Discussion
I was talking to a dealer about changing my car and he said.. 'of course, the big advantage of the 3.6 is the extra torque'.
I went off on one and told him that torque was a completely worthless concept when talking about car engines and he looked at me like I had two heads.
'torque is twisting force' he said and I left feeling insulted.
My point is this - as a static force, like doing up a nut, torque means something, but IMHO it is impossible to feel what this is in a car without taking revs into account, which means power.
I imagine torque is important for calculating drivetrain stresses, and it may be an indicator of power produced at lowish revs, but given the vastly different rpms of max torque (compare rx7 vs any tdi) I believe quoting max torques is just barmy.
Wouldn't it be better to quote power at specific rev values?
The only benefit I can think of for high engine torque is when I wash my car and the calipers stick on.
Can anyone confirm, or explain what torque actually feels like?
confused,
simon
I went off on one and told him that torque was a completely worthless concept when talking about car engines and he looked at me like I had two heads.
'torque is twisting force' he said and I left feeling insulted.
My point is this - as a static force, like doing up a nut, torque means something, but IMHO it is impossible to feel what this is in a car without taking revs into account, which means power.
I imagine torque is important for calculating drivetrain stresses, and it may be an indicator of power produced at lowish revs, but given the vastly different rpms of max torque (compare rx7 vs any tdi) I believe quoting max torques is just barmy.
Wouldn't it be better to quote power at specific rev values?
The only benefit I can think of for high engine torque is when I wash my car and the calipers stick on.
Can anyone confirm, or explain what torque actually feels like?
confused,
simon
I'm afraid your salesman bloke was correct! Torque does make a difference if only in the lower end of the rev range, as its the 'twisting force' mentioned you will find yourself changing gear a lot less in a higher torque motor, for example when going up hill the car will be less likely to lose revs quickly as the engine is able to turn the crankshaft a lot easier.
F1 cars rely on high reving horsepower but have very little torque, WRC cars have ooodles of midrange torque that can pull them out of the bends at a much lower RPM but dont have the top end grunt as they dont need to do 200mph.
F1 cars rely on high reving horsepower but have very little torque, WRC cars have ooodles of midrange torque that can pull them out of the bends at a much lower RPM but dont have the top end grunt as they dont need to do 200mph.
sprior said:
At the risk of being stupid, my point is this:
You cannot feel torque.
You feel the power in the form of acceleration, which is the torque and rpm together.
I reckon manufacturers need to know torque to work out drivetrain stresses, but it is a nonsense number for a driver to know.
You could argue that we don't 'need' to know if our cars can do 150 mph, or 0-60 in 4 seconds, since that's nonsense given that the limit is 70; but I bet those figures sell more cars than colour or how many airbags are fitted. Numptymobiles possibly excepted...
Ian
sprior said:
You cannot feel torque.
You feel the power in the form of acceleration, which is the torque and rpm together.
As far as my limited understanding of it goes, torque is the work being done and therefore what you feel and experience. Power is just the rate at which the work is being done.
If you actually work it all through, it's the torque that makes you accelerate as it's the force that turns the wheels and how hard they turn them.
The biggest indicator of acceleration is power.
The more power you have the faster you go.
Power is an independent value of everything else in your car. Torque on the other hand can be geared and reduced.
If we have an F1 car for example, the torque is low, say 500Nm developed over 18000rpm. A road car with say 100% more torque revs to 6000rpm, like a Merc SL65 AMG with 1000Nm...
Since the F1 car revs for 3x longer, we can have a gearbox with 3x the reduction to go the same speed in each gear as the Merc lets say.
So at the wheel (this is all generalised by the way), the Merc has 1000Nm, but the F1 has 1500Nm since we can recuce it's gearing 3x as much!
This car has less torque than the Merc, but will push you back in your seat 50% harder in the optimum gear!
However, having a wide torque band, ie, having a high proportion of the peak torque developed for longer across the rpm band, makes road use better, simply because you have more twisting force for more of the time in any gear.
