Brentanna:
I have had this argument before, you would all know the one who goes for 10 pages before he gets it. Yes I am talking Carryfast here. A higher horsepower engine will require lower RPM do to the same work as one of less power. On your power graph your engine will have a peak HP prior to it’s top rpm. Depending on the transmission and the rear end gearing your higher HP engine should give you better performance. The lower rpm will in theory wear less than an engine of higher rpm. I give the example of the old GMC trucks of the early 1950’s they had a high oil pressure low rpm engine that would run forever at 50 mph. The Chevrolet has a higher rpm engine with a lower oil pressure engine that would constantly have main bearing issues. With a high hp engine a high speed set of rears you should be able to mate a gearbox be it a twin shift 5 and 4 or an 18 speed that will give you your low end torque and provide lower rpm on the engine at higher speeds thus giving you better overall fuel economy. The difference is the initial cost. Many companies will look at the savings they get at the purchase price rather than the cost overall of the life of the lorry. All the chrome bling added to a lorry that reduces the airflow will decrease the fuel economy.
That’s basically it.
It’s the torque figure that’s important on diesel engines. The bhp means ■■■■ all. So long as you stay in the peak torque band and drive sensibly there is no reason for a larger engine to be less economical than a smaller one. It’s when you start thrashing them about and past the peak torque band that they really start scoffing fuel. Once you’re past the peak torque point the power drops off like stone and the engine has no puff left to make you go any faster but of course still scoffs fuel because you’ve got the pedal to the floor. That’s why companies that think they’re saving money (and ultimately fuel) by specing smaller engines end up with higher fuel costs because the drivers are reving the nuts off them to try and make them go faster.
If you into heavy haulage then a bigger engine makes sense, less gear changes, less having to rag the (zb) out of it on hills, more mpg. One of the ODs on our firm had his Scania 4 series 420 drawbar chipped to 500, hell of alot better on hills and despite the extra bhp apparently gained mpg as it wasn’t being pushed so hard.
I think most of the Scania six pots are the the same aren’t they? Just with a different ECU to up the power?
It would seem like I’m on the right wavelength with this train of thought, no doubt that means I’ll end up with a 240 Gardner engine
I’ve been talking torque as it were trying to explain that the old 420 that I used to drive had 2000Nm according to the cab decals and it pulled exactly as it needed to, and they can talk about these other engines all they want but 1750 - 1800 is still short of the mark.
Told them outright today that IMO the FM is a better tool for the job than the proposed Scania’s. Still trying for an FMX but I can’t see it happening.
Grayham:
If you into heavy haulage then a bigger engine makes sense, less gear changes, less having to rag the (zb) out of it on hills, more mpg. One of the ODs on our firm had his Scania 4 series 420 drawbar chipped to 500, hell of alot better on hills and despite the extra bhp apparently gained mpg as it wasn’t being pushed so hard.
I think most of the Scania six pots are the the same aren’t they? Just with a different ECU to up the power?
Alfaman has a chipped 420 (now 500) and has said the same.
I think the new Scania range has both 12 and 13 litre engines, as I understand it these are fairly different.
Anyway I’ve changed my mind I’d like one of these, a 600hp 12x6 Merc for a mere 112,000 Euros
Grayham:
If you into heavy haulage then a bigger engine makes sense, less gear changes, less having to rag the (zb) out of it on hills, more mpg. One of the ODs on our firm had his Scania 4 series 420 drawbar chipped to 500, hell of alot better on hills and despite the extra bhp apparently gained mpg as it wasn’t being pushed so hard.
I think most of the Scania six pots are the the same aren’t they? Just with a different ECU to up the power?
It’s not usually that that makes the mpg better, it’s because when they leave the factory they’re set up conservatively and not at their full potential. Some say that it’s to pander to the tree-huggers (possible, but doesn’t make much sense to me) and others say it’s because there’s less chance of components going pop during the warranty period which obviously comes out of the dealer/manufacturer’s pocket. Now that one does make more sense…
Our little 1.7 van was absolutely horrible from new. No guts whatsoever and wouldn’t even pull at all in 6th. It was like driving it through treacle and wouldn’t even touch 40mpg unless you had the wind behind you. Had it remapped from a top guy in Motherwell, took it from the standard 100PS to around 135PS and now it flies. Oodles of torque and it’ll pull in 6th from 1100rpm (which is insane - you try it if you’ve got a similar size engine diesel car) and will keep on pulling to around 4500rpm if you wanted to, with no flat spots and no smoke. Before it would go to 3000rpm at a push then want the next cog. MPG now increased to 49mpg combined and it’ll do 60mpg at 70.
