Interesting subject,I won’t get involved in the rights and wrongs of our different operating worlds except give you some figures of fuel consumption of my last road train prime mover which started life in the cattle carting industry of northern Aus in mainly 3 trailer double decker configuration.
For its first 300000 kms the onboard computer showed it was returning 880metres per litre which i.m told by my eldest grandson is 2.07MPG, at that point it was retired to the general freight industry mainly in the supply to the oil and gas exploration and after almost another 400000 kms the figure was showing an average of 1.3kms per litre [3.06MPG]. The truck was pulling a mixture of 2 and 3 trailer combinations and i was happy with that figure but the motor succumbed so it was replaced with a Cat C15 set at 550hp and that immediately showed a small improvement on the 575hp V8 Macks figures.
It wasn’t much of an improvement but enough to show that technology had advanced again in the engine manufacturing world. I spoke with Cats technical people and they informed me that their research and experience over a number of similar repowers showed that if I replaced the 18 speed Mack gear box with the latest 18 speed R/R I could expect another slight improvement on the fuel figure as the Mack box being of triple countershaft configuration required/absorbed slightly more slightly more power than the R/R to operate. I didn’t follow their advice as the piggy bank was little depleted at that time.
DIG:
Interesting subject,I won’t get involved in the rights and wrongs of our different operating worlds except give you some figures of fuel consumption of my last road train prime mover which started life in the cattle carting industry of northern Aus in mainly 3 trailer double decker configuration.
For its first 300000 kms the onboard computer showed it was returning 880metres per litre which i.m told by my eldest grandson is 2.07MPG, at that point it was retired to the general freight industry mainly in the supply to the oil and gas exploration and after almost another 400000 kms the figure was showing an average of 1.3kms per litre [3.06MPG]. The truck was pulling a mixture of 2 and 3 trailer combinations and i was happy with that figure but the motor succumbed so it was replaced with a Cat C15 set at 550hp and that immediately showed a small improvement on the 575hp V8 Macks figures.
It wasn’t much of an improvement but enough to show that technology had advanced again in the engine manufacturing world. I spoke with Cats technical people and they informed me that their research and experience over a number of similar repowers showed that if I replaced the 18 speed Mack gear box with the latest 18 speed R/R I could expect another slight improvement on the fuel figure as the Mack box being of triple countershaft configuration required/absorbed slightly more slightly more power than the R/R to operate. I didn’t follow their advice as the piggy bank was little depleted at that time.
Cheers DIG
You buga D those mpg figures would make grown men cry here, different world though.Just in case you know are euro motors doing any better or worse mpg wise ? paul
I have seen fuel consumption of less than a km per litre, it makes me cry my eyes out. I have found a solution to it though…
I changed the dash display so that I can’t see the fuel consumption readout!
My main consideration when buying a lorry is reliability, it doesn’t matter what else it brings to the table, if it’s in the workshop it’s no use to man or beast.
Paul/Coomsey I regret no first hand info on the latest from Europe but second hand is that The big engines are performing well,apparently now auto trans being more the norm than multi ratio manually operated boxes,i will try to find out more but don’t rush me as I.m on holiday from my busy retirement schedule.
NM Couldn’t agree more about the reliability factor but I enjoyed the challenge of improving the consumption reading over a period of 2/3 years,that decimal point took an awful long time to move.
DIG:
Paul/Coomsey I regret no first hand info on the latest from Europe but second hand is that The big engines are performing well,apparently now auto trans being more the norm than multi ratio manually operated boxes,i will try to find out more but don’t rush me as I.m on holiday from my busy retirement schedule.
NM Couldn’t agree more about the reliability factor but I enjoyed the challenge of improving the consumption reading over a period of 2/3 years,that decimal point took an awful long time to move.
DIG
My god if the euro guys can do the reliabilty thing n move the decimal point up a few we will soon be looking at world ■■■■■■■■■■, scary.
D don,t rush about on my account we,ve got all the time in the world if lucky Paul
Muckaway:
Did anyone here do the SAFED course? Your company got a grant for someone to take you around a set course, count your gearchanges and then take you back to the office. There you got criticised typically for using your gears to slow down and letting the engine rev in low gear for maximum engine braking (I know ). You were told to skip lots more gears (worked in a Cat powered Foden but the Volvo FE drivers struggled) and use the brakes more rather than gear shifts.
