C-Class (W204) 2008 - 2014: C180K, C200K, C230, C280, C300, C350, C200CDI, C220CDI, C320CDI

Gas Saving Tip!!

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Old 10-23-2009, 03:44 AM
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C350
Originally Posted by Peabody
Using the cruise control is actually a pretty good suggestion, I don't know why, but when I drive at a steady speed on the autobahn, and then I turn on the cruise control and go the same speed, I see a significant decrease in consumption.
+1... i see the same here
Old 10-23-2009, 03:46 AM
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C350
Originally Posted by Glyn M Ruck
Cruise control will only save fuel in specific conditions - namely on the flat. When running up & down hills in undulating country it will actually use more fuel because it trys to maintain constant speed which requires some large throttle inputs. If you run the same piece of road at constant throttle allowing the vehicle to slow on uphills & increase speed on downhills you will use less fuel

i.e. Constant throttle opening gives better fuel consumption than constant speed.
yup... after i read this, this is right. if its flat you will get better mpg somehow if its in cruise control. but if its up or downhill, then you will lose some mpg.
Old 10-23-2009, 05:27 AM
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Yes Carsy - absolutely. In the crazy days that I had a whole string of Alfas they had a manual throttle which gave really meaningful savings. This could easily be programmed in today's world with a safety kick out if you touched the throttle or brakes.

Constant throttle gave even better savings on carburettor vehicles because it stopped you activating the throttle pump in the carb/s.

Last edited by Glyn M Ruck; 10-23-2009 at 05:30 AM.
Old 10-23-2009, 03:06 PM
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C350 Elegance
Smile

Gas saving is the art of driving a vehicle the way you wish and enjoying it. So it is more a behavioral custom than a technique that we will start and cut off like a switch. A similar example would be to respect stop signs whether the intersection be clear or not.

This seems to me like the wrong forum for gas saving tips, because the smallest models come with a kompressor, the technology is based in sport drive-train performance, and the setup is for luxury late models quality. However, most conversations are about how expensive gas is and how to put the pedal to the metal or situations arising from situations like this. Oxymoron?

Cheers, JV
Old 10-23-2009, 04:34 PM
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C350 and a Lightning.
Originally Posted by bulletspec
ON a very long road.. like going down a hill, and if your interest is SAVING GAS.. put your car in Neutral and use your brake pads a little bit if you are going on a long trip... Decelerating with the gears makes you waste more gas..
This is a bad idea.
Don't do this people.
And, at what point and speed are you shifting your transmission back into gear?
As said above, your fuel has been cut off at decel and your are in the highest gear.

Just not a good idea at all.

On my last road trip, I averaged over 30mpg. I didn't do anything special, just drove and enjoyed the car and picked up one speeding ticket so I obviously wasn't trying to get better gas milage, but how much more then that do we need?
Old 10-24-2009, 02:42 AM
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2007 W204 220CDI Classic Sedan
Originally Posted by 2tonOfun
On my last road trip, I averaged over 30mpg. I didn't do anything special, just drove and enjoyed the car and picked up one speeding ticket so I obviously wasn't trying to get better gas milage, but how much more then that do we need?
That is pretty good but when MB decide to import the 220CDI diesel you would expect 45mpg (USgal). on a trip.

On a recent 4000km trip around France our Citroen C 4 diesel manual achieved 50 mpg (US) .

Fuel is going to be very expensive again ( with possible refining shortages)soon when India, China, Brazil, & Russian economies start to grow quickly again .

I think the C Class is way too heavy at around 1600 kg. MB should put more effort into weight reduction. Fifteen years ago a bought a compact diesel car
which achieved 40 mpg US without any modern electronic aids. The reason for this was that it weighed 1130 KG . This car is still a daily driver & original except for fuel pump seals.

Imagine what fuel economy & performance the C Class could achieve weighing 1130 KG.
Old 10-24-2009, 06:17 AM
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Yes - It's interesting. Some of the baby diesel Citroens achieve better economy than a Prius without all the gubbins - just honest good design.
Old 10-25-2009, 01:05 AM
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C350 and a Lightning.
Originally Posted by Carsy

I think the C Class is way too heavy at around 1600 kg.

Imagine what fuel economy & performance the C Class could achieve weighing 1130 KG.
Well, you can blame US crash standards on that. Cars are much, much more safer these days but yes, with that safety comes a huge increase in curb weight.
At least our modern motors have been trying to keep up.
I mean a 270hp V6 motor that is found in a C350 would kick *** in a 65 Mustang. But try running each of those cars into a brick wall at 40mph and see which driver lives to tell about it.
Old 10-25-2009, 03:18 AM
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'08 C350, '05 Mazda 3 HB, '07 330i
Originally Posted by 2tonOfun
This is a bad idea.
Don't do this people.
And, at what point and speed are you shifting your transmission back into gear?
As said above, your fuel has been cut off at decel and your are in the highest gear.

