Jonny

Butterfly valve exhaust mod

310 posts in this topic

Jonny   

Ok so basically i've been looking around on e46fanatics recently about the "Golf Tee Mod" as its free and i'm relatively broke :/

The concept is that you disconnect a vacuum hose from the exhaust therefore forcing a butterfly valve inside one of the twin pipes to remain open to allow for a deeper sound at low revs.

For those that found the above didn't make sense (and it didnt to me at first) i'll explain.

Basically because BM's are made for big fat German executives (dont flame me for my generalisation :P) the E46's with twin exhaust pipes have a butterly valve in the inner right exhaust pipe that completely shuts off that exhaust from around 1000-3000 revs to limit exhaust sound around urban areas. Once you go above that rev range, the valve opens and you get a nicer and deeper exhaust note which you would generally be after if you were revving that high.

The "golf tee mod" works by disconnecting the vaccuum hose that attaches above the exhaust and operates the butterfly valve and stuffing it with something of a similar size to a golf tee to plug the end. This then allows the valve in the inner right pipe to be constantly open and therefore give you a much nicer and deeper exhaust note even at idle and right through the rev range.

Well long story short (too late now i know lol) I attempted this mod yesterday, located the pipe, stuffed it with a short metal screw (it looks cleaner and wont melt) and started her up. Nothing. "Well i guess you get what you pay for" i said to myself thinking that it had made absolutely no difference at all. I switched off the ignition and had a look inside the exhaust pipe to see what was wrong and noticed the butterfly valve (which completely blocks off the pipe) was still closed and assumed i had disconnecting the hose at the wrong time and left it stuck in closed mode. So i tried pushing it with my finger and it wouldnt budge.

It turns out that the butterfly valve had actually rusted shut and i eventually had to go get a crow bar and bash the valve open with several hard blows. So i've basically been driving my beloved car around for the past 3 months since i've had it with only one with freaking exhaust pipe!!!

Well needless to say i personally found the exhaust sound noticeably improved and even a little bit more low down torque, though the latter is probably just a placebo affect, but makes sense in my head.

While this probably wont apply to all those with aftermarket exhausts, give it a go if your interested and while it wont be night and day it will sound a lot better imo. You may even find you've had a stuck valve and are only using one exhaust pipe like me, in which case prepare to feel cheated for your many hours of "i wish my exhaust was a bit louder and deeper and that a butterfly valve in the inner right pipe hasnt rusted shut limiting my exhaust to just one" that you've had to needlessly endure all this time!

Ok well got some pictures up, they're not great and only quick so here goes ;)

10092008146.jpg

The valve semi closed (i didn't want to push it all the way fully closed again)

10092008149.jpg

And the valve fully open, or as near as i could get it anyways!

10092008151.jpg

The valve vacuum hose plugged up with a small screw

10092008153.jpg

And finally the hose hanging down from inside the exhaust area!

For anyone wanting to do this, just slide yourself under the car around the exhaust area and have a look for that black vacuum hose. Once you've found it, feel along to where it connects to the exhaust pipe and give it several firm pulls (but not too much to tear it! Though it should be quite durable). Find something e.g golf tee, small screw to plug the end with and then take a look inside your exhaust pipe to make sure the valve is fully open as shown in simon's and my own pictures. If its closed and a gentle push wont open it, you may have a similar situation to myself and it may be rusted shut. Grab something sturdy e.g a strong screw driver and try to knock or pry it open (this may take some force so be careful!!)

If anyone needs a hand with this mod, give me a PM or a reply :)

Edited by Sam
Good write up, Photos added, Moved to DIY

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mit   
Ok so basically i've been looking around on e46fanatics recently about the "Golf Tee Mod" as its free and i'm relatively broke :/

The concept is that you disconnect a vacuum hose from the exhaust therefore forcing a butterfly valve inside one of the twin pipes to remain open to allow for a deeper sound at low revs.

For those that found the above didn't make sense (and it didnt to me at first) i'll explain.

