Fuel Matters

[simba23]

Some of you may recall i started a thread asking how many miles you guys were getting from your tank. The question was aimed at those with the 220cdi engine variant.

Although i was happy to see what others were getting with larger/smaller & Petrol/Diesel engines.

A comparative study of one sort and affirmation that, i did not have a dodgy car that was under performing.

Having come from a history of high performance cars i had built up expectations that my C220 Cdi would be massively economical.

These expectations were built on the figures that had been quoted by Mercedes. Making an allowance for their usual optimism i was still looking forward to receiving close to the claimed figures.

Having had the car for 4 months and seeing figures of around 40.0mpg on combined driving cycles i was somewhat disappointed. I would see 500 miles to a tank.

Not satisfied with these figures i asked the question in my last post.

I was unable to get a complete answer with at least one person asking me to find the exact same car and try driving that for a tank.

This was unlikely to happen and was the exact reason why i asked the question in the first place. expecting at least one member to say here you go i got 500 miles to a tank and i did a variety A and B road driving.

I know many of you will say there is no way of exactly comparing the mileage as it would depend on the driver. But this was not supposed to be a scientific study but just to find out if i was in the same ball park.

Anyway, since the post i have been experimenting with different brands of fuel, to find some interesting results.

Shell Diesel the car drove terribly and reached 470 miles for the tank.

Shell V power diesel the car drove well and reached 512 miles for the tank.

BP Ultimate the car drove terribly but reached 507 for the tank.

Total Excellium Diesel the car drove well and reached 589 miles for the tank.

Every time i filled up the car took 64 Litres of fuel. I live very close to a petrol pump so i was living on the edge a little.

I am amazed that fuel can make such a big difference.

I did as close to the same journeys as possible per tank in order to keep the results as accurate as possible.

I know the car is new and the engine should loosen up a little more i don't know how much difference that will make but lets see..............

 

[artyman]

I've been a little dissapointed with my C200cdi as well, over last 2 years 40mpg, now that is well below the 51.4 combined figure given by MB. On my previous petrol Skoda I used to get 40mpg against their quoted figure of 38mpg, so unlikely to be my driving technique. A failure on MB's part I feel on what is otherwise a very nice car.

 

[mejermy]

I'm returning 39.7 so far this year from my E220Cdi auto estate (2004 - OM646.961), but this has all been southern europe, and some of it longer runs. I've been adding 300ml of 2 stroke to each tank (which is why I began my spreadsheet instead of my usual occasional brim to brim checks every few weeks). The car has 147,000 on though, and I think that makes it looser and more efficient. My son has a 2005 C220Cdi auto saloon (OM646.963) and returns a screen display 40ish on mixed town commute and M-way runs, but few of them more than 50 miles or so. I would say you're on the money if it's a new car, but you need to up the mileage. Mine has also been de-catted, both the after turbo one and the soot trap half way down the exhaust system. My son's has a DPF and is intact.

Interesting data on the fuel brands - thanks.

 

[wemorgan]

Interesting experiment. When I used to do regular long journeys I'd track my economy. Using the same BP fuel, driving the same speed I would see maybe 15% difference in mpg due to the ambient temperature alone. And a 5% difference with no apparent change in conditions (the noise of the experiment itself)

 

[bolide]

I don't think the lack of accuracy of the fuel figures can be laid at the door of the manufacturers. They are based on a standard test so the fault, if there is one, lies with the test methodology

Nick Froome

 

[grober]

True MPG - genuine, achievable fuel economy tests from What Car?

 

[amokwa]

Thanks for the analysis I have a local Total but always use the Shell, will try the Excellium Diesel next time.

When you say "terribly" do you mean more noise or engine does not pull smoothly ?

We have the C220 BE CDI. One last thing, try not to run it bone dry your fuel filter could take a pounding picking up muck from the bottom of the tank.

 

[stoutgoose]

I went through this when I bought my C350CDI last year with 5000 miles on the clock. I was averaging around 36mpg.

However once it reached around 13000 miles, the mpg definitely improved and my average has increased.

As an experiment I drove like a nun for an entire tank, my daily commute is a 115 mile round trip outside of rush hour on the A3 between Guildford and Portsmouth, so cruise control at 60-70mph all the way resulted in over 40mpg and 601 miles from the tank. I have tried a variety of fuels and none seem to make much of a difference other than the gas to liquid blends such as Shell V-Power, which gave significantly less mpg. The ambient temperature also makes a huge difference.

