Was reading Edmunds' comparison of E550 vs. 550i vs. Jag XF, and they noted that the E crushed both in terms of realized gas mileage. So I thought I'd look up a few other cars from Inside Line's "Full Test". Surprisingly to me, the E550 has relatively excellent real-world mileage according to Edmunds. It beats all other luxury / performance V8's that I was able to find, and even beats a couple of V6's. It even beats (or at least ties) some non-performance cars of its size, e.g., Honda Accord, Mercury Grand Marquis, and Buick Lacrosse.

Thought I'd share the data here. If I have some time later, I'll see if I can find similar data from another source. Powertrains here are RWD unless otherwise indicated.


Car Edmunds MPG
2011 BMW 535i V6 22.7
2011 Inifiniti M37S V6 21.5
2010 Ford Taurus V6 FWD 21.1
2009 Hyundai Genesis V6 19.6
2010 MB E550 V8 19.3
2009 Honda Accord V6 FWD 19.3
2010 Mercury Grand Marquis V8 19
2010 Buick Lacrosse CXS V6 FWD 18.5
2009 BMW 550i V8 16.9
2009 Acura RL V6 AWD 16.8
2010 Jaguar XF V8 16
2011 Inifiniti M56S V8 16

 

I love my gas mileage for this V8.........
I think it has something to do with that 7th gear

 

Great motor, also the low coeficient of drag. One of the lowest out there, broke some kind of record? I'm sure someone could chime in as to what it exactly was.

 

In "C" mode, it's not too bad on gas for a V8 (starts off in 2nd gear, gets to 7th ASAP). "S" mode isn't so efficient (starts off in 1st gear, holds gears longer, etc.) but it sure is fun

 

Correct; 7th is your overdrive gear which is very kind to your fuel economy while cruising.

 

whoo yeah!!

 

I have about 1700 miles on my MY11 E550 4Matic. I am getting about 22-23 MPG on my usual commute. This compares favorably with the 22 MPG I was getting on my MY08 E350 4Matic (5 Speed). I am expecting the E550 might improve some more as the miles pile on.

 

You nailed it. I read somewhere (C&D or MT) that W212 has a lower coefficient of drag than a Prius.

The mileage is really impressive. It beats the socks off my last car (BMW 650i vert, 6spd) which it is also faster than. I just had a C300 loaner (also 7spd) on my regular commute for a few days and honestly the mileage wasnt that much better - maybe 1mpg. Im still thinking something mustve been wrong.

 

Yeah, it actually (W212 E-Sedan) is, if I'm not mistaken, the most aerodynamic production car of all time (or tied for it with maybe one other car at most), ASIDE from the E-Coupe, which is 1 or 2 "points" more aerodynamic (making it the most aerodynamic production car of all time).

M-B V8's have always been efficient for their times, especially on the highway. The E550 is no exception, although it doesn't exactly match the E350's gas mileage, it's pretty damn close. I'd say, it isn't the power of the E550 over the E350 that bothers me (in regards to me not having it), as much as it's the very comparable gas mileage, that comes even in leu of that extra power. Just shows that the V8 is a more efficient motor all around.

Both motors are about to get a lot more efficient (V6 and V8 M-B offerings), so things are about to change again.

 

Some people are actually reporting better gas mileage with the 550 than with the 350. I suspect, though that you only get the good mileage if you you don't actually use the power of the 550 so it's kind of a wash.

 

I use my 'power' all the time, and am on my 5th tank of gas: average 20 miles per gallon, have put about 1400 miles on my car.....it arrived with 12 on it.....

what an awesome deal!

 

It's that extra power is what the saving grace for the V8 engines is. My theory is that since the 550 has more low end torque it doesn't need to waste as much gas as the V6 engine to get the car rolling. Less gas wasted = more gas saved

 

It's an interesting theory but we need to remember that the v8 uses 2 litres more fuel and air mixture than he v6 by the time all of the cylinders fire so there must be some other factors at work as well. I think we need the Mythbusters here!

 

I averaged 22mpg on a recent trip to Bethany Beach, DE in "Comfort" mode on my E550 Coupe. Surprised me as I never saw more than 23mpg out of my '08 Subaru STI even with a custom 'no boost' map loaded on it for just such road trips (AWD and blocky aero at play for sure).

 

Where is MB E350 in the list? Is it worser than 16? It looks like for me.

 

I never said my theory was flawless; but you are correct !

 

That is why city milage for the V8 will be tough to match the V6. But on the highway the V6 may have to dump more gas per cylinder than the V8. Hence the possibility of not much of a gas milage difference.
I am no expert just offering some food for thought.

 

Well that sounds plausible. The v8 could be running more efficiently and thus saving fuel.

 

On my mixed highway/city driving loop of about 60 miles each day, I average about 22 MPG on my E550. Mileage improved after 10K, it has 16 K on it now.

For comparison, my 2002 E320 had dropped to about 24 MPG on this loop before trading it at 155K.