Basically because BM's are made for big fat German executives (dont flame me for my generalisation :P) the E46's with twin exhaust pipes have a butterly valve in the inner right exhaust pipe that completely shuts off that exhaust from around 1000-3000 revs to limit exhaust sound around urban areas. Once you go above that rev range, the valve opens and you get a nicer and deeper exhaust note which you would generally be after if you were revving that high.

The "golf tee mod" works by disconnecting the vaccuum hose that attaches above the exhaust and operates the butterfly valve and stuffing it with something of a similar size to a golf tee to plug the end. This then allows the valve in the inner right pipe to be constantly open and therefore give you a much nicer and deeper exhaust note even at idle and right through the rev range.

Well long story short (too late now i know lol) I attempted this mod yesterday, located the pipe, stuffed it with a short metal screw (it looks cleaner and wont melt) and started her up. Nothing. "Well i guess you get what you pay for" i said to myself thinking that it had made absolutely no difference at all. I switched off the ignition and had a look inside the exhaust pipe to see what was wrong and noticed the butterfly valve (which completely blocks off the pipe) was still closed and assumed i had disconnecting the hose at the wrong time and left it stuck in closed mode. So i tried pushing it with my finger and it wouldnt budge.

It turns out that the butterfly valve had actually rusted shut and i eventually had to go get a crow bar and bash the valve open with several hard blows. So i've basically been driving my beloved car around for the past 3 months since i've had it with only one with freaking exhaust pipe!!!

Well needless to say i personally found the exhaust sound noticeably improved and even a little bit more low down torque, though the latter is probably just a placebo affect, but makes sense in my head.

While this probably wont apply to all those with aftermarket exhausts, give it a go if your interested and while it wont be night and day it will sound a lot better imo. You may even find you've had a stuck valve and are only using one exhaust pipe like me, in which case prepare to feel cheated for your many hours of "i wish my exhaust was a bit louder and deeper and that a butterfly valve in the inner right pipe hasnt rusted shut limiting my exhaust to just one" that you've had to needlessly endure all this time!

If anyone needs a hand with this mod, give me a PM or a reply ;)

How old is your car? I'm starting to wonder if mine is rusted in the open position because I think my exhaust is too loud!

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More to the point how can you do such a great write up but not take any pictures!!!! Shame on you young man!!!! If i could flame you i would, but i cant so i will just have to go and figure it all out for myself.

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cbv8   

I know this may sound a bit of a stupid question but has my 2001 318i got one of these valves :P

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mit   
I know this may sound a bit of a stupid question but has my 2001 318i got one of these valves :P

Unlikely - I think 4 cylinder models only have a single pipe...

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cbv8   
Unlikely - I think 4 cylinder models only have a single pipe...
Doh :P thanks for that i will shut up now ;)

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Jonny   

@mit: Mines a 1999 323i, and i've heard on the "over the pond" forums that being rusted open is a problem as well! Though really, is that such a bad thing...

@Simon: Will get some pics up as soon as i get home from work :P Also check e46fanatics, quite a few write ups with pics there if you search for "golf tee mod"

@cbv8: I wouldnt have thought so as i was under the impression that 318's only had 1 exhaust pipe, but if it is a twin you may well have it, in which case just get down on the old hands and knees and take a look inside the inner right pipe and you might see it ;) Also dont quote me on all twin pipes having one even, i know its there on some 323's 325's and 330's.

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cbv8   
@mit: Mines a 1999 323i, and i've heard on the "over the pond" forums that being rusted open is a problem as well! Though really, is that such a bad thing...

@Simon: Will get some pics up as soon as i get home from work ;) Also check e46fanatics, quite a few write ups with pics there if you search for "golf tee mod"

@cbv8: I wouldnt have thought so as i was under the impression that 318's only had 1 exhaust pipe, but if it is a twin you may well have it, in which case just get down on the old hands and knees and take a look inside the inner right pipe and you might see it :) Also dont quote me on all twin pipes having one even, i know its there on some 323's 325's and 330's.