Ultimately though, no matter how much torque or power, revving to peak power before changing gear is optimum for acceleration.
A Honda S2000 with 240bhp will always cover the 1/4 mile and have a terminal speed the same no matter how much torque the car has in the mid range.
Power takes into account everything, since it's a function of rpm and torque. Without taking into consideration rpm, as we do with torque, we ignore gearing, which is very important as I pointed out above.
Look at an Audi RS6, loads of torque right across the rpm band and right upto peak power. The push in your back is almost constant throughout a gear. Still though, your better off in a lower gear as much as possible, since the torque at the wheel is higher through the lower gearing!
Torque can be an important figure to know if it's particularaly good, like an Audi RS6 which has a mountain of torque low down, at a 1/3rd of peak power. An S2000 has a small amount of torque at about 4/5ths of peak power rpm's. However, if your willing to rag it and use the power band, the S2000 is fine, just not that flexible!
Just driver preference really, but I like a healthy dose of torque low down... Usually having the same kind of torque in lbft as horsepower in bhp at half the rpm of the peak power makes a nice power delivery.
A nice normally aspirated 6 or 8 pot engine with a fairly big capacity usually fills this role excellently for my driving tastes!
Seya
Dave
The more power you have the faster you go.
Power is an independent value of everything else in your car. Torque on the other hand can be geared and reduced.
If we have an F1 car for example, the torque is low, say 500Nm developed over 18000rpm. A road car with say 100% more torque revs to 6000rpm, like a Merc SL65 AMG with 1000Nm...
Since the F1 car revs for 3x longer, we can have a gearbox with 3x the reduction to go the same speed in each gear as the Merc lets say.
So at the wheel (this is all generalised by the way), the Merc has 1000Nm, but the F1 has 1500Nm since we can recuce it's gearing 3x as much!
This car has less torque than the Merc, but will push you back in your seat 50% harder in the optimum gear!
However, having a wide torque band, ie, having a high proportion of the peak torque developed for longer across the rpm band, makes road use better, simply because you have more twisting force for more of the time in any gear.
Ultimately though, no matter how much torque or power, revving to peak power before changing gear is optimum for acceleration.
A Honda S2000 with 240bhp will always cover the 1/4 mile and have a terminal speed the same no matter how much torque the car has in the mid range.
Power takes into account everything, since it's a function of rpm and torque. Without taking into consideration rpm, as we do with torque, we ignore gearing, which is very important as I pointed out above.
Look at an Audi RS6, loads of torque right across the rpm band and right upto peak power. The push in your back is almost constant throughout a gear. Still though, your better off in a lower gear as much as possible, since the torque at the wheel is higher through the lower gearing!
Torque can be an important figure to know if it's particularaly good, like an Audi RS6 which has a mountain of torque low down, at a 1/3rd of peak power. An S2000 has a small amount of torque at about 4/5ths of peak power rpm's. However, if your willing to rag it and use the power band, the S2000 is fine, just not that flexible!
Just driver preference really, but I like a healthy dose of torque low down... Usually having the same kind of torque in lbft as horsepower in bhp at half the rpm of the peak power makes a nice power delivery.
A nice normally aspirated 6 or 8 pot engine with a fairly big capacity usually fills this role excellently for my driving tastes!
Seya
Dave
Griff 4.0 lot of low down torque (will pull from 1000 revs in 4th) revs to about 5500-6000, bhp 240 bhp ish
honda s2000 bugger all torque revs to 9000, about 240 bhp. (ie have to really stir gearbox use the rev range to go quickly)
GRiff much quicker to 60, much more flexible in gears engine.....
F1 cars do have bugger all torque, but don't try to drive one in traffic
B
>> Edited by bjwoods on Monday 24th May 14:33
honda s2000 bugger all torque revs to 9000, about 240 bhp. (ie have to really stir gearbox use the rev range to go quickly)
GRiff much quicker to 60, much more flexible in gears engine.....
