2013 335i F30 factory exhaust choke point?

DreamerJoe · 02-08-2019, 06:38 PM

Hey guys, so I pick up my 2013 335i sedan this weekend, and first point of business is an inspection, dealership does their own but I would feel more comfortable with a 3rd party. They would not allow a pre purchase, but I have 5 days and 200 miles to return it if their are any issues, but I do not forsee any.

Anyway, on to my topic, one of my first mods will be a exhaust, but how is the flow of the factory exhaust? I come from a G35 platform where if you just replace factory cats and y-pipe their really is no need for a full exhaust except for sound. I have searched this forum and online and cannot find anything similar on the 335i. I know the main restriction is the cats, so that will be replaced, but what about the midpipe and axle back section? are their choke points there as well? or would the gains be minimal. TIA!

future mods I plan on doing are charge pipe, fmic, a better sealed intake, and MHD. not sure what order yet, but Im super excited!

Eschmacher · 02-08-2019, 10:01 PM

The gains from anything other than downpipe will be minimal. Also keep in mind that the downpipe does a major amount of muffling on this platform. Removing will make the exhaust much louder. Keep this in mind, depending on how loud you want to go.

KC Bimmer · 02-08-2019, 10:14 PM

A grand for 5-10 hp. Plenty of other options for performance upgrades for a lot less. Dp with stock exhaust sounds pretty decent.

Munchi435i · 02-08-2019, 11:42 PM

To answer your questions, yes a upgraded Downpipe will offer the best flow, increase in HP and sound with just stock exhaust. Stock mid pipe is not restricted and most just replace just the muffler. If your looking to increase sound then a full catback along with upgraded downpipe will accomplish that. Be warned that once you replace the stock mid pipe or remove the resonator from the stock mid pipe, you will have some drone in lower rpms.

DreamerJoe · 02-09-2019, 01:10 AM

perfect, thanks! I kind of want to stay away from a too loud exhaust, especially with the new California law. I will just replace the downpipe with a catted downpipe for now, as well as other breather mods to wake up the beast. Thanks again guys.

02-08-2019, 06:38 PM	#1
DreamerJoe Captain 245 Rep 774 Posts Drives: 2017 340i M.G. w red interior Join Date: Dec 2018 Location: SoCal iTrader: (0)	2013 335i F30 factory exhaust choke point? Hey guys, so I pick up my 2013 335i sedan this weekend, and first point of business is an inspection, dealership does their own but I would feel more comfortable with a 3rd party. They would not allow a pre purchase, but I have 5 days and 200 miles to return it if their are any issues, but I do not forsee any. Anyway, on to my topic, one of my first mods will be a exhaust, but how is the flow of the factory exhaust? I come from a G35 platform where if you just replace factory cats and y-pipe their really is no need for a full exhaust except for sound. I have searched this forum and online and cannot find anything similar on the 335i. I know the main restriction is the cats, so that will be replaced, but what about the midpipe and axle back section? are their choke points there as well? or would the gains be minimal. TIA! future mods I plan on doing are charge pipe, fmic, a better sealed intake, and MHD. not sure what order yet, but Im super excited!
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02-08-2019, 10:01 PM	#2
Eschmacher Car Hypochondriac 335 Rep 903 Posts Drives: 2014 335i M-Sport Estoril Blue Join Date: Feb 2017 Location: Sterling, VA iTrader: (0) Garage List 2014 BMW 335i [0.00]	The gains from anything other than downpipe will be minimal. Also keep in mind that the downpipe does a major amount of muffling on this platform. Removing will make the exhaust much louder. Keep this in mind, depending on how loud you want to go.
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02-08-2019, 10:14 PM	#3
KC Bimmer Second Lieutenant 29 Rep 256 Posts Drives: 2013 335i xdrive Join Date: Sep 2005 Location: KC iTrader: (0)	A grand for 5-10 hp. Plenty of other options for performance upgrades for a lot less. Dp with stock exhaust sounds pretty decent. __________________ 2013 335i xdrive BSM Sportline: FBO (ER FMIC, catless DP, CP, TIC, AFE dry filter, JB4 Map 2 or 5), Dinan springs, Doss Wheels (19x8.5), DWSO6 255/35/19, M4 Style Rear Spoiler, M Grille, Painted Whiskers/Front Reflectors Previous: 2006 330i (stock), sold at 152k miles after 10.5 years
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02-08-2019, 11:42 PM	#4
Munchi435i Major 486 Rep 1,105 Posts Drives: 2014 Alpine White 435i M-sport Join Date: Jun 2017 Location: Orlando FL iTrader: (0)	To answer your questions, yes a upgraded Downpipe will offer the best flow, increase in HP and sound with just stock exhaust. Stock mid pipe is not restricted and most just replace just the muffler. If your looking to increase sound then a full catback along with upgraded downpipe will accomplish that. Be warned that once you replace the stock mid pipe or remove the resonator from the stock mid pipe, you will have some drone in lower rpms.
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02-09-2019, 01:10 AM	#5
DreamerJoe Captain 245 Rep 774 Posts Drives: 2017 340i M.G. w red interior Join Date: Dec 2018 Location: SoCal iTrader: (0)	perfect, thanks! I kind of want to stay away from a too loud exhaust, especially with the new California law. I will just replace the downpipe with a catted downpipe for now, as well as other breather mods to wake up the beast. Thanks again guys.
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