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petrol usage

Started by Maat1985, 31 August 2009, 06:52 AM

Papalangi

#30
For a very detailed odo repair method, check this out.

See the gear in figure 15?  Instead of taking the whole thing apart, I put a drop of green Loctite on the shaft and twisted the gear back and forth a bit to spread it.  Green Loctite is a wicking type that does not need the joint to be disassembled prior to applying it.  It's been working over three years now and the '76 280C I fixed the same way lasted until it was stolen by the City of Seattle.

In the states, a cheap GPS can be had for under $100.  Might be a reasonable odo substitute.  It's how I can up with my original milage estimates when we drove the car home from Dallas Texas to Seattle Washington.  Did about 17MPG at 85MPH.

Michael
'83 300SD, I'm back!  It's the son's new car (12/2020)
1976 450SEL, 116.033  Sold it to buy a '97 Crown Vic.  Made sense at the time.
1971 250C, 114.023
1976 280C
1970 250/8

flutes

I need to have a chat with my mechanic ... with a well-serviced '77 450SEL I'm lucky to get 350 - 400km per tank.  I do drive, um, enthusiastically but this seems pretty poor compared to what others are getting...

Can anyone else with a 450 add their thoughts?
Matt
1977 450SEL

TJ 450

Over 20L/100km is certainly on the high side. Enthusiastic driving around town might result in this sort of thirst, as will frequent cold starts though. If you are doing mainly country driving, then I would say a checkup is needed.
Maybe you just need a new air filter element...? I would check that first.

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

13B

There's a chart in the glovebox handbook for the W116 (non-6.9 and non diesel models) that shows the fuel consumption of the three engines (280, 350, 450) for moderate driving over a normal speed range and they are all within 2mpg of each other.

As young man interested in buying one of these cars I rationalised that the 450 makes the most sense as it has a lot more power and torque than the 280 and only uses a little bit more fuel.

Road & Track mag in the 1970s found the 450 returned 13mpg, and the 280S returned 15mpg.  A few years later when the 6.9 was released they found it also returned 13mpg, so thats why I drive one now... I get more or less the same economy as 450 drivers, but loads more power and torque on tap.  By 1978 R&T has pretty much said if you want better economy in the W116, go for the 300SE - 24-25 mpg and quicker than a 280S.

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

TJ 450

I would have to agree totally. It's funny how people automatically assume that the 6.9 should use much more fuel than it's smaller engined counterparts.

In my case, I'm pretty sure that the 6.9 uses less fuel than my 450. The condition of the drivetrain is better.

In a couple of weeks, I'll hopefully be taking the 6.9 on an 550km economy run out to Bencubbin... it should be a good test. This is weather depending of course and yes, I'm afraid it is going to be driven on unsealed roads. ;)

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

13B

Tim, if you can keep the car in the 100-120 range you should be able to do it in 1 tank.

A few weekends ago I had a return run to Winton (450km) which I sat on 120 with the occasional burst to 130 which used about 3/4 tank petrol.  I reckon 550km would be about its range in this situation, if you can resist overtaking everyone in sight (my vice).

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

TJ 450

Excellent, that actually sounds quite reasonable.

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

flutes

Thanks Tim.  Most of my driving is around town, and had certainly been from cold starts as well.

I've been using regular unleaded - based on comments here I'll try premium and see how that fares.

Regards,
Matt.
Matt
1977 450SEL

Maat1985

i have a new 2nd hand MPS ready to install to my car the only reason i have not done this yet is cus then it needs tuning.... however given the fact that i have just noticed under high revs my car blows grey smoke and smells like a 2 stroke lawnmower and therefore realised just how rich it is running.... so i am going to put the other MPS cus i figure it has to be better tuned than my broken one surely....

what i do need to know is when i do tune it is it as simple as measuring the exhaust gas under different revs and adjusting the screw on the MPS accordingly....
DRIVER - 1977 W116 280SEL Orange....
PARTS - 1977 W116 280SE White....
DECEASED - 1977 W116 280SE Maple Yellow....
DECEASED - 1976 W116 280SE Green....

13B

Hi maat, the mixture isn't adjusted from the MPS, thats set at the factory.  The mixture is adjusted at the ECU (inside the kick panel in the front passenger side footwell).  Not many people remember thats where the ECU lives and try to get the car running right by adjusting the MPS - bad move.

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

Maat1985

DRIVER - 1977 W116 280SEL Orange....
PARTS - 1977 W116 280SE White....
DECEASED - 1977 W116 280SE Maple Yellow....
DECEASED - 1976 W116 280SE Green....

Maat1985

moved this here Link as i thought the smoke and smell might actually be another issue and requires a new topic....
DRIVER - 1977 W116 280SEL Orange....
PARTS - 1977 W116 280SE White....
DECEASED - 1977 W116 280SE Maple Yellow....
DECEASED - 1976 W116 280SE Green....

Zagato

I get 7 - 8 MPG in the city, and I'm talking dense traffic, and 13 - 14 mpg on the highway.

OzBenzHead

Quote from: Zagato on 03 October 2009, 12:18 AM
I get 7 - 8 MPG in the city, and I'm talking dense traffic, and 13 - 14 mpg on the highway.

Zagato -- do you use "real" gallons in Canada or US gallons?   That sounds like terrible consumption, but if it's US gallons (3.7+ litres) it's not so bad as if it were Imperial gallons (4.5+ litres).

Also, is your engine high- (Euro) or low-compression (NA), and what grade of fuel are you using?
[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]

Zagato

QuoteZagato -- do you use "real" gallons in Canada or US gallons?   That sounds like terrible consumption, but if it's US gallons (3.7+ litres) it's not so bad as if it were Imperial gallons (4.5+ litres).

Also, is your engine high- (Euro) or low-compression (NA), and what grade of fuel are you using?

I believe I used US gallons to calculate it. Normally we do ?L/100km in Canada, but my car is American spec with American dials. So miles used for trip computer.

Don't know about compression, it's a 1974 model in US-spec. So I'd assume low compression.
I use 91 Octane fuel, as the owners manual recommends. In my country, the only octane ratings higher than that are 92 and 94.