Best MPG setting?

[dakarwu]

15.4 mpg 90% city and I drive like a grandma

[Hunt3R]

MPG in this car depends on what RPM you drive at and how much stop and go you have to do. I've found cruising between 25-70mph without any stopping gets really high mpg, like 22-26mpg. Even in traffic, even when flooring it here and there, this big V8 does ok at slower speeds if the traffic keeps moving. The faster I go though the more that number goes down. Cruising at 80mph goes down to around 20-21 mpg for me.

I mostly drive my DCT to work, thru the city and up on the freeway some and my long term MPG=19.6

[Gbiz]

You have a manual, so control your shifts. If you're really looking to high MPGs, you've got to shift 3K RPMs and drive mainly on the highway. If not, then 15-20 MPG tops. I've gotten 24 MPGs before but it was all highway on a long trip; the wind was probably pushing and I was going downhill.

[kyrix1st]

Hilarity aside, there are mainly two ways to increase MPG:

1. Move the car as much as possible. S65 drinks fuel like it is water on idle.
2. High flow exhaust with sport cat. Catless from experience worsens MPG because you lose some of the low end torque.

Suggestion: Buy a 4-banger with 30+ mpg. I don't recommend Prius 'cause I hate them

[ItsGary]

Originally Posted by Bartledoo

A few weeks ago I actually had to coast downhill for 35 minutes with my engine off from the top of a pass because I was already well below 0 miles to empty and I was certain that I was going to run out of gas since the next station turned out to be 25 miles away (poor planning I know). Managed to make it to the gas station though.

I have a photo of the fillup - 16.596 gallons!!! I think the official fuel capacity is 16.6 gallons so I feel like I must have a record haha.

My "best" is 16Gal but mainly 15.6Gal

[OldenburgerM3]

There was a great article in Motor Trend a while back, or was it Auto Motor und Sport? Either way, the bigger the engine displacement is, the less influence driving style has on mileage. I've grandma'd a tank or two and the difference to normal driving's MPG (mine's a manual transmission) is absolutely negligible. Your results may vary. I don't use the computer for my analysis, I used gas station fillup math.

[sibhusz06]

1. Run slightly higher tire pressure and run stock size tires preferably All seasons which have less resistance.
2. Change plugs air filter regularily.
3. Run slightly thinner oil (i know this is controversial) like a 5w-40
4. Use Costco 93 to offset costs by paying at chain gas stations.

[spazzyfry123]

Originally Posted by OldenburgerM3

There was a great article in Motor Trend a while back, or was it Auto Motor und Sport? Either way, the bigger the engine displacement is, the less influence driving style has on mileage. I've grandma'd a tank or two and the difference to normal driving's MPG (mine's a manual transmission) is absolutely negligible. Your results may vary. I don't use the computer for my analysis, I used gas station fillup math.

I noticed this with the big turbo diesel F-250. It didn't matter if we were cruising around town, on the highway, high payload, towing the Jeep... strictly 9 MPG.

[KevinGS]

Originally Posted by 1MOREMOD

Off

LMAO

But seriously, this things eat gas.

But on the open highway, if you set the cruise for about 80, it does pretty well...even with the A/C on. If you set it too low, like 60 or 65 MPH, the mileage is worse for some reason. This car is actually more efficient at higher speeds. Go figure.

[Ngilbe36]

I averaged 21.7 mpg on a 660 mile trip on Saturday. Probably ~440 highway miles and ~220 through the Adirondacks in NY.

[Scharbag]

Another thing is it seems best to avoid high ethanol blended fuel such as Husky 94 (not for mileage, more for performance - running a 91 octane tune).

Performance seems pretty much the same but the data shows my milage changed from ~19L/100KM when using Shell 91 to ~21L/100KM when using Husky 94. This agrees with what we see when using Husky 94 on the racetrack i.e. we always burn more Husky than Shell.

My commute is about 15KM one way and is mostly stop and go low speed roads. And, full disclosure, I like the sound the V8 makes under load...

When road tripping at 80 MPH, my M3 gets ~12L/100KM.

Personally I do not really care about the milage though. I own a wonderfully gutless Subaru Transportation Appliance for when I want to reduce my carbon footprint - or when it snows.

[highwaystardoritos]

this has been my gas log, mostly highway and in M mode once I hit the streets <3

DCT - Auto - D4

[anerbe]

^how accurate is the OBD reading vs your log?