[W126 Coupe] Fuel Requirements or How Can I Adjust 1989 560 SEC To Use 87 Octane

[Steve Nervig]

One thing that affects octane requirements is compression ratio. If  
your compression ratio is 10:1 or above, 91 might be the lowest you  
should go at sea level. If I remember, the US 560 is a bit lower;  
9.something:1, right? In that case I would suspect that the mid-grade  
might be fine if you are not really loading up the engine.

Another thing that affects octane requirements is altitude. As you go  
up in altitude, your octane requirement goes down. In the high  
desert, you might get away with 87, certainly 89 or 90.

But, like others have said, I just can't get excited with trying to  
save a couple of bucks in this situation. I'd rather be listening to  
ZZ Top then worrying about listening for a ping.  And I'm not sure  
that much is saved, because I think I get better mileage with Premium.

Regards
Steve Nervig
1992 300CE Sportline 10:1

--
I feel so much better now, since I gave up hope.



On Apr 27, 2006, at 9:42 AM, XKEOTS at aol.com wrote:

> Hi All,
>
> I am sure, any of us here in the USA, are not happy with the  
> current fuel prices. Also the fact that we have to use Super in our  
> 560 SEC's.
> I recently picked up a 1980 450 SL as it uses 87 octane and the  
> mileage is better than the 560. (I have no intention to sell my 560  
> SEC. It is the best car that I have ever owned and I have owned  
> over 100 cars)
> Is there any way to make our 560's run or 87 octane?
> I couldn't believe yesterday when I put in 12 gallons of fuel and  
> it cost me $42.00.
> I was always under the impression that fuel injected cars need a  
> lower octane than carbs.
> Any help or thoughts on this would be greatly appreciated.
>
> Thanks
> Jack Miller
> 1980 450 SL
> 1989 560 SEC




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