Sorry gone off on a bit of a tangient there , but yes remapping/chipping does normally see an increase in mpg as well as power. You’ve got to be careful you don’t overdo them though, because then you’ll lose mpg and it’ll smoke like a train.
Rob K:
Our little 1.7 van was absolutely horrible from new. No guts whatsoever and wouldn’t even pull at all in 6th. It was like driving it through treacle and wouldn’t even touch 40mpg unless you had the wind behind you. Had it remapped from a top guy in Motherwell, took it from the standard 100PS to around 135PS and now it flies. Oodles of torque and it’ll pull in 6th from 1100rpm (which is insane - you try it if you’ve got a similar size engine diesel car) and will keep on pulling to around 4500rpm if you wanted to, with no flat spots and no smoke. Before it would go to 3000rpm at a push then want the next cog. MPG now increased to 49mpg combined and it’ll do 60mpg at 70.
Sorry gone off on a bit of a tangient there , but yes remapping/chipping does normally see an increase in mpg as well as power. You’ve got to be careful you don’t overdo them though, because then you’ll lose mpg and it’ll smoke like a train.
You risk invalidating your warranty too if you remap.
Rob K:
Our little 1.7 van was absolutely horrible from new. No guts whatsoever and wouldn’t even pull at all in 6th. It was like driving it through treacle and wouldn’t even touch 40mpg unless you had the wind behind you. Had it remapped from a top guy in Motherwell, took it from the standard 100PS to around 135PS and now it flies. Oodles of torque and it’ll pull in 6th from 1100rpm (which is insane - you try it if you’ve got a similar size engine diesel car) and will keep on pulling to around 4500rpm if you wanted to, with no flat spots and no smoke. Before it would go to 3000rpm at a push then want the next cog. MPG now increased to 49mpg combined and it’ll do 60mpg at 70.
Sorry gone off on a bit of a tangient there , but yes remapping/chipping does normally see an increase in mpg as well as power. You’ve got to be careful you don’t overdo them though, because then you’ll lose mpg and it’ll smoke like a train.
You risk invalidating your warranty too if you remap.
8wheels:
Any thoughts on this, I’m not talking about an R730 18 tonner or anything daft but say a 44 tonner running with a triaxle stepframe lowloader mixed work but usually within an hour or so of base running empty one way and return loaded 75-100% weight. Would an R500 be a better bet than a 440 for example.
Currently I’m tootling around in an old Scania series 4 340 26 tonner doing the same work as I was doing with a 420 of similar vintage. I’m getting about 8mpg now compared to 10 before although there is a small amount of crane work and a couple of small differences which would account for some difference. It’s noticeable the extra effort involved in lugging the thing around though, the old motor would pull all day fully loaded whereas this old girl lumbers along with any load on.
A Scania 400 engine is £1500 more than the 360 engine, I’m sure that could be recouped fairly easily over a year or two. Some feedback would be good as I might have to start campaigning soon.
As long as you run Heavy you need not that much Trottle (lower Rps by same Work) with 500 then 400,but may still need more Fuel.Just the Truck holds longer and Maintenance is cheaper as it run,we say 70% were a 400 would be kicked by 100% of his Power.
If you kick down you are quicker but use more Fuel.
just think,Horses have to be feed.
That why many Fights as 500er drive more slowly at beginning of Hill were 400er overtake them the fall back at end of Hill when the 500er pulls up and go.But many 500er don’t like to get overtaken and so you are quick in a Race against Brain.
It’s your money. I would do it with a 430
Rob K:
It’s the torque figure that’s important on diesel engines. The bhp means [zb] all. So long as you stay in the peak torque band and drive sensibly there is no reason for a larger engine to be less economical than a smaller one. It’s when you start thrashing them about and past the peak torque band that they really start scoffing fuel. Once you’re past the peak torque point the power drops off like stone and the engine has no puff left to make you go any faster but of course still scoffs fuel because you’ve got the pedal to the floor. That’s why companies that think they’re saving money (and ultimately fuel) by specing smaller engines end up with higher fuel costs because the drivers are reving the nuts off them to try and make them go faster.
