Tuning Dual fuel

[aghatas]

whats the truth about tuning dual fuel? is there a trade off between running on lpg and running ulp? or is the carby tuned for ulp and the mixer tuned for lpg and it's the advance of the dizzy that makes it run better on either one? if so would an electronic dizzy with dual curves make it a smooth ride on either fuel? what is the solution for a finely tuned dual fuel system?

[Outlaw Torn]

as far as i know, wot u have said abou the carby being tuned for ulp and the mixer being tuned to gas is true, same for the timing of the dizzy. Whether the electronic dizzy would fix this i am interested to know. Goon or zoist? can u shed any light?

[Goon]

I'm guessing they would have to be tuned to suit both fuels, but you wouldnt be able to have differerent idles.. unless there some addons with the lpg that would help this.

[craigvk]

Most of what people say is a load of crap. I have had 3 mechanics tell me bullshit on how lpg in cars work.

To tune a gas mixer, it's a matter of adjusting the butterfly valve to either full open or half open depending how much gas you want to waste, then there is the idle mixture screw that needs to be adjusted until the highest idle is achieved.

On the petrol side it's different. Because when a car is cold, petrol needs a choke because it can't vapourise quick enough until the engine is warm. Gas and chokes don't make any difference. The only other thing for carb adjustment for gas is the idle screw.
Petrol needs to have the idle and mixture settings adjusted correctly and I think most car manuals like workshops ones tell you all about it in the tune-up section.

Not sure about the dizzy. Maybe vkberlina might shed some info on that one.

[ascension24]

"To tune a gas mixer, it's a matter of adjusting the butterfly valve to either full open or half open depending how much gas you want to waste, then there is the idle mixture screw that needs to be adjusted until the highest idle is achieved."

Thats exactly tru, well on my car anyways (a magna at the moment)
For the lpg lines just before it hits the fuel rail, theirs a knob, that I can twist open and close, the more I open, the higher the car idles. I opended it up full one day, they car felt like it gained about 30kw of power, would rev to redline instantly and spin the wheels. Ran out of gas in about 30 mins of spirited driving. That would of normally lasted me a couple of hours.

Further up the line where the converter for the gas is, their is another valve I can twist. It doesnt change the idle, but closing it does choke the engine for the lpg.

[Goon]

(a magna at the moment)

^^ I think your car would be a different setup dude.

[craigvk]

It's an EFI so it's completely different to carb setups.