Carryfast:
By the way the 620 is actually putting out more than 600 hp at 1,500 rpm and over 500 at 1,200 and more than 425 at 1,000 rpm. The torque curve is just totally flat at 3,000 nm max torque all the way from 1,000-1,400 rpm.
It’s a monster for sure, I haven’t had the pleasure of driving one, but my mate at Scania reckons that the gap between it and the 580 is about the same as the gap between the 580 and the 480, it may only be an extra 40 horses, but every one of them is a thoroughbred
Such a shame they’re wasted over there, I could really put one to work properly over here, a nice 18spd double overdrive with 3:25 gears and that baby would fly
The kind of power and torque the 730 produces it may not matter but I’m sure on most of the modern high power engines it limits the power and torque avalible especially in the lower gears to protect the driveline.
Also in the real world of driving lorrys not googling figures you would probaly need more than the 12 gears scania offer to keep it in such a limited rev band in all road conditions and taking in to account other road users messing things up.
Also those of us who ain’t as good a driver as carryfast might occasionally slip over the rev limit as we are busy singing along to the radio are in a rush or have just had a tear up with the mrs in the phone.
A good way to see how scania think it should be driven would to be test an Opticruise model and see when that changes gear.
Of course the big v8 killer for fuel consumption is dropping a cog opening the window and burying your foot in the carpet especially in tunnels. Although I’m led to believe the new 730 v8 is rather muted.
mpg for any engine regardless of torque or power is governed by how far your right foot is pushing down on the pedal.
You might only be doing 1200rpm but if your foot is flat to the floor you might as well be red lining it. The most fuel efficient way of driving is to let it ( if it could ) run on idle through all the gears.
Some drivers do think that going downhill with no throttle in a low gear uses more fuel 'cos the engines revving higher
Foxstein:
mpg for any engine regardless of torque or power is governed by how far your right foot is pushing down on the pedal.
You might only be doing 1200rpm but if your foot is flat to the floor you might as well be red lining it. The most fuel efficient way of driving is to let it ( if it could ) run on idle through all the gears.
Errr no it isn’t
A truck with a specific mass requires a specific amount of energy (from fuel) to produce the kinetic energy required to get it to a specific speed, as long as you’re operating the engine close to the lowest point in its specific fuel consumption curve then it matters not one bit how hard you step on the loud pedal, it will use the same amount of fuel, that my friend is pure physics, not a theory, not an opinion, but a cold hard fact
With a mechanical fuel pump it’s a different story, the harder you push the more fuel goes in, but not on a modern electronic engine
Foxstein:
mpg for any engine regardless of torque or power is governed by how far your right foot is pushing down on the pedal.
You might only be doing 1200rpm but if your foot is flat to the floor you might as well be red lining it. The most fuel efficient way of driving is to let it ( if it could ) run on idle through all the gears.
Errr no it isn’t
A truck with a specific mass requires a specific amount of energy (from fuel) to produce the kinetic energy required to get it to a specific speed, as long as you’re operating the engine close to the lowest point in its specific fuel consumption curve then it matters not one bit how hard you step on the loud pedal, it will use the same amount of fuel, that my friend is pure physics, not a theory, not an opinion, but a cold hard fact
With a mechanical fuel pump it’s a different story, the harder you push the more fuel goes in, but not on a modern electronic engine
So if I understand your theory correctly the electronics govern the amount of fuel going into the cylinders regardless of how far the pedal is pushed down.
if that were the case it why ( apologies for using a car engine as an example) does a Mondeo accelorator flat to the floor only give 8 mpg ?
Also why put turbos on engines that force more air and fuel into the engine to produce more power ?
Foxstein:
mpg for any engine regardless of torque or power is governed by how far your right foot is pushing down on the pedal.
You might only be doing 1200rpm but if your foot is flat to the floor you might as well be red lining it. The most fuel efficient way of driving is to let it ( if it could ) run on idle through all the gears.
Errr no it isn’t
A truck with a specific mass requires a specific amount of energy (from fuel) to produce the kinetic energy required to get it to a specific speed, as long as you’re operating the engine close to the lowest point in its specific fuel consumption curve then it matters not one bit how hard you step on the loud pedal, it will use the same amount of fuel, that my friend is pure physics, not a theory, not an opinion, but a cold hard fact
With a mechanical fuel pump it’s a different story, the harder you push the more fuel goes in, but not on a modern electronic engine
That would be true if you don’t allow for air resistance load/ friction on tyres etc. The more you press the accelerator down the more fuel it uses, that is how engines work, it’s the burning of the fuel that produces the power, if you want to go faster you need to burn more fuel. If you have a head wind you will use more fuel. Going up a hill you use more fuel even though your not going any faster because you’ve got your foot to the floor to try and maintain the speed and the engine is using that extra fuel to produce the extra power to make it happen.
