calculating difference not that easy..
Air fuel ratio is 14.7 in ideal conditions but for lpg the ratio is 17.1 and their calorific values depends on the type of fuel and mixture of LPG ..
By mass, that's correct, although at maximum power you need to be running about 12.5:1 on petrol for best power (and to avoid melting things) and the same goes for LPG.
A given mass of petrol takes a much smaller volume than a similar mass of LPG vapour, though, and this is what limits the power available from a conventional SGI system.
so the only real way is to check on dyno for some specific LPG and fuel..
Agreed. I need to get my little black box out and test it on
the A32 my private test track one day. It's certainly a small enough power drop that it's not noticeable when driving.
Kevin