Exhausts....

Ed Doe

Ed Doe

Veteran
 Ashbourne or Frimley
Hi all,

OK so I'm kind of exploring the idea of an aftermarket exhaust - for a bit of weight saving and for a bit more noise. Currently I have a supersprint manifold and race cats, connected to oem rear silencers.

I must stress I do not want a car that will give me tinnitus - been there done that in my early 20s :lol: I also really do not want to trigger noise limits on trackdays.

I'm also keen not to spend a load of money on it - yes I know 'pay peanuts, get monkies' and all that, but I don't have £1k+ kicking about that I'd want to spend on a supersprint setup or similar; given the choice I'd rather spend that on trackdays instead lol

I'm not averse to getting something made up either - so any recommendations for decent exhaust places localish to Surrey would be welcomed!

Cheers in advance!
 
I've no idea of costs or any weight saving, but my M came fitted with Powerflow back boxes and it sounds great IMHO.

But one had a hanger missing, so I tracked down a Powerflow distributor in Slough:- https://www.enigmatec.co.uk/

Naz fitted a new hanger for me for £30 which I thought was very reasonable. So it might be worth seeing what they may be able to offer.

Before and after photos.
 

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Stromung? They’re ~6kg per side and not too expensive. Seem to be louder than OEM but not insane and the jury’s out re. drone (which I take to mean that it can’t be too bad).

I’d like the Remus but they barely drop any weight.
 
Ed Doe said:
Hi all,

OK so I'm kind of exploring the idea of an aftermarket exhaust - for a bit of weight saving and for a bit more noise. Currently I have a supersprint manifold and race cats, connected to oem rear silencers.

I must stress I do not want a car that will give me tinnitus - been there done that in my early 20s :lol: I also really do not want to trigger noise limits on trackdays.

I'm also keen not to spend a load of money on it - yes I know 'pay peanuts, get monkies' and all that, but I don't have £1k+ kicking about that I'd want to spend on a supersprint setup or similar; given the choice I'd rather spend that on trackdays instead lol

I'm not averse to getting something made up either - so any recommendations for decent exhaust places localish to Surrey would be welcomed!

Cheers in advance!
Click to expand...
I didn't realise the SS manifold fit a rhd car? Does it not clash with the steering column?
 
Either debaffle your existing backboxes or go for the likes of second hand premium mufflers (e.g Supersprint, Eisenmann, Bastuck, Meisterschaft etc).

But seeing as you have headers and race cats, you may find the car too asbo with aftermarket backboxes...
 
I have the Remus on my MC currently and they’re the best of the 4 different exhaust set ups I’ve had (including the stromung ones). They pop and crackle a little bit on the overrun and are certainly have a good deal more base than stock.

The oem boxes in my view are unacceptable looking, they simply look crap...but if you stick with them then powder coat them black to hide the god awful cows udder look.
 
Angelus666 said:
I have the Remus on my MC currently and they’re the best of the 4 different exhaust set ups I’ve had (including the stromung ones). They pop and crackle a little bit on the overrun and are certainly have a good deal more base than stock.

The oem boxes in my view are unacceptable looking, they simply look crap...but if you stick with them then powder coat them black to hide the god awful cows udder look.
Click to expand...
They’re hardly cow udders like the backbox on the M2 Competition...
 
I've had stromung and am currently running remus backboxes. The stromungs are louder with some drone at motorway speeds which mean you need to raise your voice to talk. The remus have no drone and are a good match for the AFE intake in terms of volume. Would like to go louder again now as the MC is now a weekend car..
 
Angelus666 said:
I have the Remus on my MC currently and they’re the best of the 4 different exhaust set ups I’ve had (including the stromung ones). They pop and crackle a little bit on the overrun and are certainly have a good deal more base than stock.

The oem boxes in my view are unacceptable looking, they simply look crap...but if you stick with them then powder coat them black to hide the god awful cows udder look.
Click to expand...

