Z4M roadster MPG poll

[mousitch]

Just wondering your average miles per gallon. I guess I drive pretty hard as I only am getting about 16MPG. Just wanted to see the average because I'm wondering if something might be up and my mileage is down because of the DME tune I received on the car.

[mimsterzx7r]

When I'm pushing the car definitely under 17mpg. But with a little bit cruising on the highway its usually in between 17-20. Once on a long drive from Houston to Dallas I did about 22mpg but that's the best I've seen.

[U235]

19-20mpg city for me, but most of my time is spent at 45-50 which is ideal for a car.

21-22 on the hwy driving at the speed limit or slightly above. I was expecting better hwy mileage based on some of the e46 M3 guys "claiming" 26-28; I don't know how they do it.

[Hughbert]

I'll get 24-25 hwy and 16-18 stop & go around town.

[AusTTin Bob]

I averaged 5.9 mpg this weekend. But then again, I was at Harris Hill Road Raceway

[jrich4411]

Originally Posted by Hughbert

I'll get 24-25 hwy and 16-18 stop & go around town.

ditto

[VitaminT]

The onboard thing pretty much stays at 20.8MPG.

[DarkstarZero]

Originally Posted by VitaminT

The onboard thing pretty much stays at 20.8MPG.

Same. My mileage is split between highway and city so the one I never reset stays at 20.8 or around there. On the highway I get 24 with the cruise control set at 75. Don't know if the RPI scoop and GruppeM intake help with that at all? Not like it matters though, the cost of a GruppeM would pay for 327 gallons...

[sirmalloc]

I've gotten up to 26.1mpg on a 600mi road trip, top down with cruise control on most of the way. Around town I usually get between 16 and 18.

[nmulax]

On 4 hour plus freeway drives I've averaged about 24 mpg.
Otherwise it seems to sit around 18 mpg.

[fiberguy]

Since moving up to a Z4M (from a 2.5) last August, I've driven 3343 miles and used 154 gallons of fuel for an average of 21.7 MPG. This is about 65% highway and 35% light city driving.

The same driving mix in the 2.5 averaged 27.1 MPG based on mileage of slightly over 10K.

The "M" penalty appears to be slightly over 5 MPG.

[mousitch]

Originally Posted by fiberguy

Since moving up to a Z4M (from a 2.5) last August, I've driven 3343 miles and used 154 gallons of fuel for an average of 21.7 MPG. This is about 65% highway and 35% light city driving.

The same driving mix in the 2.5 averaged 27.1 MPG based on mileage of slightly over 10K.

The "M" penalty appears to be slightly over 5 MPG.

Well it must be my heavy foot because when I had my 2.5 I was getting around 19-21MPG. That would reflect the 16-18 MPG I get with the M right now comparing your prior experience to mine.. It's me not the car. My driving style is not helping my MPG.

[k2pilot]

i get about 26-28 on the freeway (65 giving 28-30) and 75 giving 26-26.5. and in stop go i drop to around 20-21...

anyone else notice how stepped the mpg indicator is on this car? it really bothers me... my e46 m3 would adjust it's mpg etc linearly, the m coupe seem to go 21.3, 21.5, 21.7,22.1.. it really bothers me(i don't like odd numbers!)does everyone elses m coupe do that? it seems like the computer is just running really coarse on it's measurement..

[epbrown]

Originally Posted by AusTTin Bob

I averaged 5.9 mpg this weekend. But then again, I was at Harris Hill Road Raceway

You might have done worse han that. When I was at Performance Driving School, the instructors said the computers don't show lower than ~6mpg no matter what.

[Hawkeye]

Wow, I average right over 25 in my 3.0si.... thought there would be a bigger difference. On the highway, following a friend that does not speed I got 33.2 mpg on a 2 hour trip once.... but only once. I usually am doing well over the speed limit.

My truck gets 10-12 mpg now driving it very nicely (much less when flooring it)... haha. Guess a full size pickup with a 5.6L V8 and 4WD will do that for you.

[aerobod]

Originally Posted by k2pilot

i get about 26-28 on the freeway (65 giving 28-30) and 75 giving 26-26.5. and in stop go i drop to around 20-21...

anyone else notice how stepped the mpg indicator is on this car? it really bothers me... my e46 m3 would adjust it's mpg etc linearly, the m coupe seem to go 21.3, 21.5, 21.7,22.1.. it really bothers me(i don't like odd numbers!)does everyone elses m coupe do that? it seems like the computer is just running really coarse on it's measurement..

It is just the conversion and rounding from litres per 100km that is causing that. The car resolves to 0.1 of a l/100km, then converts it to mpg for display. The increments in l/100km are even, in mpg they get more course as you use less fuel. It does the same thing in the E46, but depending on what the actual mpg is, it may be odd or even increments, or a combination of both, for example:

8.7, 8.8, 8.9 l/100km corresponds to 27.0, 26.7, 26.4 mpg
9.7, 9.8, 9.9 l/100km corresponds to 24.2, 24.0, 23.8 mpg (assuming rounded to the nearest, or 24.2, 24.0, 23.7 if truncated)
11.6, 11.7, 11.8 l/100km corresponds to 20.3, 20.1, 19.9 mpg (assuming rounded to the nearest, or 20.2, 20.1, 19.9 if truncated)

[k2pilot]

Originally Posted by aerobod

It is just the conversion and rounding from litres per 100km that is causing that. The car resolves to 0.1 of a l/100km, then converts it to mpg for display. The increments in l/100km are even, in mpg they get more course as you use less fuel. It does the same thing in the E46, but depending on what the actual mpg is, it may be odd or even increments, or a combination of both, for example:

8.7, 8.8, 8.9 l/100km corresponds to 27.0, 26.7, 26.4 mpg
9.7, 9.8, 9.9 l/100km corresponds to 24.2, 24.0, 23.8 mpg (assuming rounded to the nearest, or 24.2, 24.0, 23.7 if truncated)
11.6, 11.7, 11.8 l/100km corresponds to 20.3, 20.1, 19.9 mpg (assuming rounded to the nearest, or 20.2, 20.1, 19.9 if truncated)

thank you so much for explaining this... i was confounded with why the car with the superior ecu seemed to have less accurate mpg indicator.

Originally Posted by U235

19-20mpg city for me, but most of my time is spent at 45-50 which is ideal for a car.

21-22 on the hwy driving at the speed limit or slightly above. I was expecting better hwy mileage based on some of the e46 M3 guys "claiming" 26-28; I don't know how they do it.

i just noticed this username