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hiya all
the more i delve into home tuning my lpg/petrol ute ( 253 auto HQ impco system on 350 holley ), the more confused i become
i am reading posts which say LPG needs more advance coz of its theoretical higher octane ...
and i am reading posts which say LPG needs less advance coz it burns hotter/faster
and i dont know who to believe, but i sure wouldn't trust my installer ( should have known when he said "i've never worked on a carburetted car before ")
so please help a poor dual fueler, and put him out of his misery
yes sonny, it's an HQ ute |
yes sonny, it's an HQ ute |
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LPG needs more initial advance at lower RPM, but less total advance at higher RPM.
Cheers,
Mick
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Mick
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the problem with duel fuel is can can only really get one or the other working properly
gas needs more advance set you car up for straight gas and only switch to petrol for emergency if you get the petrol running good gas will be crap and ping all the ti
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im running straight gas have a impco 450 on a rochester base plate and elec dizzy the question i ask is how do u set the more intial timing at lower rpm and and less total advance at higher rpm plz explain commodorenut
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sorry it was me who dont the last post forgot to sign in plz help with the timing question
jump on if you want a holdon |
jump on if you want a holdon |
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quote:
Originally posted by commodorenut
LPG needs more initial advance at lower RPM, but less total advance at higher RPM.
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You need to get the distributor regraphed for less centrifugal advance, limit the vacuum advance and set the static timing to suit LPG.
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tenticles There is not much you can do to home tune a LPG car apart from playing around with the gas mixture at idle and cruising speeds. Even then you can make it worse if you are not experienced. Gas is a fairly high octane fuel and it burns a litt Edited by user Saturday, 15 December 2007 11:26:04 PM(UTC)
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I fitted the electronic ignition to the 202 HQ, tuned it to petrol, took 40thou off the head to give around 10:1, ran the mid grade or high octane ULP,would not run on standard ulp, motor nearly died when I accidentally put standard ulp in, had no problem
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John
I think you will find that the computer in the VN/VP etc does not have a separate program for petrol and gas. I bought a straight gas system from Impco for a VP engine in another car (Impco supplied the factory system) and was told to use the sto
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I think it was Kalmaker who used to do the dual program VN/VP memcal, where you could flick between 2 programs (say 1 set up for 98RON & 1/4 mile passes, whilst the other set up for 91RON & the daily commute).
Might be worth investigating for dual fuel.
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Cheers,
Mick
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Sorry I did not mean the Vn etc computer would do the dual fuel from standard, the computer does need to be programmed for the dual use. It has the capacity to be so programmed.
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Hi just wonderin if you can tell me what my 350 chev should be timed at to run on LPG?
Thanx man
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the economical way of sorting it out would be get a cam profile to suit straight gas, a good cam will also come with an advised distributor advance curve, this is farily generic but alot bette rthan a standard bump stick and a twist of the dizy
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