WDB
Full Member
Posts: 7,427 
|
Post by WDB on Dec 3, 2017 6:03:55 GMT
Details. Pressures are correct; the E ran on 225x16 tyres (same compound as the 45mpg Volvo), while the CLS has 285x19s.
I think it's simple physics. 1.8t of car, plus 400kg of load, will take more energy to accelerate than a lighter combination. In that sense, four or six cylinders, two or three litres, is irrelevant; either engine has to convert enough energy to move the mass, and that energy has to come from the fuel tank.
|
|
|
|
Post by Humph on Dec 3, 2017 12:01:20 GMT
It could also be that here in the North West, due either to interminable miles of 50 mph restricted motorway, or indeed sheer traffic volume keeping speeds low, and vast stretches further north where there is little or no traffic a lot of the time, that my car is either bumbling along at 50 or cruising at an uninterrupted higher speed. Both of which scenarios lead to better mpg.
For example, my old Merc only had two sets of brake pads on it in nearly 200,000 miles and the current one, is now up to 60,000 from new with no need yet for any replacement pads. Tells you quite a lot about the traffic conditions it spends its time in. I do notice that further south, the conditions are much more often "stop start".
I'm not really buying the weight argument too much, the fuel consumption doesn't change much at all on mine whether it's packed to the roof or running empty, and for what it's worth, what I'm carrying is damned heavy, so I think it's much more to do with far fewer accelerations from rest in my typical journeys.
And the obvious thing of me being a smooth as a baby's bum driving God of course. That helps.
😎
|
|
|
|
Post by tyrednexited on Dec 3, 2017 12:22:01 GMT
And the obvious thing of me being a smooth as a baby's bum driving God of course. That helps. 😎 ...many a true word..... As an aside, I have for many years generally noticed an improvement in fuel consumption on Continental roads (and I've done a good few miles in vehicles where direct comparison can be made with the figures at home). The most convincing explanation I've ever seen was from a learned study (with all the underlying details and specifications) of road surfaces in mainland Europe and the UK respectively. The conclusion was that the tarmac specification used abroad, combined with the road-laying methodology, created a surface that had noticeably less rolling resistance abroad than that resulting from UK practice, and that the difference could account for a 5% or more improvement in consumption. Rolling resistance is something that every cycling muppet MTB enthusiast will be very aware of. As you were.... |
|
Avant
Full Member
Posts: 691
|
Post by Avant on Dec 3, 2017 17:45:01 GMT
Humph is clearly a very modest man, comparing his driving style to a dirty nappy. Perhaps he's just browned off with having only four pots.
|
|
WDB
Full Member
Posts: 7,427
|
Post by WDB on Dec 3, 2017 19:19:34 GMT
Let him brag. All that time in the car doesn't leave him time for much else in his life. 😢
Anyway, he's not the only one who's got 100,000 out of a set of brake pads - although he possibly is the only one to have done it more than once.
Back to fuel economy: cylinders cost you in fuel only when you make use of their extra capacity for energy conversion. At speeds and rates of acceleration that a smaller engine could match, a six is doing the same work - perhaps with a little extra to shift its own mass. I wouldn't go as far as some, by suggesting that the bigger engine is working less hard; it just sounds better while doing the same job.
|
|
|
|
Post by Humph on Dec 3, 2017 19:46:56 GMT
I know, and I'm so envious of all that spread sheet creation and alteration time I'm always missing out on. Must be so exciting.😉
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Dec 3, 2017 20:12:47 GMT
Interesting that the E220 only ran on 225x16 whereas my E350 runs on the smallest available for that engine being 245x17.
|
|
WDB
Full Member
Posts: 7,427
|
Post by WDB on Dec 4, 2017 6:29:29 GMT
My E220 was an S211, a design that dates back to 2002. Fashions in wheels and tyres have changed dramatically since then; 225x16 is for Corsas nowadays.
I admit that part of the reason for choosing a 220 rather than a 320 (or the rare 280) was that most six-cylinder 211s then came as Sport models, with staggered 18in wheels, which made me worry about replacement cost. I didn't know then that the E is surprisingly light on tyres for a heavy car. I imagine its suspension is well-enough designed to keep the tyres from working too hard, but whatever the reason, I'm hoping it applies to the CLS too, which has 255x19 at the front and 285x19 aft.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Dec 4, 2017 10:35:45 GMT
I've still got the S60 which can push 800 miles to a tank as a back up, how many tanks is that to the 540i ? It's over 3 tanks to the Focus - that gets 240 miles to a 52l tank. Two, if I cruise. 68 litres per fill. Got it up to 27.5 mpg now. Oh dear. Fuel economy anxiety is biting. |
|
|
|
Post by Humph on Dec 4, 2017 11:06:34 GMT
Yes indeed the E class, and presumably the CLS ( E class in drag? ) is very light on tyres. Approximately even wear front and back too.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Dec 4, 2017 12:11:49 GMT
Hmmm. Not sure. Looking more closely at my tyres, on which I have done 18,000 miles (out of 39,000 in total), I think they have all be replaced once but the front done at a different time to the rears. Certainly they were all at roughly similar depth in October 2016 (approx 6mm) but the service in 2017 indicated more rapid wear on the rears (down to within the 3mm - 4mm range), whereas the fronts are at 5mm. This indicates about 25,000 miles wear from the rears, but these are Conti's and I intend to replace with Michelins very shortly, which everyone says are simply much better.
|
|
|
|
Post by Humph on Dec 4, 2017 12:37:21 GMT
So, your back tyres are wearing prematurely, and your mpg is disappointing?
Think we've got the picture...
😉
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Dec 4, 2017 12:49:56 GMT
Well, you have to enjoy six cylinders sometimes  |
|
|
|
Post by Hofmeister on Dec 4, 2017 15:17:24 GMT
Two, if I cruise. 68 litres per fill. Got it up to 27.5 mpg now. Oh dear. Fuel economy anxiety is biting. Yeah, but my number is going up - good thing. Yours is coming down - bad thing (sorry to use Trumpspeak) |
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Dec 6, 2017 13:55:47 GMT
So the Silent Pool arrived yesterday just in time St Nikolaus today, just need to work out how to broach the subject of getting SWM to open the bottle to sample it.
Think it'll need to be a stiff one after pricing up replacement tyres for the Focus. 253€ each - 235/35x19 Michelin Pilot Sport Cup 2.
Considering the forged alloys and tyre pack was only 1000€ they must have thrown the wheels in for free.
|
|