This is exactly the case with our FE7s. My Foden’s got less BHP, but from a start, will outpull even our 360 Daf manuals.
Rob K:
It’s the torque figure that’s important on diesel engines. The bhp means [zb] all. So long as you stay in the peak torque band and drive sensibly there is no reason for a larger engine to be less economical than a smaller one. It’s when you start thrashing them about and past the peak torque band that they really start scoffing fuel. Once you’re past the peak torque point the power drops off like stone and the engine has no puff left to make you go any faster but of course still scoffs fuel because you’ve got the pedal to the floor. That’s why companies that think they’re saving money (and ultimately fuel) by specing smaller engines end up with higher fuel costs because the drivers are reving the nuts off them to try and make them go faster.
This is exactly the case with our FE7s. My Foden’s got less BHP, but from a start, will outpull even our 360 Daf manuals.
That doesn’t make any sense, unless you’ve missed out some other key details?
My '54 plate Alpha; 12l cat 345bhp
57 plate Dafs; don’t know what litre (9?) 360bhp
From a stand the Foden will outpull the Daf and mine’s better on fuel.
The FEs; 7litre Maggie Deutz 320bhp. These things drink the fuel about 1.5 to 2mpg worse than mine and the revs go out of the green band in top gear unless you don’t go above 49-50 mph.
Muckaway:
My '54 plate Alpha; 12l cat 345bhp
57 plate Dafs; don’t know what litre (9?) 360bhp
From a stand the Foden will outpull the Daf and mine’s better on fuel.
The FEs; 7litre Maggie Deutz 320bhp. These things drink the fuel about 1.5 to 2mpg worse than mine and the revs go out of the green band in top gear unless you don’t go above 49-50 mph.
Some engines are just better than others. Personally I’ve always found the DAF engines to be gutless in comparison to same size engines in Volvo, MAN, Scania, Merc.
Muckaway:
My '54 plate Alpha; 12l cat 345bhp
57 plate Dafs; don’t know what litre (9?) 360bhp
From a stand the Foden will outpull the Daf and mine’s better on fuel.
The FEs; 7litre Maggie Deutz 320bhp. These things drink the fuel about 1.5 to 2mpg worse than mine and the revs go out of the green band in top gear unless you don’t go above 49-50 mph.
Some engines are just better than others. Personally I’ve always found the DAF engines to be gutless in comparison to same size engines in Volvo, MAN, Scania, Merc.
agreed… personally i think volvo and scania pull the best… my 500 bhp topline pulls well and is ALOT better on fuel then the premium 420’s… they are always up and down the gears struggling to pull up the hills whereas the scania just holds top gear and takes hills in its stride…
Rob K:
It’s the torque figure that’s important on diesel engines. The bhp means [zb] all. So long as you stay in the peak torque band and drive sensibly there is no reason for a larger engine to be less economical than a smaller one. It’s when you start thrashing them about and past the peak torque band that they really start scoffing fuel. Once you’re past the peak torque point the power drops off like stone and the engine has no puff left to make you go any faster but of course still scoffs fuel because you’ve got the pedal to the floor. That’s why companies that think they’re saving money (and ultimately fuel) by specing smaller engines end up with higher fuel costs because the drivers are reving the nuts off them to try and make them go faster.
This is exactly the case with our FE7s. My Foden’s got less BHP, but from a start, will outpull even our 360 Daf manuals.
That doesn’t make any sense, unless you’ve missed out some other key details?
It’s actually the power figure and at what engine speed max power is produced that’s important.In that comparison it’s big engines which always have the advantage which is why they don’t fit small capacity F1 race engines in trucks or ships and in powerful piston aircraft like the Spitfire.But the idea that (torque) drops off like a stone after peak torque has been reached is a contradiction in that peak power is basically a measurement of how well torque is sustained up the rev range after peak torque has been reached and usually relates to a drop of around just 10% of the peak torque figure at peak power.It’s after that peak power point,not peak torque,when torque,and therefore power,drops like a stone.
