Fuel econonomy on lpg v8

[evil_mx6]

Just wondering what typre of fuel econonomy you guys are getting on your cars been either straight gas or dual fuel.....
my vs 5LT statesman has averaged about 17L/100km
i have worked this out by litres filled divided by km's travelled.
Highway driving she mite drop to about 15L/100km.

I have changed the o2 sensor and coolant temp sender. This has probably only helped by a litre if that.

I know lpg burns more than fuel but i think that the figures i have are way too much.

Gas system is a Gas research with Gas research throttle body.

Mods to the car are a cat back exhaust.
Nothing else.

What are you guys getting either as is or pre tune and after tune.

Looking at getting a foam tune and then finalised on the dyno to fine tune some points via a gas research specialst.

Let me know....i am wrecking my brain about this.....

The cars trip computer reading will say about 8-10L/100km on highway driving.

City driving will read about 13L/100km

[Cheap6]

Multiplying the petrol consumption by ~1.3 gives pretty close to what the consumption should be on LPG - although it depends on what is actually in the LPG (and the petrol but that doesn't vary as much).

On that basis, the city consumption is about right. It's also only a little above what my V6 gets when running closed loop (stoichiometric): ~16L/100km.

The highway consumption seems a bit high. I get (V6 again) ~10L/100km when running closed loop.

Constant speed highway running is light load so you should be looking at the tune at and near idle. It's been a while since I've looked at a GasResearch carb. but I think that they have a screw that adjusts how much air bypasses the metering rod at idle. Might be worth marking the position of that (so you can get back to where you started) and winding it out some. I think that the metering rods may be available with different profiles too.

One other thing is that the petrol computer has a lean cruise mode, active with constant speed/load conditions like highway running, whereas the LPG will (unless it is unusually sophisticated for an LPG computer) stay in closed loop. That will be worth a little bit, perhaps 10%?

[DvS_Ls1]

hey i got a 5liter im geting 320 a tank of 55liters of gas so not sure if its got or bad

[strgas]

1360 km from 140 ltrs of lpg running twin GRA carbys last trip to deni ute muster , wasnt to easy on the accelerator and cruising the muster with a load of people on the back , running closed loop setup mild cam 4 into 1 headers with 3 inch s/steel system , re-curved dizzy to suit LPG 11.5 -1 comp

[Phoenixx]

My VR 5 Litre Stato is unmodified engine wise and is on dual fuel and when running on LPG gets around 15.8 Litres per 100 K's in the city and about 12.3 on the highway. That's not stomping the loud peddle all the time but still making it work and perform all the same.
I don't know what brand of Gas system it's running but the previous owner just had a new processor and valve fitted before I bought it as they felt it wasn't economical enough when on LPG.

[5ltvsstaty]

400 to 450 km from 58 litres on my 5 lt vs staty mainly country driving with a bit of city


Jon

[evil_mx6]

hmmmm well it seems that my system may be running a bit rich then and may be out of tune....have any of you guys got a memcal tune done to your gas cars at all? how do you find it....what about dyno tunes?

[5ltvsstaty]

Nah mine runs an adj power valve that senses of the 02 sensor and tunes itself to that

[slepar]

ive got a vs berlina 5ltr duel fuel im getting on average ( just cruising) 17ltrs/100km around town and about 12-13ltrs on long drives wich basicly works out to $9.50 per 100ks wich for a 5ltr is preety dam good i wreckon, only mods are exhaust oh and i also have a crack in my drivers exhaust manifold so once that is fixed it will probably get a little better also, but honestly man if your getting around 17ltrs per 100km around town id be preety happy