mdp c230k

I can't believe I got over 40mpg with the car going 80 mph! I reset the computer while I was on the freeway going a steady 80 on a nice flat area and I got over 40mpg over a 10 mile run! If only all the milage was that good in this car I'd be in heaven as I'm used to 13-14 around town.

Mark08859

Were you in cruise control mode or "standard" driving.

13 or 14 mpg around town seems very low even for a SC 4 cylinder. This is big SUV territory.

viper

I don't believe it either. Unless you were going downhill in neutral I don't believe you can get that kind of mpg.

Rick

I got 34.1 mpg on the trip to/from Montreal. Most of that driving was 72-77mph with climate control in EC mode. As soon as I turned AC on..it dropped to 31.8mpg.
I only dropped the hammer once on the way home....a white BMW 325ic wanted to run near Half Moon, NY....heheh.

avlis

Not surprising. It really doesn't require much power to maintain a constant speed on a relatively flat road with properly inflated (low rolling resistance) tires and no wind.

I remember reading years ago that it only required something like 5-10 horespower to keep a 5.0 Mustang going 55mph on a flat road.

I'm sure there's a way to calculate how much hp is needed to keep a coupe at 80mph.

The problem is: power is needed in accelerating up to that speed. My prediction for the future: transmissions will have more gears (like "big-rigs"), CVT transmissions (which will accomplish the same thing), and higher top-gear overdrives. Engines will have lower hp ratings and higher torque ratings (again, like "big-rigs"). When talking about fuel economy, I think the transportation industry knows what's required and how to get there. Auto manufacturers don't care about ecomomy because (at least in the US) the consumers don't care. Yet....

trench

This is correct. I have one of those G-Tech toys and very little HP (usually less than 10) is required to keep a car at steady speeds on the highway.

I agree with you - I'll bet CVT transmissions will be the norm, with one of these controlled by a computer there is no reason for a standard gearbox, a less powerful motor can give similar perfomance when mated with an optimized gearbox. Also, the newer diesel motors coming from MB already have much higher torque ratings with about the same HP as their gas counterparts.

Cheers, BT

MB-BOB

Viper, if you reset the "after start" computer while you are already moving at cruise speed, it will indeed calculate a higher mpg, because it resets the clock to zero and start speed from zero to your present speed, present throttle position, etc.

Try it sometime. Just call-up that "after start" page while you're on the highway and then reset it. Interesting, but totally unrealistic. Because you can't ignore the stop and go bits that get you to cruise speed. That is what chews up the gas.

vadim

GTech can't possibly measure this kind of things, since it's accelerometer based. This means that it requires that the car accelerate to produce any meaningful reading. It's just as useful as your wrist watch at a steady pace. The ~10hp reading likely reflects its accuracy (or, rather, inaccuracy in this case).

In real world the higher the speed the more air resistance comes into play, the drag being a function of speed^2. This means, for example, that if at 40mph a car needs (hypothetically) 40hp, then at 80mph it would require 160hp to propel it forward at a steady pace.

nboyd

I don't know what the MPG was but I got from San Francisco to Santa Monica (LA) on one tank of gas. It was not even filled up that day but the day before.

Nathan

viper

Yes it sure is unrealistic. Just made my comment in case someone starts replying "How come I can't get that kind of mpg" and then makes a service appointment.

trench

That's why I called it a toy. However in HP mode it does show how much power is required to provide the subtle increases in acceleration (it keeps in its memory roughly how fast the car is going so slight accelerations at high speeds require more HP than slight accelerations at low speeds). Of course you've hit the nail on the head with it not being able to measure the amount of power necessary to overcome air resistance. However, at 80 mph the amount is almost negligible (less than 20 hp). One of the car magazines (CD or RT?) used to calculate the amount of HP to keep a car at highway speeds in the mid-80s (I'm not sure if they still do this or not, I hardly ever read them anymore) and most cars required about 10-20 hp to maintain highway speeds (and these were with the much less aerodynamic cars of the 80s). One cool thing I remember from these old tests is once they compared a car with a factory-modified "hot rod" version (with a bigger air dam, fatter tires and a rather large spoiler on the back). The addition of the more drag-producing (both air and rolling resistance) elements required about 5-7 more hp to keep the car at the same speed as its more simply adorned counterpart.

Cheers, BT

gab

aerodynamics and direction of the wind plays an important role too.

the Honda Insight get close to 80mpg by driving behind a big truck

40mph might not be unrealistic

WebGuyNJ

Without traffice I am consistently getting 31.5 MPG on my 33 mile commute in NJ including 5 miles on local roads with lights.

C230 Sport Coup

Hey web guy,
How many miles are on your car?
DO you have automatic or manual?

I notice that if I go verrrry easy on the engine, I can get up to 27mpg, but thats my best so far, using cruise control with 91 octane gas.
What octane gas do they have in NJ, what are you running?
I only have 5K miles on it, and it seems to be getting a little better as time goes on.
It only take a couple of good romps to destroy my mileage, put it down to 20mgp. Having the car for a while now I see it's not neccessary to put the pedal down very far to get normal acceleration, something that took getting used to. Just barely touch the pedal most of the time.
Wish I could get closer to 30mpg on highway.

