Performance of the 4.5L GU Patrol?

[Jamie]

I purchased my 98 Patrol about 18 months ago. First one I've owned and I'm having some issues with performance. I'm hoping someone can give me some idea as to whether my patrol is performing badly or this is what I can expect from the Nissan.

Engine 4.5L dual fuel. I average approx. 300km per tank of gas (90L tank) and used to get approx. 120km on the standard auxillary tank. Don't know what the capacity is of this tank?

I recently installed a snorkel and 76L auxillary tank to give me greater range with the dual fuel and this is where the problems have begun.

Took the car to a gas expert to fit a balance tube and retune the gas system for the snorkel. He has made some modifications to the gas system (mainly electrical). He also reset the timing saying it was too lean 5 degrees retarded (I think) to 5 degrees avanced. I may have this the wrong way but anyway its now back to factory settings. The initial result is improved power, similar gas consumption but a real decline in petrol economy. I took the car back and he said the mixer had to be replaced. When I picked the car up he told me they drilled it out rather then replacing it and it should be okay.

I recently went to Dargo with the family towing our 7x4 Camper trailer. I got the best economy ever on gas 370km, but from there it was dissappointing. On petrol I was struggling to get much more then 100km to the tank and it was terrible going up a hill dropping back to 40km (no trailer).

On the trip back home I went back to gas and it was okay on economy but still lacking power. The cars only done 150,000 km so I expect more then I'm getting.

Can any add some light to the economy and performance I should expect. I'm going back the mechanic and I'll get a compression test to see whether the engines shagged or not. Assuming its okay what mods could I make to improve performance?

Also I wonder whether the gas mixer should of been replaced and whether this is the issue. If anyone can give me info on the gas that would be great.

I love the car, but 76L/100km is rediculous!

Cheers Jamie.

[growler2058]

Mate someone will have a better idea than me but that sounds way way way excessive

[Bigrig]

Ahhh, the joys of dual fuel .... there aren't many mate unfortunately ...

My 4.2 used to bang out about 400klms on LPG on the open road with a 90litre tank, had it tuned because petrol was ordinary and ended up same as you - more power, far less fuel economy. Hopefully someone can help you out - mine has changed a great deal since (straight petrol and turbo) as it was proving fruitless trying to tune it for both.

The 4.5 is a thirsty animal, but you should be getting better than what you are stating.

Good luck with it mate.

[Jamie]

Thanks for the comparison, it confirms that somethings not right. Looks like more money and time at the mechanics

[Jamie]

I've booked in for a dyno with a supposed gas and 4WD expert on the 15 February so that will I hope sort it out one way or another.
I had read about others who had added extractors, bigger exhaust, turbo and a chip with good success. The chip apparently gives you the ability to run seperate tuning setups to suit both petrol and gas.
Was the gain you had from the turbo both power and economy? What sort of cost would I be looking at if I went down the turbo option?

[Bigrig]

I've booked in for a dyno with a supposed gas and 4WD expert on the 15 February so that will I hope sort it out one way or another.
I had read about others who had added extractors, bigger exhaust, turbo and a chip with good success. The chip apparently gives you the ability to run seperate tuning setups to suit both petrol and gas.
Was the gain you had from the turbo both power and economy? What sort of cost would I be looking at if I went down the turbo option?

Don't know yet mate - having some issues with the new ECU, so not going to dyno till next week now - straight petrol, with big injectors etc, so hopefully it'll throw out some berries.

Quick spool do the bolt on Garrett turbo kits for $3999 plus fitting and tuning, so I'd reckon you'd be lucky to get out of it for less than $6000 or thereabouts ... mine has cost more than that due to the (quite incorrect) path I initially took and now in going back to petrol etc ... that said, I don't think I'd ever have a dual fuel rig again ... but never is a long time!

[Jamie]

Others have said the same to me; gas is just a headache and I'm starting to think they're right. The turbo could be an option down the track after I've explored some more basic options. Alternatively I might just have to bite the bullet and change over to a diesel. I would have gone this way straight up except the 3.0L has such a bad reputation for blowing up, although I have read on the forum that post 2005 they may have overcome the problems.

Thanks for the info.