General questions about C240 sport

[Lazarus]

Hi All,

Just bought my first Mercedes, a 1999 (non-tip) C240 Sport in Green Metallic with grey leather, and I absolutely love it.

Just got a few questions, sorry if these are answered elsewhere, but couldn't find any specific threads.

Firstly, what do most people tend to get out of a tank of fuel? Most of my driving is either fast motorway (c. 85mph +) or local traffic. I've just got around 320 miles and the light has just come on. Is there a speed I should adhere to to get better MPG?

Secondly, I will need to service the car before long, and can anyone recommend an independant MB specialist in the Oxford area?

Finally, are their any 'quick wins' such as replacing the OEM air filter with a K&N item that would improve performance and or economy?

Thanks,

Lazarus
--

 

[nickmann]

Hi Lazarus

26 mpg sounds pretty good to me. You get 100 more miles to a tank than I do, but my motoring is all urban. I'd steer clear of K&N filters, there are doubts about their compatibility with hot-film airflow meters as fitted to MBs.

 

[Flash]

Congratulatiosn on ur pucrhase - I hope u enjoy it.

K&N Filter will improv eperformanc eBUT can in long trem harm/kill ur MAFF which is expensive to replace. I would lav eit alone personally.

 

[se97mlm]

I have averaged 30mpg in my C240 over the last year/18000 miles. One third of that is probably my commute which is a narrow twisting and hilly A road, the rest motorway at about 80mph. I tend to keep the engine below 3000 rpm as this markedly improves economy (80=3000rpm).

My tank ranges have varied from 300 to 430 miles depending on the type of journies. long journies over 100 miles will drastically improve mpg. That 430 mile tank was an average of about 37mpg (only put 53L in to top up!) and was two 215 mile trips in one day. Driving in Germany, similar distances but at 95 - 120 mph I averaged 31mpg. If i only commute on a tank of fuel, ie no motorway work i average about 27mpg.

I would definately echo Nick's comment about avoiding an oil lubricated air filter like a K&N: Graeme killed a new MAF in 300 miles when he fitted one to his c230k!

For a quick upgrade you could buy a new MAF sensor from ebay and see if it makes a difference; if it doesn't, you could always reauction it for £5 less! Nick and I will definately agree that this was a worthwhile experiment!

 

[tinkypot]

Hi,

I've got a C240 (1998) and I return about 300 miles with 41-ish litres. I try to stick under 2500rpm @ 60mph, but it can feel v. slow at times, so there is an occasional burst of speed - I love the noise above 4000rpm!!

Most of my commute is dual carriage way, but 20 mins can be stuck in non moving traffic, literally watching the fuel gauge droop towards empty.

Does anyone know what the optimum speed specific to this model is? A friend has a 420SE and he says 56mph is the spot. Any ideas?

Also, after the needle sits at empty is that when the 7 ltr reserve kicks in?

Cheers

 

[Steve_Perry]

Firstly, what do most people tend to get out of a tank of fuel? Most of my driving is either fast motorway (c. 85mph +) or local traffic. I've just got around 320 miles and the light has just come on.

On average I get around 260 miles a tank, all of that is stop/start town driving though and..... I tend to drive like an idiot, I like the sound of the V6 too much If I do long motorway runs (which is seldom) then I can get mid to high 300's out of a tank.

Is there a speed I should adhere to to get better MPG?.

If you're cruising on the motorway I think 70mph is a good balance for increased MPG, if you get up to 80 there is a significant hit on fuel consumption.

Secondly, I will need to service the car before long, and can anyone recommend an independant MB specialist in the Oxford area?.

Sorry, I know nothing about indies in Oxford area

Finally, are their any 'quick wins' such as replacing the OEM air filter with a K&N item that would improve performance and or economy?

As posted above, there's been some discussion as to whether perfomance filters such as K&N actually reduce lifespan of the Mass Air Sensor (MAS) most people stick with OEM but I think a couple of members have used Green Cotton filters with no ill effects. Also as mentioned above, you might want to get your MAS tested to see if it needs replacing as this can have a significant effect on performance. Other items to check are:
- spark plugs, these need changing approx every 60k miles on the V6.
- Auto gearbox oil... there are many lengthy posts about this subject, MB official line is that the new electronic 5 speed autos are sealed for life however most peeps (me included) have noticed a big improvement in ride quality when changing the auto box oil at approx 50-60k miles.

Good to hear another C240 owner that enjoys their car Do you have any pics?

S.

 

[BTB 500]

A friend has a 420SE and he says 56mph is the spot.

Passed an SL55 AMG doing that sort of speed on a clear M40 on Sunday ... I did wonder what he was up to!

"Best" speed for MPG will surely be as slow as possible. Striking the balance between economy and boredom is the key!

 

[mickl]

quicky question about the MAS sensor, do you need MB specific tools to check or can any garage do it?

 

[Steve_Perry]

quicky question about the MAS sensor, do you need MB specific tools to check or can any garage do it?

The stealers will use the MB Star Diagnose PC hooked up to the ECU to check out the MAS sensor.

S.

 

[mickl]

The stealers will use the MB Star Diagnose PC hooked up to the ECU to check out the MAS sensor.

