Interesting link on Engine Codes...

[Aleksander Mierzwa]

At 12:39 00-11-22, quk at isham-research.freeserve.co.uk wrote:

>No Audi engine has needed lead for at least two decades.  The MB and 1B
>specifications SPECIFICALLY state '95 RON unleaded'.

I didn't mean to impose that these engines require leaded fuel, just higher
octane rating. I believe in the early 80s unleaded fuel was still not very
popular in Europe, that's why I said leaded. Is the 95 RON the
"recommended" or "minimal required" octane rating for MB and 1B?

>US octane ratings are different from European ratings.  European 95 RON
>is usually the same as US 91 octane - the North American rating is
>actually AKI (anti-knock index) and is the arithmetic mean of RON and MON.
>
>In Europe, MON is not published for most fuels but tends to be in the
>high 80s.
>
>We're using the same fuel.

I realize that. All cars sold in the USA are required to be able to operate
on 87 AKI = 92 RON fuel. No such regulations ever existed in Europe. Over
here you can't even buy 92 octane, it starts with 95. Many older European
high performance cars require nothing less than 98 RON, or at least 95.
That's why they had to be detuned for US market.
I believe some late model high-performance Audis (S6+ comes to mind) still
require 98 RON (unleaded of course) to achieve nominal output.
--
Aleksander Mierzwa
Warsaw, Poland
87 5KT