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Head-In-Sand Dumbass
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Discussion Starter · #1 ·
Yeah so I was parking at my apartment for lunch today and decided to take that vacuum tube off the exhaust valve mechanism just to see what happens. On my drive back to work I noticed several very cool things:

1) the car maintains its low-rpm growl when not at WOT throughout the rpm band, rather than just up to a certain level when (I presume, before) the valve used to shut one of the pipes

2) when rev-matching the engine is not only more freely responding (to the gas pedal) but also much more noticeable since it's louder

3) when downshifting to slow down, you can actually hear the engine's rpms dropping as opposed to just seeing the tach go down (as it was with the exhaust valve enabled)

4) no more annoying "clack" from the valve as it swings open

All in all I'd say it's an overall improvement for sure! I should probably get something to close up that tube with though, right now it's just hanging there under the bumper.
 

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Here since day one
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This club you are talking about sounds like the kind of club I want to join . . .

What is this tube you speak of ? ?

Do you have pictures of what it is I need to do ??

Please don't make me wait forever for you to answer . . . I NEED TO JOIN THE CLUB RIGHT AWAY !!!!
 

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Head-In-Sand Dumbass
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Discussion Starter · #3 ·
Alan F said:
This club you are talking about sounds like the kind of club I want to join . . .

What is this tube you speak of ? ?

Do you have pictures of what it is I need to do ??

Please don't make me wait forever for you to answer . . . I NEED TO JOIN THE CLUB RIGHT AWAY !!!!
Sorry alan, we only allow the coolest coolest members, no simpleton coolest members.

:tsk:
 

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Head-In-Sand Dumbass
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Discussion Starter · #4 ·
OK ok I'm just kidding. =)

(I needed a little photoshop time to get this up for ya)



Follow the arrow. You will see a small (maybe 1/2") wide black tube running into your exhaust valve solenoid. Using your thumb and pointing finger (index finger?) wiggle the thing off its connecting metal tube (it slides right off).

I suppose you should plug up the tube with something to prevent water from going up there and dust, but I'm not sweatin it right now. Someone mentioned they used a golf tee.

This completes your hazing for the no-exhaust-valve club.
 

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Crazy Canadian
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alternativly you could remove the valve and is control to save weight :p
 

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Thanks Chris, I don't have the Bimmer with me today (actually I think my wife's driving it . . . yesterday she put both carseats in it ) Oh well . . . that's the end of that car ;)

But anyway, I'll try it out when I get home

and BTW you are now the ultra coolest member :thumbup:
 

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I'm guessing there is some reason for it being there...anybody know what it does? Is there a long term problem running without it?
 

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Its for the 330's, I've had my valve disabled for awhile, and i'm lovin it. Aftermarket exhaust type sound without the aftermarket exhaust :p
Anyhow, yeah, I think you should plug up that tube ASAP with a screw or somthing (thats what I used) then I used a twist tie to keep it up and out of the way...
 

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wyu said:
Its for the 330's, I've had my valve disabled for awhile, and i'm lovin it. Aftermarket exhaust type sound without the aftermarket exhaust :p
Anyhow, yeah, I think you should plug up that tube ASAP with a screw or somthing (thats what I used) then I used a twist tie to keep it up and out of the way...
And some 325 models. I forgot if we ever figured out the exact ones which have it. The only way to be sure is to check the muffler itself.
 

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Parking Spot Maven
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There have been several extensive discussions about this valve here, at .org, and on the fanatics board. It has been concluded that these valves are on 330* and 325xi cars. Among other things, it adds necessary backpressure for extra torque at lower RPMs. Do a search for 'exhaust valve' for more details.

I am going to keep mine intact - IMHO it serves several important purposes (extra low-end torque, cleaner emissions, etc) so to me it doesn't make sense to trade it for what amounts to some extra noise and a placebo effect. :D

Good luck...
--SONET
 

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Head-In-Sand Dumbass
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2,192 Posts
Discussion Starter · #15 ·
SONET said:
There have been several extensive discussions about this valve here, at .org, and on the fanatics board. It has been concluded that these valves are on 330* and 325xi cars. Among other things, it adds necessary backpressure for extra torque at lower RPMs. Do a search for 'exhaust valve' for more details.

I am going to keep mine intact - IMHO it serves several important purposes (extra low-end torque, cleaner emissions, etc) so to me it doesn't make sense to trade it for what amounts to some extra noise and a placebo effect. :D

Good luck...
--SONET
I bet if you unplug it and give it a try you will switch over to the dark side my friend. :angel: :thumbup:

I just got a chance to reconfirm the extra sound -- it is DEFINITELY there. The sound may be different for the 325 cars, hence Nick's disgust with the tummy-turbulant sound waves. I also wanted to reconfirm the rev-matching (the engine seems to just rev much MUCH more freely than before) and sure enough it worked perfectly... and the sound is intense when you're doing it around 1500-2000 rpms. Good stuff!

I'm stickin with it folks! wyu, thanks I'll take care of that tonight.
 

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Hmmm, think if I replace my muffler with one from a 330 and modify it similarly it will have the same effect? Got me thinking now...
 

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Parking Spot Maven
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webguy330i said:


I bet if you unplug it and give it a try you will switch over to the dark side my friend. :angel: :thumbup:
Naah, I've had enough loud exhaust to last me several lifetimes (in fact I've lost some hearing in my left ear over it! :yikes: ). I'm happy with the way that it is and really like the low-end torque. And I can rev-match just fine the way it is, so I'm happy! :D

--SONET
 

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I know the discussion regarding low end torq has been beaten to death, but whenever the subject of the valve comes up, I like to point to this link.

Just somthing more to think about.. :thumbup:

Different strokes for different folks I guess. :dunno:
 

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Parking Spot Maven
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wyu said:
I like to point to this link.

Just somthing more to think about.. :thumbup:
It's always important to take your source of information into account. Consulting a source that stands to gain (financially in this case - UUC) by providing falsified information isn't always the best idea. You may as well ask a tobacco company if it's okay to smoke.

I want to see an independent source that has nothing to gain make the same claims with actual hard facts (as in dyno / 1/4 mile times). Anyone? :D

Just my two cents.

--SONET
 

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Sonet . . . your a cool person . . .so Chris and I discussed it and we're gonna let you in the club . . .:D :D

Please have this mod done to your car no later then thrusday ;)
 
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