How do you make the exhaust valve flapper always open?

timwhayden · 07-17-2011, 08:41 PM

Just bought a new 35IS and will be picking it up next week. I want the exhaust louder at idle and lower RPM also and I have read to pull the vacuum line at the passenger side muffler. Exactly where does the line enter the exhaust system and do you just plug both ends? Thanks in advance.

jparnes1 · 07-17-2011, 09:41 PM

The rubber vacuum line is on the vacuum actuator which is on the passenger-side tailpipe just before it exits the rear bumper. Pull off the line and plug it,but not with something that will get drawn up farther into the tubing. Some have suggested a golf tee. It makes a very minor difference in sound, mostly when the engine is cold.

bmwmick · 07-17-2011, 09:41 PM

Quote:

Originally Posted by timwhayden

Just bought a new 35IS and will be picking it up next week. I want the exhaust louder at idle and lower RPM also and I have read to pull the vacuum line at the passenger side muffler. Exactly where does the line enter the exhaust system and do you just plug both ends? Thanks in advance.

Lay on the ground at the right rear corner, look up just inboard of the right side pipe. Pull the vacuum hose off the actuator and plug it with something like a golf tee or a suitable sized screw. Now it will allow both pipes to exhaust spent gasses.

ManiacGT · 07-18-2011, 09:28 AM

You'll probably want to change it back. It actually doesn't sound good at idle, it makes the exhaust sound like its 'blown' all gassy and not very impressive. Its better left alone IMHO as it then kicks in to give a better sound when under load/WOT.

bmwmick · 07-18-2011, 09:46 AM

Quote:

Originally Posted by ManiacGT

You'll probably want to change it back. It actually doesn't sound good at idle, it makes the exhaust sound like its 'blown' all gassy and not very impressive. Its better left alone IMHO as it then kicks in to give a better sound when under load/WOT.

Must be the air in the UK, here, ours sounds noticeably better with the flap blocked open. Sounds great at idle too. It IS blown.

Vintage · 07-18-2011, 09:57 AM

for me, louder is better even when at idle

cdeslandes · 07-18-2011, 11:13 AM

I undid mine. It caused the engine to run rough at idle and low RPMs after a cold start. And not much sound difference.

tot · 07-18-2011, 11:21 AM

Likewise I undid mine after trying it. I did not find the noise pleasant on a cold start, and once it is warmed up it is open anyway.

STOOF · 07-18-2011, 07:01 PM

With the JB4 you can control it electronically on the fly.

bmwmick · 07-18-2011, 07:34 PM

Quote:

Originally Posted by STOOF

With the JB4 you can control it electronically on the fly.

Heavens,
I would NEVER even think about adding something like that evil JB4 to our
35i, NEVER.

STOOF · 07-18-2011, 07:45 PM

I got the JB4 before i even have the car hahaha

Stallion · 01-06-2012, 01:46 PM

Quote:

Originally Posted by bmwmick

Lay on the ground at the right rear corner, look up just inboard of the right side pipe. Pull the vacuum hose off the actuator and plug it with something like a golf tee or a suitable sized screw. Now it will allow both pipes to exhaust spent gasses.

Hi guys, this is going to sound like a stupid question, but what the hell I'm going to ask anyway!!

I just did this mod on my exhaust and haven't noticed an appreciable difference so I'm unsure whether I've done things correctly.

Can someone just clarify when you say pull the hose off the actuator and plug it. Which side of the hose do you pull off and which end/ends do you cap?

I.e. I left the 's' shaped hose attached to the silver acuator and unplugged the other end where the 's' shaped pipe joins the more rigid pipe. I then plugged both the 's' shaped pipe (still attached to the acuator) and taped the end of the rigid pipe (just to avoid any dust getting in the pipe). Is this the correct procedure? Or should I have removed the 's' shaped pipe from the acuator and plugged the 's' shaped pipe? Would you then tape over the acuator end, to avoid dust getting in, or does this then defeat the point? So do you instead leave the acuator end open?

Hope this makes sense to someone and look forward to your help!!

jparnes1 · 01-06-2012, 04:02 PM

Quote:

Originally Posted by Stallion

Hi guys, this is going to sound like a stupid question, but what the hell I'm going to ask anyway!!

I just did this mod on my exhaust and haven't noticed an appreciable difference so I'm unsure whether I've done things correctly.

Can someone just clarify when you say pull the hose off the actuator and plug it. Which side of the hose do you pull off and which end/ends do you cap?

