Lpg systems and tuning advice

[Dec_head]

I am after a bit of info regarding lpg as i will be setting mine up shortly to run dual fuel any info relating lpg setups and tuning would be great.
as mine is a holley throttle body with built in iac and tps i am looking at different options at the moment i seem to be limited to a 425 impco with an adaptor.
Has anyone seen any other options like a holley mixer ring or alternative that does not restrict airflow.

And as for timing any suggestions i was told more intitial advance and less overall with vacuum advance distributor lpg cars does the same apply.

[yoda69]

Info below is taken from a VT factory LPG bin and is the base spark map for Petrol and LPG.
It is MAF based but the MGC is similar to the MAP in terms of the table shape ie. a low mgc equates to a low MAP value and a high mgc to a high MAP.
Cruise mgc is around the 200-300mgc range, WOT throttle around 700mgc on a Ecotec V6 NA.
Obviously teh amount of psark you can run will be determined by the engine configuration, but the basics will be similar.
I'll let you worj through where the factory added and removed timing timing from.

Petrol Spark Map

Petrol.jpg (148.84 KiB) Viewed 6414 times

LPG Spark Map

LPG.jpg (151.71 KiB) Viewed 6406 times

yoda69

[antus]

go lpg injection with a piggyback computer if you can. they are more expensive than the old carbie style setups, but are vastly superior too. you get an extra set of lpg injectors installed in your manifold and generally speaking you cars intake wont be restricted like the carbie style so you will make the same power on petrol and more power on gas! (its approx 110 octane). ive got a great article here about it, ill see if i can dig it my. my mates put it on his vy with ls1 and it works well.

[antus]

Here it is. Ive also been taken for a blast in the car in this article too. It did go awesomely fast and transition from lpg to petrol without you noticing. I have seen

http://www.megagas.com.au/main_pages/Sequential.html

[Dec_head]

Thanks i have noticed lpg injection setups have come down in price heaps lately and at a later date i think it would be the way to go but for now i am really after the most effective adaptor without pulling the inlet off and having injectors fitted.
looks like the timing has some major changes needed for lpg as well thanks yoda that sort of gives me an idea i might get more of an idea later when i play with my v6 sc with the afm at the moment i am still a long way from fully understanding .
my v8 with map has so many options and equasion factors to deal with it does my head in sometimes.

[jacomms]

Here is a link for LPG Injector that I use

http://www.gas-injection.com

The DELCO will control them without an extra computer....LPG Lock Offs can be powered in place of a fuel pump and still meets all LPG reglations.
Realtime tunning just like petrol.

I ran these Injectors in my Twin Turbo V6 for a few years....Im about to reuse them in my current work car... they work VERY well

Justin

[ivanovbg]

http://www.icomitalia.it/lang1/imp_jtg.html -this is the best-Attachments
if you are interested I can share my experience with LPG settings

[antus]

Not everyone here has rar, so I've converted your pic to png so its easyer to see. Impressive stats!

[Dec_head]

If only my commodore had that sort of power
With them stealth gas injectors is that for straight gas only or do they run fuel as well ?

[ivanovbg]

Gas is liquid