6MT 08 fuel consumption 20mpg possible?

[han0355]

hello guys

i have a 6MT 08 m3 and i am shipping it to Taiwan. For vehicle inspection i need to pass 20mpg combined (50% highway 50% local). The car will be dyno'd for inspection. I am running 18" wheels so i hope i get better mpg. I'm wondering how is everyone's fuel consumption, is 20mpg combined possible?

I am open to all sorts of mods such as ECU tuning and final gear, hope our fellow members can chime in some opinions and experiences. Thanks

[X5-User]

20mpg combined for s65 engine? I don't believe that's even possible

[TheSnail]

Mine stays around 15mpg combined. However that's with me driving it how it was meant to be driven. 20mpg combined is doable tho. Before X-pipe and tune, I drove to my hometown in NC which is 400miles away. Averaging 80mph, I got 23mpg there, reset it and got 23mpg back.

With the intake, pulley muffler mods then (20-30hp), along with 50lbs of weight reduction helped the car work less in maintaining 80mph. The biggest impact in my opinion was the ride height. My car is lowered to a one finger gap. The rule of thumb is for every 1" ride height is equal to .01 CD. So I would say that the reduced .015-.02 CD had the biggest impact on the 23mpg I got.

Now the car has an additional 30-40hp, and weight is further reduced by 50lbs. I would imagine I could get 24ish on the highway and 20 combined. I'll check it next time I go to NC, but until then, I'm happy with my 15mpg and driving it like I want to drive it.

[jaco]

I'm getting 12.2 mpg right now.

[pbonsalb]

I have averaged as high as 19, mostly highway, but I drive without regard to maximizing fuel economy. Never tried driving at 55-65 for a tank.

One thought would be to swap the 6MT diff for a DCT diff during the testing. 3.85 up to 3.15 would really lengthen the gears and drop the rpm. Maybe that would help.

[Sered]

I usually average around 22-23 on the highway at 75mph in my E93. Local is different.

[thekurgan]

Your vehicle isn't going to pass inspection.

[BimmerRookie]

I think ive got 14 on right now, and maybe I've been able to get 19 on my combined. I guess it could be possible

[W///]

0 chance. Pure highway, I get about 22mpg. Combined, I normally get about 19, but that's with probably 60% or more highway, and barely any stop and go.

Hell of a crazy rule, never heard that one before. Swap in a 2.0L diesel engine, do the testing, put back the S65

[italyix]

Originally Posted by han0355

hello guys

i have a 6MT 08 m3 and i am shipping it to Taiwan. For vehicle inspection i need to pass 20mpg combined (50% highway 50% local). The car will be dyno'd for inspection. I am running 18" wheels so i hope i get better mpg. I'm wondering how is everyone's fuel consumption, is 20mpg combined possible?

I am open to all sorts of mods such as ECU tuning and final gear, hope our fellow members can chime in some opinions and experiences. Thanks

I average 21 combined almost every day. Switch to a thinner oil to reduce the parasitic losses on the engine and you should achieve the goal.

[squartus]

Not going to happen, max you will get 23mpg HWY town your looking at 13mpg or so, most people average 15-16 MPG combined. Im sure you can super baby the throttle and drive it like a granny but still wont hit 20mpg combined.
Silly ass law though.

[bogdan]

I'm with everyone else. I usually saw a combined average of 16-17mpg. Highway was "better." at 22-23mpg. Pure city was 13mpg...or something. Track driving you ask? Well, how about 6, probably less.

That was all with 19" wheels. I wonder if you can have someone "detune," the car for optimum mileage.

I guess you could run some 18x7 wheels with low rolling resistance tires inflated to 60psi.