I.e. I left the 's' shaped hose attached to the silver acuator and unplugged the other end where the 's' shaped pipe joins the more rigid pipe. I then plugged both the 's' shaped pipe (still attached to the acuator) and taped the end of the rigid pipe (just to avoid any dust getting in the pipe). Is this the correct procedure? Or should I have removed the 's' shaped pipe from the acuator and plugged the 's' shaped pipe? Would you then tape over the acuator end, to avoid dust getting in, or does this then defeat the point? So do you instead leave the acuator end open?

Hope this makes sense to someone and look forward to your help!!

You pull off the end that attaches to the tailpipe and plug it. It's that simple. It doesn't make a huge difference in sound.

Mr Breeze · 01-06-2012, 07:18 PM

Pull the short rubber vacuum hose between the valve and the flap actuator. (it is "S" shaped under the rear bumper) Cover each end nipple with carb vacuum caps (you can find on amazon or ebay - search on "Holley vacuum line caps". This will give you more rumble and it's easy to put back if you are worried about BMW service folks. I've had this set up for over a year, with no problems. Love the sound, the cost is cheap, and it can be reversed if you don't like it.

Memphis1 · 01-06-2012, 09:44 PM

i used this.

Stallion · 01-07-2012, 10:27 AM

Hi Guys,

Thanks for your replies. I was really just trying to establish which end of the 's' shaped pipe should be disconnected for plugging. i.e. remove the end which connects to the silver unit (which I assume is the flap acuator) or instead remove the other end of the 's' pipe which connects to the rigid pipe.

If you were to disconnect the end from the silver box you can cap the end of the 's' shaped pipe easily but there isn't an easy way to cap the silver box, except by using electrical tape, but I didn't know which was more important, i.e. which way the vacuum draws.

If instead you leave the 's' shaped pipe connected to the acuator you can cap the other end of the 's' pipe but it is then difficult to cap the end of the rigid pipe, as it has a plastic connector joined to the end, again you can use tape to cover this but if the vacuum is drawn in this direction then tape might not be sufficient on its own.

Anyways, as I still don't really know which way the vacuum draws I plugged both ends of the pipe properly by leaving the 's' pipe attached to the rigid pipe - plugging the end. Then I cut a small piece of clear tubing (used from my biorb fish tank pump) and attached this to the acuator and capped the end. Therefore both pipes are now fully plugged in both directions and taped. I tied them together with a cable tidy so they didn't move.

Thing is, having done the mod, I wouldn't recommend it to anyboby as its just not worth it. Even though it only takes a few minutes the difference is hardly noticable and I have to agree with previous posts that it sounds a bit rough and rattley.

Just my 2p's worth.

cheers again tho.

