The V8 Owners Forum -

Hi all,

Does anybody have any information on ignition advance for LPG?

Have a Rover V8 on gas and have a Megasquirt ECU that I hope to fit soon; this allows different ignition maps to be used on petrol and LPG, but haven't been able to find much info about best advance to use for LPG.

There are various ignition advance gizmos available that set a fixed advance (often around 10deg) at all engine revs. But I have seen other advice recommending that at low revs about 10 degrees of (additional over petrol) advance is beneficial, but at higher revs (above 3000 rpm) it is actually better to have no advance or even retard the spark compared to petrol.

Curious to know if anyone here has any info on this, or anybody experimented with different ignition maps on their adjustable ECU?

I've always used about an extra 6-8 degrees static for gas with no vacuum.

Gas likes a lot of initial advance, all in by 1800-2000rpm but doesn't like much more (if any) total advance than petrol.

Of course someone will have another opinion

I run LPG with my MegaSquirt ECU and have switching maps for petrol and LPG. When you fit the ECU let me know and I will ping you an LPG map like this...



If you have a close look at the petrol map below you will see where I have advanced then retarded the spark on the top map.




Don't forget that all RV8's run slightly different but these maps will give you a very good place to start.


HTH
jeff

Thanks guys.

Interesting that neither of you two add any advance in the high rev ranges - makes me wonder why fixed advance units are sold specifically for LPG.

Jeff - you seem to do exactly as I have read about, i.e. advance then retard, but you don't seem to deviate very much from the petrol map - especially at low rev range - was expecting bigger differences.

How did you guys tune your maps? Was it from experience, or rolling road etc?

Thanks for the offer of the map - that would be great. I've been playing with TunerStudio, so would be great to start getting it configured for LPG. Will try and message you directly.

Thanks again.

I would also be interested as i have been fiddling around with my recently installed MegaJolt. Still need to wire the option to swap maps so that they change when i switch fuel, and for this reason i havent really done much tweaking yet to suit the LPG specifically as i dont want to have my engine explode if i have to run on petrol!

Has anyone got any suggested reading in relation to advance on LPG?

Thanks