Nevada Jack

I just noticed in one of Steve's pics the EPA figures for the GL550. 13 City, 17 Hwy... Looks like the new one is a pretty thirsty animal...

mbslk350

It would be interesting to compare the 2008 GL550 rated mpg against the 2008 GL450 rated mpg. For 2007, the 450 was 14/18 or 15/19 (can't remember which). For 2008, those should be reduced by 1-2 mpg, since all cars use the new mpg formula. If the 450 ends up around 13/17 for 2008, then the 550 at 13/17 isn't bad at all by comparison. I was expecting much worse.

Nevada Jack

I think the '08 GL450 comes in at 13/18 with a combined 15...so you are correct, not much difference between the two models.

StevethePilot

So get a 320CDI?

Nevada Jack

Been there, done that (almost)...LOL

mbslk350

I did!

StevethePilot

By the way, impressive catch on the mileage. You're a real PhotoShop pro!

nantucketsleigh

My quess in that overall mpg will be almost identical to the 4.6 liter. I get about 17 overall in 30% local 70% highway driving-rare bumper to bumper trafic.
What kind of mpg did you get on your S550?

Nevada Jack

I get about 15/16 or so mostly city driving but on the highway it is fantastic for such a big car. Average about 25mpg at interstate speeds on long trips.

nantucketsleigh

I quess it has a lot to do with aerodynamics. The computer on my GL indicates about 22 mpg at a steady 70mph but it drops to 18 at a steady 85mph. I have seen 25mpg on the computer at a steady 45 on a rural road. My E500 hardly varies between 70 and 85mph.

jpeardm

Yes definitely aerodynamics and the horsepower to weight ratio is much higher on the E so it doesn't work so hard at speed. I think the GL must be 1500 lbs heavier and 50 hp less.

StevethePilot

Which brings back up my position that the higher horsepower and torque of the GL 420CDI (or better yet Bluetec) should translate into higher MPG numbers on the highway. Right? Increase the HP/Weight ratio (actually decrease it by increasing HP) and the engine works less to move the same mass over the same route, translating into more efficiency.

I think.

jpeardm

Yeah but it all depends how the extra hp is achieved. The same drive train in a lighter car would get better mileage but add more hp by jamming more fuel into a higher compression engine in the same vehicle and it might be less efficient. It's really about energy in vs energy out. Get's complex real fast.

nantucketsleigh

Venturing into an area I know next to nothing about, I thought that HP/Weight ratios impacted efficiency most during acceleration and that at a steady speed weight had little impact on mpg beyond any slight difference in internal engine friction caused by different gearing and any variability in rolling resistance.

emayer

I think you're absolutely right here. The slight mpg differences btw. the 450 and 550 are likely due to tire size and perhaps ride height (eg. resistance).

StevethePilot

My head hurts.

jpeardm

Yes that's right and more weight in the same vehicle will require more hp to maintain speed so the efficiency will drop.

Waiting-4-550

But I was always taught that bigger is better!!!

blittle

.....and, none of us bought these vehicles because we were worried about the mileage That being said...........I have been greatly impressed with my 450 mileage..........I do a 450 mile trip every month and have been regularly getting 19.5 or 20.5 on that trip. Pretty darn good for a vehicle with AWD and of that size, weight, etc.!

samuelwang

I've just empty out my very first tank through a combination of 70% city and 30% highway driving, rack up 350 miles or ~14 MPG. That's not bad at all, however the major shocker is that the first refill was exactly $75.00, not a penny more or less

abcdef

Amazing . . . I also had a recent fill-up $75.00 (not a penny more or less). Perhaps it has something to do with the credit card fraud limits they are using at gas stations these days

oknish

BINGO.........that is the max they will allow you to fill up on an unattended sale.

Newbie_2_MB

Shell seems to be the one chain that always does this. Ticks me off. I had an Expedition and $75 didn't come close to filling that barge. They used to shut it off at $50 which made me want to strangle somebody.

samuelwang

Learn something new everyday!

oknish

Mobil does this to me every time and, yes, it is annoying to the strangulation level.