Anyway, I finished top and got sod all extra in wage packet.
I did this twice; first time in a DAF 95 artic/16 speed box c2002. Second time was in a Volvo FL6 23t urban artic/6 speed box. Needless to say, there was far less scope for ‘fuel saving/block changing’ in the Volvo
I did ‘play the game’ though; drove round second time as instructed to glean the ‘benefits’, shook the instructors hand, thanked him for his time/advice and the free hi-viz vest and certificate… then went back to ‘my’ driving the following day
Not sat one since the I-shift become universal - should think that makes much of the old course redundant. The other training about anticipation etc, is what you should be doing in the first place!
i became the safed trainer for the company I worked for, a mixed fleet on pallet deliveries and the overnight trunking, we had two erf units with the kit installed to do the fuel monitoring, I explained to the driver that I was not there to teach them how to drive, I was only there to see if they could get the fuel figures better, some accepted that some disagreed, but all got better results, some only tiny amounts but the theory worked, one thing we did not do was name and shame as this can bring out the I don’t care bravado which can greatly increase the amounts used, I only got enthusiastic about paying for there brew and sandwich on the break between drives, and that paid dividends straight away,
newmercman:
My main consideration when buying a lorry is reliability, it doesn’t matter what else it brings to the table, if it’s in the workshop it’s no use to man or beast.
This is the attitudes that tipper firms are doing now. More and more subbies buying steel bodied trucks that can carry anything rather than just the lightest alloy.
He’s retired now, but I knew an OD who always had a really lightweight alloy body but liked to pick and choose his work, and cry about rates per ton. Where he was doing a round trip with nearly 21t on board, the steel tippers were going out with 19 and backloading stuff so 38t carried. He could’ve done the same but re rubble “no, it’ll damage the body…” When offered muck shifting “no, it sticks like ■■■■ to a blanket if it’s wet.” Even dry clay and dry topsoil was refused because he couldn’t get the full weight on.
DIG:
Paul/Coomsey I regret no first hand info on the latest from Europe but second hand is that The big engines are performing well,apparently now auto trans being more the norm than multi ratio manually operated boxes,i will try to find out more but don’t rush me as I.m on holiday from my busy retirement schedule.
Ironically I’d bet that the Scania 730 at least would actually be more economical with the 18 speed Fuller.For some reason the factory seems to think that up shifting in around 400 rpm chunks at around 1,400-1500 back to around 1000-1100 is supposedly more economical,in so called ‘eco’ mode,than up shifting it at 1,200-1,300 rpm using the close ratios of the 18 speed would be.Bearing in mind the 15% + torque advantage at the equivalent rpm over the 620.
Carryfast:
Ironically I’d bet that the Scania 730 at least would actually be more economical with the 18 speed Fuller.For some reason the factory seems to think that up shifting in around 400 rpm chunks at around 1,400-1500 back to around 1000-1100 is supposedly more economical,in so called ‘eco’ mode,than up shifting it at 1,200-1,300 rpm using the close ratios of the 18 speed would be.Bearing in mind the 15% + torque advantage at the equivalent rpm over the 620.
At what engine speed is minimum full load SFC on these modern engines?
Carryfast:
Ironically I’d bet that the Scania 730 at least would actually be more economical with the 18 speed Fuller.For some reason the factory seems to think that up shifting in around 400 rpm chunks at around 1,400-1500 back to around 1000-1100 is supposedly more economical,in so called ‘eco’ mode,than up shifting it at 1,200-1,300 rpm using the close ratios of the 18 speed would be.Bearing in mind the 15% + torque advantage at the equivalent rpm over the 620.
At what engine speed is minimum full load SFC on these modern engines?
Bearing in mind that their own eco programming,of the standard fit auto,up shifts at no more than 1,400-1,500 rpm,as expected it’s a reasonable bet that it more or less tracks the torque curve ?.Which in this case is just a completely flat line from around 1,000 - 1,400 rpm and then more or less falls off a cliff to the point where it’s dropped more than 30% at peak power and that actually taking place a bit sooner than 1,400 rpm in the case of the 730 v the 620.Thereby making use of the 18 speed at least in the 730 even more relevant.I’d really like to be given the chance to test such a spec pulling a decent weight.
