muffler valve/golf tee alternative---
 

Reading posts about forcing the muffler tailpipe valve to stay open by removing the vacuum hose and plugging it---If you open the rear hatch and remove the drivers side cover (where the DVD and Sat radio go) you will see a small solenoid valve with 2 vacuum hoses attached--the soft hose goes directly to the vacuum pot on the muffler--you can disconnect it at the solenoid valve and put a short piece of plugged hose in the valve output--now you don't have to crawl under the car and if you go for service no one will see the hose with a golf tee stuck in it! Should be goood for about 15 to 20 HP and 3 to 5 MPG by my dyno reading :nanana:

I just doubled the hose over and tied it. No disconnecting, no plugging of open valves or hoses, no potential loss of vacuum in the system.

What did the modification do for you--I'll bet with the V8 the exhaust tone is nicer!

:rofl: Sorry, I should have been more specific. It wasn't on my X5, it was on my 330. As far as I know the 3 litre M54 is the only engine that has the muffler valve.

It sounds much louder on startup and the exhaust note is much more noticable at lower RPMs. I found no noticable effect on performance or mileage. Hey, what do you want for a free mod? ;)

Yes just got back from a ride--the exhaust is definitely nicer--I like it--can't beat a free modification!

warranty
 

Does this cause any warning lights in the system? Did you notice an increase in power? Can you show a picture of it?:)

Shouldn't do any damage or increase in power. The sport package does not have one of these devices installed on the muffler and is rated that same as a non sport. Maybe it's a stainless tips on my muffler that make it go so fast.

No warning lights--as far as power goes when the throttle is opened far the valve opens anyway--so either way at full throttle its the same--its worth it for the sound--it now sounds like my Z4 with the drilled out muffler. May be more at lower throttle openings because both tailpipes are wide open??

Muffler vacum cap off
 

I found the valve right where you said it was and capped the soft side to the vacum assembly. It is a little louder at low rpm's and it seems to run at about 200 lower at 25 in second gear for example.

Some have reported on other BMW sites, that some dealers are even doing this mod. ;)

I've been planning on doing this for such a long time, but keep forgetting to do so. Anyone happen to know where the vaccum lines are under the X5 3.0?

See first post.

I found it in the X3 by laying under the muffler and looking on top of the muffler for the vacuum pot--feel around the muffler outlet area--use a mirror if you have to not all models have the valve--on the X3 it can be seen looking through the tailpipe with a flashlight.

Some pics
 

Here are some X3 pics where to disconnect if you don't want to do it at the muffler.

I unplugged mine and immediately noticed a 20 hp gain at idle and below 2000 rpm ;) In the long run and during long trips the sound may be annoying but it's easy to plug it back if needed.

- p

Don't forget to plug the vacuum pipe that you took the hose off--Don't know if this will cause a vacuum leak or other problems

Per the suggestion on the first page, I just zip tied the hose closed as shown in the pictures. Very easy to do and no vacuum leaks. It was interesting to start it up with the hose pinched and then let it go to hear the difference in sound. Quite a change.

Also, if I didn't know any better, the engine feels a bit stronger. It's probably all in my head, but without a dynamometer to prove me wrong, maybe - just maybe - it is...

http://greggpeterson.com/aux_images/X3/GolfTee01.JPG

http://greggpeterson.com/aux_images/X3/GolfTee02.JPG

Ya know I thought I felt an increase in part throttle response but was afraid to say so--I completely forgot about the modification and I took the car out a day after I plugged the hose and --I noticed a different feel (similar to the sport button on my Z4 but more subtle) then I remembered I had plugged the hose--then I paid attention to the nicer sound from the exhaust--I will have to do an A B comparison some time.----Enjoy--Its a fun modification..:)

Thanks for the reminder. I got carried away and went for a test drive immediately after unplugging :) I have driven it unplugged for a week now and no issues discovered so far. Other than I seem to drive more and more every day...

For others thinking of doing this, the vacuum seems to be on the plasic 'nipple' side and not in the hose left hanging around (see the pic in my previous post). So it might be worth putting something there to fool the system. Or do the zip tie trick like X3eme did his.

I might check if there are any fault codes activated now that I drove it unplugged.

- p

Why are we doing this exactly? My understanding of the system is that it helps heat up the cats and O2 sensors when cold.

