Fw: [Diy_efi] The Hunt effect

[Bernd Felsche]

On Monday 10 October 2005 08:44, Don Sauman wrote:

> Does this apply when Premium ULP (98 octane) in Perth is between 8
> to 10 cents per litre dearer than standard ULP (93 octane). I have

7 cents around here; last I checked.

> 5 lt V8 VN that is giving a freeway mileage (kilometerage???) of

fuel consumption. :-)

> 12.7 l/100 km on standard ULP driven hard. Do you think I would

Since when can you put in any freeway km driven hard around Perth?
:-)

> see at that rate any cost benefit in moving to Premium ULP.

The engine is sufficiently-new so that it should be able to take
advantage of the higher Octane.

Depending on your driving style, it might take 2 tank-fulls to get
the full benefit. City driving with low Octane in a high-output
engine tends to gum up the work a bit. An "Italian tuneup" can be
used to blow out the cobwebs earlier; but don't try it unless you
know that the engine is in otherwise good condition.

Changing from ULP to PULP reduced fuel consumption an average of 10%
on my Golf GTI (1990 model); which made it worthwhile even when fuel
cost around 80 cents/litre. The change from PULP to 98 didn't make
what I would rate a significant difference in terms of fuel
consumption, though it did delay the onset of ping/knock.

The 98 RON is a nominal figure btw. I've been informed by some
people in the industry that the actual fuel batches are closer to
100 RON, sometimes even on the high side.