Thread: D2 Fuel Consumption 4.0 and 4.6 Litre Engines

Originally Posted by Grumndriva

G'day all.

Last August I replaced the 4 litre engine in my 99 V8 Auto Disco 2 with a new 4.6 litre (spare RR HSE) after slipping two cylinder liners, and I thought you might be interested in fuel consumption after 12,350 km with the new engine.


Overall, which includes Canberra city driving (about 55%), some highway driving (15%), some track work in the Brindabellas (5%) and some towing (25% with a 2.5 tonne 20 foot dirt road van with the aerodynamics of a very large brick), the fuel consumption with the 4.6 has been 19.62 litres per 100 km.

On a recent 900 km trip with the van all the way, it returned 25.69 litres per 100 km overall.

I cruise at around 85 kph locked in third with the van, and 100 or 110 kph without the van. The climate control is always on, and I use the sports mode for all on-road operations.

Over the 69,629 km I had the vehicle with the 4.0 litre engine, it averaged 17.02 litres per 100 km, which also included a range of uses, but less towing percentage-wise, and mostly with a wind-up camper instead of the big van. Consequently the figures do not compare apples with apples. However what I deduce from this is that the 4.6 is probably not noticably thirstier than the 4.0 given similar usage.

The catch, which I did not appreciate when I bought the new engine, is that being a high compression engine it runs best on Vortex/V-Power, not straight ULP (although it can use ULP). I have been using 95 octane but have just changed to 98 octane to see if there is a difference. If there is I haven't been able to pick it yet.

The Disco with the 4.6 is a greatly improved vehicle perhaps except for the need for higher octane fuel.

Hope this helps for others considering the change.

Cheers,
Terry

I don't know how relivant this will be but pretty well all the HSE rangies I work on are returning 12 to 14 lts per 100klms hwy cycle and around 16 to 17 in town. This includes my 01 HSE. I must say I don't normally have the auto in any other setting but drive and don't use the sport mode too often.
Regards Russell.

Hi Terry,
likewise to yourself I have had the 4.6 dropped in after splipping a liner and overheating (prior to my ownership) Range Rov dropped in the 4.6 and aside from overcoming some intitial niggles, the engine has performed with no issues. Have had the first oil change after 1500k's and have now done 4,000k's. I have not done a fuel consumption test yet as most cars I have had do not reach their optimum until after the 10,000k mark.

I have had mixed results though when I go by K's travelled per tank. Have run it on either V power or optimax since day one (was told to run on PULP nothing else) and on average am getting 400-450 per tankful. Looking at 85% city 15% hwy. Alot of heavy traffic driving on a weekday.

Interesting that I did a weekend away up past Warburton 4wding etc and spent a day in the bush with allot of time in low range, and returned basically the same coverage of 400+k's out of a tank.

Worst result I have had was 325k's about two tanks ago, very weird no change in driving but it was evident that it was Going through juice alot quicker, next tank was 400k's and this tank it's on now is at halfway and 300k's.

Anyway once a few more k's on the clock i'll start doing some measuring. Don't think I am going to be impressed though, even though everyone has told me the 4.6 SHOULD deliver better economy.

Cheers
JB.

Roughly what's the cost of a 4.6 relacement? if I was to buy son of Bundaleen's 4.6 for $3k. Any idea of installation costs?