpm. It's to keep the noise down for urban driving.

The 1st thing I did when i got my 335i was to unplug it.

10-03-2015, 07:27 AM	#1
cbmotorsport New Member 3 Rep 16 Posts Drives: 335i Msport Coupé Join Date: Sep 2015 Location: Chepstow iTrader: (0)	E92 335i Exhaust noise on start up Hi guys, Having owned my 335i for a couple of weeks now, I'm over the moon with it. One thing that I have notice is that on start up when cold, the exhaust note is quite a bit louder / deeper, then after a couple of minutes it quietens down. I have done a bit of research and discovered (like my e46 330ci had) that there is a butterfly valve in one of the tail pipes. I discovered on another page that disconnecting the connector by the N/S tail light stops the valve from closing. Went out this afternoon to look at it and it has already been disconnected, so I guess this doesn't work? It does sound nice on cold start up, wanted to see what it sounds like all the time. Was hoping this connector was the solution - if it was too noisy for everyday use then I could just plug it back in and go back to normal! Anybody shed any light? Thanks Chris
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10-03-2015, 08:44 AM	#2
pmmcbl Lieutenant 35 Rep 435 Posts Drives: E91 335i M-Sport Join Date: Aug 2015 Location: Berkshire iTrader: (0)	To my knowledge what that plug does is allowing both tail pipes to let smoke out. By default the near side one won't come into action until you get to certain rev ranges or speeds. I guess it was designed like this for a reason which at the moment can't remember in detail. I have a e91 335i and I love the noise in the morning. Difficult to compete with my next door neighbour with the rs6.
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10-03-2015, 08:47 AM	#3
pmmcbl Lieutenant 35 Rep 435 Posts Drives: E91 335i M-Sport Join Date: Aug 2015 Location: Berkshire iTrader: (0)	Meant to say that it's normal to the exhaust to sound louder at the start then within 20 seconds it calms down once the revs drop. I will go for longer when the winter kicks in.
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10-03-2015, 10:01 AM	#4
RajB Brigadier General 447 Rep 3,303 Posts Drives: E92 335i Join Date: Nov 2014 Location: Midlands iTrader: (4)	Yup totally normal. Mines decatted and got the Akrapovic system too so it's proper loud on first start up. I love it lol. __________________ E92 335i / M3 Hybrid - The Build
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10-03-2015, 10:03 AM	#5
Sparky68 Brigadier General 798 Rep 4,358 Posts Drives: 2016 M2 Alpine White Join Date: Oct 2012 Location: Cambs UK iTrader: (11) Garage List 2016 BMW M2 [0.50] 2017 BMW F30 330D [0.00] 2014 M135 [0.00] 2007 BMW 335i [0.00]	Mine isnt overly loud, not sure next door agree though! __________________ OG M2 7sp DCT Masata FMIC -Masata Boost Pipe - Cobra Catless DP - Powervalve Exhaust - Devilsown Methanol Injection Turbosmart BOV BM3 Stage 3 Halim custom map Pure 500
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10-03-2015, 10:29 AM	#6
old grey steve Colonel 286 Rep 2,796 Posts Drives: MK 7.5 Golf R Join Date: Oct 2012 Location: UK in Hertfordshire iTrader: (2)	As the others have said perfectly normal mines got a primary de cat and on start up does sound a little louder(it was louder with the BMW PE Exhaust mind)and thst sounded the nuts but sadly not to the wife's liking. __________________
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10-03-2015, 03:28 PM	#7
pmmcbl Lieutenant 35 Rep 435 Posts Drives: E91 335i M-Sport Join Date: Aug 2015 Location: Berkshire iTrader: (0)	I would love to change my system with a Remus performance but the noise would kill my neighbours and my kids would kill me.
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10-03-2015, 04:35 PM	#11
pmmcbl Lieutenant 35 Rep 435 Posts Drives: E91 335i M-Sport Join Date: Aug 2015 Location: Berkshire iTrader: (0)	You guys kill me! I can't justify spending big money on a car which I don't do many miles and don't plan to keep it for years. But ohh my they sound amazing with a decent system.
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10-04-2015, 03:10 AM	#12
Dann Major 131 Rep 1,374 Posts Drives: E90 LCi 335i Join Date: Feb 2015 Location: Portsmouth, United Kingdom iTrader: (0)	The flap closes at idle and opens at about 3000rpm. It's to keep the noise down for urban driving. The 1st thing I did when i got my 335i was to unplug it.
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