Timing Setting LPG 5L

[Snitz92]

Hi, my VQ Statesman has a 5 litre V8 with an APA gas system fitted in 2007. I am aware that on normal petrol setting it should 10 degrees advanced from TDC. Just wondering if anyone knows what the timing is on an LPG fitted car?

[db_notso]

generally lpg is higher like 15 but im in no way sure of this fact!~
no seriously only had to mess with one i just set it drove set it drove withan adaptor module thingy
was a long time ago and i cant remeber what it ended up at

[Snitz92]

Ok mate well I will soon be getting the LPG removed and stuff like that - was just curious as to what needs to be adjusted with the engine timing. Incase the LPG specialists are a-holes and don't reset the motor back to normal for me, i can do it myself with timing light. :-D

[db_notso]

will post standard timing check method for you...

http://forums.justcommodores.com.au/...n-setting.html

[Snitz92]

Yeah cheers man. i've done bits and pieces of timing and ignition with my old man who's a mechanic, so that's not an issue. Mainly just want to know what setting best suits this engine and gas system.

[db_notso]

yeah know what you mean i asked one of the old 20year guys today and he said set to +5
i asked huh +5 on standard?
he said yeah because the lpg is a higher octane rating and burns differently!

he did also add it depends on the motors internal conditions and that hed start at 15 and see if missed etc then lower it to 12 if had misses?

not exactly sure what he bases this on but he is experienced? i guess 2o years had to teach him something about vq lpg v8's timing?

[Not_An_Abba_Fan]

Petrol has an advance curve right through the rev range and is therefore not the ideal timing for LPG. LPG needs the advance to stop at 2500 rpm then stay static from there. If you run dedicated LPG then the memcal needs tuning, but since you are getting rid of the LPG anyway your original question is quite pointless....as is this post.....

[db_notso]

lol anyways not an abba fan do you know what setting to suit both petrol and lpg on vq v8?
has got me scratching my brain after what you said and the old guy at work!~

[Snitz92]

I ain't sure guys. I think I'll just bump it back to 10 degrees BTDC as it says in Workshop Manual and chuck the gas tank.. Mmm.

[db_notso]

well it only ignition timing set it drive it hear for pinging and then advance it and drive again when it starts to ping drop 5-8 degrees off timing and your done

[Snitz92]

Yep, well I'll discuss it with my old man and have a play round. Cheers.

[Not_An_Abba_Fan]

The way I set timing on non EFI cars is to advance it until it pings, then back off a touch until it stops.

You can safely go to 14 deg BTDC but you need to run 95 RON or better. Leave it at 10 if you intend to just baby it around.

[Snitz92]

Yeah that's understandable. Although it's an efi 5 litre which at it's current setting is running quite thirsty. I reckon i might just back it to 10 and from there decide a more precise setting later.

[Not_An_Abba_Fan]

lol anyways not an abba fan do you know what setting to suit both petrol and lpg on vq v8?
has got me scratching my brain after what you said and the old guy at work!~

Some people retard the timing a bit to make it run better on LPG, but leaving it at the stock 10 deg is fine. For the best results load a dual map on the existing memcal, one for petrol, one for LPG that is switched when you switch from petrol to LPG.

[Circlotron]

Bit of an old thread but if anyone cares, I have this gas curve in my V8 VP. Also is the details of degrees vs rpm and manifold absolute pressure (MAP). As well, a petrol curve for comparison.

[strgas]

most gas fitters won't upload a dual curve pattern to these engines and leave it set a 10 degrees , sure the system is a APA ? apa is normally a brand of tank and not the system .