This might be useful

https://www.zpost.com/forums/showthread.php?t=1078199

I also could be completely wrong, but I remember a thread from back in the day (I think Exodus was the poster) where the exhaust and rear diffuser were designed to help improve aerodynamic efficiency and stability at the rear of the car.

Edit: Here is the thread

https://z4-forum.com/forum/viewtopic.php?f=9&t=65142&hilit=exodos+aerodynamics

"In section, the OEM silencers are rounded structures which must inherently generate a “Coanda effect" as air passes over them: this must create a zone of low pressure beneath them which should counteract lift at the rear provided that the airflow passes beneath them rather than around them.

Likewise, the air flowing between the silencers will improve the effectiveness of the OEM diffuser part. Further the outer strakes will prevent air from the rear wheelhouses causing turbulence in the rear diffuser section. As such, the jetting vortices produced by the rear wheels should exit in a straight line behind the car which should help pull the air through the underside of the car."
 
They have been mentioned above and are quite tricky to come by, but i have the the Stromung system on my Z4M and cant fault it!
There is a tiny bit of drone from 1900-2100rpm as mentioned above, most aftermarket exhaust's will suffer from this but you can easily drive around it.
Contary to whats been said above i experiance no drone/noise on motorway as in 6th your cruising at way above the rpm zone that drones, but overall a really nice sound thats subtle a low speed but really ramps up when you step on it!
Not to mentioned they are way less than half the weight of stock and look the dogs danglies filling the exhaust cutout nicely!
 
I have the BCS Powervalve Exhaust on mine (cost £900 inc fitting.) Makes a lovely rumble when you turn it on, growly in the low revs and once you're above 3000 it gets raspy.

Downside being that you're not going to sneak anywhere (but that's not the point of a Z4MC (for me) anyway).

There is a drone inside the cabin between 1500 - 2000 so sometimes that forces you to change gear up or down depending on what's in front of you.

I have no idea about weight difference with these.

I bought it from @stujefferey on here and he wrote this review soon after he put them on - https://z4-forum.com/forum/viewtopic.php?t=94382
 
Thanks all!

I have done a bit more research and discovered my cats are actually Hayward & Scott 100cell race cats.... So I think those BCS cans will be ridiculously loud! Shame as they do look good.

The remus ones I have to say I think look the best - I guess I'll jusy have to keep my eyes open!

@Tom - surely the aero effect of the rear cans can't be that significant!? Id be amazed if it made a tangible difference at anything other than max speed?!
 
Doesn’t make much sense to me. Coanda is based on a jet of fluid (in this case, air) interacting with the surrounding fluid and/or a nearby surface. E.g. in F1 exhausts gases are used to charge the airflow and make it stick to the skin of the car so it can be directed towards aerodynamic components like the rear diffuser.

To reduce lift using the Z4M udders as an aerodynamic component you’d need to accelerate air ahead of them (so that it attaches to their underside), e.g. using a tunnel, and then finish their trailing edges in a clean, upwards slope to direct the attached flow upwards. I’m not sure you could even achieve laminar flow under the backboxes without skinning everything so it’s probably a non-starter.
 
Yeah, I mean not entirely as factually based but I simply assumed that where most racecar teams endeavour to have as 'clean' and flat underside as possible, I'm sure they'd have cottoned onto the 'udderside downforce potential' by now!! :lol: :lol: :lol:
 
Thread hijack sorry - If anyones looking for an exhaust swap, I've got some Remus cans and keen to get something louder (but not RPi loud)
 
zmaster007 said:
Thread hijack sorry - If anyones looking for an exhaust swap, I've got some Remus cans and keen to get something louder (but not RPi loud)
Click to expand...

If you find something let me know if you wanted to sell yours on :) thanks!
 
I have Supersprint back boxes fitted. I like the very low speed bit of extra noise. Back road speeds, if me and the Mrs are out, I can't hear her :D . Motorway speeds it gets quiet again and we can hold a conversation :x .
All accelarating is noisy enough. Reading around on previous occasions the Remus is a popular choice.
 
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