[Vwdiesel] Octane and Cetane Comments

Wade Yorke wade at carsand.com
Thu Aug 25 20:34:52 EDT 2005

What Octane to Use:
We have a monthly automotive call in show on CBC radio in the Maritimes 
hosted by a former automotive instructor and now an automotive 
consultant.  His explanation is as follows:
-Use the lowest octane fuel that is recommended for your vehicle or you 
are simply wasting money
-High octane fuel as a burn suppressant which allows the air/fuel 
charge to reach a higher temperature (in a high compression engine) 
without pre-igniting
-High octane fuel actually yields less energy when used in a low 
compression engine since the fuel does not burn as efficiently

Comments on Cetane Improvers:
If you have never used a cetane improver in your diesels, give it a try 
and you will be in for a treat.  I have been using it for the past 
5,000kms and while I have never conducted fuel consumption tests 
(virtually impossible to due accurately) the engine runs much smoother 
and no smoke on missing on start-up.  I use the Stanadyne Performance 
Formula and Lubricity Formula.  The lubricant will become even more 
important next year when most of the road diesel fuel will be ultra low 
sulphur at 15ppm as opposed to the present low sulphur at 500ppm.  The 
fuel is hydro treated (hydrogen gas) to get to 15ppm and this removes 
the lubricating properties.  I am not sure if the sulphur provided the 
lubricating properties or if there is some chemical change with the 
hydro treating.
Here is a link to the Stanadyne site

Wade Yorke
Nova Scotia
'84 Westy 1.9TD

More information about the Vwdiesel mailing list