Need for Higher Octane Fuels

[rgrewar]

We have recently purchased a 1970 250 and have been told to only use high-grade (higher octane) fuel.  Is this really necessary? The car seems to run the same regardless of the fuel we use.  What is the advantage to using the higher octane fuels?  Also, is it advisable to use fuels containing ethenol in this older Benz.

[Peter van Es]

I mostly use 95 octane, and once in a while, 98 octane. Do not use fuels with more than 5% ethanol... it's bad for your old Benz. Just search the forum  for Ethanol to find loads of threads.

Check this post: http://www.sl113.org/forums/index.php?topic=11150.msg74455#msg74455

Peter

[Raymond]

Unfortunately here in the US 10% and 15% Ethanol fuels are almost all you can find.  The only station I can find that sells ethanol free fuel only has 87 Octane and costs as much as Premium.  Mostly it's for boats.  I haven't tried it in the Pagoda.  So far, though I haven't suffered any ill effects from the Ethanol except that the fuel mileage is worse and it stinks a bit more.