Experiment for petrol CLS350 / E350 / C350 / S350 owners?!

[clk208]

I know this is likely to be a very select audience due to the limited numbers of the 3.5 petrol engine around, but hoping for some stats. Also appreciate variation likely due to variation in size/weight of cars.

Earlier this week I decided perform out a non-scientific test of my car's MPG after having recent work on cam sensors/o2 sensors. I set the cruise at 80mph on a stretch of fairly flat motorway and reset the "from start" mpg. Motored along for about the next 30 miles at a constant indicated 80mph. The indicated mpg for this experiment - a rather disappointing 27.5

Appreciate on board computer is not going to be fully accurate but this seems poor for a relatively new-tech 3.5 engine. Please could other owners feedback their results from a simlar run (where safe and legal)?
Thanks!!!

 

[MWCLS]

I purchased the car last month on the drive back (120 miles or so)I managed 32mpg at a steady 70, I'm getting 18.9 around town CLS 350 petrol.

 

[clk208]

^Thanks. I haven't been able to see 30mpg yet, I will have a cruise at 70 and see if I can hit the magic number.

I did an 800 mile motorway run over a weekend before I had my sensor issues addressed and saw a fairly dreadful 23-24 mpg for the whole trip, I think my 27.5 therefore represents an improvement but not sure if there are still issues that need to be addressed. Obviously I ideally need to get it hooked up to a star diagnostics again.

 

[Bellow]

The problem with these motorway tests is the wind. Quite significant differences in mpg have been recorded when the journey is immediately repeated in the opposite direction. It would require a very still day to be valid.

 

[V12]

Mercedes-Benz C350 MPG Reports | Fuelly

and

Mercedes-Benz E350 MPG Reports | Fuelly

 

[clk208]

Agree on the headwinds. Having piloted a large old school Volvo for many years I recognise a strong headwind can have a significant impact, particularly on a car with limited areodynamic qualities,

However I'm coming up to 4000 miles usage in the CLS and haven't once seen MPG approaching 30. My cheat "in motion" reset the other day at 27.5 being the closest. Incidentally the return journey an hour or so later saw a similar (slightly worse) mpg.

Just wondering if this is all these heavy cars can manage with regard to mpg in normal usage.

 

[clk208]

Mercedes-Benz C350 MPG Reports | Fuelly

and

Mercedes-Benz E350 MPG Reports | Fuelly

Interesting. A lot of yank figures recorded here (think a US gallon is smaller than UK equivalent) but something to go on at least.

 

[R2D2]

My C350 has hit 35.9mpg on a 70mph cruise. In fact getting above 30mpg between 60-70mph is pretty regular. I havent done a test run at 80 but will in the next week. I reckon low 20s around town and an average of 26-28mpg. I'll keep checking!

 

[bobmedley]

Over 130,000 miles my dearly departed ML350 did 21 mpg - oddly, it never seemed to vary much at all however you drove it.

 

[V12]

Interesting. A lot of yank figures recorded here (think a US gallon is smaller than UK equivalent) but something to go on at least.

You can change the figures to UK gallon. That's what it shows when I log into the site.

Sent from my GT-I9300 using MBClub UK