Thanks mate will do :P

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cbv8   

Just had a look and mine DOES have two pipes going into one so where abouts is this butterfly valve then look forward to the pics :P

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Here are some piccies i "cough" found of this mod. The pic on the left is the thingermejigger plugged up and the pic on the right is where you should be able to see the whojermedinger. In this picture it would seem the valve is open.

post-366-1221058100_thumb.jpg

post-366-1221058110_thumb.jpg

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MattBMW   

I'm gonna have a look at this later but I know mines fine as you can tell by the way it idles in neutral.

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cbv8   
wow cb.. you will make my day if our cars also have this valve thing, keep me informed lol
Sorry to piddle on ya fire as it were but i dont think ours is whats in the pic i have two down pipes coming from exhuast manifold the qoing into one but it dont look like the one in the pic :P Take a look at yours and let us know what system you have i will try and take a pic of mine if i got time later?

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MattBMW   

tbh I wonder about this butterfly valve...I know people say it gives better sound in lower revs however I wonder if valve closes when in gear.....noticed the revs drop quite low when in neutral maybe this is when the valve has engaged...

I see no reason to close the while in low RPM while moving as it would affect exhaust gases flow. and lest face it in low rpm the noise is not gonna be exactly huge is it?

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Jonny   

Ok well got some pictures up, they're not great and only quick and i see simon already beat me to it so here goes :P

10092008146.jpg

The valve semi closed (i didn't want to push it all the way fully closed again)

10092008149.jpg

And the valve fully open, or as near as i could get it anyways!

10092008151.jpg

The valve vacuum hose plugged up with a small screw

10092008153.jpg

And finally the hose hanging down from inside the exhaust area!

For anyone wanting to do this, just slide yourself under the car around the exhaust area and have a look for that black vacuum hose. Once you've found it, feel along to where it connects to the exhaust pipe and give it several firm pulls (but not too much to tear it! Though it should be quite durable). Find something e.g golf tee, small screw to plug the end with and then take a look inside your exhaust pipe to make sure the valve is fully open as shown in simon's and my own pictures. If its closed and a gentle push wont open it, you may have a similar situation to myself and it may be rusted shut. Grab something sturdy e.g a strong screw driver and try to knock or pry it open (this may take some force so be careful!!)

@matt: http://forum.e46fanatics.com/showthread.ph...t=mods+under+10 I'm only going on what i've read over at several threads at e46fanatics but i think the general consensus is that it does in fact operate closed at low rpm. Have a look, people can make they're own decisions, im rather pleased with mine either way, and hey 2 pipes are better 1! lol

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///Marty   

Good diy dude. Will have to give this a go see if it makes any difference.

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Dicky   

Mate, great write up and photos, I am sure this will help loads of people ;)

I hope you don't mind I moved your pics into the first post and have stuck it in the DIY section so that others will be able to find it when searching for this mod :P

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Sod it, its stopped raining, im going to go have a play! :P

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[Lmao ive just got my car back from Bms coz i could hear this s*** noise coming from wot i thought was the Gearbox coz it only dont it from 1st-3rd gear changes when changing gear between 1k-2.5k like a rattly noise and being that ive got the smg i thought its gona be a pain in the arse to fix. Turns out its the exhaust making the noise coz of the butterfly and he demonstarted to by removing the vacuum pipe! once removed the noise went... they also told me if i wanted the noise removed then i needed a 325 exhaust which BMW's wont be prepared to pay for coz there is nothing wrong with the exhaust and therefor isnt covered under warranty!

Also the 325 exhaust wouldnt be a nice rumble like the 330's one which is pointless having it on then. Now im gona go and get a screw and take the damn pipe off and plug it!

Once ive plugged the pipe do i just start and rev it slightly for the butterfly to open and then it stays constantly open?

Many thanks guys, damn im glad i joined here.

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Jonny   

Glad i could share and help at the same time! :P

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Jonny   

@Mark: The valve should already be open as it only closes due to a vacuum made when the car is on, however if its still closed when the car is off you should just be able to push it open!

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///Marty   

Also done this this evening and got a little concerned at first as it seemed to make the engine hesitate a little. Took it to the trafford centre and back (to watch rocknrolla - quality film) and can confirm it sounds great! Best when cruising at *0mph, between 2-2.5k, lovely deep burble. Reminds me of my supersprint. :P The free mods are always the best mods aren't they?

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