91 or 95 octane in 95 W124 E220?

[davekmoore]

The main handbook tells me to use 95 and the supplement says 91.

Which is correct?

 

[davekmoore]

Any thoughts??

 

[television]

These cars will run on 91 but 95 is better, just avoid too much hard acceleration when using 91

 

[syncropaddy]

Can you still get 91 octane petrol?

 

[television]

Can you still get 91 octane petrol?

That is all you can get in some countries

 

[davekmoore]

These cars will run on 91 but 95 is better, just avoid too much hard acceleration when using 91

Hard acceleration. In a big heavy auto wagon with a little 4 pot motor. I wish. Fortunately I also have a 300bhp Mx5 for the weekends . He's called BARMY.

But thanks for the thoughts. I'll go with 91 when I next get to half a tank and if no pinging (aka pinking) will go to a full tank of 91 next time.

Yes, 91 is available in Victoria and it's cheaper, hence the question.

 

[WDB124066]

Use 95. I think you will find your fuel economy will drop a fair bit if you use 91. Measure it and see........

 

[Ben Longden]

Use 95. I think you will find your fuel economy will drop a fair bit if you use 91. Measure it and see........

He's right.... My W124 says to use 95 octane, but Im in the habit of putting in 98.
I now average 70km more per tank of fuel, and the performance is so much smoother.

Bendigo, eh? Dave, We should have a meet!!

By the way, dont go for the discounted Safeway 95 (Caltex) fuel, as many mechanics here have noted injector issues from that. Use the BP or Shell brews.

Cheers,
Ben

 

[syncropaddy]

That is all you can get in some countries

Didnt notice he was down under ....

 

[davekmoore]

Ff I understand correctly then:

91 is ok but will sacrifice "performance"

95 is what's recommended

98 will add performance and/or economy

 

[Ben Longden]

Thats it in a nutshell, Dave.

 

[Alex M Grieve]

He's right.... My W124 says to use 95 octane, but I'm in the habit of putting in 98.
I now average 70km more per tank of fuel, and the performance is so much smoother.

Agreed Ben. I used to have a 190 carburrated car and the advantage of using 98 octane was obvious in performance and economy terms.

There is a lot of urban mythology on this subject, but I guess many MBs are so powerful, and the power is so seldom fully used, that it would be hard to spot any real difference.

In the 190 (and probably the 220) the difference should be clearly beneficial - and better mpg should soothe any anxieties about price.

 

[grober]

Use 95 Octane as that's what the car's ignition advance curve and compression ratio is designed for. The engine ECU will alter the ignition timing to allow the car to run on 91 octane but as has been said power and economy will suffer -possibly to the extent that any money saved on fuel will be negligible. It may also run hotter. With 4 cylinder engine hauling a W124 estate you want all the power/torque you can get!

 

[kth286]

The main handbook tells me to use 95 and the supplement says 91.

Which is correct?

check your handbook - it may shown an under bonnet adjuster setting device for low octane fuel.

 

[davekmoore]

Use 95 Octane as that's what the car's ignition advance curve and compression ratio is designed for. The engine ECU will alter the ignition timing to allow the car to run on 91 octane but as has been said power and economy will suffer -possibly to the extent that any money saved on fuel will be negligible. It may also run hotter. With 4 cylinder engine hauling a W124 estate you want all the power/torque you can get!

Tried some 98 yesterday. The car is less slow so I'll always be doing that in the future. Gearbox service next week will hopefully further improve it - sorry, I mean make it less bad, because for sure that drivetrain and body combination is never going to be fast!

In hindsight I should have paid more for a 6 cyl or a diesel but the E220 is otherwise soooo good and only $8000 with a decent 3 year transferable warranty. So I'll run it for 2 years, add another 300,00kms, and sell it with 12 months warranty still left.

Anyone ever tried any simple go-faster mods such as K&N filter?

 

[turbopete]

k&n filters make no difference, just add to noise levels and may even filter LESS effectively than the original.
a more free flowing exhaust may make a small difference, but to do much with that engine, it means spending bigger amounts of money, especially when its linked to an auto box