Exhausts why did hey switch to 2x2 pipes v 1x2?

[Welshbeef]

All M cars pre the E39 M5 and E46 M3 were strictly 1 side of the car with two pipe exit.

Why did BMW change to two side exit thus making it more obvious it's not a stealth car) plus adding additional weight (though marginal is additional weight none the less).

Was it style? Stamping a standardised trait for all M cars. Was it identified as offering higher BHP that would negate the additional weight ?

[Welshbeef]

Doesn't look like any PH M owners know?

[NickXX]

Probably doesn't add a lot of weight on the e46 at least- it's a single backbox just turned 90 degrees with 4 holes cut into the side.

[Welshbeef]

But why change the lovely single twin exit which M cars first started to a twin double exit?

[SebringMan]

Probably to help differentiate them from 'normal' BMWs, like the M Sports.

Let's be honest unless you looked inside an E36 M3 and it didn't have the wheels on or badges they do look like like a 328i Sport. Same for the E39s.

[Welshbeef]

SebringMan said:

Probably to help differentiate them from 'normal' BMWs, like the M Sports.

Let's be honest unless you looked inside an E36 M3 and it didn't have the wheels on or badges they do look like like a 328i Sport. Same for the E39s.

I'd agree. Though the principle of the E28 M5 was to be an utter Q car which it is the two double exit exhausts.

[reggie82]

SebringMan said:

Probably to help differentiate them from 'normal' BMWs, like the M Sports.

I think you're right.

Very interesting article about the development of the exhaust system here - http://www.unofficialbmw.com/images/BMW_M3_Exhaust...

[Rob_R]

The move from 6 to 8 cylinders probably necessitated this change as well.

[GroundEffect]

Most of it is style.

And so what?

My M3 looks better with 2x2 than it would with 1x2.

[89pgy]

well here's my thinking, as all 4 outlet m cars have a transverse rear box I think it is about getting rid of condensation and water from inside the box. if the outlets are just on one end the water would sit at the other end of the box and rot it out from the inside. its not just BMW who do this with transverse boxes , look at the later VW golf R.

[AW10]

It's all marketing/image. In the good old days (think E21) the twin pipes (one each side) meant 323i rather than 320i. And things just slowly escalated from there. Hopefully they stop at 4 and don't ever go to 6!

My V10 E61 has two separate rear back boxes - no transverse silencer. Ditto for the Z4M. So no hard and fast rule on the config.

[Output Flange]

Welshbeef said:

I'd agree. Though the principle of the E28 M5 was to be an utter Q car which it is the two double exit exhausts.

The E28 M5 doesn't have two double exit exhausts. It has a single backbox with twin pipes mounted just to the right of centre, to avoid the spare wheel well.

[jm doc]

I thought it was to accomodate the V8 configuration in the E39 M5 and carried over to other M cars?

[rassi]

The Z3 M came out at the same time as the E39 M5, and had two separate back boxes. Same engine as the E36 M3 that had a simple back box with dual exits.

Slightly OT, but the same inflation in exhaust pipes has also happened to the non-M models, where a dual exit always meant a 6 cylinder engine, which disappeared with the F10 5 series and now also the F30 series.

[Zod]

Welshbeef said:

But why change the lovely single twin exit which M cars first started to a twin double exit?

With the E39, E60, E90 and F10 there were always going to be two backboxes, so it was two large pipes or four smaller ones.

[Zod]

rassi said:

The Z3 M came out at the same time as the E39 M5, and had two separate back boxes. Same engine as the E36 M3 that had a simple back box with dual exits.

Slightly OT, but the same inflation in exhaust pipes has also happened to the non-M models, where a dual exit always meant a 6 cylinder engine, which disappeared with the F10 5 series and now also the F30 series.

E39 Msport six cylinder models had a single large diameter exhaust.

[Markbarry1977]

Just a thought, by mounting it transverse and making it a slight (if you squint right when looking at it) aerofoil shape could it be used as a primitively downforce device at high speed. Just a guess on my part

[mark.c]

Off the top of my head the only BMW to use that theory was the Z1.

[rassi]

Zod said:

E39 Msport six cylinder models had a single large diameter exhaust.

Forgot about that one, thanks for pointing it out. Makes the E39 M Sport even cooler - a bit like the 340 bhp Audi RS Q3 with a single exhaust when a VW Golf R has 4...!

[Billy_Whizzzz]

As a general principle, the fewer exhaustss the better. I loathe the Golf R exhausts and the E46M3 ones - and the ones on my Z4 M. They are also too close together on the e46. E39 530i looks great with its single exhaust, as does e28 m5 with its single disceet pair on one side.