Thread: Real World D4 fuel consumption

Does a 2.7 D4 with its different engine management ecu that appears to provide more low-down torque get better real figures than a late model D3?

Originally Posted by Graeme

Does a 2.7 D4 with its different engine management ecu that appears to provide more low-down torque get better real figures than a late model D3?

Comparing with Dads D3 which is identical as far as accessories etc (so one would assume weights are close and aero drag similar) yes... My D4 is around 1-1.5l/100km better than his.

My engine is also only 4k old, his is 16k old.

Originally Posted by Tombie

Comparing with Dads D3 which is identical as far as accessories etc (so one would assume weights are close and aero drag similar) yes... My D4 is around 1-1.5l/100km better than his.

My engine is also only 4k old, his is 16k old.

Jeeze you Dad does not do too much driving!

I have a 2.7 D4 and it gets about 10.5L/100 (actual not optimistic trip computer) around town, and the best I have done on the highway is 8.5, which was Canberra to Syd and return, sitting on about 110-ish. Towing an Ultimate Camper trailer in the hills it gets into the 13's.

Its interesting how regardless of road speed, the D4 always wants to sit at 1900rpm, I guess to keep it near peak torque and make the car more responsive.

This means at 80kmh its stays in 5th, but if you drive up to 100 it will change to 6th and stay there even if you slow down to 80 again. Or if you manually shift it to 6th then go back to auto its happy to stay in 6th and do 1300rpm.

Originally Posted by Weird Al

Its interesting how regardless of road speed, the D4 always wants to sit at 1900rpm, I guess to keep it near peak torque and make the car more responsive.

This means at 80kmh its stays in 5th, but if you drive up to 100 it will change to 6th and stay there even if you slow down to 80 again. Or if you manually shift it to 6th then go back to auto its happy to stay in 6th and do 1300rpm.

That is exactly what my D3 does now as well since I got the software upgrades done.

How many people on here take into account when doing their fuel consumption figures that there speedo is out because of the incorrect calibration for the standrd tyre size?

As has been mentioned previously by others if your D3/4 has 265x60x18's fitted instead of the standard size factory fitment then your speedo reading will be true. This will change your actual mileage / fuel useage numbers by a reasonable amount either way.

cheers,
Terry

Originally Posted by Weird Al

Its interesting how regardless of road speed, the D4 always wants to sit at 1900rpm, I guess to keep it near peak torque and make the car more responsive.

CC causes the gbox to use a shift programme more suited to constant speed so drops to 6th sooner.

Originally Posted by JayBee75

Thanks Les, that gives a good understanding of where its at, not bad really for 2T+car! Better than a Commadore, or Falcon and alot more useable.

Used to have a X5 Diesel, out of 80 litres used to get up to 800k's around town, up to 1000 hwy, but then again the wife used to drive it most so it got alot less......

I hear the onboard computer isn't super accurate but I guess with everybodies input you get a feeling for the fact that the beast does pretty well. I'm not sure how often the system 'averages' the numbers, so if I'm looking for something more specific I reset the trip meter.

I just spent the best part of the week on Fraser Island and was often in low range Sand Mode. 13/100L was the worst I got.

Today on the cruise home, I was getting between 7 & 8 before I hit traffic where it then moved to just over 9.

A 3.0l D4 is over 2.6 dry.....if I remember rightly. Full of people, fuel and stuff, work on the best part of 3T.

Cheers,

Kev.

Originally Posted by TerryO

That is exactly what my D3 does now as well since I got the software upgrades done.

How many people on here take into account when doing their fuel consumption figures that there speedo is out because of the incorrect calibration for the standrd tyre size?

As has been mentioned previously by others if your D3/4 has 265x60x18's fitted instead of the standard size factory fitment then your speedo reading will be true. This will change your actual mileage / fuel useage numbers by a reasonable amount either way.

cheers,
Terry

I think you will find with modern cars the speedo and odometer are two completely different things, its all just computer data but is processed differently.

That is the odometer is pretty much spot on, but the speedo will intentionally read low.

This is because our legislation states that the speedo shall read accurate or low, but never high. That is when you spoeedo says 100kmh you are doing 95 to 100 kmh....but never 105.

So I agree that the speedo would be more accurate with bigger rubber, but are you sure the odo is out in the first place?