At 08:05 PM 2/5/2012, Dave Mcneely wrote:
>and are there if at all, for marketing reasons.  mcneely

I can't agree with that.  At the time our vans, at least the earlier
ones, were being made, fuel injection was becoming common and
injector clogging was a problem because of insufficient detergents in
gasoline; and various car makers specified acceptable brands/grades
for use in their vehicles.  BMW developed a testing standard and
classified brands as acceptable or not based on that standard.

Naturally this situation would not go on forever as fuel injection
became ubiquitous, and as far as I know all gasoline now sold
contains enough detergent to eliminate this problem.

I'm with you on Shell's "nitrogen" marketing.  Is the stuff
inert?  Is it explosive?  Does it increase NOx emissions?  Curious
minds would like some explanation beyond "Now!  With NITROGEN Wheeeee!"

Yours,
DAvid