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fuel comsumption on 280

Started by aus280, 06 February 2008, 03:08 AM

OzBenzHead

Quote from: aus280 on 08 February 2008, 03:52 AM[...] what fuel do you guys use by the way?

Only ever 98 RON
(Ultra Premium) - usually Caltex Vortex 98 and, whenever possible, from the same servo (there's only one of my towns' four Caltex stations that serves 98, and then  from only one bowser).

No additives or boosters.  And because I don't like to run stale fuel, I top up weekly rather than fill the tank, say, monthly, because modern fuels go off very quickly - in summer it can be as rapidly as two weeks. 

I do not drive like a pensioner, either - but neither do I burn rubber or hoon it.   On the open road I regard the posted speed limits as minima provided the conditions allow.

When I acquired this 116 three and a half years ago, I replaced the injectors and high-tension leads - and a number of other items just to be sure the car was in top condition.

It had then done about 230,000 km; it has now done 300,000 km.  It has been well maintained - by the book - by (mostly) M-B specialists all its life (I have almost all service records from new, despite being the car's fifth owner).

Apart from probably needing new valve-guide seals sometime in the next year or so, it's hard to fault mechanically.

I run on 205/70x14 tyres on standard 14" bundt alloys.

I am frequently amazed at the terrible fuel consumption that other 280SE drivers claim to get.  Why their consumption is so high I've no idea. My highway consumption is pretty well spot on what the factory suggested it should be when new.

(Around town it increases considerably, but that's to be expected.)
[img width=340 height=138][url="http://i12.photobucket.com/albums/a215/OzBenzHead/10%20M-B%20Miscellany/OBH_LOGO-2a-1.png"]http://i12.photobucket.com/albums/a215/OzBenzHead/10%20M-B%20Miscellany/OBH_LOGO-2a-1.png[/url][/img]

13B

They used to say to us in order to get the best economy, drive like there is a raw egg between your foot and the accelerator pedal.

My experience is that this is only really possible with V8s because if you drive that way with 4 cyl or rotary engine cars they are so down on low-speed torque you end up holding up the rest of the traffic... modern 6 cyl cars I better I guess but I'm going to risk being flamed here by saying that the 280 doesn't have enough low end torque to easily feather it around....

450SEL 6.9 #5440 = V MB 690 , 450SE # 43094 = 02010 H , 190E/turbo # 31548 = AOH 68K

Martin 280s

#17
Quote from: OzBenzHead on 07 February 2008, 07:19 PM
Quote from: Martin 280s on 07 February 2008, 05:53 PM
I get about 800Ks from a tank of fuel, and my blue lady has a carb...so not as frugal.

Martin:  You are the first poster to this and related threads whose 116 I6 seems to get fuel consumption similar to my Boris.   The consumption I get is in line with what was claimed by the factory to be the expected figure, so I don't know how it is you and I are the only 116 280 owners to enjoy that kind of (relative) economy.  And yours, particularly, is good because it has carby rather than injection.  A friend of mine got rid of his carbied 116 280S because he couldn't do better than 400 km per tank.

Yes, I am fanatical about servicing (at every 5,000 miles rather than the recommended 6,000), use only the best consumables, and run my tyres at the top end of the recommended pressures (36 psi for light duty and 38 psi for long, fast highway runs).

My 280SE also came fitted with a FuelSaver device.  Although I'm usually sceptical of such devices, it causes no problems so I've left it in line.  I've no idea how or if it affects my consumption, but as I'm happy with the status quo I'm not voluntarily changing it.

OBH,
I am fanatical about maintenance too. I also keep my tyres at the correct pressure and try to use 'good' quality fuel.
On a foot note here, Brazilian fuel has a 60% gasoline 40% Alcohol mix but, this can vary and I do add 1Lt of 2/stroke to every tank of fuel, even in the W124. 
I also do my own maintenance, unless I don't have the necessary tools or skills. However, I prefer to do things myself because I trust myself as I DO know how the job was done. Last year I overhauled the carb, put in slightly bigger main jets and blanked off some of the vacuum lines and that really made her sing without detrement to consumption.

A well-kept six shouldn't be so heavy on fuel, Over the years I've had 6 6-cyl cars (2x 2.8lt, 2x 3.0lt, 2x 4.1lt) and, quite frankly, enjoy similar economy to 2lt 4-cyl cars.

