Probably asked, answered MPG

[Blobcat]

No. The “real world” tests you suggest would then require:

a) if a test track, way more availability than it has, as environmental emissions test chambers are used pretty much solidly and test tracks ditto.
b) if a disused runway, someone to take over and pay for the surface upkeep and maintenance, then see a) above.
c) if a road, then other traffic will have to be managed off it for the duration of the tests.

The reality is that the test chambers are by a very long way, the best way of actually delivering variables- minimised results in accordance with the test requirements as specified by the supra- national standards agencies. The problem isn’t with tests being done in “lab” conditions by eeeebil carmakers (well, unless you’re VAG). It’s how those tests are proscribed by the authorities that the carmakers must comply with. One plays the game by the letter of the rules (again, unless you’re VAG) and therefore the carmakers are free to explore any avenue within those rules to improve their performance claims.

People want to pay less VED so manufacturers "met" the rules and made cheaper VED cars, customers then complained they can't get the MPG and governments complained because they're losing out on revenue...

 

[Zolly]

Blimey, didn’t think we would go so in depth. I was very very happy with my w204 just at the next MOT I would have had to spend more than the value of the car+ I got a great offer for PX

I do exactly the same journeys Urban wise except rather than 35-40 I get 31-33 I don’t floor it never have with cars.unless it’s a c auto box or something else that is killing my consumption? Never use AC , I don’t know ..What are the main culprits, apart from tyre pressure , AC stop start, braking excessively and hammering the accelerator? I have the car set to economy with the suspension etc. One last point this car has done 127K 4 yrs old AA inspected no obvious defects

 

[Craiglxviii]

Feel free to use AC. On your car it will run constantly anyway, the only difference is whether it inputs cooled air to the HVAC system or not

 

[Blobcat]

Blimey, didn’t think we would go so in depth. I was very very happy with my w204 just at the next MOT I would have had to spend more than the value of the car+ I got a great offer for PX

I do exactly the same journeys Urban wise except rather than 35-40 I get 31-33 I don’t floor it never have with cars.unless it’s a c auto box or something else that is killing my consumption? Never use AC , I don’t know ..What are the main culprits, apart from tyre pressure , AC stop start, braking excessively and hammering the accelerator? I have the car set to economy with the suspension etc. One last point this car has done 127K 4 yrs old AA inspected no obvious defects

Pump the tyres up to the maximum that you’re comfortable with. Get up to speed smoothly, don’t open any windows or sunroof and don’t brake if at all possible.
You’ve burnt the fuel to get up to speed so converting it to heat via the brake discs is just wasting energy.
Set your cruise at 65 and drive as smoothly as possible.
Empty any junk from the car

 

[Craiglxviii]

Pump the tyres up to the maximum that you’re comfortable with. Get up to speed smoothly, don’t open any windows or sunroof and don’t brake if at all possible.
You’ve burnt the fuel to get up to speed so converting it to heat via the brake discs is just wasting energy.
Set your cruise at 65 and drive as smoothly as possible.
Empty any junk from the car

And tailgate every wagon you can for as long as possible

 

[LostKiwi]

And tailgate every wagon you can for as long as possible

That was how I managed to get 38mpg from our 2.6l petrol E class...

Really really boring though.....

 

[Dean Fletcher]

The claimed figure is often way off as it relies on tyres pumped up to ridiculous pressures ( not pleasurable driving) and the AC switched off (not pleasurable driving)
Conclusion: to enjoy your driving relax your wallet opening...I think this shall be the new mantra

Sounds like my kind of driving John

 

[Craiglxviii]

That was how I managed to get 38mpg from our 2.6l petrol E class...

Really really boring though.....

You and every Leaf driver!!

 

[davidsl500]

I've only ever used published mpg figures as a means of comparing different cars / engines. I've never expected to achieve them... It does help if the Manufacturer doesn't cheat though.....I mean, beyond the normal cheating..

 

[BillyBoy]

Only applies to current range cars I think, but the WLTP figures are a lot more realistic. WLTP for my car is 36.6 - 38.1, and over the first 1,400 miles, it has averages 37.2 mpg. Due to lockdown and no commute, that has included a lot of short journey urban driving, so I suspect it will go up a bit over time.

 

[sonic]

We have had two 171 SLK200K's with the 1800 M271 engine. We live in a semi rural area normal consumption 30-32 mpg. On a long motorway run we have had up to 38 mpg.
Replaced it with a 2016 SLC250d now getting 45mpg overall. Long motorway runs it will manage 60 mpg. Road tax is £30pa against £300 for the SLK.

 

[s5tuart]

Not bad for 3 litre V6 thats 5 metres long and weighs almost 2500kg

 

[BillyBoy]

Not bad for 3 litre V6 thats 5 metres long and weighs almost 2500kg


View attachment 60904

Or my 3 litre straight 6

 

[grayb]

I would so like a 400d... Still too much money, unfortunately!

 

[BillyBoy]

I would so like a 400d... Still too much money, unfortunately!

It'll be worth the wait when you can afford it though. They are so nice to drive. Funnily enough, and maybe by design, they don't feel that fast at first, but unlike my 220d, there just seems to be more and more power as you push the accelerator down, and it doesn't fade away as you get faster and go up the gears - just keeps pulling and pulling

 

[Wighty]

It'll be worth the wait when you can afford it though. They are so nice to drive. Funnily enough, and maybe by design, they don't feel that fast at first, but unlike my 220d, there just seems to be more and more power as you push the accelerator down, and it doesn't fade away as you get faster and go up the gears - just keeps pulling and pulling

That description has just made me want one of them now buddy

 

[Zolly]

Well Just a little update . As Blobcat said I had forgotten about my windows which are invariably open all the time and on checking my tyre pressure it was way to low.
Once these are done we’re sorted my MPG came up by an extra 4mpg taking it to an average of 35 which I can live with .

What I have found and surprisingly was a nice one. Is that even though it’s a 180+ HP engine it really pulls more so than my W204 diesel ever seemed to do. Like I said it’s years since I last drove a petrol so I can’t really compare. But thanks to this forum I am a relatively happy bunny

Thanks