Loud 'crack' from exhaust

sgmpw · 12-21-2008, 10:54 PM

Weather turned pretty nasty here in the GTA recently - finally some truly cold stuff. Anyway, when starting cold there has been a pretty loud 'crack noise' from the exhaust area when starting - only one pipe on my 335 is steaming. I assume it is a redirect valve getting the engine up to temp.

After a run and a restart both pipes are rumbling at full bore - until yet again, a 'crack' sound and it's back to one pipe.

Is there a valve in the exhaust system? What triggers it and should I get it in for a warranty check?

Thanks.

john0213 · 12-21-2008, 11:03 PM

i'm not sure about the crack sound but i sure know that there is a butterfly valve at the end of our exhaust section. I guess the crack sound might have been coming from the butterfly valve.

like another members, i will tell you to go check it up with your dealership of course just to make sure that there is no problem.

btw, i guess a golf tee mod might be a fast solution to the sound but i personally won't touch anything until you get a check up with your dealer first

charlie335 · 12-22-2008, 01:20 AM

Quote:

Originally Posted by sgmpw

Weather turned pretty nasty here in the GTA recently - finally some truly cold stuff. Anyway, when starting cold there has been a pretty loud 'crack noise' from the exhaust area when starting - only one pipe on my 335 is steaming. I assume it is a redirect valve getting the engine up to temp.

After a run and a restart both pipes are rumbling at full bore - until yet again, a 'crack' sound and it's back to one pipe.

Is there a valve in the exhaust system? What triggers it and should I get it in for a warranty check?

Thanks.

under normal temperatures, there's still a slight cracking noise when u start the car because the butterfly valve closes, but it's only noticable if you're standing directly behind the car. in your case i think the cold temperatures probably froze the valve when the car was off, making it harder to close when you start the car, thus making a louder "cracking" noise.

im pretty sure your car is just fine.

GAM3OVR85 · 12-22-2008, 01:24 AM

Vtec just kicked in YO

GAM3OVR85 · 12-22-2008, 01:26 AM

Quote:

Originally Posted by sgmpw

Is there a valve in the exhaust system? What triggers it and should I get it in for a warranty check?
Thanks.

yea man, bring it to the stealership and should be able to fix it.
GL

KkSc · 12-22-2008, 01:57 AM

Quote:

Originally Posted by MTL Bimmer

Vtec just kicked in YO

sgmpw · 12-22-2008, 08:40 AM

Thanks all. Probably right about the butterfly valve. Anyone know the reason for the valve? What alters it's position?

charlie335 · 12-22-2008, 09:17 AM

^

it's there to warm up the cats when you start up the car. also reduces the exhaust note a little to prevent droning.

john0213 · 12-22-2008, 02:24 PM

and obviously we all know that we love the louder exhaust note~

12-21-2008, 10:54 PM	#1
sgmpw First Lieutenant 27 Rep 330 Posts Drives: M240i Join Date: Oct 2008 Location: Southwestern Ontario iTrader: (2)	Loud 'crack' from exhaust - redirect valve? Weather turned pretty nasty here in the GTA recently - finally some truly cold stuff. Anyway, when starting cold there has been a pretty loud 'crack noise' from the exhaust area when starting - only one pipe on my 335 is steaming. I assume it is a redirect valve getting the engine up to temp. After a run and a restart both pipes are rumbling at full bore - until yet again, a 'crack' sound and it's back to one pipe. Is there a valve in the exhaust system? What triggers it and should I get it in for a warranty check? Thanks.
	Appreciate 0 Tweet Quote

12-21-2008, 11:03 PM	#2
john0213 The Allergy Season 48 Rep 1,008 Posts Drives: E92 Blk Saph. 335xi Join Date: Aug 2006 Location: Vancouver iTrader: (1)	i'm not sure about the crack sound but i sure know that there is a butterfly valve at the end of our exhaust section. I guess the crack sound might have been coming from the butterfly valve. like another members, i will tell you to go check it up with your dealership of course just to make sure that there is no problem. btw, i guess a golf tee mod might be a fast solution to the sound but i personally won't touch anything until you get a check up with your dealer first __________________ 2008 - E92 Blk Sapphire / Coral Red 335xi (Delivered) Nav / Premium + Sound / Sport / CA / 6AT + Shift Pad 2003 - Silverstone / Burnt Orange Fairlady 350Z (Sold)
	Appreciate 0 Quote

12-22-2008, 01:24 AM	#4
GAM3OVR85 Major General 316 Rep 8,049 Posts Drives: E92 M3 Join Date: Aug 2007 Location: Montreal, QC iTrader: (18) Garage List 2008 BMW M3 [0.00] 2010 Sea-Doo RXT-X 260 [9.00] 2007 E92 328i [10.00]	Vtec just kicked in YO __________________ 08 E92 M3/Melbourne Red/6MT/Exec Pack/MDrive/EDC/PDC/19" 220M Mods: VRS Front Lip, HID Angels, KW V3, Stoptech BBK, SS lines, 18" TE37SL, Bastuck Exhaust, MS Air Filter, OEM Aluminum Padels, LED Interior Light 07 E92 328i/Jet Black/Cream Beige Leather/Premium/Step/Heated Seats...check garage!
	Appreciate 0 Quote

12-22-2008, 08:40 AM	#7
sgmpw First Lieutenant 27 Rep 330 Posts Drives: M240i Join Date: Oct 2008 Location: Southwestern Ontario iTrader: (2)	Thanks all. Probably right about the butterfly valve. Anyone know the reason for the valve? What alters it's position?
	Appreciate 0 Quote

12-22-2008, 09:17 AM	#8
charlie335 Shiodome Redeveloper 23 Rep 761 Posts Drives: lawllercoaster Join Date: Oct 2006 Location: Richmond, BC iTrader: (1)	^ it's there to warm up the cats when you start up the car. also reduces the exhaust note a little to prevent droning. __________________ 2006 E63 M6, Alpine White/Indianapolis Red 2007 E92 335i, Space Gray, 6MT, ZSP, BMW Performance Shifter/Boot, CF Wrapped Trim, Aero Lip, M3 Sideskirts, Mtech Rear, CF Diffuser, Custom Quads, FK Silverline X, iForged Essen 2008 GSX-R750, Blue/White, Power Commander, Straight Pipe 2011 BMW S1000RR, Akrapovic Evolution
	Appreciate 0 Quote

12-22-2008, 02:24 PM	#9
john0213 The Allergy Season 48 Rep 1,008 Posts Drives: E92 Blk Saph. 335xi Join Date: Aug 2006 Location: Vancouver iTrader: (1)	and obviously we all know that we love the louder exhaust note~ __________________ 2008 - E92 Blk Sapphire / Coral Red 335xi (Delivered) Nav / Premium + Sound / Sport / CA / 6AT + Shift Pad 2003 - Silverstone / Burnt Orange Fairlady 350Z (Sold)
	Appreciate 0 Quote