A previous post stated that its there for sound control only and it does do that--Many X3 don't have the valve--and of course I guess we can do this only if we want to at our own risk!:)

After living with the defeated valve for a day or two I would agree that the reason for the valve is sound control. Without the valve, the X3 does not sound like it has a refined 6 cylinder BMW engine. At low revs it reminds me of a bigger Honda engine with one of those huge aftermarket exhausts. It needs that valve to sound like a near-luxury BMW.

If I have hypothesized correctly, would it be a stretch to think BMW gave up a little power to get it to sound like it should?

I still think it feels a little... not much... but a weee bit peppier.

Pardon my ignorance, but how does this improve HP? If it improves HP and MPG and has no drawbacks, why wouldn't BMW have the stock setup like this?

The unrefined, non-BMW like sound is the drawback... to BMW. I kinda like it.

max HP increase... not going to happen with this mod, the valve is open under WOT conditions

MPG increase... maybe a .01 increase in you do a lot of red lights and stop signs

but don't you just luv the sound

ab

So Cleaner, you have to teach now. What are the potential hazzards here. Want some input
before I do this to my 2006.:dunno:

The car is running rich when the engine is cold. You would want the cat to come up to temp as quickly as possible to work properly...putting out less contaminants. Also, you would want a bit of back pressure in the low RPMs to help with torque. BMW would NOT go through all that trouble to just "muffed" the exhaust sounds as there are other simpler ways of doing that!

Just to play devil's advocate... :stickpoke



Given that sport package X3's don't have the valve at all, and have slightly wider diameter muffler tips causing even less back pressure:

1. If the closed valve is helping the cat heat up faster thereby reducing contaminates, does that mean that it is OK for sport packages to pollute more?

2. Wouldn't you expect the "sport package" to have more torque at low RPMs than the non-sport? It certainly wouldn't have less. Why don't sport packages have the valve if it provides for more torque?



Here is where my crazy hypothesis from before kicks in:

3. It might be safe to say that someone who buys a sport package vehicle would be happier with a louder, more sporty exhaust note. Perhaps leaving the valve off, but tuning the sound a little with a slightly wider opening would make it louder, but still sound like a BMW.

4. For those that do not choose to buy a sport package X3 we might assume that they want a more civilized, even luxurious driving experience. To do that we may make the muffler openings a little smaller to quiet the sound at higer RPMs. What if these smaller openings caused a wild, uncivilized exhaust note at lower RPMs? Perhaps plugging one hole up with a valve would work at these lower RPMs. We will sacrifice a little power, plugging up one hole in the muffler, but it isn't much and it will be worth it to give a more civilized, luxurious driving experience.



Sound too crazy to be true? :dunno:

The solenoid muffler flap is to reduce noise at low RPM. It is closed below ~4500 RPM and open open above that. I doubt it has anything to do with warming up the cats or sensors as it is controlled by RPM and not exhaust temperature.

Why is it there? It's there to pass certain noise standards at lower RPM while maintaining performance characteristics at WOT.

Seems harmless, but I would not know, I May be wrong about what the valve does. Someone else mentioned it was only to quiet the exhaust. I was thinking there are easier ways to quiet the exhaust but it’s very possible thats the only purpose. I have been reading the 335i has a similar valve and exhaust only exits one pipe till it warms up. I just have a feeling it’s doing more than it appears.

My idea on this-;) -BMW put this in to reduce gas mileage because of heavy pressure from the big oil companies--they are concerned anytime a manfacturer comes out with a more powerful engine that gets better EPA numbers than the previous model, its bad for the oil business--so I say stick it to the oil guys--leave your valves wide open--better mileage and more noise--sounds like a win-win to me. BTW my mileage is up 5 MPG since the modification..(:D ). Beware of oil company investigators looking up our tailpipes. I'm afraid if too many of us do this the price of oil will rise just like the recent "Merry Christmas" rise.-So open those valves and have A Happy New Year!!

Thx to all for letting me hijack here, Would love to here some more performance responses.:thumbup:

Well, I have a sport package and it has this muffler valve. My X3 is year model 2004 (02/2004).

BTW: I have done this mod also, no error codes so far :thumbup: I have read OBD2 codes several times after this modification.

I did it this morning. I didn't notice a big difference. I'll get out this afternoon without the family and see what she does.

