add 8-10° of advance with LPG

Phil Lamovie phil at injec.com
Wed Apr 10 15:03:20 GMT 2002



This is a good point.

Petrol powered ignition has a much broader range of
variation in timing vs rpm. You may start with 10 deg
at idle and finish at 40 deg WOT at 6000 rpm.

The same rev range with lpg would be from 20 to 30 degrees.

Mix the two together and it's faster than the sum of the components.

Much anecdotal evidence is not well analyzed. That's not
to say that the data is wrong.; but that very often the "why"
is a stab in the dark.

Resellers are generally confronted with gas guzzlers
not 1100 cc 4 cyl. These GG's have big bores and flame
propagation does take time. It's the increase in bore size
together with low compression that causes the need for
the extra advance. (don't forget other sins such as domed pistons
or valve cutouts) these help cool / quench the flame.)

If the engine was designed and built for Propane injection
then we would be able to say something about the fuel
and it's characteristics. Most engines are simply not completely
suitable for the fuel on an as is basis. But money is a very powerful
advocate.

Try putting diesel in a petrol engine and you could safely assume
that it really doesn't work at all. (the fuel that is !!)

Phil

----------------------------------------------------------------------------
To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes)
in the body of a message (not the subject) to majordomo at lists.diy-efi.org




More information about the Diy_efi mailing list