OzBenzHead

Quote from: 13B on 08 February 2008, 05:30 AM
They used to say to us in order to get the best economy, drive like there is a raw egg between your foot and the accelerator pedal.

Yup - know that one. More relevant to carbies than to injection, I think.

QuoteMy experience is that this is only really possible with V8s because if you drive that way with 4 cyl or rotary engine cars they are so down on low-speed torque you end up holding up the rest of the traffic... modern 6 cyl cars I better I guess but I'm going to risk being flamed here by saying that the 280 doesn't have enough low end torque to easily feather it around....

No flame - I agree.  I use the stick and a heavy-ish foot (but am not violent in accelerating, just "brisk") when I want to get somewhere - like overtaking. Around town I don't use the stick, but still manage to be ahead of the pack wherever conditions allow. I believe in reaching cruising speed asap (within reason).

My lighter I6 Benzes - W108 280SE and W111 220S - are both somewhat brisker off the mark.   The 108 is not a helluva lot lighter than the 116, but it has no power-sapping torque converter; the 111 is more than 300 kg lighter and also has no t/c.   Neither of those cars requires as much stick or as much foot to get them moving as does the 116 (but they are both far thirstier: the 108 about 15% - 20% more, and the 111 about double with its twin dual-choke Zeniths!).

I'm about to be able to ascertain the consumption of my ultimate land-barge, the W112 300SE coupe - for which I obtained H-plates today after two years off the road.   I'm not expecting great economy from that beast - but what the hell, it's only an occasional  weekend cruiser.
[img width=340 height=138][url="http://i12.photobucket.com/albums/a215/OzBenzHead/10%20M-B%20Miscellany/OBH_LOGO-2a-1.png"]http://i12.photobucket.com/albums/a215/OzBenzHead/10%20M-B%20Miscellany/OBH_LOGO-2a-1.png[/url][/img]

Andrew280SEL

I dunno....

The 280 isn't that quick off the mark (Unless you ram it into L and floor it  :o but that's not exactly economical I guess...) and requires more pedal than others I guess but I find once it's actually rolling, my 280 just moves along pretty easily even at low speeds.

In fact, the problem can sometimes be keeping the car under the speed limits, because it seems to always want to go faster- it's very eager, surprisingly. Mostly once the revs start going towards it's 'sweet spot'.

Certainly if your doing 100-110 km/h, you barely have to touch the throttle in the 280.
'79 280SEL- 560,000 Kms
'73 350SE- getting an AMG facelift
'79 450SEL 6.9

OzBenzHead

Quote from: Andrew280SEL on 08 February 2008, 05:54 PM[...] In fact, the problem can sometimes be keeping the car under the speed limits, because it seems to always want to go faster- it's very eager, surprisingly. Mostly once the revs start going towards it's 'sweet spot'.

Certainly if your doing 100-110 km/h, you barely have to touch the throttle in the 280.

Agreed.  On the open road my 116 just wants to boogie, and if I'm not very careful to keep an eye on the speedo I can be going far in excess of the legal speed.  Its sweet spot in top gear starts at around 110 km/h. Pull the stick back a notch and give it some foot and it leaves the majority of others - which might have more impressive low-speed acceleration but which run out of breath at overtaking speeds on the highway - for dead.

And of course there's nothing quite like the song of that twin-cam motor working hard.   ;D
[img width=340 height=138][url="http://i12.photobucket.com/albums/a215/OzBenzHead/10%20M-B%20Miscellany/OBH_LOGO-2a-1.png"]http://i12.photobucket.com/albums/a215/OzBenzHead/10%20M-B%20Miscellany/OBH_LOGO-2a-1.png[/url][/img]

mabryt

I am green with envy at your reports of such outstanding mileage (as we say here in the states). 

The engine on my '79 280SE is now in perfect mechanical condition (new plugs, cap, rotor, wires, rockers, lifters, fuel pump, fuel accumulator, fuel and oil and air filters, etc.) and it is my daily-driver commute car. 

