FL Diesel

Just got back from my first road trip from Pensacola, FL to Orlando, about 480 miles each way. I started out with about 2300 miles on my R320 CDI. I averaged just over 21 MPG going about 80-85 MPH on the way there and about 24 MPG on the way home. I admit, I have a bit of a lead foot, but I still thought I would do better than that. Will fuel economy improve significantly as the engine continues to break in?

mitaka

It will improve. I get about 27-29 highway @ about 70 mph.

R. Reyes

Wow. I would have thought for sure the 320 would be way better even w/out break-in. I get 22-22.5 driving 75-80 on highway over 300+ miles.

Right now w/ gas prices what they are, this is when I don't wish I had got the R500.

f-rod

I get just over 24 on my 350 at 70-75mph. I would have expected the CDI to be closer to 35mpg

albellenchia

I, too, regularly get 23-24 mpg on highway trips and have averaged about 20 mpg over the last 10k miles (about 60% highway.)

Scotsman

I was beginning to wish I'd gone for the CDI but maybe not now if that mpg is normal. I'm getting 21-25 most tanks. Would have expected the CDI to have a good bit more.

acrafton

Add to that that in the DFW area it seems that diesel is 10-15% more expensive than gasoline and the mpg argument for the CDI is less/non-existent. The extra torque would be nice though. . .

Scotsman

10-15% more? Jeez. Petrol here is now around £1.04 per litre with diesel about £1.08. Yup, and you're right about the torque at times.

acrafton

My local gas station today had these prices posted:

Diesel $3.29
Unleaded $2.79

That is an 18% delta. . .

iolithblue

actually, on the open road the 500 may not be greatly worse than your 350

harkgar

The same engine in the Bluetec E320 CDi returns much superior mpg.

The R is not much under 5,000 pounds.
Full time all wheel drive.
Presumably you have the full 3 rows of seats filled with kids and their gear too?

harkgar

My Suburban returns 16-19 mpg cruising on the highway, 13 mpg city so your R320 CDi is an economy car by comparison.

FL Diesel

From what I understand, diesels take a while to break in. My next road trip will be over the holidays so I'm going to wait and see. I'm still getting about 480 miles between 20 gallon fill ups which is much better than my Acura MDX.

DonMario2k

now i got about 12k miles on my R, and this weekend on my trip to washington, dc i got a 32mpg in my cdi 8)

R. Reyes

Um, no. A guy in the neighborhood liked my R so much he traded his E350 in for an R500. On our golf trip to San Antonio from Austin and back he averaged 18.3 cruising at 75-80 on I-35. I mean it's not bad for a V-8, 'cause he gets almost 350 miles/tank. Meanwhile I get a little over 400 miles/tank.

50 miles...that is more than just a little worse in my wallet.

mbslk350

My GL320CDI experienced a bump up in fuel economy at around 1K miles and another noticable improvement around 6k miles. I've heard that the fuel economy continues improving even up to and thru 10k miles on this engine.

Gas engines tend to hit their peak MPG a lot sooner. So it would make sense that a 350 gas engine may return same or better MPG than a 320CDI when both have only a couple thousand miles.

CynCarvin32

EPA rates the 500 as 1 MPG worse than the 6.

That takes driver out of the equation. 1 mpg I go with the 500!

The 6 works very hard to keep the car moving.

Love my R350 but its not the quickest thing around.