Discussion
On phone so excuse lack of searching and perfhickt grammah skillz.
Say you have two identical cars in every way shape and form, except one has 100bhp with 100ftlb or torque the other has 200bhp but 50ftlb of torque, both set off at the same time on the flat with the intent to go up the same hill, which would be faster up the hill?
Say you have two identical cars in every way shape and form, except one has 100bhp with 100ftlb or torque the other has 200bhp but 50ftlb of torque, both set off at the same time on the flat with the intent to go up the same hill, which would be faster up the hill?
The car with 100ft of torque on a short hill
in the 200bhp car you'd have to rev the nuts off the car for the same power,
change gear, rev the nuts off again, change gear.
It takes time to move up the rev range the less torque you have the longer it takes.
On a long hill however the 200bhp car would win with a much faster exit velocity.
in the 200bhp car you'd have to rev the nuts off the car for the same power,
change gear, rev the nuts off again, change gear.
It takes time to move up the rev range the less torque you have the longer it takes.
On a long hill however the 200bhp car would win with a much faster exit velocity.
pits said:
On phone so excuse lack of searching and perfhickt grammah skillz.
Say you have two identical cars in every way shape and form, except one has 100bhp with 100ftlb or torque the other has 200bhp but 50ftlb of torque, both set off at the same time on the flat with the intent to go up the same hill, which would be faster up the hill?
They won't be exactly the same.Say you have two identical cars in every way shape and form, except one has 100bhp with 100ftlb or torque the other has 200bhp but 50ftlb of torque, both set off at the same time on the flat with the intent to go up the same hill, which would be faster up the hill?
HP = torque x rpm/5252
So to get 200hp from only 50lb ft would require much high revs. This would then dictate gearing.
Small light vehicles (bikes, open seaters and small sports cars) can get away with this better than heavier vehicles.
So it would then depend on the type of vehicle you where comparing too.
Lastly, how the power is made is also quite important. PEAK figures are pretty pointless unless you know the "under the curve" figures too.
The annoyingly practical answer is that it's torque at the wheels that matters, and if one car is revving twice as high as the other one, it'll need gearing half as long to do similar speeds during the race (and certainly if the car is to be useable), so the torque at the wheels would probably end up being similar between the two cars, giving similar acceleration. This then just leaves the power, which is much higher in the 200bhp car, so that would win the race eventually if it was long enough.
This is a common comparison seen between 330i and 330d for example. In most situations, the 330i has been shown to be quicker for the same reasons as I give above. For the other way round, compare a 120i with an S2000 - both have about 150lb-ft of torque and yet the S2000 does 0-60 in 5.4 seconds compared with the BMW's 8 seconds.
This is a common comparison seen between 330i and 330d for example. In most situations, the 330i has been shown to be quicker for the same reasons as I give above. For the other way round, compare a 120i with an S2000 - both have about 150lb-ft of torque and yet the S2000 does 0-60 in 5.4 seconds compared with the BMW's 8 seconds.
xyphod said:
The car with 100ft of torque on a short hill
in the 200bhp car you'd have to rev the nuts off the car for the same power,
change gear, rev the nuts off again, change gear.
It takes time to move up the rev range the less torque you have the longer it takes.
On a long hill however the 200bhp car would win with a much faster exit velocity.
Only if the gearing doesn't suit the engine though. Low, close gearing on a low torque engine will get the same torque at the wheels as longer gearing with a higher torque engine. Having their nuts rev'd off is what high power, low torque engines are designed to do so don't let that get in the way of a good debate.in the 200bhp car you'd have to rev the nuts off the car for the same power,
change gear, rev the nuts off again, change gear.
It takes time to move up the rev range the less torque you have the longer it takes.
On a long hill however the 200bhp car would win with a much faster exit velocity.
busta said:
xyphod said:
The car with 100ft of torque on a short hill
in the 200bhp car you'd have to rev the nuts off the car for the same power,
change gear, rev the nuts off again, change gear.