My drive is a bit more than 8 miles (13 Km) in each direction, and I take a route through a beautiful park in Washington, D.C., though the entire trip is start/stop driving.  I only use the highest octane gas/petrol, yet I just figured out that my fuel consumption is about 13 miles per US gallon- that's less than 6 Km/liter!!!!  Any ideas on what is sucking down the fuel, other than constant start/stop driving?
1977 280SE - Silver Green

aus280

well mines sitting on half a million kilometres i have just changed the oil and usual service bits, since ive owned it i have always used 98ron fuel guy before me was 80 years old and had it since new so that says something with the condition of the car as outside is immaculate and interior is pretty good

Betsy

Since reading this forum i have only ever put the Caltex 98 or the BP 98 in my 280 and I reckon the power AND the fuel economy is better.

In city driving I am getting 480km per 85litres but the standard fuel was only giving me 425km.  Thats better than a 10% increase in Kms and the cost is under 10% difference in many cases.

The car seems much more "spirited" to me on the 98.   Makes perfect sense I suppose.

When I was flying the big radial engined aircraft 20years ago we ran 145 octane and got much better range and happier engines!

Now I wonder where can I get a little  145 octane for my 6.9  ;D

John

arman

#24
I use 98 octane (super unleaded) in my 450 SEL with an additive for the missing "lead". When I drive on the highway (speed: 110km/h, constantly a couple of hours) travelling somewhere, my fuel economy is almost like the manual booklet says: about 14 liter per 100km. Prior to these longer trips I check my tyres/tires and have them on 2,4 Bar (~35 PSI) all around (14 70 205). This results in about 600km on 83 liter.

I change my air filter every 10 000km and engine oil and filter (almost) every year (engine oil Castrol 15W40).

BUT: I haven't changed the spark plugs for a long time (Champion) and only once since I own this car! This change is about 25 000 km ago. But I must add that I don't do city or short trip driving only. I think it is not so good for this oldy: condense water in engine oil, condense water in exhaust pipes (corrosion) and a really terrible fuel economy. If I drive to my work an back (two separate trips of about 25km) the fuel economy is down to about 520km on 83 liter.

In the manual the fuel economy for a 450 is said to be between 14-22 liter per 100km. Only if you drive a steady 80-90km/h for a long time you can get under this, I think.

But I will inspect the spark plugs this spring and inform you folks about the result.

Regards Arman
1974 W116 450 SEL 340.000km
Black exterior (040), olive green velours interior (966)
[url="http://gallery.w116.org/v/show_room/Armans450sel/"]http://gallery.w116.org/v/show_room/Armans450sel/[/url]

NAS_878

I got 700km for 80 Liter of fuel on my 1979 280SE K-Jet. (Average speed 90km/h, max 110km/h)

Sure no match for Martin 280s 800km!! Wondering how you tune your M110 to get such a great result? Or mind telling us more how fast you drive in order to get 800km? (hopefully not 60km/h lol)

My M110 just follow the usual IN 10, EX 25 Valve Clearance Setting.


allrock

my 280sel drives 4-6kms/liter if its city traffic driving and 10-12 for highway cruising..

s class

I get 600km on 85 litres in my k-jet 280SE, during my daily mix - and I accelerate hard.  I admit I get max about only 630 on a tank on the open road. 

A suggestion to those getting really poor consumption - check your valve timing (ie chain stretch) and very importantly, valve clearances.  This seems to have a big impact on performance and economy. 

In the case of k-jet engines, the WUR needs to be spot-on.  I have also found that if the thermostat is too cold - operating temp less than 82 degrees - the WUR sits permanently partially in warm-up enrichment mode, and give you 350km per tank instead of 600. 


[color=blue]'76 6.9 Euro[/color], [color=red]'78 6.9 AMG[/color], '80 280SE, [color=brown]'74 350SE[/color], [color=black]'82 500SEL euro full hydro, '83 500SEL euro full hydro [/color], '81 500SL

NAS_878

totally agree with s class

When I bought my 280SE 2 years ago, it was doing 4.5km/L ... guess what? Valva clearance was IN 5 EX 15  (default is IN 10 EX 25) and mixture was so rich (my new plug/cleaned plug always ended up with carbon on the tip)

Of course the old IN 5 EX 15 settings gives the engine more power & torque... may be that's the cause of the rough shifting gearbox.

Now it's doing 7.0 ~ 7.5km/L (city) & 8.5 ~ 9.0km/L (extra urban) and I am looking forward to make it 10km/L (extra urban)  ;D