Finally the fuel computer lies/overreads by @3.5 mpg.

I have been logging my true mpg on Fuelly since last November but cannot link it to here; any ideas how to?

 

[Linko]

I got my 61 plate C220 BE CDI with around 6000 miles on about a month ago. Work isn't far away so I mainly do lots of short trips, taking that in to account I was expecting mid to low 40's MPG. However my first tank came out at 34.78MPG (road trip app calc) vs 36MPG (car display)! :-(
I drove gently for the 1st tank so I could test the economy (Shell regular) and cos she was new (to me).

Car before last, I had an Audi which was a 55 plate that regularly returned mid to late 40's and that was driving like I stole it!

It's a great car, but I'm not impressed with the Merc MPG claims vs real-life. A nice steady 70mph run only returns mid 40s.

 

[RobertoMercini]

Mines an 08 and the first trip I took it on earlier (it's well run-in mind) was around 50 miles, a mix of traffic light stops on 30mph Roads and about half if it was motorway / a-road and I got just over 48. That was on normal diesel. Do the cdi's 'improve' with age perhaps?

 

[gIzzE]

I think I asked this before, what year is it?

Is it using the latest 7g tronic+ gearbox?

The older car with a 5 speed auto has completely different figures to the latest MY2012 model.


The saloon c220cdi with a DPF and only 205 wide tyres has these figures....

Fuel Consumption Imperial (miles per gallon)
Urban 31.00 MPG
Extra-Urban 55.40 MPG
Combined 42.80 MPG


So if you're averaging around 38mpg I would say that is better than expected.


Compare that with the 2012 model which gives...

Urban 47.90 MPG
Extra-Urban 72.40 MPG
Combined 60.10 MPG

If it is the latter than yeah, I would be disappointed but not surprised.

 

[Deleted member 37751]

120 miles difference in a tank is unbelievable!

I'm going to find out my nearest Total garage and give it a try myself, I have also found that I get slightly better mpg when using 'premium' fuel.

 

[Sp!ke]

I have to say that I have had similar findings in my Smart.

If I use Shell Fuelsave diesel my tank range appears lower than any other Fuel.

Normal Total diesel seems to be best.

 

[removed]

Is there a similar comparison for premium unleaded petrols?

In the UK I use BP Premium Unleaded, but am now wondering if this is the best one, or should I perhaps, switch to a different brand?

 

[Khamen]

I would try an experiment with the BP and Shell high octane stuff, but the problem is that the 2 nearest places for both are about 15 miles away. May not sound a lot, but when you only get 250-300 per tank it can make things a bit hairy and I'm bound to run out at some point by cutting it too fine.

K

 

[Rosun]

Sorry to turn up to this thread but C220 CDI (C class 2011 model) trip computer says 22,000 miles / 37 mph / 54.3 mpg average.

I don't drive like a nun. When I do it shows a 68.9 average.

The 22k includes 3 trips to Italy / Germany.

The attached trip is a Manchester / Heathrow / Luton / Leicester / Manchester jaunt last week, leaving Manchester @ 5.00am and getting home at 10.00pm.

 

[JohnEclass]

Economy?

I have a CLK220 CDI 2009, I drive a good mix of A roads / in traffic / motorways.

Just relying on the on board computer, the best return shown was 43mpg, Manchester to South Wales and back, went to Newcastle yesterday struggled to achieve 40mpg even with the 50mph roadworks on the M62 and not thrashing it when on the A1M!

Have to say after the figures i used to achieve in my 2.0 TDI VW Jetta(2006) of between 50 - 60mph on similar trips, was a little dissapointed....but after 6 weeks of ownership of CLK...would not swap back

 

[gIzzE]

OK, I have just done two tankfuls with the Excellium fuel, first tank was 30.5 on the computer, second tank was 30.6 on the computer.

This is the worst two tanks I have had in this car.
Tried a second time in case it was driving style, but it was nearly exactly the same.
I usually get 33/34 with each tank and that is using Shell or Waitrose.

I thought I better calculate it manually too, and I managed to get exactly 70.5 litres in the tank and that was for 476 miles travelled, so think the computer is bang on if I have done my maths correctly?
476ml / (70.5l/4.54) = 30.67mpg

 

[BlackC55]

Remember that some 220cdi's have DPF filters which does no favours for the fuel economy.

 

[finisterre]

very disappointing figures

luckily when we headed out to buy a 220
we came back with a Z4 (38 mpg)