125i coupe / 325i sedan Q

laissez-faire · 4 Apr 2008 at 23:35

Hi,

Not too sure how the 125i coupe emits 190g of CO2 per km while the the 3 series with the same engine and the same efficient dynamics only emits 170? 3 series also gets about 6 more mpg.

Is this a mistake on bmw.co.uk?

Sam

West · 4 Apr 2008 at 23:38

a lot of the newer BMW Engines (e.g. the 1 series) were better on CO2 overall wern't they? because of the way they were made? or am I just thinking the of the new Diesel ones?

[TW]Fox · 4 Apr 2008 at 23:38

No, this is not a mistake. The BMW website is correct.

NickXX · 5 Apr 2008 at 11:09

3 series is heavier.

Joe T · 5 Apr 2008 at 11:10

NickXX said:
3 series is heavier.

Which would imply they should be the other way round?

NickXX · 5 Apr 2008 at 11:12

Joe T said:
Which would imply they should be the other way round?

Oh yeah, didn't spot that

JRS · 5 Apr 2008 at 11:18

Different gear ratios in the two cars? The 125i coupé could be higher revving than the 325i.

laissez-faire · 5 Apr 2008 at 15:15

It makes absolutely no sense when all the other engines emit 3-4g more CO2 in the 3 series and then this one there's a massive difference. Does no-one know why?

Ed · 5 Apr 2008 at 16:38

Are there any power of torque differences that would indicate a different map? A lighter coupe and heavier saloon may require different settings.

jaykay · 5 Apr 2008 at 17:07

Thers nothing different in the hp or torque figures.
325i se
http://www.bmw.co.uk/bmwuk/pricesan...bs-Mw==@bb-M0xJ@bm-WjNTOQ==@sit-bmwuk,00.html
125i se
http://www.bmw.co.uk/bmwuk/pricesan...bs-MQ==@bb-Q1A=@bm-WkUyOA==@sit-bmwuk,00.html

georges · 5 Apr 2008 at 17:18

Does the 3 series have more of the efficient dynamics features?

Ed · 5 Apr 2008 at 17:23

The peak torque in the 325i is 100 rpm lower than the 125i. Although not a lot this would indicate either a different map or gearing which could influence the figures. However since there's quite a difference and it's in the wrong logical direction I'm inclined to think the figures aren't right. Unless someone can come up with a definitive and learned response, the mystery deepens.

mjt · 5 Apr 2008 at 20:47

aerodynamics?

georges · 5 Apr 2008 at 20:49

Emissions are measured at standstill.

Could explain the MPG though, although I can't imagine the difference is 6mpg drastic.

jaykay · 5 Apr 2008 at 20:53

Maybe different exhaust system?

1ofaKind · 5 Apr 2008 at 21:25

I would guess it's either weight or aero. My 350z converitble is rated 8 Co's higher than the coupe with the same engine. Go figure

Ed · 5 Apr 2008 at 22:18

1ofaKind said:
I would guess it's either weight or aero. My 350z converitble is rated 8 Co's higher than the coupe with the same engine. Go figure

But the less polluting, more economical car is the heavier one! :confused:

[TW]Fox · 6 Apr 2008 at 00:57

georges said:
Emissions are measured at standstill.

CO2 isnt - its roughly proportional to mpg.

Ed · 6 Apr 2008 at 09:22

Is the 325i a popular company car and the CO2 output is a sniff under some magic tax bracket? It could be a case of a different map to suit the market.