07-17-2011, 08:41 PM	#1
timwhayden Private 10 Rep 64 Posts Drives: '11 Z4is AW/Walnut Join Date: Jul 2011 Location: Jackson,TN iTrader: (0) Garage List '07 Lamborghini Gal ... [0.00] '09 Audi Q5 [0.00] '11 BMW Z4is [0.00]	How do you make the exhaust valve flapper always open? Just bought a new 35IS and will be picking it up next week. I want the exhaust louder at idle and lower RPM also and I have read to pull the vacuum line at the passenger side muffler. Exactly where does the line enter the exhaust system and do you just plug both ends? Thanks in advance.
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07-17-2011, 09:41 PM	#2
jparnes1 Colonel 241 Rep 2,387 Posts Drives: 2016 340i, 2012 Z4 35i Join Date: Jan 2010 Location: NY iTrader: (1)	The rubber vacuum line is on the vacuum actuator which is on the passenger-side tailpipe just before it exits the rear bumper. Pull off the line and plug it,but not with something that will get drawn up farther into the tubing. Some have suggested a golf tee. It makes a very minor difference in sound, mostly when the engine is cold. __________________ 2016 340i XDrive, EBII/black, 6 MT, M Sport, Track Handling, Cold Weather, Tech, Lighting, Driver Assistance Plus. 2012 Z4 35i, ED 2/24/2012, Melbourne Red Metallic, Black Leather, Carbon Trim, 6MT, M Sport, CW, PP, PS, NAV, CA.
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07-18-2011, 09:28 AM	#4
ManiacGT Major 85 Rep 1,448 Posts Drives: Z4 sDrive 35i Join Date: Jan 2011 Location: Manchester, UK iTrader: (0)	You'll probably want to change it back. It actually doesn't sound good at idle, it makes the exhaust sound like its 'blown' all gassy and not very impressive. Its better left alone IMHO as it then kicks in to give a better sound when under load/WOT.
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07-18-2011, 09:57 AM	#6
Vintage Colonel 378 Rep 2,588 Posts Drives: BMW G80 (MT), 718 Spyder Join Date: Aug 2009 Location: Austin, Texas iTrader: (0)	for me, louder is better even when at idle
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07-18-2011, 11:13 AM	#7
cdeslandes Captain 27 Rep 676 Posts Drives: 2010 Z4 s35i Join Date: Apr 2010 Location: Connecticut iTrader: (0) Garage List 2014 Jeep Wrangler ... [0.00] 2013 Volvo XC90 [0.00] 2010 BMW Z4 sDrive35i [8.67]	I undid mine. It caused the engine to run rough at idle and low RPMs after a cold start. And not much sound difference. __________________ 2010 BMW Z4 s35i 2014 Jeep Wrangler Rubicon 2013 Volvo XC90
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07-18-2011, 11:21 AM	#8
tot Private 0 Rep 65 Posts Drives: BMW Z4 sDrive35i Join Date: Jan 2010 Location: Cote d'Azur iTrader: (0)	Likewise I undid mine after trying it. I did not find the noise pleasant on a cold start, and once it is warmed up it is open anyway.
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07-18-2011, 07:01 PM	#9
STOOF Sunburned 238 Rep 1,097 Posts Drives: '16 F83 M4 Convertible 6MT Join Date: Jul 2009 Location: Staten Island, NY iTrader: (2) Garage List 2013 BMW 535i [0.00]	With the JB4 you can control it electronically on the fly. __________________ 2016 M4 Convertible 6MT - SO/SO 2013 535i 6MT MSport - Retired 2011 Z4 SDrive35i 6MT- Retired
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07-18-2011, 07:45 PM	#11
STOOF Sunburned 238 Rep 1,097 Posts Drives: '16 F83 M4 Convertible 6MT Join Date: Jul 2009 Location: Staten Island, NY iTrader: (2) Garage List 2013 BMW 535i [0.00]	I got the JB4 before i even have the car hahaha __________________ 2016 M4 Convertible 6MT - SO/SO 2013 535i 6MT MSport - Retired 2011 Z4 SDrive35i 6MT- Retired
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01-06-2012, 07:18 PM	#14
Mr Breeze Private First Class 22 Rep 140 Posts Drives: 2011 Z4 35is Join Date: Jul 2010 Location: Scottsdale, AZ iTrader: (1)	Pull the short rubber vacuum hose between the valve and the flap actuator. (it is "S" shaped under the rear bumper) Cover each end nipple with carb vacuum caps (you can find on amazon or ebay - search on "Holley vacuum line caps". This will give you more rumble and it's easy to put back if you are worried about BMW service folks. I've had this set up for over a year, with no problems. Love the sound, the cost is cheap, and it can be reversed if you don't like it.
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01-06-2012, 09:44 PM	#15
Memphis1 Lieutenant Colonel 89 Rep 1,838 Posts Drives: Z4 SDrive 35i Join Date: Oct 2009 Location: CT iTrader: (0)	i used this. Attached Images __________________
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01-07-2012, 10:27 AM	#16
Stallion New Member 1 Rep 5 Posts Drives: BMW Z4 35i Join Date: Jan 2012 Location: Norfolk iTrader: (0)	Hi Guys, Thanks for your replies. I was really just trying to establish which end of the 's' shaped pipe should be disconnected for plugging. i.e. remove the end which connects to the silver unit (which I assume is the flap acuator) or instead remove the other end of the 's' pipe which connects to the rigid pipe. If you were to disconnect the end from the silver box you can cap the end of the 's' shaped pipe easily but there isn't an easy way to cap the silver box, except by using electrical tape, but I didn't know which was more important, i.e. which way the vacuum draws. If instead you leave the 's' shaped pipe connected to the acuator you can cap the other end of the 's' pipe but it is then difficult to cap the end of the rigid pipe, as it has a plastic connector joined to the end, again you can use tape to cover this but if the vacuum is drawn in this direction then tape might not be sufficient on its own. Anyways, as I still don't really know which way the vacuum draws I plugged both ends of the pipe properly by leaving the 's' pipe attached to the rigid pipe - plugging the end. Then I cut a small piece of clear tubing (used from my biorb fish tank pump) and attached this to the acuator and capped the end. Therefore both pipes are now fully plugged in both directions and taped. I tied them together with a cable tidy so they didn't move. Thing is, having done the mod, I wouldn't recommend it to anyboby as its just not worth it. Even though it only takes a few minutes the difference is hardly noticable and I have to agree with previous posts that it sounds a bit rough and rattley. Just my 2p's worth. cheers again tho.
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