From: noel shelley (noel@shelley1722.freeserve.co.uk)
Date: Sun May 02 2004 - 02:42:20 PDT
Gentlemen ,
Allow me to make a few comments on this one !
Fuel economy is affected by many factors some obvious others not so .
Firstly for best economy the fuel must be burnt at the right mixture ,
obviously if to rich it will use more BUT if the mixture is to weak it will
ALSO burn far to much as what is there is not burning properly and so
requires greater quantities of weak mixture , the symptoms are poor
performance and high fuel consumption .
This was born out by my trying to get better than 15MPG out of an Austin
Champ , a 13/4" SU carb was fitted , I gave up, 10MPG and lousy performance
. The makers settings were right and I couldn`t improve on them , ------a
Champ does 15 to the gallon !
Secondly SHORT runs from cold , a 130 ci {2 L } gas engine doing only 9MPG
,normal journey length 5miles or less . The engine was stripped , nothing
was wrong , rebuilt . Soon after it did a round trip of 500 miles on fast
roads and returned 28 MPG . back to base and short runs again it was giving
9 MPG .
The economy of a diesel is down to two main factors , fuel injection is far
more precise in metering fuel charges than a carb , and much higher thermal
efficiency of the compression ignition engine . A small gas engined truck
was fitted with replacement diesel and went from 13 to 25 MPG .
Just a rough outline Noel
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