[mmwwhats]

I'm trying to understand why/how the new M3/M4 has worse fuel economy than the current gen car? I have an M2C and was thinking about moving to the new M4, but am scratching my head and these numbers: 16 city 23 hwy for the G82 M4, 18 city 25 hey for the F82 M4 F87 M2C. I know it's a powerful car and all, but in 2021, I'd expect to be able to have performance and economy at the same time. At the very least, I wouldn't expect the car to take a step backwards in fuel economy. I'd appreciate any insight, thoughts, or knowledge on the matter... and if it's at all possible to avoid the "if you want MPGs buy a Prius" comments, that'd be swell.

[Benjamin]

Has to be the tune, any turbo engine will get worse fuel economy the more boost the engine gets. If your on a casual 2 lane cruise I'm sure it will still return low 30s as long as you are going 55 in 6th

[SickGTR]

Originally Posted by Benjamin

Has to be the tune, any turbo engine will get worse fuel economy the more boost the engine gets. If your on a casual 2 lane cruise I'm sure it will still return low 30s as long as you are going 55 in 6th

Exactly. If you drive it like a mad man ( Which i Do and Recommend ) then yes, your economy will blow. If you putz around the town, it will be better than what they are saying. Switch to E-85 for a few months, then 16 a mile will seem like the best thing ever

[Benjamin]

If you are doing some pre dawn back road/highway loops you can burn over 10 gallons in under an hour easy. Sometimes people road trip and get 33MPG.

[rak299]

I live in San Francisco and do a fair amount of city driving up and down hills, stop and go. My gas mileage will probably suck and be worse than any estimates, even though I drive like an old fart. If that were my primary consideration, I would drive a Prius.

[Boiler Up!]

Weight: ~10% heavier = ~10% lower fuel economy

[Insane_Dawe]

If you look into the details of the S58, it's closer to an upgraded S55 than the B58(Amazingly Efficient).

The B58 has a longer stroke, less bore and much higher compression than even the S55. While the S58 is same bore and stroke as the S55 but less compression. That is more of a traditional "boosted" engine setup, less CR, bigger turbo, more boost PSI. Less efficient but more reliable. Granted the the S58 does have newer valvetronic 4.

That and as mentioned, weight and probably some aero.

[Lo2]

The G80/G82 utilizes a S58O engine and the competition models utilizes a S58T engine. It shares the same turbos as the F97 X3M and F98 X4M which has the S58 engine.

Minus the weight and more aero on the G80/G82 versus the F97/F98, its a bit better in fuel economy.

Comparing the F80/F82 towards the G80/G82, the latter is heavier in weight alone.

Read more here

https://www.bmwblog.com/2020/09/23/b...82-vs-g80-g82/

[heavyD^2]

I'm getting 18.3 mpg on my X3M Competition in the city which isn't too bad. Better than my 5.0L Mustang or STI and those cars weren't remotely as powerful.

[maddmatth]

Thought efficiency was their cited reason for dumping the DCT for the ZF Auto. I guess they needed to counteract some of the efficiency they lost with the added weight...

[N1rve]

It’s probably due to the weight gain of like 300~500 pounds.

As I’ve stated before, feels like this generation was a cost cutting one and more engineering went into the F8X.

However!! You don’t buy these cars for miles per gallons but for smiles per gallons! 😁😁😁

[nathanm4]

Cruise control set at 85 MPH on 6th gear on highway, average MPG was 24 MPG, never even reached 25 MPG.

Yes, it's worse than F8X.

[SickGTR]

Why would peeps expect better fuel milage than the F models? More horsepower normally needs more fuel.

[TigahRouge]

The fuel economy is terrible for my G82. But I will say that the engine is very edgy and seemingly always ready to pounce!! There are no docile settings. Even when set to the the softest settings the engine is still eager.

Saying all that to say this...the G82 is no Prius. It feels like a sports car all of the time. This translates to poor fuel economy.

The bright side of this equation is the car is special, and it feels special at all times. If you are looking for a mild mannered dual personality automobile this ain't that. The G82 is an event every time you get behind the wheel!!

[Machtavian]

More weight equally more ponies to feed!