Gas &diesel for Landcruiser

Its made a big difference to the Discovery TD5.

Much less throttle required to maintain constant speed (judging by the ScanGauge readout)

Faster acceleration.

Better fuel economy: 8.7 L/100km at 120 kph between Pt Augusta and Alice.

More power up dunes.

The only problem is at the servo - when you drive from the diesel bowser to the gas outlet they think you are doing a runner.

Yes,

Had the diesel gas Australia LPG injection added to the 1992 model 80 series cruiser about 2.5 years ago - after approx 200,000 km's since it has payed for itself a few times over in fuel savings and extra range etc.

Hasn't caused any mechanical problems at all yet.

On the highway and at highway sppeed sof 100 - 105 kph we save about 2 cents a liter overall (more when the fuel cost goes up).

There are a few caveats tho..

We removed the 50 liter sub tank and added a 175 liter long ranger diesel tank under the rear of the vehicle, which along with the standard 90 liter tank gives a total of 265 liters of diesel.

You use abpout 1/3 as much LPG as diesel, so we fitted a 116 liter LPG tank in the rear of the cab where the 3rd row seats were fitted (have the pair of 3rd row seats in grey trim going cheep if anyone wants them!).

With the total fuel load of 265 of diesel and 116 of LPG - the vehicle if NOT towing anything hige like a van - can go somewhere around 3000 km's before you need to worry about fuellling up.

It easily gets 10km / liter (yep 28 miles per gallon!) (sometimes 11.0 / liter that 30 mpg) IF you stick with a constant 100 kph. Pulling our 750 kilo single axel trauiler chiockers with fuel and gear drops thise figures a little but not much - it changes IF you MUST go faster than 105 kph - some reason 110 kph (which is legal in WA minus the trailer) seems to drop the fuel consumption a bit... 100 - 105 os the sweet cruising speed for fuel economy with the gas switched on - aout 95 is the sweet spot with the gas swiitched off.

Last thing.

Oil.

There IS (so far) no diesle oil manufactured SPECIFICALLY for diesel gas fitted vehicles, and the LPG does make the cruiser run a whisker hotter than it normally would. (I recommend fitting a Pyrometer gauge to monitor EGT's (Exhaust Gas Temps).

As a result - because we run used oil analysis on the sump oil since we fitted the lpg just to make sure there were no excess wear metals (which there haven't been), we DID find out that - the LPG seems to cause the normal diesel oil to use up it's add pack of chemicles designed to keep soot in suspension and so on - a LOT more than without the LPG switched on.

We would consistently get results back that said it appeared the engine was running hotter than normal because the oil was oxidised to the point it needed changing at 5000 km's. It also said there was elevated nitration and sulphation levels in the oil...

That means it becomes even MORE critical that you change oil EVERY 5000 KM's when running diesel gas! You should NOT run extended oil change intervals of 10,000 or worse 20,000 km's that SOME of the new fully synthetic oils CLAIM can be run between changes.

We tried the very expensive Mobil Delvac 1 Fully Synthetic and it needed changing at just 7000km's - apparently due to the diesel gas mix.

We wrote to Mobil about this and last I heard they were trying to re formulate Delvac 1 as a result.

As too whether it is cost efficient - for US it was.

Thats because we are in WA and at the time we had the conversion done some 2.5 years ago, the cost was about $4150 & rebates was:-

Fed Govt = $ 2000
WA State Govt = 1000
Rebates Total $3000

Out of Pocket conversion cost = $1150!

Savings (2.5 years ago fuel costs) of 2c a liter - we only needed to do 57,500 km's to pay off the difference.

We've done about 200,000 kms so almost saved that 3 or 4 times over now since the conversion.

Would I do the conversion again?

Well - yes and no.

I DID convert the F 250 7.3 liter intercooled turbo diesel at the same time however it's only done some 20,000 kms (i.e. not enough to make any real savings yet) and worse - due to the weight of the vehicle it didn't qualify for ANY rebates state or fed govt so the whole $4500 will take 225,000 kms before break even.

The same used oil analysis issue about high sulphation oxidisation and nitration levels exists with the F 250, as the cruiser.

Also - because I had some mechanical (electrical issues) with the F 250 while up in the Pilbara - I found tha NO mechanics wanted to work on the vehicle. Most took one look and just said "must be the LPG gas system" and shrugged their shoulders, blaming something they don't understand as the "obvious cause" when in the end it turned out to be a small computer called a "Injector Drive Module" that runs the diesel injectors that was faulty and nothing whatever to do with the LPG gas injection!

Sometimes when you are remote located - the old KISS principle (Keep It SIMPLE stuipid ) makes a lot of sense where pratical, old fashioned hands on type diesel fitters / diesel mechanics are going to have to work on the vehicle!.

I'm in two mnds whether I would convert another vehicle to Diesel Gas after the experience with these two so far.

Theres a bit more too it than just simple "maths" (will i save money) consideration.

I wan't and still am NOT impressed woth the whole issue of suitable oils for diesel gas vehicles - its an issue the installers / manufacturers of the diesle gas system would sooner not address...

They make some unsubstantiated claims about cleaner eng9nes etc in their web sites - which my used oil analysis proved quite wrong.

Again - like the oil manufacturers - they don't want to know.

IF disel gas conversions was a big business I giuess manufacturers would make oils specifically suited to use of this "unusual" fuel source, AND the manufacturer installers, would need to be a bit more comitted to backing up their claims to cleaner engines etc.

Lastly I agree about the issue of two fillings - and servo operators thinking your doing a runner without paying, when simply moving between the diesel pump and the LPG pump!

Cheers