Just not a good idea at all.

On my last road trip, I averaged over 30mpg. I didn't do anything special, just drove and enjoyed the car and picked up one speeding ticket so I obviously wasn't trying to get better gas milage, but how much more then that do we need?
I used to drive since i was 6yo as an Amateur in a Pro Circuit tournament here in SGI in PR and competed @ procircuit nationals in GoKarts and then in Sportpro comp in Solo1 (local amateur circuit) in my Evo8.. Trust me Neutral doesn't do anything to cars and specially when you drive a mercedes that's so high tech ..the car itself will shift to the highest shift change... 7th and then adjust.. people say that all the time... that this practice damages transmissions... All I know is I drive a manual as an everyday and the more i put it in N, the more Mpg i suck out of it...

But then, i found out it's useless! ...It's true what Glym M Rock says that there's a fuel cutoff.. I knew about it but never took a moment to test it... i pulled out an old AEM A/F wideband i have from my Evo and connected it to the O2Sensor and drove around in it .. it really doesn't use fuel when you depress the accelerator!..
Old 10-25-2009, 08:38 AM
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Originally Posted by 2tonOfun
Well, you can blame US crash standards on that. Cars are much, much more safer these days but yes, with that safety comes a huge increase in curb weight.
At least our modern motors have been trying to keep up.
I mean a 270hp V6 motor that is found in a C350 would kick *** in a 65 Mustang. But try running each of those cars into a brick wall at 40mph and see which driver lives to tell about it.
Yes & Euro NCAP. Greater use of composites could overcome this & modern gluing techniques. Look how strong an F1 tub is. Problem is cost.

Also need weight to achieve the Mercedes ride feel. All will be overcome ultimately.
Old 10-25-2009, 03:59 PM
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Originally Posted by Glyn M Ruck
Also need weight to achieve the Mercedes ride feel. .
I don't know whether I altogether agree here. The 1130 kg 1994 Peugeot 405 diesel has a great ride / handling balance & that is on 65 profile tyres. The suspension also feels tight & quiet & is not distracted by corrugations.

I would much prefer to ride in the Peugeot on a twisty & sharp rutted rough road than the W204 as it is more comfortable . But on a freeway or smooth good quality twisty road give me the W204.

Probablly the new Citreon C5 with its hydropneumatic suspension is the most comfortable car on rough roads but unfortunately is is front wheel drive & lacks traction on steep hills.
Old 10-25-2009, 04:32 PM
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Another round of ICE
The conversation on the costs and benefits of weight are absolutely correct. However, the current car seems a reasonable balance. I wonder about the parasitic losses in the predominant automatic transmission. Note the average speed and fuel consumption with a manual, below.

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Old 10-25-2009, 07:39 PM
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late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
Originally Posted by Carsy
I don't know whether I altogether agree here. The 1130 kg 1994 Peugeot 405 diesel has a great ride / handling balance & that is on 65 profile tyres. The suspension also feels tight & quiet & is not distracted by corrugations.

I would much prefer to ride in the Peugeot on a twisty & sharp rutted rough road than the W204 as it is more comfortable . But on a freeway or smooth good quality twisty road give me the W204.

Probablly the new Citreon C5 with its hydropneumatic suspension is the most comfortable car on rough roads but unfortunately is is front wheel drive & lacks traction on steep hills.
Yes - But the French beasts - which are certainly comfortable - French cars always have been - will have you with the door handle poking your butt in hard cornering. They don't have the taught handling of the Benz. You can't have it both ways. A soft sprung, softly damped complaint suspension inevitably ends up with with weight transfer in cornering & braking which makes things a bit of a handful. Very stiff roll bars with compliant springing don't help either. It's all an issue of balance. I even find a Benz S Class with air suspension a bit of a floating tank at speed. A taught body that does not flex with taught suspension is always going to compromise ride without weight to damp it.

Better compromises will be achieved over time but you can't defy physics. Light spacious vehicles with variable spring rates & compromised damping will have to come. They won't, however have that feeling of solidity on the road that Benz owners cherish. The C Class already compromises this. Efforts to make them handle like a BMW 3 series are to blame.

EDIT - & 65 profile tyres help a lot with cutting harshness of ride.

Last edited by Glyn M Ruck; 10-26-2009 at 06:18 AM.
Old 10-25-2009, 07:43 PM
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late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
Originally Posted by Sportstick
The conversation on the costs and benefits of weight are absolutely correct. However, the current car seems a reasonable balance. I wonder about the parasitic losses in the predominant automatic transmission. Note the average speed and fuel consumption with a manual, below.

Yep! - but Benz transmissions like the 722.9 7 speed with converter locked up 99.9% of the time comes awfully close to a manual. One of the most efficient auto's on the market.

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