kimyoung_k

I have C300 4Matic. After I read a thread saying that C350 made max 30+MPG on flat highway with constant speed of 70mph, I had to test my car. I set cruse control at 70mph on flat highway for 20 mins. Of course, I reset my mpg trip computer as soon as I set the cruse at 70mph.

The result? dissapointment.

24mpg at avg speed 70mph for distance 20 mils.

What's up with that???

My C300 4Matic has not done with break in yet. Still 200 more miles to go.
But, still it's close to break-in and should have decent mpg.
Prior to the test, my avg mpg was reporting at about 18mpg. I guess I cannot complain since MB advertised mpg as 17/23 for C300. But, still I would expect more when C350 has max 30+mpg for same test. Maybe it is because of 4Mactic? (heavier, bigger rear differential gear ratio than rear wheel drive C300 and C350)
Will it differ after 1000miles? At 1000mil dealer check up, will they adjust something that helps better gas milage?

How is your 4Matic's gas milage?

430752

Mine is down near 16, but I've had too few miles on it, only around 400, to say with any certainty. Plus, a lot of my avg. gas mileage was due to idling while reading the manual or flirting with the controls as I'm learning the car. Still, in anye vent, the 4matic will be worse than non-4matic due to its portly weight (~3800 pounds) and 4 matic tranny. AWD vehciles have the worst loss of power between the crank and the wheels than of either a fwd or rwd vehicle. Still, if the c350 is getting 30 mpg on the highway, I'd think we should get 27 or 28, and at least above 25!

oblu

Not 4matic, but I've only seen 28mpg max in level cruising with my 300.

There are times when a bigger motor is more efficient. It's got more torque lower in the rpm range so it can sit in a higher gear under low rpm/load at freeway cruise speeds.

I had an 01 Audi A8L with a 4.2 V8. At 70-75mph, level or not, I averaged over 32mpg freeway. But it was barely ticking over idle in top gear. Plus I don't think it weighted a whole lot more than the C believe it or not. Cars are getting piggy piggy oink fat.

PS. If I hit any hills I'm right down into 26-27mpg range with the 300.

kimyoung_k

I guess bigger engine and a difference of rear Axle ratio makes the C350 the winner for the gas mileage.

According to the MB C class spec.

Rear Axle Ratio
C300 Luxury and Sport = 3.07:1
C300 4MATIC Luxury and Sport = 3.27:1
C350 Sport = 2.82:1

Well, the mpg of my C300 4Matic is not much better than my 4800 pound 2006 Pacifica All wheel drive. I get 15-16 mpg average driving around the town with that car. and I thought it was bad.. Wire thing is that my Pacifica has 3.5L engine that produce excatly same hp and torque as C350 engine does. Maybe they are the same engine?? I remember that the 3.5L pacifica engine was the most powerful V6 engine that Chrysler ever made for production car in 2005 or 2004... hmm.. I'm not sure exactly when though...

430752

The pacifica is the unholy mother of the c350? Wow, Daimler won't live down this chrysler thing for a long, long time.

kimyoung_k

I'm not saying both engines are exactly the same. Even though both have the same size with same power, pacifica engine is alot louder and rougher. Also, the engine block of pacifica is cast ion instead of cast aluminum like C350 engine.
My guess is since Diamler engineer designed pacifica, not by Chrysler engineer, they might have given to Chrylser the same blue print of Mercedes 3.5L engine and have them to build with cheaper parts at chrysler plan in US or Canada. Actually, besides the engine, Pacifica shares a few of same designs that were done for Mercedes.

P.S.
Chrylser dropped the 3.5L engine for all 2007 Pacifica and I believe entire line of Pacifica model has been dropped since the seperation from Diamler.
But I believe Chrysler 300M still uses the same 3.5L engine

mkaresh

The Chrysler and MB V6s are not at all related. I'm pretty sure the Chrysler is a 60-degree V, and the MB is a 90-degree V. Also, the Chrysler is SOHC, the MB is DOHC.