F1 cars do have bugger all torque, but don't try to drive one in traffic
B
>> Edited by bjwoods on Monday 24th May 14:33
An current F1 car has more torque than many supercars today.
The peak torque of say this years Ferrari F1 car is probably in excess of 650Nm...
Thats alot, especially with gearing for say 200mph, and a top end rpm of 18000rpm.
Give it the same gearbox as an Enzo, but double the final drive reduction since it revs twice as hard, and you have double the kind of torque at the wheel an Enzo can muster!!!
Still though, power, and power to weight are the best indicators of outright acceleration.
I agree though, on real roads a torquey Griff will be faster than a peaky S2000. On a racetrack they'll be similar down the straights though, if they weigh the same anyhow! (though a griff has quite long gearing compared to the S2000, which offsets the large torque at low end rev range somewhat)...
Hmmmm
Dave
The peak torque of say this years Ferrari F1 car is probably in excess of 650Nm...
Thats alot, especially with gearing for say 200mph, and a top end rpm of 18000rpm.
Give it the same gearbox as an Enzo, but double the final drive reduction since it revs twice as hard, and you have double the kind of torque at the wheel an Enzo can muster!!!
Still though, power, and power to weight are the best indicators of outright acceleration.
I agree though, on real roads a torquey Griff will be faster than a peaky S2000. On a racetrack they'll be similar down the straights though, if they weigh the same anyhow! (though a griff has quite long gearing compared to the S2000, which offsets the large torque at low end rev range somewhat)...
Hmmmm
Dave
[quote=Mikey G]WRC cars have ooodles of midrange torque that can pull them out of the bends at a much lower RPM but dont have the top end grunt as they dont need to do 200mph. [/quote
Sort of. They breathe through nasty restrictors which limit power.
If they were unshackled, and had a flat torque curve to 6500rpm then we're talking in excess of 500bhp I suspect.
Sort of. They breathe through nasty restrictors which limit power.
If they were unshackled, and had a flat torque curve to 6500rpm then we're talking in excess of 500bhp I suspect.
Mr E said:
Sort of. They breathe through nasty restrictors which limit power.
If they were unshackled, and had a flat torque curve to 6500rpm then we're talking in excess of 500bhp I suspect.
And because they have these nasty restrictors they have developed the engines to produce more in the midrange by not bolting on huge turbos to start with, this geared correctly makes the cars very quick off the mark and nothing to do with peak BHP
Mr Whippy said:
An current F1 car has more torque than many supercars today.
The peak torque of say this years Ferrari F1 car is probably in excess of 650Nm...
Thats alot, especially with gearing for say 200mph, and a top end rpm of 18000rpm.
Give it the same gearbox as an Enzo, but double the final drive reduction since it revs twice as hard, and you have double the kind of torque at the wheel an Enzo can muster!!!
Still though, power, and power to weight are the best indicators of outright acceleration.
I agree though, on real roads a torquey Griff will be faster than a peaky S2000. On a racetrack they'll be similar down the straights though, if they weigh the same anyhow! (though a griff has quite long gearing compared to the S2000, which offsets the large torque at low end rev range somewhat)...
Hmmmm
Dave
650 Nm? No way, I guess it´s 450 Nm maximum. If you do the maths, you´ll find 650 Nm is well too high for an estimated 900´ish HP @ 18000 rpm. I´d say 400-450 Nm @ 15000? rpm, or 13-15 Nm/liter.
BTW, I agree with the whole Dave´s point about power/torque.
OutOn said:
If you do the maths, you´ll find 650 Nm is well too high for an estimated 900´ish HP @ 18000 rpm.
I didn't think peak torque was often anywhere near as high in the rev range as peak power. So converting 900bhp @18000rpm to torque (262lbft/354Nm) is going to be an underestimate at best.
Also, the idea of the original poster (if I'm correct) was comparing torque at the wheels. As the F1 car revs to more than double that of a road car, it's gearing will give it more than double the engine to wheels torque ratio. So, the F1 cars 350Nm is then equivalent to a road car's 700Nm.
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