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07-17-2011, 08:41 PM | #1 |
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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 |
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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.
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07-17-2011, 09:41 PM | #3 | |
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2011 35i 6-speed, ///M Sport, Deep Sea Blue, Black leather, Carbon trim, Cold Weather package, Premium package, 6CD changer. Delivered 7/15/11. Michelin Pilot SuperSport tires 10/24/12 Tucson,AZ/Santa Paula,CA |
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07-18-2011, 09:28 AM | #4 |
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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, 09:46 AM | #5 |
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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.
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2011 35i 6-speed, ///M Sport, Deep Sea Blue, Black leather, Carbon trim, Cold Weather package, Premium package, 6CD changer. Delivered 7/15/11. Michelin Pilot SuperSport tires 10/24/12 Tucson,AZ/Santa Paula,CA |
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07-18-2011, 11:13 AM | #7 |
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I undid mine. It caused the engine to run rough at idle and low RPMs after a cold start. And not much sound difference.
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07-18-2011, 07:01 PM | #9 |
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With the JB4 you can control it electronically on the fly.
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07-18-2011, 07:34 PM | #10 |
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Heavens,
I would NEVER even think about adding something like that evil JB4 to our 35i, NEVER.
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07-18-2011, 07:45 PM | #11 |
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I got the JB4 before i even have the car hahaha
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01-06-2012, 01:46 PM | #12 | |
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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!! |
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01-06-2012, 04:02 PM | #13 | |
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01-06-2012, 07:18 PM | #14 |
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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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01-07-2012, 10:27 AM | #16 |
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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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