TheNewStandard

Well my ML430 does 16.5-18mpg on the freeway, which is ok considering i moved to a sea-leveled city. (Might still need to have the MAF, spark plugs, oil and air filter checked though!)

Anyways I noticed it jumps close to 25mpg while following a car within 3.5 car lengths BUT in the next lane.
I'm not a fan of drafting/tailgating right behind another vehicle especially at high speed. While doing this, you will still be right out of their blindspot.
This concept of formation is something birds internalize when flying in order to reduce aerodynamic drag.
http://en.wikipedia.org/wiki/V_formation
This was just something interesting to throw out there for those like me who did not know!

m1943

I don't know, I just got 19 MPG out of my ML 350 (w163 of course) when on a long, long road trip. Mixed City/Hwy driving I average about 14 - 16 MPG, all depending on how much I get stuck in traffic jams. I never thought following somebody on the freeway would affect anything, so I haven't really tried. Most of that 650-mile road trip took place on a narrow, one lane in each direction highway. Threre were lots of slow-moving 18-wheelers and such, so I often had to pass them on left, which involved accelerating, so the consumption perhaps could've been even better. Than again, perhaps it was when I was behind those truck and trailers that drag was reduced? I couldn't always pass them due to incoming traffic and sections of the road where passing was not permitted. Their speed was often between 40 mph and up to 60 mph at most. Otherwise I would go no faster than 80 mph due to pretty poor road conditions.

m1943

Apparently, our cars have a drag coefficient of 0.39, which is probably pretty good for an SUV. G-class is something like over 1.0.

BD-C63

Drafting works when bicycling (you expend about 2/3's as much energy when drafting someone), there's no reason that it wouldn't increase mpg in a car.

m1943

Actually, the G-class has cd 0.54 or 0.6, depending on various sources on the Internet. Come to think of it, I would expect the ML to have lower numbers, like .28 - .32, while the G-class I was sure I've read somewhere to be at around 1. I wonder, what coefficient of drag would a car-sized rectangular box have?
So OK, what really is drafting and how do you do it? Tailgaiting an 18-wheeler does that? Or driving in the next lane to an 18-wheeler and a little behind it? Have any benchmark tests (so to speak) been done on that, regarding fuel efficiency?

TheNewStandard

- I haven't tested this much, but i'm positive that it was more effective to stay in V formation rather than being directly behind the car you're following.

- I would imagine if you wanted to see a significant mpg gain by drafting RIGHT BEHIND, you would have to find a cross-over or an 18-wheeler. Be cautious though, about 2 weeks ago I witnessed a minor rear end collision on the freeway no more than 60 meters ahead of me.

- While staying in the next lane, yesterday I noticed I was doing 23-25mpg following a civic coupe for about 2 miles, doing 65mph with Cruise Control on. I tried to record it but the driver exited before I could. I'll record next time when I get the chance!

EDIT: following distance would actually be within 2 car lengths.