SPARK PLUG change. fr5dtc???

[prj]

Basically LPG will need a lot more advance in low-load conditions where the engine spends 99% of it's time.
Up top it should be fine.

To find MBT and best EGT timing at low load conditions, you need a load bearing dyno.

[FabS6]

yeah...it looks exactly like my friend's Alfa with the very bad lpg mapping. And that was all my fear on lpg indeed

[prj]

Well, you can map all you want, but your car will still be at lambda=1 at low load and with too little ignition advance.
Unless you modify the Motronic.

[diesel des]

I'm not sure I am at mbt on petrol or gas as I just played with timing on the road for a compromise setup. But yes egt is 30 deg cooler at max power on gas. I agree with prj, that these things should be fine tuned on a dino.

That head has real bad valve seat wear. I'm guessing someone set the lpg way to rich at wot which raises egt and with non advanced timing, this was the result.

One petrol you richen up afr at wot to inject extra liquid to cool combustion temps. But on gas you can run afr 0.85 for max power with no further richining needed.

Prj I can't make my engine ping at all on lpg. Even at peak torque where 10 deg was added there was no ping.

[prj]

Interesting.
But yeah, LPG has a much higher effective octane rating, so it should always make more power if mapped correctly.

I agree about 0.85 lambda. Bad idea to go richer on LPG...