Thanks for the rapid information Vic and to all the others who have posted
interesting comments here

The gps input helps measure the actual speed made good over the ground which
is needed for calculation of best speed for fuel consumption in litres/km
relative to the ground which is what I'm interested in (ie starting and
ending points of my trips are attached to the earth!)

Graham

"Vic Smith" wrote in message
...
On Fri, 04 Jul 2008 06:27:42 GMT, "Graham" wrote:

Does anyone know if these gauges display miles per gallon (or litres per
km)
or just miles travelled and gallons consumed?

Do they need any special interface to work with standard GPS's like a
Raytheon chart plotter?

Thanks, Graham

Check this - don't know if it applies to yours.
About halfway down is pic.

http://www.thehulltruth.com/forums/t...tart=1&posts=1

--Vic