Posted: Fri Feb 20, 2009 10:55 pm
Sorry for the late reply but was a bit busy during the week.--ALPINA-- wrote:Whats it like with LPG? do you notice the fuel consumption is less? and also the power on LPG over petrol, do you feel any loss in power?
LPG on the 2002...
Fuel consumption
8,5km for 1l LPG 1:8,5 (5.3mls for 1l LPG 1:5.3). I want to see how much difference I get with knock control (hope to get it working in the weekend). Because LPG has a higher octane number you can advance the ignition. Most people say because LPG the engine runs hotter but thats because theres no knock control advancing the ignition. Therefore; igntiting the mixture to late cause hotter engine! During my study we tested the same vehicle on petrol and LPG and the exhaust temperature was lower on LPG (car with knock control). That temperature is comparable with the combustion temperature (relative).
The best way is to retard the ignition before 2200rpm (back-fire) and advance it above 2200 rpm (compared to petrol). For the exact numbers Ill have to get in my books again... (which I'm planning to do). Keep you guys updated on this.
Power
Because I have to create a vacuum before the gas/air mixer the power is down on LPG
. On petrol with an open air filter the gain is much higher, I expect at least 20-30% in torque. I barely rev it to +5.000rpm due to the long intakes from the 318i E30. So peak power I don't know. Last time when the air intake exploded due to a back-fire it was way more fun to drive than on LPG 
.Next thing is to install injected LPG (liquid). I can get rid of the "blocked" air filter.
Thanks for the links Alpina/j. Really helpfull understanding what things you did. If you need help with MegaSquirt PM me.
top man!!