S.

cheers Steve.

 

[Copiertech]

slower isnt always better for mpg below a certain point. the saving by putting less load on the engine is offset by the fact it is running longer to get you where you are going. for helping economic driving you cant beat the analouge instantaneous consumption meter in bmws.

 

[sym]

slower isnt always better for mpg below a certain point. the saving by putting less load on the engine is offset by the fact it is running longer to get you where you are going. for helping economic driving you cant beat the analouge instantaneous consumption meter in bmws.

hmmmmm... yes, the BMW 'slurp'ometer - can make for frightening reading when driving hard, even with an oil burner ! (a steady 70mpg when cruising along the motorway is nice to look at though !)

I'm sure MB used to fit this to certain older models ... SEC etc as well. I wonder who had it first !

S.

 

[Dieselman]

slower isnt always better for mpg below a certain point. the saving by putting less load on the engine is offset by the fact it is running longer to get you where you are going. for helping economic driving you cant beat the analouge instantaneous consumption meter in bmws.

As that is basically a vacuum gauge does it take into consideration the gear the vehicle is in? i.e does the mpg go higher as a higher gear is selected?

Wifeys digital instantanious readout doesn't always give expected readings. For example sometimes it's more economical to not be in sixth gear depending on engine speed/load.
But seeing 150+ mpg is satisfying even if it's only breif.

 

[Dieselman]

A general rule of thumb is meant to be to keep within peak torque -500 rpm and +1000 rpm. The engine is most efficient at peak torque.
Don't forget the more power an engine creates the more heat it is losing due to inefficiency.
When cruising in top keep the speed down as air resistance goes up with the square of the speed.

I don't think there is an optimum speed that applies to all cars.

In town traffic anticipation is key. Hold back from the car in front and always try to arrive at green traffic lights, even if that means slowing down early. Accelerate gently but quick enough to get into the highest gear possible.
These measures will give an easy 10% increase in economy, but you need to concentrate like mad.

 

[sym]

As that is basically a vacuum gauge does it take into consideration the gear the vehicle is in? i.e does the mpg go higher as a higher gear is selected?

Wifeys digital instantanious readout doesn't always give expected readings. For example sometimes it's more economical to not be in sixth gear depending on engine speed/load.
But seeing 150+ mpg is satisfying even if it's only breif.

It does seem to take the gear into account - with my auto box anyway - there are subtle improvements when it changes up, with no throttle movement involved. Don't know how it works, but it is highly sensitive to the loud pedal !!

S.

 

[Dieselman]

It does seem to take the gear into account - with my auto box anyway - there are subtle improvements when it changes up, with no throttle movement involved. Don't know how it works, but it is highly sensitive to the loud pedal !!

S.

Yours is a bit different Sym as diesls have no manifold vacuum. I guess yours is fully electronic but I'm not sure about the petrol ones.

Do you have the trip computer with mpg. if so can you check it's accuracy by doiong brim to brim calcs. Every BMW i've heard of has over read by approx 20%. I wonder if they are set for US gallons.

 

[sym]

Yours is a bit different Sym as diesls have no manifold vacuum. I guess yours is fully electronic but I'm not sure about the petrol ones.

Do you have the trip computer with mpg. if so can you check it's accuracy by doiong brim to brim calcs. Every BMW i've heard of has over read by approx 20%. I wonder if they are set for US gallons.

Haven't actually checked mine - but will get around to it some time. 20% sounds high though - people on the BMW forums who have checked this out claim that its no more than 1-2% optimistic (and that assumes that the odometer is accurate !!)

S.

 

[Steve_Perry]

...I'm sure MB used to fit this to certain older models ... SEC etc as well. I wonder who had it first !

S.

MB's used to have a "swing-o-meter" with a red zone and a black zone. Black being good and red being bad. I think they got phased out towards the end of the W124's and the W201's. I miss my swing-o-meter from my old 190E and my oil pressure gauge too.

S.

 

[Copiertech]

my mums 230te has a swingometer, but its just a vacuum gauge, you can make it swing by blipping the throttle in neutral. the one on petrol bmws is controlled by the ecu, its worked out by the speed the car is travelling and the pulsewidth of the injectors. you can observe it by accelerating up to 40, then coming off the throttle in gear, the gauge goes up to infinity as the overrun cut in is working but if you dip the cluth the gauge shows your economy getting worse as the car slows down, even though it is ticking over the whole time. it helps economical driving as you can experiment with the throttle, maintaing a steady 70 you can gain a few mpg just by coming off the throttle without slowing down.

 

[Dieselman]

my mums 230te has a swingometer, but its just a vacuum gauge, you can make it swing by blipping the throttle in neutral. the one on petrol bmws is controlled by the ecu, its worked out by the speed the car is travelling and the pulsewidth of the injectors. you can observe it by accelerating up to 40, then coming off the throttle in gear, the gauge goes up to infinity as the overrun cut in is working but if you dip the cluth the gauge shows your economy getting worse as the car slows down, even though it is ticking over the whole time. it helps economical driving as you can experiment with the throttle, maintaing a steady 70 you can gain a few mpg just by coming off the throttle without slowing down.

If you are at a constant speed and change up a gear does the consumption reading fall?