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Someone explain power and tourqe
- Thread starter JaysonD
- Start date
Torque is measured, power is calculated using torque (Nm) and time (RPM)
Hence why you can fudge power figures so easily but that's a different conversation.
Regarding which car is quick you need more information that just power and torque in the majority of cases. You can calculate acceleration figures using some fairly basic and easily obtainable info.
Hence why you can fudge power figures so easily but that's a different conversation.
Regarding which car is quick you need more information that just power and torque in the majority of cases. You can calculate acceleration figures using some fairly basic and easily obtainable info.
BoatNonce
ClioSport Club Member
Torque is the turning force the engine applies to the wheel.
Power is torque, multiplied by RPM, divided by 5252 (which is a constant figure, please don't ask why)
Power is torque, multiplied by RPM, divided by 5252 (which is a constant figure, please don't ask why)
From my understanding....
Horsepower is a measure of engine power, or "rate of work". Horsepower is typically calculated from a torque measure at a known engine speed.
HP = torque x RPM/ 5252
So they are directly related and what it boils down to is power at a given usable rev range. The peak figures are nigh on irrelevant. More torque = more power, but until you know the rpm it's literally impossible to gauge.
Horsepower is a measure of engine power, or "rate of work". Horsepower is typically calculated from a torque measure at a known engine speed.
HP = torque x RPM/ 5252
So they are directly related and what it boils down to is power at a given usable rev range. The peak figures are nigh on irrelevant. More torque = more power, but until you know the rpm it's literally impossible to gauge.
E46 M3, Clio 182
Power is how fast you hit the wall.. torque is how far you have moved the wall.
I'd say that Aswell in my clio 3k upwards seems to roar and fly haha! Heard about the 2.0 has a sports cam valve or something which gives it a little boost!
Strange quote that one, as its all down to the speed and weight of the car if you hit something, not the characteristics of the engine.
BoatNonce
ClioSport Club Member
Sports Cam Valve, that's a new one.
As Mcgherkin says, torque is simply how strongly the engine is capable of turning.
And then horsepower is the combination of how hard it can turn multiplied by how fast it is turning at the same time.
BHP is the one that is important from a performance point of view really, its often misrepresented because of a quote from carol shelby in the context of getting a drag car off the line, where torque matters so much as if you needed to rev the engine to get your power down then you wouldnt be able to hook up properly.
In the context of a road car though, a nice wide spread of torque means you dont have to chase around the gearbox as much to make progress so does tend to make for a pleasant drive.
And then horsepower is the combination of how hard it can turn multiplied by how fast it is turning at the same time.
BHP is the one that is important from a performance point of view really, its often misrepresented because of a quote from carol shelby in the context of getting a drag car off the line, where torque matters so much as if you needed to rev the engine to get your power down then you wouldnt be able to hook up properly.
In the context of a road car though, a nice wide spread of torque means you dont have to chase around the gearbox as much to make progress so does tend to make for a pleasant drive.
Clio.
Power sells engines, torque wins races?
Yes I quote often look upwards thinking Ive heard a lion overhead only for it to turn out to be a 1.2 clio souring through the air roaring.
Its got a dephasor solenoid which moves the cam slightly, which allows you to run cam timing that would otherwise give you poor idle emissions.
Yes thats the quote I was referring to, but the races he was talking about were RWD drag racers on massive slicks where all that really matters is the first 60ft, in a FWD car on road (or trackday) tyres, this is just completely irrelevant as you dont want enormous low down torque to fire you off the line, it would just spin the wheels.
Assuming you can set the gearing appropriately BHP is going to be the thing that determines how hard it can accelerate you everywhere else .
Hush
BoatNonce
ClioSport Club Member
Is that the sound it makes? 
Is nowIs that the sound it makes?
Hahaha that is so true! And oh fair enough!!
I've just moved next door to a citrus fruits plant. I'm fed of the smell souring the air too
I've just moved next door to a citrus fruits plant. I'm fed of the smell souring the air too
Oh cool a thread thats turned into people looking for autocorrect/spelling mistakes/typos, those never get dull at all.....
