I am about to purchase a new Merc but cannot decide whether to go for really good MPG or performance with reasonable MPG. Firstly, I would love to know if anyone can tell me what I can expect to get to the gallon with the 350d if driven steadily? Secondly, does wheel size make a difference in MPG? If so why? If the wheels are larger, the tyres are smaller so that the overall diameter is the same. Going back to economy, if I do decide to go with the 220d SE/AMG what economy is possible with this new aluminium engine?
Thanks

Isn't the E350d engine the same as I have on the V222 S350 Bluetec? My average fuel consumption for the current mileage (30 000 km or so) is 6.1 litres/100 km. This is the true figure, the cluster reading is 5.7 l/100 km.

I guess a larger wheel does not make much difference but larger wheels usually come with wider tyres that decrease fuel economy. Difficult to give any exact numbers though.

Absolute mileage depend too much on conditions, how the car is driven etc. The official mileage figures give a good idea of the fuel economy difference between different engines.

Don't you want to wait for the new I6 diesel instead of the current V6?

Dont think the E350D is the same engine as the one you are quoting. converting 6.1L/100km to MPG shows 38mpg. The quoted figure is about 55mpg which is about 4.2l//1000km. Now i know that all motor manufacturers lie, but I would have hoped for a real world economy of 50mpg.

Regarding the wider tyres affecting economy, well that does make sense. It's a shame cos if I want to go for the E220d AMG then I lose about 5mpg instantly. I drive about 30,000 miles per year and if I don't say sod it and go for performance, i would like the stunning economy of the E220d SE.

You speak about an I6 Engine. Is this coming out soon for the E-Class? Forgive me for being ignorant but what is the advantage of the I6 over the current V6 please?

It is being introduced in the US late this year in the MY19 CLS. I don't know about the EU schedule, but the EU get products before the US. Here is an article about the engine.

I went with the E220d. Running on cruise control at 100 km/h for a sustained period, with some hills and curves, as well as slowing down for some built up areas, I achieved 4.8l/100km. It was as low as 4.3 before I struck the hills.

At that speed you could be in 9th gear for even better economy (at least in the US E300).

Well, I thought you were talking about the current V6 E350d. Useless to ask experience about the coming I6.

The 220d figures are what I can easily reach on a road trip (we would need to know the "calibrated" fuel consumption figures based on actual fill ups). Would expect the new I4 be more efficient, it probably is but real life consumption figures difficult to compare.

The below is all in miles per Imperial gallon (I'm in the UK). Using honestjohn.co.uk real mpg section it shows the E350d averages 37mpg, the E220d 51mpg. I've got an E220d AMG and that's pretty much what I get over the year. Less in winter, I'm getting mid 40s at the moment, more in summer. These are actual tank full up figures, not relying on the trip computer which overestimates mpg by about 3 to 5 mpg on mine.

On a run sticking to legal speed limits it'll nudge high 50s. I tend to cruise at 76mph or more as that's the lowest speed mine will reliably hold 9th gear. Easy 50 plus mpg on a typical run doing that.

The new 2 litre engine is very good, it has decent pick up and over taking power but it's never going to be as outright fast or smooth as the 350. However, for all the extra fuel you'll spend and the extra cost/depreciation for the 350 compared to 220, you'll really need to cherish that difference in performance to make it worthwhile. And if that's the case, why not try a 535d (540d depending where you are), fair bit more power for similar mpg.

You won't lose 5mpg due to different rolling diameter and tyre width, it will be a much smaller difference unless you're doing slow speed trips. Aero drag is a bigger impact on mpg at speed than rolling resistance.

Also, if you haven't tried both AMG and se you need to do so. I hate the 19 inch run flat tyres with a passion that come on the AMG line. I love the artificial cow dash covering that AMG line brings as well as the black ash (which can be ootioned on SE) but the se rides so much better. Less fidgety, quieter, calmer all round.

Interesting! I had a MY18 E300 loaner and it locked into 9th gear at about 55 mph on an in-town 3 mile bridge I was crossing with a 65 mph speed limit. I rarely exceed the speed limit in town.

From memory I think 9th gear in the little diesel is only pulling just shy of 1500rpm at 76ish mph. Even with a bit of downhill gradient it won't shift in to 9th noticeably below 70. I guess petrols are geared differently to suit their power band.

Just had a look on https://www.car.info/en-se/mercedes-benz/e-class/e-class-sedan-20-a-2018-16242845/specs. Suggests both e220 and e300 have identical gear ratios. But the petrol peak torque starts at 1300rpm, the diesel doesn't start to peak till 1600. Possibly why the diesel needs more Revs and thus higher road speed (if ratios are the same) before it'll select a bigger gear.

What model do you have? SE or AMG? What size tyres do you have?

Thanks. Good info

That is really good feedback. Thanks.
I think you are right, I need to stick to the E220D. Question is, do i go for the SE or AMG line? The latter looks slightly better, has nicer wheels (the ones on the SE are pretty dull), however the tyres seem to hit the mpg quite heavily. 5 MPG or so. I am a tight Yorkshireman and if i am going to forego the power that I currently have in my A6 Allroad, then I want summat pretty special in terms of economy. My job involves a lot of driving in the Lincolnshire Fens, which is extremely rural and flat. I was hoping for 60mpg in reality on a nice steady 56mph average run. Perhaps I am in dream world.

On a different topic, what extras would you go for and what would you ignore? HUD and Drive pilot are an absolute must, as is the 360 degree camera and suspension upgrade. Oh and I will be having the command line display. Anything else?

Thanks

Interesting.

So what you are saying is that it is more like the AMG bodywork that is affecting the MPG rather than the tyres. Now that DOES make a lot of sense.
This makes the decision all the harder. Money is not an issue as it is a company car, but MPG is important. then again driving enjoyment is also really important and that flattened steering wheel on the AMG does look lovely. I am a fickle person.

It may very well just be my car but if all 19 inch AMG ride the same I would steer well clear due m due fenland use. Those roads are typically a bit uneven with lovely ditches at the side and mine, at least, moves around so weirdly on such roads it would make the SE a no brainer.

The AMG does look better, wheels are lovely, front brakes look great but as I said, if I had the choice now I'd get se wheels/tyres all day long.

Options? Drive pilot well worth it. The 13 speaker Burmester stereo is great. I love the multibeam lighte and the pan roof gets more use than I ever thought it would. So basically get premium plus spec if you can. HUD seems a waste of time to me, but 360 camera, which I don't have, would be a good choice.

60mpg at 56mph on pancake flat terrain like the fens will be achievable in warmer weather. Maybe more. I shadowed lorries up the M1 one day and was mid sixties.

Good info.

SE it is then

Thank you for the advice.

Hope to place the order shortly.

Thanks again.
Chris