[alfa] Re: Fuel economy vs. RPM

[Keith Walker <100662.3423@xxxxxxxxxxxxxx>]

>>Maybe this is elementary, but:  At what RPM is the two liter motor most
efficient?  Asked another way: At 50 MPH should I drive in 4th at 4000
RPM or 5th at 3200 RPM?  Those numbers are rough estimates, but you get
the idea.<<

General rule of thumb is that an engine is at its most efficient on full
throttle
at peak torque. Trouble is that it is unlikely to maintain those revs. The
throttle when anything other than fully open will restrict the airflow into
the engine and increase pumping inefficiencies.

The main killer I find for fuel consumption is acceleration. For example on
the lhd 1.3 carbed Alfa 33 I have floating round, a steady motorway run
sitting about around 90mph will return about 40mpg (imperial gallons).
Used round town in stop start traffic and it will be lucky to manage
20mpg.

All the best

Keith
--
to be removed from alfa, see /bin/digest-subs.cgi
or email "unsubscribe alfa" to majordomo@domain.elided