Unplug Mod to Exhaust

TiAg335i · 06-03-2008, 08:58 PM

I just did this to my E92...and wow, it does sound amazing. Much deeper and throatier tone, VERY noticeable at idle. Doesn't sound ricey at all (kind of sounds like an FX45 at idle).

BTW - I noticed it prevents the butterfly valve from closing...so its kind of permanently open, even at idle.

I am guessing that is all it does. Will this harm the exhaust system? And what exactly is the purpose of the butterfly valve?

nj335i · 06-03-2008, 09:06 PM

No harm to the exhaust. The butterfly valve is just there to reduce drone during highway driving and at lower RPMs.

ChaneRZ · 06-03-2008, 09:13 PM

+1 called gold-tee mod.

tintivilus · 06-03-2008, 09:21 PM

Quote:

Originally Posted by nj335i

No harm to the exhaust. The butterfly valve is just there to reduce drone during highway driving and at lower RPMs.

Haven't noticed any effect on drone... isn't normal operation just to close at low throttle?

The general consensus is that it's a cold-start emissions tweak (to help the cats warm up faster).

TiAg335i · 06-03-2008, 09:29 PM

Quote:

Originally Posted by tintivilus

Haven't noticed any effect on drone... isn't normal operation just to close at low throttle?

The general consensus is that it's a cold-start emissions tweak (to help the cats warm up faster).

I see, but once you go above a certain RPM they open up anyway...and it is not recommended to idle for too long following a cold start. So they are essentially pointless? I've always noticed that 30 seconds after my cold start they open up (with the plug in)...I'm sure the cats aren't fully warmed after 30 seconds. In any case, I'm gonna have the plug out for all of tomorrow to see how I like it.

thekurgan · 06-03-2008, 10:38 PM

Quote:

Originally Posted by tintivilus

Haven't noticed any effect on drone... isn't normal operation just to close at low throttle?

The general consensus is that it's a cold-start emissions tweak (to help the cats warm up faster).

It's really the E90 that drones, and it's quite noticeable, the e92/93 have different exhaust systems so it really sounds nice; the way it should have come from the factory.

TiAg335i · 06-04-2008, 06:28 PM

So I drove around with it unplugged today...

There isn't any different in exhaust tone at the higher RPM's...but there is at lower RPM's..deeper and throatier.

I'm probably gonna plug it back..not a huge difference and probably not worth any long term problems.

Dan335i · 06-05-2008, 10:00 PM

Only difference your really gone hear is at cold start. PERIOD!

TiAg335i · 06-05-2008, 10:01 PM

Quote:

Originally Posted by Dan335i

Only difference your really gone hear is at cold start. PERIOD!

Yeah...that's why I think its not worth it. The butterfly valve opens after a minute or so of idling after cold start anyway. And it stays open above a certain RPM. Pointless mod.

StarrDlux · 06-05-2008, 10:04 PM

yeah no kidding it was cold start only. but quite honestly whatever dinan does changes the sound of the exhaust. more so than the golf tee mod.

Fraggy · 06-05-2008, 10:18 PM

Quote:

Originally Posted by thekurgan

It's really the E90 that drones, and it's quite noticeable, the e92/93 have different exhaust systems so it really sounds nice; the way it should have come from the factory.

Yea, I did it on my E90 335 and hated it, it was just a bunch of drone. I eventually had to get an exhaust.

06-03-2008, 08:58 PM	#1
TiAg335i Trance Life 315 Rep 4,706 Posts Drives: 2007 E92 335i Join Date: Jan 2007 Location: Long Island, NY iTrader: (4)	Unplug Mod to Exhaust I just did this to my E92...and wow, it does sound amazing. Much deeper and throatier tone, VERY noticeable at idle. Doesn't sound ricey at all (kind of sounds like an FX45 at idle). BTW - I noticed it prevents the butterfly valve from closing...so its kind of permanently open, even at idle. I am guessing that is all it does. Will this harm the exhaust system? And what exactly is the purpose of the butterfly valve?
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06-03-2008, 09:06 PM	#2
nj335i Modaholic 88 Rep 1,705 Posts Drives: with 3 pedals Join Date: Jan 2007 Location: East Coast iTrader: (7)	No harm to the exhaust. The butterfly valve is just there to reduce drone during highway driving and at lower RPMs. __________________ Euro Delivery - April 2007
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06-03-2008, 09:13 PM	#3
ChaneRZ If You Aint First, You're last !!! 81 Rep 2,509 Posts Drives: 08 BMW 335i, 01 Honda Prelude Join Date: Sep 2007 Location: California iTrader: (0)	+1 called gold-tee mod. __________________ 08 BMW BSM 335i 6MT (Sports, Premium, NAV, PDC, AS, IPOD, HD Radio, Rear Sunshade, OEM Alarm) Angel iBright V3, Luminics Fog Bulb, Turbo Tuner, K&N Drop in Filter, Dinan Exhaust, Dinan Pedals, Vorsteiner CF Front Lip, and CF Rear Diffuser. Ordered:08/25/07 Started: 09/09/07 Finished: 09/14/07 On Ship: 09/15/07 Arrived: 10/08/07 Delivered: 10/10/07
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06-04-2008, 06:28 PM	#7
TiAg335i Trance Life 315 Rep 4,706 Posts Drives: 2007 E92 335i Join Date: Jan 2007 Location: Long Island, NY iTrader: (4)	So I drove around with it unplugged today... There isn't any different in exhaust tone at the higher RPM's...but there is at lower RPM's..deeper and throatier. I'm probably gonna plug it back..not a huge difference and probably not worth any long term problems.
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06-05-2008, 10:00 PM	#8
Dan335i Lieutenant Colonel 32 Rep 1,786 Posts Drives: 07 335i coupe 6MT,w/sp. pack. Join Date: Oct 2007 Location: orange county NY iTrader: (2)	Only difference your really gone hear is at cold start. PERIOD!
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06-05-2008, 10:04 PM	#10
StarrDlux Pussycat's Meow 9 Rep 682 Posts Drives: '08 335i montego \| Stock Join Date: May 2008 Location: Midtown (Altanta) iTrader: (0)	yeah no kidding it was cold start only. but quite honestly whatever dinan does changes the sound of the exhaust. more so than the golf tee mod. __________________ 2008 335i montego \| stock 2002 A4 1.8TQS \| APR 1+ 1990 VW Corrado \| Stage 4 by SNS
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