My site has a real-world fuel economy survey that is more sophisticated than most. I don't know if I have any results for the 2008 C-Class yet. But feel free to join and post some:

Real-world fuel economy survey

inFiniTE LooP

just got through the 1st tank today. ended up with ~17.8 mpg average...

i expect mpg numbers to go up once winter passes, snow always kills fuel economy.

kimyoung_k

Thank you for the information

Stryder04

I've been averaging about 17 mpg on my 4matic. i've got about 1300 miles on it. plus does it matter if its winter or summer? I mean will i get a little better MPG in the summer time as oppose to the winter?

radiance

Yes, thats is true. Cars tend to get better mileage in the summer compared to winter season.

I'm not quite sure what is the effect, maybe because of the lower temperature (more oxygen packed together) result in a better combustion? Just thought of it from what i've learned in chemistry class long time ago.

omgitselaine

5200 miles here and im in the high teens with MPG. I dont have a heavy foot and im about 50/50 on city/hwy miles as well. I would think during the winter mpg goes down since im always heating up the car before driving away but then again during the summer we got the a/c on so i would think its a tradeoff ?? Anyways im not too upset about the MPG since i didnt purchase the car for its high mpg

zebra1550

I've got about 300 miles on my C300 4Matic and have averaged about 18.5 with mostly city driving. We keep it on comfort mode 95% of the time and have not been letting it idle at all.

Goggles Piasano

Why doesn't MB offer a Bluetec® engine for the C's in Canada and USA? I would rather have one of those than a gas guzzling 3 L or 3.5 L V6 gas engine in the 4Matic.

sdunham

In Colorado, and most of the Rockies, Winter blend gasoline has 10% Ethanol
to reduce smog. It negatively effects gas mileage and performance to some extent. Summer blended fuels here don't have Ethanol and thus MPG's are a little better... You may have a similar situation where you live if they have Winter and Summer blends of fuel.... The Ethanol content of your gasoline should be clearly marked somewhere on the gas pumps if your fuel has it...

ColoradoDriver

Not all of Colorado requires the Ethanol. Colorado Springs and many of the mountain communities do not--including Woodland Park where I live. Actually, the high altitude helps fuel economy. With the closed-loop fuel management system, your engine is only able to burn as much fuel as there is oxygen available. Also, the thinner air at altitude results in lower drag on the highway. Net result is about 10% better economy.

nyca

alot of posts about poor MPG on this car, yet they are not bringing the DFI engines to the US for 2009.

430752

my mileage still sucks. 18.4 mpg for avg spd of 31 mph, pretty much tank after tank, or at least the past 4 I've monitored. I'm up just past 2000 miles now.

Seeing the discrepency b/w 4matics and rwd on this baord, it would appear Merc has a lot, I mean a lot, of learning on a proper awd system that doesn't waste like 70% or 80% of the power. I'm exaggerating of course, but the loss of power through their 4matic system is the only explanation b/w the two (okay, that and the extra weight, but I lump that in with the inefficiency of the 4matic system).

Curtiss

ColoradoDriver

It is due to the difference in final drive gear ratios--not weight differences and 4matic inefficiencies.

ColoradoDriver

FYI. Our new C300 Sport 4matic is still in Germany awaiting shipment our way. But our dealer was so kind as to loan us a 2007 C280 4matic to use until our new car arrives. Everything I have heard suggests the new model should get slightly better MPG than the 2007. Today we drove about 160 miles round trip from our home. Mostly interstate miles cruising at 75-80, but also some slow going side trips between stores and restaurants. Total average for the day turned out to be 29.8 MPG. I don't consider that too bad. And I expect our 2008 to do about one MPG better. (Altitude does help. We live at 8500ft, but our trip took us "down" to Denver (5280ft elevation) and back.

sou98

I joined Mercedes benz club of America. We have a forum sponsored by MB Canada and one of the product manager told us that the reason is that in the focus group in North America...the Bluetech diesel have less demand than the gasoline engine in NA.
I wondered why since VW have Jetta or Golf (Rabbit in Canada next year ) with diesel engine.
So...MB Canada told me..most luxury buyer tend to avoid Diesel. I love diesel especially bluetech engine given that one of my neighbour have one in E class.

nyca

what the final drive ratio on that 2007 C2804M compared to the C3004M's?

ColoradoDriver

Identical 3.27:1

JohnGjolaj1

just let the car break in. if your only at lets say 1500 miles, dont expect a great mpg. once my car hit 2500 miles, i saw the mpg odometer significantly increase. and i only expect it to get better unless of course, a few bimmers there and there pull up next to me....

nyca

and what does the canadian C3504M use for a final drive?