Hi there

A good friend has a 635csi with an almost brandnew M102 (3.2 turbo 252 HP) - engine. We can't really find any data on which type of fuel it needs.. The engine is euro-spec, and we can choose from 92, 95 and 98 octane, with and without lead-subsitute additives.

Any ideas?

Rgds, Lars Vestman, Denmark.

the m102 has a waste gate with maximum 12 psi boost.

So use 98 octane to prevent the knock detector from shutting off the boost.

Later,

Thanx. But do you (or anyone else) know whether it needs lead or not?

Rgds, Lars

there has been no leaded fuel in the USA since 1979.

I have a 1977 m10 built for lead and it is now over 500k miles and it is just fine.

No big deal as to leaded or not.