GRX4.8 - Mods for better fuel consumption

[Christo_Smit]

I found a turbo kit for the 4.8ltr petrol engine as per website below as advertised by an Aussie company. I have read that it is not possible to improve the fuel consumption of the 4.8ltr Petrol Engine, but your insight on the info below will be appreciated:

"http://hpdiesel.com.au/gu-patrol/nissan ... -turbo-kit
HPD manufacture a complete bolt on turbo kit to suit the Nissan Patrol 4.8 Litre petrol models. Our kit has been tested in the worlds most harsh climates including the Middle East and has proven to be a durable, performance leading product. Torque and power increases are massive over the factory format.

Using the supplied dual ball bearing Garrett GT35/40R, power levels of around 270rwkw on a standard engine are common. Supporting fuel system and engine management modifications will be required to accompany this kit. Larger turbos can be selected to suit individual needs."

[Peter Connan]

Turbo engines are not known for improved fuel economy over the standard versions. And if you use that extra power, you will definately use more fuel.

Do not expect an elephant to operate on a racehorse's diet.

[Alex Roux]

Piet,

On fuel economy with turbos, do you refer to the big 6 cylinder engines only, or only to petrol engines, or always?

[Tinus lotz]

I think on big engines and big cars ....need more power you are gonna use more feul....light car like polo or ammarok a small turbo engine can work less weight more power......rule no1 ...if you want horses you must feed them

[Alex Roux]

...and if you cruise at 100, with a light foot (requiring the same number of horses), would having the turbo not be more efficient in a big petrol?

[Peter Connan]

My understanding is that putting a turbo on an existing engine will virtually always result in worse fuel economy.

Where manufacturers "crook the books" is that a turbo allows them to use a much smaller engine than would otherwise have been the case, resulting in better fuel consumption for the car...

Remember that a turbo does not improve the efficiency of the combustion process, it merely forces more air in there so that you can in turn burn more fuel.

[Clem]

Remember that a turbo does not improve the efficiency of the combustion process, it merely forces more air in there so that you can in turn burn more fuel.

And that folks, is the bottom line with any forced induction engine.

[Christo_Smit]

So that's that then. I hoped that a turbo will improve the efficiency and therefore improve fuel consumption. However, the risk involve will most probably not justify the cost and the improved efficiency.

[JoshJ]

I agree. More power more feul. Even these tiny turbo engens they put in the cars these days are only economical if you drive on the 1200cc's as soon as you put foot for excelleration the economy goes down the drain. I have 2 co workers that are crying. They bought the cars on manfacture promises and thought they could beat the pump. But that is all miths.

[Alex Roux]

So that's that then. I hoped that a turbo will improve the efficiency and therefore improve fuel consumption. However, the risk involve will most probably not justify the cost and the improved efficiency.

On the 4.8 what may help is the 'chip' or otherwise the unichip.
If you are prepared to risk an extra piece of tech in the system.
Rob Green offered me a unichip to vary the settings from lean for long road and rich in low range for off roading.
It is till an option and not that expensive. But personally if I had a 4.8 I would not "peuter" with the engine set-up.