WHY Low Octane???

["Al Powell" <APOWELL@agcom.tamu.edu>]

The author of the following quote shall be anonymous in my post, 
because I do not intend to criticize him personally....
 
> With modern Audi engines being equipped with knock sensors the timing 
> can be retarded to accomodate lower octane fuel fuel (87 RON).  My 
> 1993 100cstqw requires premium fuel according to the owners manual.  
> I have been running 89 octane grade without any appreciable 
> difference in performance.  I dont think there is any danger of 
> damaging the engine but, I think there may be a difference in fuel 
> economy.  I have only owned this car sine August so I haven't done 
> a comprehensive comparison of octane vs. fuel economy.
> 
> The Audi technician at the local dealer recommends 89(RON) but do not 
> go below this for fuel economy reasons.  I wonder though if the much 
> higher cost of premium generates enough of a gain in fuel economy to 
> offset the higher cost?

I have followed this discussion and confess to being absolutely 
confounded and confoozled as to why someone would buy a car designed 
to run with one level of octane, then try to run it in a manner for 
which it was not designed.

It is clear to me from the commentary that one can run a slightly 
lower octane than required in an Audi, and **provided that** the 
knock sensor setup is working, engine damage may be avoided.  
However, it reduces the car's performance and slows it down.  I 
seriously doubt that it makes any significant difference in fuel 
mileage.

If the knock sensor happens to **fail**, it appears likely to me that major 
engine damage can result, as the engine would then be running in a 
condition for which it is not designed.

So WHY would someone buy a superbly designed car which cost over 
$30,000 new, then reduce the car's performance and put it in a 
position to suffer major engine damage if the knock sensors fail?  To 
save a few cents on gas? IMNSHO, this makes **NO sense**.

Perhaps a VW Golf would be a more appropriate vehicle?  Runs on 
regular, has German parts!



+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Al Powell                        Voice:  409/845-2807
107 Reed McDonald Bldg.          Fax:    409/862-1202
College Station, TX 77843      
Http://agcomwww.tamu.edu/agcom/satellit/alpage.htm

"Some people can tell what time it is by looking at the
sun...but I have never been able to see the numbers."
             [From 5th/6th grade essays....]