LPG tuning experience

[lestraw]

Hi,

l am looking at purchasing a RR 1990" with 3.9 motor which they run on LPG during the week and ULP on the wekend. The owner says that the motor runs perfectly on both? l have heard that you have to tune the engine to one or the other and have it re-tuned to say ULP if you wanted to run it on petrol for an extended time. It has been set up with 150ltr of ULP and 60 gas all underneath which is great. Is the engeine tuning settings difficult for someone with commonsense to perform or do you neeed a specialist? Thanks for your help

[disconut]

My understanding is that the modern dual fuel systems are computer controlled giving the best of both worlds. My old Jag was dual fuelled and ran poorly on LPG. It was tuned to run both moderately well, but gave lousy performance.

http://www.bp.com.au/products/LPG/lpg_product_info.asp

http://www.impco.ws/products.htm (better link).
Trev.

[loanrangie]

Originally posted by disconut
My understanding is that the modern dual fuel systems are computer controlled giving the best of both worlds. My old Jag was dual fuelled and ran poorly on LPG. It was tuned to run both moderately well, but gave lousy performance.

Not quite, late model cars with efi systems have a piggyback computer that will change the igniton timing depending on which fuel is being used.
Dual fuel is a compromise unless you have one of the new expensive lpg injection systems or a closed loop system which uses a computer and some of the engine sensors to correctly alter the lpg mixture and ignition timing.
Being a 90 model rangie it probably have a simple type lpg setup. What brand hardware does it use ? Impco is a very basic but reliable system and there are various others with different degree's of complexity.
I have 2 dual fuel rangies both carby but both have reasonable performance and economy.
Where do they fit 150 ltrs of ulp ? i have 2 sill tanks (45 ltrs each ) and twin lpg tanks (70 ltrs useable) and there is only one other space to fit a petrol tank and thats behind the original fuel filler and they only hold 35 ltrs ?