BMW's power to engine capacity?

[PsyCLown]

Hey all,

So a friend and I got talking about cars and the power being made by some cars our friends have and then we ended up on the topic of how BMW seems to have low KW output in terms of engine capacity size.

For example:
Audi S3 is a 2L engine and makes 225KW
Merc A45 is a 2L engine and makes 284KW
BMW... Well, 128TI / 30i is 2L and makes 180KW - 190KW

The 35i and 40i are both 3L and then make 225KW and 250KW respectively.

So got me wondering why this is the case and wanted to get some of your opinions on it as well. I am not saying it is a good or bad thing, it is what it is and I am sure BMW have their reasoning for it and I am curious as to what they may be. To me it really doesn't make any difference, just something I notice.

 

[yush1]

The latest A45 actually makes 310kw from its 2L. Bear in mind also that BMW is notorious for unquoting power, especially on the S55 and B58 engines.

 

[PsyCLown]

The latest A45 actually makes 310kw from its 2L. Bear in mind also that BMW is notorious for unquoting power, especially on the S55 and B58 engines.

Yes, the A45 S makes 310KW from 2L.

When you say unquoting, you mean it actually makes more than BMW state?
So a 140i with a B58 engine may actually make more than 250KW on the flywheel in stock form despite BMW stating its 250KW?

 

[EthanJappie]

They normally make more power than it states on paper, more so with the B58 in the A90 Supra. Same goes for some Audi RS models

 

[PsyCLown]

Is there a reason why BMW do not try push for more power from a 2L?

 

[realtrevor]

BMW uses straight 6 Turbo engines to compete with those powerful 2L from those manufacturers you've mentioned. They don't have a reason to have a powerful 2L.

M2C 3.0L vs A45s
F20 M135i/40i vs S3

The highest 3.0L BMW output is 375kW on an S58 not 250kW, even the B58 produce 285kW in some applications such as M440i and M340i. Mercedes and Audi don't have 3L engines that can produce more than 331kW.

At the end of the day any manufacturer is capable of building any engine, it depends on what fits in their products lineup and appeal to their customers, and the regulations that the engines have to meet.

Sent from my BLA-L09 using Tapatalk

 

[SubLoaded]

Is there a reason why BMW do not try push for more power from a 2L?

Because the 135kw ones blow themselves up

 

[yush1]

Yes, the A45 S makes 310KW from 2L.

When you say unquoting, you mean it actually makes more than BMW state?
So a 140i with a B58 engine may actually make more than 250KW on the flywheel in stock form despite BMW stating its 250KW?

Typical B58's (M140i, M240i, 440i/340i) make between 240 and 260 wkw stock, which, based on different calculations equates to around 270-280 kw at the crank.

 

[gumpertapolloss]

B48 now produces 225kw in 35i form.

In all honesty, I think reliability is key.
3L straight six is tried, tested and proven.

Sent from my VOG-L09 using Tapatalk

 

[PsyCLown]

BMW uses straight 6 Turbo engines to compete with those powerful 2L from those manufacturers you've mentioned. They don't have a reason to have a powerful 2L.

M2C 3.0L vs A45s
F20 M135i/40i vs S3

The highest 3.0L BMW output is 375kW on an S58 not 250kW, even the B58 produce 285kW in some applications such as M440i and M340i. Mercedes and Audi don't have 3L engines that can produce more than 331kW.

At the end of the day any manufacturer is capable of building any engine, it depends on what fits in their products lineup and appeal to their customers, and the regulations that the engines have to meet.

Sent from my BLA-L09 using Tapatalk

So I guess BMW then make the most power from a 3L engine and Merc from a 2L engine (comparing these 3 brands).

I am sure BMW could get crazy power out of a 2L engine if they wanted to, was just wondering why Audi and Merc went that route and BMW did not.

Because the 135kw ones blow themselves up

Hahahaha, touche!

Typical B58's (M140i, M240i, 440i/340i) make between 240 and 260 wkw stock, which, based on different calculations equates to around 270-280 kw at the crank.

