Exhaust bypass on f10 M5 - M5POST

whiteM5 · 01-19-2013, 09:33 AM

Featured on BIMMERPOST.com

Anybody played with the idea of the exhaust bypass valve. I've seen systems on AMG's and various other cars, for off-road use only of course. But it would be a toggle switch that would be a side exhaust exit just aft of the downpipes. Real loud, no emissions.

Just curious what this would do to the car? For $8k on an akrapovic system I think my fabricator could mock this up nicely, with a nice button in the cabin to toggle between the two setups.

I assume this would throw a check engine light but would the car still run ok?

Thanks in advance.

cpiguy · 01-19-2013, 11:54 AM

My son had this exact thing done on his M3, except the cutout is just before the mufflers. It cost him $500 total including the valves and switch, including labor to install and weld the valves in place. He did the wiring himself. Sound is awesome open. Better than my $7000 aftermarket system on my M3.

That being said, it does not create any horsepower like my system does. My full race exhaust system gives me about 35 HP. We dyno'd our cars with valves open and closed, and there was 2 HP difference on his car.

Charlie Brown · 01-19-2013, 12:57 PM

I like this idea. I've seen it done on several V8 muscle cars but never a BMW much less an F10 M5. Very intrigued though. So who's going to try this first!

stealth.pilot · 01-19-2013, 01:26 PM

Quote:

Originally Posted by cpiguy

My son had this exact thing done on his M3, except the cutout is just before the mufflers. It cost him $500 total including the valves and switch, including labor to install and weld the valves in place. He did the wiring himself. Sound is awesome open. Better than my $7000 aftermarket system on my M3.

That being said, it does not create any horsepower like my system does. My full race exhaust system gives me about 35 HP. We dyno'd our cars with valves open and closed, and there was 2 HP difference on his car.

So your car had 35hp over his car on the same day and same dyno?

M54ccibo · 01-19-2013, 01:36 PM

Valve after the downpipes? If that's the case on the F10 M5 you'll still have the cats (emissions) as they are in the downpipes, unless you gut them

Still, wondering about the sound and any HP increase.

greentrbo95gst · 01-22-2013, 01:13 AM

Not exactly sure how it would work on a f10, but the idea is to install cut out after the primary o2 sensors and before secondary ones. If you install them pre-o2 (primary) you ecu might go into limp mode. Electric cut-outs in the right spots will actually help a ton when it comes to a car with forced induction.

whiteM5 · 01-22-2013, 09:12 AM

im having a local tuner fabricate, we'll do pre and post dyno runs, give me a week or so and should have an update.

greentrbo95gst · 01-23-2013, 03:05 PM

Quote:

Originally Posted by whiteM5

im having a local tuner fabricate, we'll do pre and post dyno runs, give me a week or so and should have an update.

Do you know exactly where he is installing it?

stealth.pilot · 01-23-2013, 03:25 PM

Cool. Hamann also makes a bypass kit.

01-19-2013, 09:33 AM	#1
whiteM5 Private Drives: 2013 M5 Join Date: May 2012 Location: Scottsdale Posts: 93 iTrader: (0)	Exhaust bypass on f10 M5 Featured on BIMMERPOST.com Anybody played with the idea of the exhaust bypass valve. I've seen systems on AMG's and various other cars, for off-road use only of course. But it would be a toggle switch that would be a side exhaust exit just aft of the downpipes. Real loud, no emissions. Just curious what this would do to the car? For $8k on an akrapovic system I think my fabricator could mock this up nicely, with a nice button in the cabin to toggle between the two setups. I assume this would throw a check engine light but would the car still run ok? Thanks in advance.
	Tweet

01-19-2013, 11:54 AM	#2
cpiguy Lieutenant Drives: 2010 M3 & 2011 458 Join Date: Aug 2009 Location: Westlake Village, CA Posts: 561 iTrader: (0) Garage List 2011 Ferrari 458 It ... [1.83] 2013 BMW M5 [0.00] 2010 BMW M3 [0.00] 2010 BMW X5 3.5D [0.00]	My son had this exact thing done on his M3, except the cutout is just before the mufflers. It cost him $500 total including the valves and switch, including labor to install and weld the valves in place. He did the wiring himself. Sound is awesome open. Better than my $7000 aftermarket system on my M3. That being said, it does not create any horsepower like my system does. My full race exhaust system gives me about 35 HP. We dyno'd our cars with valves open and closed, and there was 2 HP difference on his car. __________________ CPIGUY 2010 M3 Coupe, 2010 X5 35D 2011 458 Italia, 2013 M5

01-19-2013, 01:36 PM	#5
M54ccibo Captain Drives: '13 F10 M5 AW/SO Join Date: Apr 2012 Location: Orange County, CA Posts: 658 iTrader: (0)	Valve after the downpipes? If that's the case on the F10 M5 you'll still have the cats (emissions) as they are in the downpipes, unless you gut them Still, wondering about the sound and any HP increase. __________________ Current ///M: '13 F10 M5, Alpine Weiss III/Sakhir Orange Full Akrapovič Evolution, CF Delete, H&R Sport Springs, iND Cosmetics, RKP Lip, Color matched M-Performance Spoiler, V1 Hardwire, Coded, Morr 21" MS54 RIP: '09 E60 M5 Space Gray/Black

01-22-2013, 01:13 AM	#6
greentrbo95gst Second Lieutenant Drives: 2008 M5 Join Date: Jan 2011 Location: Orange County Posts: 202 iTrader: (0)	Not exactly sure how it would work on a f10, but the idea is to install cut out after the primary o2 sensors and before secondary ones. If you install them pre-o2 (primary) you ecu might go into limp mode. Electric cut-outs in the right spots will actually help a ton when it comes to a car with forced induction. __________________ 2013 M5 Azurite Black.....May 10th 2013 ED 2008 Saphire Black M5/2003 BMW M5 (My favorite) 2011 Lemans Blue 335d M/2001 AA supercharged 325ci http://i280.photobucket.com/albums/k...63542371_n.jpg

01-23-2013, 03:25 PM	#9
stealth.pilot Knight Commander /// Drives: 2013 M5 Individual Join Date: Aug 2010 Location: South East USA Posts: 2,300 iTrader: (0)	Cool. Hamann also makes a bypass kit. __________________ 2013 ///M5 Individual Monte Carlo Blue, Platinum Full Individual Merino, Platinum Alcantara, Piano Black, Exec Pkg, Drivers assistance pkg, Bang and Olufsen, 20" wheels Eisenmann Sport Exhaust, Bel STiR+, Laser Interceptor QUAD HP, Zaon MRX

01-19-2013, 12:57 PM	#3
Charlie Brown Second Lieutenant Drives: F10 M5 Azurite Black Join Date: Jun 2012 Location: USA Posts: 267 iTrader: (0)	I like this idea. I've seen it done on several V8 muscle cars but never a BMW much less an F10 M5. Very intrigued though. So who's going to try this first!

01-22-2013, 09:12 AM	#7
whiteM5 Private Drives: 2013 M5 Join Date: May 2012 Location: Scottsdale Posts: 93 iTrader: (0)	im having a local tuner fabricate, we'll do pre and post dyno runs, give me a week or so and should have an update.

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search