Carryfast:
Ironically I’d bet that the Scania 730 at least would actually be more economical with the 18 speed Fuller.For some reason the factory seems to think that up shifting in around 400 rpm chunks at around 1,400-1500 back to around 1000-1100 is supposedly more economical,in so called ‘eco’ mode,than up shifting it at 1,200-1,300 rpm using the close ratios of the 18 speed would be.Bearing in mind the 15% + torque advantage at the equivalent rpm over the 620.
At what engine speed is minimum full load SFC on these modern engines?
(zb) A can you translate to the illiterate/stupid, me. Paul
Carryfast:
Ironically I’d bet that the Scania 730 at least would actually be more economical with the 18 speed Fuller.For some reason the factory seems to think that up shifting in around 400 rpm chunks at around 1,400-1500 back to around 1000-1100 is supposedly more economical,in so called ‘eco’ mode,than up shifting it at 1,200-1,300 rpm using the close ratios of the 18 speed would be.Bearing in mind the 15% + torque advantage at the equivalent rpm over the 620.
At what engine speed is minimum full load SFC on these modern engines?
(zb) A can you translate to the illiterate/stupid, me. Paul
SFC is just a measure of how efficiently/how much of the burnt fuel is actually turned into power and at what engine speed shown plotted on a graph v engine speed.
Which usually reflects specific torque ( how much torque the engine makes relative to its capacity ) and at what engine speed it makes the most of it.Which is also shown by the torque curve plotted against the engine speed on a graph.In this case that’s between around 1,000 rpm and almost 1,400 rpm.Which is therefore the ideal most fuel efficient rev range to work the engine over under load.
The goal for fuel efficiency accepted as being the lowest possible engine speed v the highest possible ( specific ) torque figure which hopefully should then be reflected in the SFC figure.
Dig, those decimal points put a lot of money in the bank. The savings per tenth are huge when you’re in the low single digits, but hardly noticeable when you get up in the high 3kms per litre and better.
newmercman:
Dig, those decimal points put a lot of money in the bank. The savings per tenth are huge when you’re in the low single digits, but hardly noticeable when you get up in the high 3kms per litre and better.
Yes Indeed N/M especially when a 1000 litres was ingested every 3rd day or so and was expelled via the sooters.
I could only get 3km/litre bobtail. lol.
Carryfast:
Ironically I’d bet that the Scania 730 at least would actually be more economical with the 18 speed Fuller.For some reason the factory seems to think that up shifting in around 400 rpm chunks at around 1,400-1500 back to around 1000-1100 is supposedly more economical,in so called ‘eco’ mode,than up shifting it at 1,200-1,300 rpm using the close ratios of the 18 speed would be.Bearing in mind the 15% + torque advantage at the equivalent rpm over the 620.
At what engine speed is minimum full load SFC on these modern engines?
(zb) A can you translate to the illiterate/stupid, me. Paul
SFC is just a measure of how efficiently/how much of the burnt fuel is actually turned into power and at what engine speed shown plotted on a graph v engine speed.
Which usually reflects specific torque ( how much torque the engine makes relative to its capacity ) and at what engine speed it makes the most of it.Which is also shown by the torque curve plotted against the engine speed on a graph.In this case that’s between around 1,000 rpm and almost 1,400 rpm.Which is therefore the ideal most fuel efficient rev range to work the engine over under load.
The goal for fuel efficiency accepted as being the lowest possible engine speed v the highest possible ( specific ) torque figure which hopefully should then be reflected in the SFC figure.
The makers don’t publish the fuel consumption curves of the engines any more. The marine versions have more detailed specification sheets, presumably because you can still pick and choose which engine goes in what “chassis”. With modern lorries, there is no such choice, although you would think that the maker of a vehicle with a good SFC graph would be keen to use that as a pointer to good MPG in its adverts. You can’t argue with test results… oh yes you can- see above. The next two numbers are 9 and, I think, 9.
). You were told to skip lots more gears (worked in a Cat powered Foden but the Volvo FE drivers struggled) and use the brakes more rather than gear shifts.
and got sod all extra in wage packet. 
and then more or less falls off a cliff to the point where it’s dropped more than 30% at peak power and that actually taking place a bit sooner than 1,400 rpm in the case of the 730 v the 620.Thereby making use of the 18 speed at least in the 730 even more relevant.I’d really like to be given the chance to test such a spec pulling a decent weight. 