It takes time to move up the rev range the less torque you have the longer it takes.
On a long hill however the 200bhp car would win with a much faster exit velocity.
Only if the gearing doesn't suit the engine though. Low, close gearing on a low torque engine will get the same torque at the wheels as longer gearing with a higher torque engine. Having their nuts rev'd off is what high power, low torque engines are designed to do so don't let that get in the way of a good debate.in the 200bhp car you'd have to rev the nuts off the car for the same power,
change gear, rev the nuts off again, change gear.
It takes time to move up the rev range the less torque you have the longer it takes.
On a long hill however the 200bhp car would win with a much faster exit velocity.
People always say "rev the nuts off" as if it's an effort to do it. I don't recall it being more effort to do 7,000rpm in an S2000 as it is to do 4,000rpm in a 320d! RobM77 said:
busta said:
xyphod said:
The car with 100ft of torque on a short hill
in the 200bhp car you'd have to rev the nuts off the car for the same power,
change gear, rev the nuts off again, change gear.
It takes time to move up the rev range the less torque you have the longer it takes.
On a long hill however the 200bhp car would win with a much faster exit velocity.
Only if the gearing doesn't suit the engine though. Low, close gearing on a low torque engine will get the same torque at the wheels as longer gearing with a higher torque engine. Having their nuts rev'd off is what high power, low torque engines are designed to do so don't let that get in the way of a good debate.in the 200bhp car you'd have to rev the nuts off the car for the same power,
change gear, rev the nuts off again, change gear.
It takes time to move up the rev range the less torque you have the longer it takes.
On a long hill however the 200bhp car would win with a much faster exit velocity.
People always say "rev the nuts off" as if it's an effort to do it. I don't recall it being more effort to do 7,000rpm in an S2000 as it is to do 4,000rpm in a 320d! I mean, how long would it take you to get to 7000rpm and what sort of speeds if you had a 28" tall tyre with a 2.73:1 final drive ratio with a 1st gear of say 306:1??
300bhp/ton said:
RobM77 said:
busta said:
xyphod said:
The car with 100ft of torque on a short hill
in the 200bhp car you'd have to rev the nuts off the car for the same power,
change gear, rev the nuts off again, change gear.
It takes time to move up the rev range the less torque you have the longer it takes.
On a long hill however the 200bhp car would win with a much faster exit velocity.
Only if the gearing doesn't suit the engine though. Low, close gearing on a low torque engine will get the same torque at the wheels as longer gearing with a higher torque engine. Having their nuts rev'd off is what high power, low torque engines are designed to do so don't let that get in the way of a good debate.in the 200bhp car you'd have to rev the nuts off the car for the same power,
change gear, rev the nuts off again, change gear.
It takes time to move up the rev range the less torque you have the longer it takes.
On a long hill however the 200bhp car would win with a much faster exit velocity.
People always say "rev the nuts off" as if it's an effort to do it. I don't recall it being more effort to do 7,000rpm in an S2000 as it is to do 4,000rpm in a 320d! I mean, how long would it take you to get to 7000rpm and what sort of speeds if you had a 28" tall tyre with a 2.73:1 final drive ratio with a 1st gear of say 306:1??
Edited by RobM77 on Friday 16th July 14:45
RobCrezz said:
Assuming you have a gearbox with ratios to suit the nature of the engine, then high BHP with low torque will ALWAYS be faster than high torque with low BHP. end of story.
But it isn't. Take your CTR for exmaple, it isn't a case of making low torque, infact it makes quite high torque for a 2.0 litre n/a motor. The key is being able to sustain that torque at higher rpms, that is what makes the power, and with appropriate gearing it can be harnessed.But in order to drive the car, so as to cover the "always" part of your argument, you need it to be tractable enough. e.g. 90hp and lots of torque will work better (and likely be faster) in one of these:
Than a revvy motoring making 100hp but very little torque.
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