Steve-o:
The Morrisons DAF CF crap is plated to 44t and has a 360hp engine. Gawd it’s soul destroying driving them. They die on hills when empty never mind loaded
Christ! have you seen the Robert Wisemans Daf’s and Volvo’s they’re only like 340’s and 360’s and there going all over the place, nobody seems to have a problem overtaking them although they do get Scania’s in at christmas.
Rob K:
It’s the torque figure that’s important on diesel engines. The bhp means [zb] all. So long as you stay in the peak torque band and drive sensibly there is no reason for a larger engine to be less economical than a smaller one. It’s when you start thrashing them about and past the peak torque band that they really start scoffing fuel. Once you’re past the peak torque point the power drops off like stone and the engine has no puff left to make you go any faster but of course still scoffs fuel because you’ve got the pedal to the floor. That’s why companies that think they’re saving money (and ultimately fuel) by specing smaller engines end up with higher fuel costs because the drivers are reving the nuts off them to try and make them go faster.
This is exactly the case with our FE7s. My Foden’s got less BHP, but from a start, will outpull even our 360 Daf manuals.
That doesn’t make any sense, unless you’ve missed out some other key details?
It’s actually the power figure and at what engine speed max power is produced that’s important.In that comparison it’s big engines which always have the advantage which is why they don’t fit small capacity F1 race engines in trucks or ships and in powerful piston aircraft like the Spitfire.But the idea that (torque) drops off like a stone after peak torque has been reached is a contradiction in that peak power is basically a measurement of how well torque is sustained up the rev range after peak torque has been reached and usually relates to a drop of around just 10% of the peak torque figure at peak power.It’s after that peak power point,not peak torque,when torque,and therefore power,drops like a stone.
Now there’s a valid argument for big power engines, they don’t have to work as hard is the usual answer, although that’s not strictly true, a loaded lorry will require a specific amount of power to move down the road, for argument’s sake, let’s say that figure is 250hp to do 50mph on the level, that power is overcoming wind and rolling resistance and also the mechanical losses that are necessary to produce that power and put it to the road.
So it doesn’t matter, with all other factors being equal, engine displacement, gearing etc, if you’ve got 251hp or 1251hp, the engine will need the same amount of fuel to do 50mph, but a higher power engine will be better on fuel if that extra power is developed more efficiently. If two engines have a different power rating and the higher power is achieved by increasing the rpm limit of the engine (adding more fuel) then the lower power version is the best bet, unless you’re constantly in severe mountain terrain where you need a bucketful of rpms to allow you to change up without coming to a stop.
Mind you, put a leadfooted driver in charge and it all changes, the difference between a good driver and a bad one can be as much as 30% in fuel costs alone.
The Volvos I mentioned are ideal for work in Oxford city; their fuel consumption is as good if not better than the Fodens. It’s on mway work running on the limiter that brings them down. Maybe a splitter would help?
Muckaway:
The Volvos I mentioned are ideal for work in Oxford city; their fuel consumption is as good if not better than the Fodens. It’s on mway work running on the limiter that brings them down. Maybe a splitter would help?
What transmission do they have? We have the FL7 with speed I-Sync and running in cities will give a 1-2mpg drop. If I’m maybe 30% city/70% trunk roads then I’ll get 11-12 out of one, push it up to 50%/50% and it drops to 10-11. Although ours are 18t limited to 52mph. The odd couple that do 56 are well over the green band when running at 56.
Muckaway:
The Volvos I mentioned are ideal for work in Oxford city; their fuel consumption is as good if not better than the Fodens. It’s on mway work running on the limiter that brings them down. Maybe a splitter would help?
What transmission do they have? We have the FL7 with speed I-Sync and running in cities will give a 1-2mpg drop. If I’m maybe 30% city/70% trunk roads then I’ll get 11-12 out of one, push it up to 50%/50% and it drops to 10-11. Although ours are 18t limited to 52mph. The odd couple that do 56 are well over the green band when running at 56.
8 speed zf manuals. They’ve had their diffs altered due to poor low end power, although having driven them before and after I’d say they were better before (so what if crawler had to be used now and again?)
, but yes remapping/chipping does normally see an increase in mpg as well as power. 
You’ve got to be careful you don’t overdo them though, because then you’ll lose mpg and it’ll smoke like a train.
That doesn’t make any sense, unless you’ve missed out some other key details?
although they do get Scania’s in at christmas.