Update:

After couple of months testing: No OBD2 error codes so far, but I have noticed that my automatic transmission does not work as smooth as without this "mod". So, I removed the mod during last week and yes, automatic is very smooth again. I do not know the reason, maybe this happened only in my car :confused:.

Just for your information: I have a friend in BMW USA and based on his comments, there should not be any negative effects, other than huge noise increase ;)...well I do not believe him anymore:)

BTW: US X3 version seems to be pretty good winter car. I shipped my X3 from CA USA to Finland and we have here now about -30 deg. C (about -22F). Car runs like a dream....and Xdrive is great:thumbup:

Follow up on muffler valve
 

I reconected the muffler valve vacuum hose for our trip to FL and back to make cruising quieter--I forgot about it until last week when I disconnected and plugged it again. The next day I went out (completely forgetting that I did the Mod) and found the car to be noticeably snappier at part throttle--then I remembered I pulled the hose--So I don't think it was my imagination.. :thumbup: Any one else do an A-B comparison??

Checked the MY 2006 with SP and there is no valve in the tips of my exhaust system. With that in mind after reading your post and the before and after comparision I must be at full power all the time.
cheers
vern

If you look carefully in the panel on driver side you will see the kanuter valve Just move your muffler valve hose to that valve. WOW!

I tried that--way too much power for me. ;)

I have the sport package and my muffler has the gate on it. So maybe its not specific, but more generic at this stage. A BMW mechanic told me it was for more torque at low RPM's, by creating more back presure.

Vipz

After reading through this tread yesterday and looked at the valve on my wife's X3. I noticed that it was open so I watched the valve as she cranked up the car. It stayed open for about 2 seconds after the car was cranked and then it closed. I could tell a difference in the sound when it closed. Also I always thought that a free flowing exhaust (less back pressure) would produce more HP and torque. That's usually where most of your HP gains come from when you put a Flow-master or Borla exhaust system on. I would think that having the valve open would produce a little more power which might help a little on gas mileage. As for 5 mpg.... I would be very impressed but I would be more inclined to think you aren't as heavy on the throttle because of the increased sound at lower speeds. Just my 2 cents... if I am wrong let me know.

Telling us you have SP and the gate tells us very little if you don't tell us the YEAR of your X3
cheers
vern

Click on SAV in his post for this info :thumbup:

Thank you !!!!!!!! Wouldn't it be nice if he put it in his SIG. with the rest of his options ?
cheers
vern

If you checked my SAV link, you would have seen it is a 2007, actully it is only 3 weeks old.

But you are right, I should have been more specific, sorry.

Vipz

No need to be sorry, but like I said before if all the information was in your Sig. it would be nice and people wouldn't have to keep refering to your OP to find out what you have. Enjoy your X3
cheers
vern

Well, after seeing this thread pop up again I decided to give it a try. I bent and tied the hose with a wire tie. The valve staying open really does change the sound of the exhaust at low RPM. I could notice the deeper, throaty sound while cruising. Sounds pretty cool! Don't know if I'll leave it that way, I'm going to give it a week or so and see what I think.

What does the muffler valve do?

Apparently all it really does is quiet the sound a little at lower RPM's. If you read this whole thread you'll get some other opinions/ideas on what it does or is supposed to do.

From what I experienced today I'd have to agree that all it does is give a quieter exhaust note. I never was able to really hear the exhaust before but after doing the mod I really noticed the difference. Though not unpleasant you can definately hear it more in normal driving.

And thats a good thing?

No. Mods are evil.

:popcorn:

I suppose it is if you'd like a more sporty exhaust note from your sporty X3 :D It's not all that much louder or anything. With the radio on you wouldn't even notice it. It does give a nicer sound to the wonderful inline 6 though.

Whatchutalkin'bout Willis?


:rofl:

Arnold: My pet goldfish, I call him Abraham

Mr. Drummond: I have never seen a black goldfish before.

Arnold: That's okay, he's never seen a rich white man before either.

:rofl:

Good one, Rebound! :rofl:

To continue the golf tee saga.....

Still trying to decide if I'd rather have the valve working or not. There is no performance gain and the sound is not too obtrusive but is noticeable even at freeway speeds with the radio on at moderate volume. If there were any real benefit to having it open all the time other than the sound I'd probably stick with it open but the quieter ride has it's benefits, especially on a long trip. I think I understand now why BMW put the valve there in the first place. To balance performance with luxury.

