Outer Limits 4x4 Board

I got a GQ patrol with the 4.2l motor with a impco 300a gas setup. my problem is that for the past 2 years ive never had good economy on fuel or gas. it has not changed at all from 31in tyres to 33in or 35in ,,, ive done stuff like ,,rebuilt gearbox, new head, rebuilt both diffs with new breaks and rebuilt calipers, electronic egnition, new sports exhaust. Nor has it changed from standard hight to a 5in lift... Its had countless tunes on a dino and it has not changed. I get 2.5 to 3k/l on gas and 3to 4k/l on fuel . it has a new carby and all the leads and plugs extended rotor is all new,you name it has probably been done so any help will be great.

I use to have wagon GQ with the 4.2 carby petrol as well. I gave up trying to use the words economy and carby in the same sentence. I could only get about 300-350k's out of a 100L tank running 33's. I ended up selling it. Wish i had have kept it now and whacked in a V8 instead.

i have a 120lt gas tank and can only ever get 60 to 75ltrs in it and the fuel tank is bout 65
running on fuel i get about 250klm to a tank
running gas i get bout 150klm out of 65lt

talking to my local gas supplier and installer (who have done Gas for over 10 years so i trust their info) the Impco setup with the carby on patrol is by far "THE WORST" when it comes to design and use

First off the top hat as its referred to, restricts the air flow through to the carby, resulting in extreme fuel usage. the Impco converter can't be used with any other mixer, so you can't just drop in another mixer.

the design of having to pull a cable to move the diaphragm when going between gas and petrol is the most ridiculously setups ever designed

I have been told to look at only the Sprint Gas setup on patrol, as its ring design keep the original cleaner unit, allowing for easier snorkel installs, as well as keeping the larger box for more air.

Using a Sprint gas system on 35's with extractors and a Crane Cam Fireball pointless conversion out of 100L of usable gas i got 450/500K's around town and over 700K's on long trips. thats just gas, on the 75L petty tank i got an extra 250-500K's out of her. its possible, but you need the right setup and tuning

MyGQ wrote:the design of having to pull a cable to move the diaphragm when going between gas and petrol is the most ridiculously setups ever designed

I was wondering about this when I had to do a bit of overhauling on my carby... can you explain exactly what the cable is doing here? I mean, I can see what it lifts and drops down again, but I don't understand the purpose exactly except that it seems to be to do with air supply..?

ok that useless POS thing drops a diaphram down when your on Gas to make the air flow across the LPG mixer, when on petrol you pull it up so air goes straight to the carby. Its restrictive in both forms cause it doesn't allow a full amount of air to get into the carby at any stage, causing huge performance hits and fuel usage goes though the roof.

Did a race with a friend of mine in the club at the lights once, he had his Impco 4.2L on 32" tyres and i had my Spring setup with 35" tyres. i left him for dead at the lights on take off, more power and better economy,

Problem is if you have impco setup there is nothing you can do as you can't just change the mixer, you need new converter and mixer.

MY gq wrote

I have been told to look at only the Sprint Gas setup on patrol, as its ring design keep the original cleaner unit, allowing for easier snorkel installs, as well as keeping the larger box for more air.

Using a Sprint gas system on 35's with extractors and a Crane Cam Fireball pointless conversion out of 100L of usable gas i got 450/500K's around town and over 700K's on long trips. thats just gas, on the 75L petty tank i got an extra 250-500K's out of her. its possible, but you need the right setup and tuning[/quote]

I have the exact same set up exept a smaller tank i get around 300-350 ks to 85ltrs around town or down the highway and no difference with or with out trailer i have had severel people tune it and its only ever got worse no i just dont think about it and wait patiently till i get my sbc.