Thread: Range Rover engineers - what were they smoking?

I used to think the same way too, untill both of dad's 3.5s died. One at over a million km, and the other at 740,000km. The first one was worked very hard on occassion, towing a 25 foot van all around the south east; and doing silly things like 97kph in 2nd in the south aussie dunes. The second one towed almost 2 tonne every day for the last 7 years of it's life. In reality, it's proper servicing that will make an engine last, unless you burn the ringer out of it every single day that is.

But, by and large the largest influence of fuel economy is the nut behind the wheel. On a hwy run, I can get 11.7L/100km out of my 93, and 14.2 (instrument cluster reading) out of my 96 - and that's with knackered injectors. 21L/100km tells us there's something wrong, I got that fuel economy when towing the LSE back from Melbourne, and get 17 around town.

I havn't read the OP's details of his new engine (as jelous as I am though), but if it's got larger injectors, or higher fuel pressure, the ecu reading will be way out.

Originally Posted by Brian Hjelm

No substitute for cubic inches. Small engine working hard, revving its ears off equals disastrous fuel economy, short engine life and unreliability.

Indeed, but the OP didn't change the gearing, so we can discount the revving it's ears off bit. Unless he intentionally kept the auto out of top.

Originally Posted by Brian Hjelm

Also requires many speed gearboxes to keep small engine in its narrow power band. A 300 hp x 2 litre modern motor cycle engine can not replace a 12 litre 300 hp diesel in the front of a medium truck. Theory might give the academic engineers a warm fuzzy feeling but doesn't work out there on the tarmac. Give your project some capacity and some draft horses.

I can't see any engineer (academic or otherwise) thinking that example is a good idea.

One thing worth noting though, 300hp truck diesels are smaller than they used to be. Same with 200 and 100hp car engines. The vehicles themselves haven't got any smaller (park a current corolla next to a 15 year old V6 camry), but engine size for vehicle size has reduced and fuel economy has increased.

I would think increases in compression ratio and the cam profile would be the major reasons for the improved economy, I can't see it passing NOX emissions tests though. VVT engines can get better power and economy than any single cam engine and meet stricter emissions too.

Originally Posted by PhilipA

Are you running the same size injectors and the same fuel pressure?

If either is larger larger the consumption figure will be wrong as AFAIK the computer reads the duration of the injector pulse to calculate the fuel consumption, based on the capacity of the stock injector and pressure.
Regards Philip A

What you suggest seems sensible, and yes, I changed the injectors. So perhaps the computer read out is incorrect but anyway, I am getting much greater distance per tankful.

I've today returned from a trip Sydney-Winton Raceway-Sydney towing a 4 wheel trailer with racecar; computer showed consumption as 15.3 L per hundred and I'm accustomed to seeing 22-24L per hundred towing. I had lots of fun with the increased torque and power.

Given the comment about how consumption is calculated I will fill the car and check the mileage and do the math and in due course, report on any difference.

Originally Posted by Sydr

What you suggest seems sensible, and yes, I changed the injectors. So perhaps the computer read out is incorrect but anyway, I am getting much greater distance per tankful.

I've today returned from a trip Sydney-Winton Raceway-Sydney towing a 4 wheel trailer with racecar; computer showed consumption as 15.3 L per hundred and I'm accustomed to seeing 22-24L per hundred towing. I had lots of fun with the increased torque and power.

Given the comment about how consumption is calculated I will fill the car and check the mileage and do the math and in due course, report on any difference.

Petrol is cheap today, and so I took advantage and filled my truck. Here's the math, then:
I used 340 L to tow a distance of 1737 km
so my usage was 19.6L per 100, not the 15.3L per 100 that the trip computer showed me. Hats off to those who realised that the change of injectors would affect the computer calculations.

Oh dear, it was a nice feeling while it lasted. Still heaps better than before; - I shall now check the consumption on the urban cycle.

If you were towing a race car on a trailer i would still be very happy with those figures.I bet it pulls alot better with all that torque now.

Originally Posted by SPROVER

If you were towing a race car on a trailer i would still be very happy with those figures.I bet it pulls alot better with all that torque now.

Thanks for the positive view, yes, it is almost obscene how easily it tows. Even major climbs, on cruise control I just snick it down to 3rd and it just hauls away.

Originally Posted by Brian Hjelm

No substitute for cubic inches. Small engine working hard, revving its ears off equals disastrous fuel economy, short engine life and unreliability. Also requires many speed gearboxes to keep small engine in its narrow power band. A 300 hp x 2 litre modern motor cycle engine can not replace a 12 litre 300 hp diesel in the front of a medium truck. Theory might give the academic engineers a warm fuzzy feeling but doesn't work out there on the tarmac. Give your project some capacity and some draft horses.

Extreme example- 50cc Suzuki GP bike with a 16 speed gearbox to keep it on the power revolution (not power band).

I have had the 3.3,4.2TD nissans,the 1HZ,FTE,D4D tojo's,Tdi,Td6,TDCi LR's,2.8,3.0 Isuzu's and the TDCi at 2.4Ltres eats everything other than the Td6 and FTE and use's less fuel and oil to do it.A 12ltre 300hp engine would be a dog in real life. Pat