The only times I got less that 15mpg, I was pushing the car very hard down mountain roads.

When i bought the car I asked about break in, and they said just go easy on it. With the automatic there's little you can do to keep the revs down, it does what it wants so I have no doubt that the car went beyond that, but not within my control to get it to shift when I want it to. Sometimes it sorta hangs and just won't go; likely the adaptive tranny trying to help me out. They should program it to break itself in for the first 1K miles.

mdp c230k

The whole idea behind my original post was to show how efficient the car is at speed. Any fool knows that it is not representative of the mpg during acceleration.

C230 Sport Coup

!!
FOOLS!?
ANY Fool?
Hey buddy, we're not ANY fools, as in
Common Fools, we're more like uncommon fools!
;-)
No I think it was good someone pointed out how you did the reset WHILE already at speed.
Makes sense...fool!
Milage is of interest to me. I'm not too particularly satisfied with mine.

'sup foo ?

mdp c230k

C230 S C,
If you read my original post you will see that I mentioned that I reset it at speed and that I normally see an average of 13-14mpg! 'nuf said Fu.. Read before you fu...

FrankW

talking about low mpg...my usual local mpg is only 10.4 mpg...

trench

I think you need some lighter shoes, Frank!



BT

AMGracer

Damn, this is exactly why i wish we could get the CDI diesel coupe here in america, with more or almost the same torque as the gas 2.3 liter engine and 60 mpg you can drive in style, have performance and still have money left over to take your woman out for ice cream. I think the diesel coupe accelerated 0-60 in 8 seconds. that's hardly slower than the gas, give that a chip and you'll probably have better performance and probably even better gas mileage.... I own a Passat right now and It rarely gets less than 48mpg. At 10 mpg I'd be freakin out!.

Mike T.

From Mercedes-Benz German market brochure:

C 220 CDI Sportcoupé
105 kW @ 4200 rpm
315 Nm @ 1800-2600 rpm
0-100 km/h: 10.3 s
Fuel economy:
8.6 L/100 km (27.3 MPG US), city driving
4.8 L/100 km (49.0 MPG US), highway driving

...so the car is not a realistic 60 MPG (US) prospect and it is certainly not an 8 second 0-60 MPH car either. The 220 CDI is the only diesel presently offered in the Sportcoupé (that's about to change, with the AMG Diesel coming soon). Note that the C 220 CDI has 35 Nm more torque than the 2002 C 230 Kompressor, and 55 Nm more than the upcoming 2003 C 230 Kompressor.

But what if they offered the C 270 CDI five banger in the Coupé?

From German C sedan brochure:
C 270 CDI Sedan
125 kW @ 4200 rpm
370 Nm @ 1600-2800 rpm
0-100 km/h: 8.9 s
Fuel economy:
9.7 L/100 km (24.2 MPG US), city driving
5.1 L/100 km (46.1 MPG US), highway driving

The stats would be identical if this engine was in the Coupé, except the highway figure might rise by 0.1 or 0.2 L/100 km due to the sedan's better aerodynamics. Even this car could not reach 60 MPH in 8 s, and it's not quite a 50 MPG car.

Either CDI car is damned nice on its own merits, but let's be realistic, there is no free lunch and so with these cars, 0-60 MPH in 8 s combined with 60 MPG US is not possible.

AMGracer

Okay yes your right... US MPG might not be quite so good..I keep forgeting AMERICAN MPG are different.......that's why every time i look at your TDI VW Beetles I wonder why you don't get 64 MPG like ours do. IT's interesting..... Still you have to admit even without 60 MPG US, your still getting amazing mileage and awesome performance figures. AMG DIESEL? that's definitely my kind of engine

FrankW

actually it is not too bad because on the freeway i can get 23-24 mpg and the average of the two i can usually get 16 mpg out of it.

i guess fast car comes with a price of using a lot of fuel.

my C32 just went over 3k miles. i'm sure the mpg will get better as more miles are put in.

BTW i did freakin freak out with that 10 mpg. i thought something were wrong with my car...lol

AMGracer

I can understand your low mpg with the supercharged v6 I Mean correct me if i'm wrong but your pushing over 350 hp in your c32. 20mpg would be about what I would expect, but a little coupe I'd hope would have a few digits toward the upper half of 20's to mid thirties

WebGuyNJ

I have 3,500 Miles

Manual

Premium fuel in NJ tends to be 93 Octane

Romping on the engine is what causes poor mileage. When commuting, my intent is to get good mileage. On the weekends and at night I drive the car for fun. I use the accelerator as needed, rarely use it going down hills except to take advantage of them to go up the next one.

I've driven a lot of highly efficient vehicles, the C230 is not one of them. But it will exceed the rated 29MPG on the sticker. To be fair here, my average on tanksfuls has been about 27MPG. This is a far cry from my last car that got 54MPG on average.


The only time I got less than 15MPG was standing still