Exhaust options

[Simon 3.2M]

I love the car and the gruppe however, I feel as though the exhaust is somewhat muffled and doesn’t emphasise the 6 cylinder engine note. What have others done who have found the same? Obviously I don’t want a boy racer type exhaust but there must be an option.

 

[mmm-five]

Don't go for the Rogue Diablo or Eisenmann then as you'll drown out the Gruppe-M

I spent a fair while deciding which end to keep on the car (still got original rear exhaust boxes in the garage), but the Gruppe-M would keep me revving up & down all the time just to hear it, whereas the almost embarrassingly loud exhaust makes me cruise more sensibly - so I kept the exhaust.

Still want a CSL-style airbox though - but that plan in on hold until the delayed (due to serious mechanic illness) engine rebuild/replacement is done.

Not sure the E46 330D would benefit from either a carbon airbox or a phat exhaust - would look like a chimney from a German coal-fired power station

 

[Angelus666]

I've gone through 4 different exhaust options with the Gruppe and I think my current Remus boxes seem to offer the best blend of looks with the pops/crackle with just a little drone.

In an absolutely ideal world, you'd only hear the induction on acceleration and then the exhaust pops when coming off the gas. Kind of like the 981 GTS does.

 

[R60BBA]

The way I see it you have 3 options:

• Debaffle the rear boxes - cheap and effective

• Buy aftermarket boxes (from the likes of Supersprint, Eisenmann etc) - expensive but boxes hold their value come resale

• Keep the rear boxes standard but install a de-resonated X pipe - more expensive than debaffling the boxes but not as expensive as buying aftermarket boxes - again I would recommend either buying a top quality off the shelf product from an exhaust manufacturer or getting a custom job done by a qualified exhaust fabricator.

 

[Simon 3.2M]

Thanks R60BBA - does de-baffling the rear boxes affect the back pressure at all?

 

[scootr]

Thanks R60BBA - does de-baffling the rear boxes affect the back pressure at all?

Debaffling will reduce back pressure.
I ordered the Remus cat back exhaust. Found a demo unit was used at a car convention for demonstration purposes. It was couple hundred off the original price. I'm hoping it will give the car a little more sound. Stock is absolutely too civilized.

 

[R60BBA]

Thanks R60BBA - does de-baffling the rear boxes affect the back pressure at all?

It varies by car, but I wouldn’t have thought so for your Z4M. The only way to really test this would be to dyno the car with the stock exhaust and then dyno it the same day with the debaffled exhaust.

But to be honest, most aftermarket backboxes contain free-flowing perforated pipes with slight baffling so I wouldn’t worry.

See below for examples of what I’m talking about.

OE box cut to expose baffles:


OE box cut open with original pipework (in a loop style) and removed baffles:


Debaffled OE box with new ‘free-flowing’ pipework:


Aftermarket ‘free-flowing’ box:

 

[Mister T]

I'm very happy with my Supersprint "Racing" cat-back setup.

 

[Attilio]

Hi,

I got the "job" done on my back boxes and I am not keen on the outcome: too boomy and only minor pops and crackles on the overrun...
I am going to re-fit the original boxes and think about it as I am not sure I am willing to spend £800 plus just to enhance the sound of the exhaust

When I eventually go crazy, I will buy myself some welding equipment and have a go at straightening the "pipes" inside the box. At the moment it seems to be too much work for very little and uncertain return... my twopence worth

A

 

[Allan280]

Hi
I am new to Zs I only got my "M" on Saturday but mine is fitted with Cobra back boxes from Sheffield which sound great when you wind her up and going under bridges- through tunnels and on overrun. Also look great with etched Cobra names on each pipe .

 

[woolybear]

... I think my current Remus boxes seem to offer the best blend of looks with the pops/crackle with just a little drone

X2..


Fitted a pair of new Remus back boxes, earlier in the year & it has added a very subtle Sound Improvement, over the OEM boxes - IMHO..
Still on the fence, over adding a GruppeM - but, the more I read on here - it just seems the natural next positive step 8)

 

[BMWZ4MC]

I’ve had my Remus boxes for years and always like them, but as they’ve accumulated miles, the tone has become richer and the pops and crackles more noticeable. I have an aFe intake which complements them perfectly. It emphasises the metallic bark of the S54 induction that might otherwise be lost with noisy exhausts.

 

[wspohn]

Love the exhaust note the RPI rear boxes give, though I have heard that there is a break in period when they are too loud (bought my car with them installed so no idea how long they had been on there.

 

[ga41]

Love the exhaust note the RPI rear boxes give, though I have heard that there is a break in period when they are too loud (bought my car with them installed so no idea how long they had been on there.

I'm a long term RPI owner and they still sound amazing. I get how they'd annoy most people though... It's an acquired taste for sure but the sound when going flat out is sensational.

 

[wspohn]

I'm a long term RPI owner and they still sound amazing. I get how they'd annoy most people though... It's an acquired taste for sure but the sound when going flat out is sensational.

And when just driving around normally, the sound is quite acceptable (to me, anyway).

Did you fit your RPIs new? I have heard that there is some noise that may be objectionably loud until they break in....

 

[ga41]

I'm a long term RPI owner and they still sound amazing. I get how they'd annoy most people though... It's an acquired taste for sure but the sound when going flat out is sensational.

And when just driving around normally, the sound is quite acceptable (to me, anyway).

Did you fit your RPIs new? I have heard that there is some noise that may be objectionably loud until they break in....

Got them off eBay but they were unused and still in the factory wraps. The did seem to mellow a bit but to be honest that may just be me getting used to them. I don't really remember the exact point they mellowed down though.. it was almost 10 years ago that I put them on!

 

[wspohn]

Thanks.

I figure it is a self solving problem. Those likely to object to a 'spirited' exhaust note are the most likely to never give it enough stick to really bring out that aggressive tone.