Wow ok, quite a big difference if that is what they're making on the wheels but it's still this is from a 3L engine.

B48 now produces 225kw in 35i form.

In all honesty, I think reliability is key.
3L straight six is tried, tested and proven.

Sent from my VOG-L09 using Tapatalk

I was wondering whether reliability had anything to do with it but honestly I am not sure how reliability differs between some of these engines.

 

[TurboLlew]

The displacement argument is irrelevant to most people - getting more out of a smaller engine is great as an engineering brag. Any Honda S2000 owner (or former owner) will proudly tell you about kw/litre and how Ferrari only 'caught up' with the F430 etc... whilst getting killed by a repmobile in a straight line.

Yes BMW undercalls numbers (my M5 made 389 kw on the wheels from a supposedly 412 flywheel kw car when I bought it... and nearly 20kw more on a less stingy dyno a few weeks later) but we also forget the little bit of BMW heritage and DNA still left in the modern cars is RWD and the inline 6.

There are many reasons the I6 is great from an engineering perspective which you will come across if you look into it. The reason that many manufacturers are going with small 3 and 4 cylinder engines is because of the % of cars that need to hit euro and US emissions targets... even on the performance side. The way the cars make and deliver power is also different in practice between the 8, 6 & 4 beyond what numbers will tell you. It is not taking anything away from the 4 cylinder cars and how much power they make... there is a great youtube video of the engineering that went into that A45 and getting it to that power number. It also makes it quite exotic which comes with its own challenges.

 

[PsyCLown]

The displacement argument is irrelevant to most people - getting more out of a smaller engine is great as an engineering brag. Any Honda S2000 owner (or former owner) will proudly tell you about kw/litre and how Ferrari only 'caught up' with the F430 etc... whilst getting killed by a repmobile in a straight line.

Yes BMW undercalls numbers (my M5 made 389 kw on the wheels from a supposedly 412 flywheel kw car when I bought it... and nearly 20kw more on a less stingy dyno a few weeks later) but we also forget the little bit of BMW heritage and DNA still left in the modern cars is RWD and the inline 6.

There are many reasons the I6 is great from an engineering perspective which you will come across if you look into it. The reason that many manufacturers are going with small 3 and 4 cylinder engines is because of the % of cars that need to hit euro and US emissions targets... even on the performance side. The way the cars make and deliver power is also different in practice between the 8, 6 & 4 beyond what numbers will tell you. It is not taking anything away from the 4 cylinder cars and how much power they make... there is a great youtube video of the engineering that went into that A45 and getting it to that power number. It also makes it quite exotic which comes with its own challenges.

I agree, doesn't really make much difference except for bragging rights really.

I was just wondering why BMW do it this way, although seems as if for BMW its more about their heritage and keeping their more performance orientated cars (not M cars) as an inline 6 engine and RWD then?

I know the emission requirements continue to get stricter, makes one wonder what cars would be like if these emission regulations weren't in place and if there as much of a drive towards efficiency.

 

[individj]

and if you want to brag just say BMW had a 4 pot turbo just out of the 60's pushing 125kw & in the 80's they had a 162kw NA 4 pot Production. Dont even talk about the M12/13/1 Engine. Tell them when they make 1000kw 4 pot turbos they must come speak to you hahaha

 

[realtrevor]

One other reason for the other manufacturers to favour high powered 2L engines is the same reason BMW has gone with a high powered 2L on the F40 M135i. FWD based cars are better with 2L engines because these are lighter and compact. A V6 can fit in a FWD but will make the vehicle more nose heavy as the gearbox, diff and engine all sit in frot of the front axle. And fitting a straight 6 motor on a FWD based vehicle is close to impossible.

The reason BMW uses a straight 6 on on the smaller F2x and F87 M2 models is because the engine is readily available (N55/B58/S55) being used by other BMW models already. So there was no business case of developing smaller 2L engines to be used in these vehicles up until now with the FWD based F40 1 Series and 2 Series Gran Coupé.

Sent from my BLA-L09 using Tapatalk