Foxstein:
mpg for any engine regardless of torque or power is governed by how far your right foot is pushing down on the pedal.
You might only be doing 1200rpm but if your foot is flat to the floor you might as well be red lining it. The most fuel efficient way of driving is to let it ( if it could ) run on idle through all the gears.
Errr no it isn’t
A truck with a specific mass requires a specific amount of energy (from fuel) to produce the kinetic energy required to get it to a specific speed, as long as you’re operating the engine close to the lowest point in its specific fuel consumption curve then it matters not one bit how hard you step on the loud pedal, it will use the same amount of fuel, that my friend is pure physics, not a theory, not an opinion, but a cold hard fact
With a mechanical fuel pump it’s a different story, the harder you push the more fuel goes in, but not on a modern electronic engine
That would be true if you don’t allow for air resistance load/ friction on tyres etc. The more you press the accelerator down the more fuel it uses, that is how engines work, it’s the burning of the fuel that produces the power, if you want to go faster you need to burn more fuel. If you have a head wind you will use more fuel. Going up a hill you use more fuel even though your not going any faster because you’ve got your foot to the floor to try and maintain the speed and the engine is using that extra fuel to produce the extra power to make it happen.
Which is why they use load sensing in electronic engines in addition to engine speed sensing.It is possible that it will call for more fuel under high load and low rpm conditions than at low load and high rpm situations such as when running on the flat at high speed compared to pulling 40 t gross uphill.However it’s the situations when high load and high engine speeds are combined which use most fuel and the best way of decreasing load and engine speed is to increase the power/torque to weight ratio with an engine that puts out more power/torque,at equivalent weight,at a lower engine speed.
Foxstein:
mpg for any engine regardless of torque or power is governed by how far your right foot is pushing down on the pedal.
You might only be doing 1200rpm but if your foot is flat to the floor you might as well be red lining it. The most fuel efficient way of driving is to let it ( if it could ) run on idle through all the gears.
Errr no it isn’t
A truck with a specific mass requires a specific amount of energy (from fuel) to produce the kinetic energy required to get it to a specific speed, as long as you’re operating the engine close to the lowest point in its specific fuel consumption curve then it matters not one bit how hard you step on the loud pedal, it will use the same amount of fuel, that my friend is pure physics, not a theory, not an opinion, but a cold hard fact
With a mechanical fuel pump it’s a different story, the harder you push the more fuel goes in, but not on a modern electronic engine
That would be true if you don’t allow for air resistance load/ friction on tyres etc. The more you press the accelerator down the more fuel it uses, that is how engines work, it’s the burning of the fuel that produces the power, if you want to go faster you need to burn more fuel. If you have a head wind you will use more fuel. Going up a hill you use more fuel even though your not going any faster because you’ve got your foot to the floor to try and maintain the speed and the engine is using that extra fuel to produce the extra power to make it happen.
What you say about aerodynamic and rolling resistance (no Kev & Spanky, not tyres this time ) is true, but that affects the amount of kinetic energy required to get the truck up to speed, so it still doesn’t relate to where your right boot is. Carryfast and KR79 explain that (They make such a lovely couple ) It all relates to an engines specific fuel consumption and on an electronically controlled diesel engine fuel use depends on where the RPMs are in relation to that, no matter what you do with the pedal. You know how on a modern lorry you pull away without pushing the accelerator down, that’s because the electronics are supplying the right amount of fuel to get you going, it’s the same principal.
Going uphill or into a head wind requires more kinetic energy, so that will obviously require more energy input to reach the same velocity
Driving pedal on the floor is the most fuel efficient way, no matter mechanical or electric engine. Just keep the revs down and change gears as little as possible. Opticurses and I-■■■■■ are not fuel efficient, a skilled driver always uses less fuel with manual.
Thank you. Although I hope your not insinuating anything due to my choice of football team lol. It’s a geographical allegiance to my home town nothing else.
Foxstein:
You might only be doing 1200rpm but if your foot is flat to the floor you might as well be red lining it.
As has been said Foxstein, that is totally wrong. Specific fuel consumption is measured as; g/KWh
That is g= grams (absolute mass) of fuel divided by KW= killowats (power) h= hour
so, a specific fuel consumption of 192 g/KWh is worked out as above. (am I boring you yet?)
@ 1,200 rpm a Scania R620 (being driven, not freewheeling) is producing about 430KW so if the SFC was 192 g/KWh, each hour it would use 82,560g’s of diesel.
@ 1,900 rpm its producing 540 KW (again under power) so would use 103,680g’s of fuel each & every hour.
So there it is, keeping the revs @ a constant 1,200 rpm rather than 1,900 it will use 21,120g’s LESS diesel which is almost a 25% saving.
The torque curve is just totally flat at 3,000 nm max torque all the way from 1,000-1,400 rpm.
