E46 Exhaust "Trick"

[daveco]

I remember a thread many moons ago where someone revealed you could make the exhaust note more apparent on an E46 by messing with wiring behind one of the rear light-is this true?

If so, how would one go about it? It's always annoyed me that the 6 cylinder isn't as audible as it should be.

[Frances The Mute]

What would wiring behind the cluster have to do with the exhaust?

There is a butterfly in the tailpipe on certain 328 models that remains closed at lower revs to quieten the car. This can be removed.

[mmm-five]

You could drill holes in your boot floor to allow more of the sound through, or you could remove some of the baffles in the silencers to give you a bit more noise, or you could just buy an aftermarket rear box.

[daveco]

I'm not willing to get an after market box or anything too OTT. I was looking to get the same thrum of exhaust note the car has at idle when it is switched on from cold and thought there was a trick with wiring you could use to achieve this.

[Phunk]

On 6 cylinder E46 models there is a butterfly valve operated by vacuum connected to the back box.

Look at it and you will see a hose coming out of it, pull it out, plug it with something, job done.

I don't recommend it on a auto, as it drones a lot.

[Maxus]

Frances The Mute said:

What would wiring behind the cluster have to do with the exhaust?

The control box for the valve is situated behind the trim near the rear light cluster.

OP - Search golf tee mod and you will find plenty on the subject of opening the valve.

[Pierscoe1]

so is it electronically controlled, or via vacum?

if it's the latter, surely it opens when the throttle is pressed? so by opening it all the time you'd just make it noisy at constant/closed throttle?

[obscene]

Google the "golf tee" mod on E46 fanatics or an E46 forum. Voila.

[daveco]

Thanks for the info folks! *doffs cap*

[Gad-Westy]

Just as a slight warning, don't expect much difference if you do the 'golf tee' mod. It barely seems to have any effect.

[adam85]

Gad-Westy said:

Just as a slight warning, don't expect much difference if you do the 'golf tee' mod. It barely seems to have any effect.

+1 I found it made no real noticeable difference, a slight bit deeper below 2k rpm perhaps

[daveco]

Phunk said:

On 6 cylinder E46 models there is a butterfly valve operated by vacuum connected to the back box.

Look at it and you will see a hose coming out of it, pull it out, plug it with something, job done.

I don't recommend it on a auto, as it drones a lot.

I've got a facelift 325 coupe and there is no butterfly valve in either pipe or wire coming out of it. Is this mod only possible on the 330?

[S3_Graham]

adam85 said:

Gad-Westy said:

Just as a slight warning, don't expect much difference if you do the 'golf tee' mod. It barely seems to have any effect.

+1 I found it made no real noticeable difference, a slight bit deeper below 2k rpm perhaps

+1 i cant tell a difference from the driving seat of my 130.

[Phunk]

Should 100% be there, as above, search on the e46 forum

[TheEnd]

It is ECU controlled, and vacuum powered.

[daveco]

Phunk said:

Should 100% be there, as above, search on the e46 forum

Nope, checked both pipes and no butterfly flap. Also, no cable extending from either exhaust or the backbox. Checked and checked again. Went on the relative fora and see exactly where the items are...looks like mine doesn't have it. Strange, considering it's a facelift model...

[adam85]

daveco said:

Nope, checked both pipes and no butterfly flap. Also, no cable extending from either exhaust or the backbox. Checked and checked again. Went on the relative fora and see exactly where the items are...looks like mine doesn't have it. Strange, considering it's a facelift model...

Strangely it is not listed for your car on realOEM, here is an example of a car with the system:

http://www.realoem.com/bmw/showparts.do?model=BM32...

This was listed under a 325ci of the same year as yours:

http://www.realoem.com/bmw/showparts.do?model=BD32...


This may well explain it

[Gaygle]

Gad-Westy said:

Just as a slight warning, don't expect much difference if you do the 'golf tee' mod. It barely seems to have any effect.

Many people that commented similar to this had actually had their butterfly valve rusted close. On my car it made quite a bit of difference below 3KRPM - makes it rumble more.

To free the valve, people either got a screwdriver and lubricating fluid to free it or simply got a chisel and bashed it to make the changes permanent!

[daveco]

adam85 said:

daveco said:

Nope, checked both pipes and no butterfly flap. Also, no cable extending from either exhaust or the backbox. Checked and checked again. Went on the relative fora and see exactly where the items are...looks like mine doesn't have it. Strange, considering it's a facelift model...

Strangely it is not listed for your car on realOEM, here is an example of a car with the system:

http://www.realoem.com/bmw/showparts.do?model=BM32...

This was listed under a 325ci of the same year as yours:

http://www.realoem.com/bmw/showparts.do?model=BD32...


This may well explain it

Cheers Adam. So what does that mean? My exhaust is slightly louder without the butterfly valve?

[adam85]

daveco said:

Cheers Adam. So what does that mean? My exhaust is slightly louder without the butterfly valve?

I would imagine you are getting the same sound currently to those who have modded the butterfly valve, your exhaust is using both pipes at all times. I can only assume BMW at some stage stopped fitting butterfly valves.