I'm still on the fence at this point. I'll give it another few days.

Your are right--On a recent 1300 mile trip I noticed it was causing a slight drone in the cabin--I reconnected until I got home--now it is again plugged. Would be nice to have a control from the dash. :thumbup: :thumbup:

I have a funny suspicion that the two wires on top may just have something to do with the operation of the valve.
A jumper switch mounted under the dash....
flip up = quiet
flip down= louder

It looks like you guys are gonna make me do this...

Be good,
TomK

OK you got the job--let us know how it works out..:thumbup:

:rofl: :iagree: Go for it ace!

Guess I'm off the fence, I've kept the valve plugged for around town driving. I do like the way it sounds. But if I get ready to go on a long trip I'll hook it back up.

(That switch would really be n-i-c-e :thumbup: )

Does the X5 have this valve?

i don't know--shine a light up your tailpipes--:confused:

OK...I went out back and checked out the system. I'm sad to say that I will not be messin' with the valve...it's staying open...forever.

I started the car and asked the wife to rev "her" motor with the valve closed....very quiet - actually, too quiet.

With the valve open, tube folded over on itself and zip-tied....very quiet with a hint of mouse farts....still WAY TOO QUIET. Amazing how quiet this exhaust is, regardless of valve position. I'm actually surprised they let the X3 out of the factory with such a tame sound...expecially with the Sport Package.

Really, if it made a difference I'd go at it and hook up a switch for when I drive it...but it's just not worth the effort. Driving around town, on the highway, rpms high or low....the exhaust is ridiculously quiet, making it difficult to heel-toe downshift.

Keep in mind, I'm not the typical "luxury" client for the upscale manufacturers. My last few cars I've had were for autoxing/roadcourses FIRST, daily-driving/commuting/comfort LAST. The only two cars I've had that even relate to the "luxury-sport" market are an Audi A4 (turbo, manual) and a Cadillac CTS-V. The Audi very quickly was chipped and the mufflers (there were two) were cut-off and replaced with a straight pipe. The CTS-V had it's exhaust removed on arrival at the dealership, prior to me taking posession, and a Corsa Sport exhaust bolted on.
My current track-weapon is an STI with a full race-exhaust from header to tail-pipe....no cats/no resonators/and the loudest muffler I've ever heard.

So this X3 with the Sport package and 6speed is quite tame for me, but impresses me more and more every time I drive it. I really think it'd be a great tool for a roadcourse, with proper tires and brake-pads. As the miles add up and as my experience deepens, I'll probably "mess" with it more and more.

I've been known to open a hood or two and go a little crazy with a sawzall and rotary tool....

(very OT...but here's a video of my last trip to Pocono East with my STI...
http://s160.photobucket.com/albums/t...I-05052007.flv )

Be good,
TomK

I did this mod over the weekend and am very happy with both the sound and the extra responciveness at part throttle. To do it you don't even need to pull the vaccume line. just kink it and put a zip tie arround the kink. No chance of vaccume loss and your good to go.

Recently I've noticed that my muffler was louder than normal. Initially thought it might be something loose (~30k miles right now on my E83) and now realizing that its most likely this valve. Not sure but I think its bad or has gone bad. The vehicle is still under warranty and wondering if I can check the valve's operation or remove and clean it and re-install it. What are your collective thoughts?

Answering my own question. Checked for vacumn first and noticed that it did exist. Checked the hose and noticed a small crack in the hose above the flapper valve, enough for the flapper valve not to work correctly. I did not like the sound it was making. Cut about .5" of the hose (at the line of the crack) and refitted it. This corrected my problem. Its kind of difficult to work in the area of the flapper valve. I know there is a lot of heat in the area. Is this a common occurance for a vehicle with 30K miles on it?

This is my X3, the exhaust is stock. Is louder to me than other X3 I've driven locally, don't know why :dunno:.

YouTube - E83 X3 3.0i Stock Exhaust

Do you guy's X3 sound like that?

Its hard to tell with the backround noise but I really only noticed it when I would first start it. The easiest way to tell is to disconnect the power from the solenoid. If you don't hear a different then your solenoid isn't working or you have a hole or leak in the hose to the flapper valve. Personally I didn't like the sound it made when there was a leak in the vacumn hose.