My thoughts exactly, I'd like to learn about this so I'm hoping people still comment.
Tbh I still need a proper laymans explanation.
Torque is literally just a measure of force.
So grab a 2 foot long bar, add 75lbs of weight to the end of it, and thats 150lbft of torque, roughly what a 172 engine makes, but for that force to propel you down the road it needs to be making it not just while stationary like the weight on the bar, it needs to make it happen quickly.
The quicker it manages to rotate whilst still maintaining that same amount of force, the power BHP it makes.
I guess a good analogy is the boxing one, how hard you hit is torque, how often you can hit is revs, bhp is the overall amount of damage you can do in a given amount of time when taking both into account.
So grab a 2 foot long bar, add 75lbs of weight to the end of it, and thats 150lbft of torque, roughly what a 172 engine makes, but for that force to propel you down the road it needs to be making it not just while stationary like the weight on the bar, it needs to make it happen quickly.
The quicker it manages to rotate whilst still maintaining that same amount of force, the power BHP it makes.
I guess a good analogy is the boxing one, how hard you hit is torque, how often you can hit is revs, bhp is the overall amount of damage you can do in a given amount of time when taking both into account.
This has probably explained it to be the best at the moment!
That still kinda mind f***s me abit?
No not at really.
Well not in the sense of one impact anyway.
I guess you could say that if you were trying to knock a wall down by smashing into it at high speed that is down to BHP, where as if you just put the nose of the car against it and then try and drive forward that is torque, but its still a bit tenuous.
The key fact in how fast your car accelerates is a very simple equation
f = ma
Force = Mass * Acceleration
Therefore
Acceleration = Force divided by Mass
The "force" in that context is torque at the wheels.
Torque at the wheels is a product of two things, torque from the engine, and torque multiplied by the gearbox.
which means that the more rpm you have the torque at (higher bhp) the more you can exploit gearing to increase torque at the wheels
So basically, torque at the wheels is effected most by BHP, and its that which is what accelerates the car.
BoatNonce
ClioSport Club Member
OK, here's a good example.
A London underground train has lots of torque, a bullet train has lots of power.
The London Underground can accelerate very quickly to its top speed because of its torque, but it has little in the way of power so that top speed isn't very high, only 40-50mph for example.
The bullet train has a f**king huge amount of power so it can go very fast, 170mph, but because it has little in the way of torque it takes several miles to get up to speed (it takes longer for the bullet train to reach 30-40 than the london underground one).
In a car, if you're driving on a technical twisty course when you're not likely to hit very high speeds, more torque is king because you can accelerate quickly between corners, but if the track is really open and fast you won't be accelerating much, more like maintaining speed near the top end of the car, so power would win there as it would allow you to reach higher speeds.
A London underground train has lots of torque, a bullet train has lots of power.
The London Underground can accelerate very quickly to its top speed because of its torque, but it has little in the way of power so that top speed isn't very high, only 40-50mph for example.
The bullet train has a f**king huge amount of power so it can go very fast, 170mph, but because it has little in the way of torque it takes several miles to get up to speed (it takes longer for the bullet train to reach 30-40 than the london underground one).
In a car, if you're driving on a technical twisty course when you're not likely to hit very high speeds, more torque is king because you can accelerate quickly between corners, but if the track is really open and fast you won't be accelerating much, more like maintaining speed near the top end of the car, so power would win there as it would allow you to reach higher speeds.
Right, I think I get it. It's been a long day so I'll come read this all again tomorrow and hopefully crack it.
Thanks for explaining!
Thanks for explaining!
Sorry but you are forgetting the effect of gearing, if you have more BHP its cause your engine can rev higher, so you will be in a lower gear and therefore getting plenty of torque.
What torque does help with is cutting down the number of gear changes required and making it less important if you are in the right gear, so for something like rallying for example its very useful. But even then BHP is still hugely important to acceleration as well.
How much would you be looking at to achieve a high powered n/a f4r clio 1*2, and whats the next stage after cams and itbs if this was the route someone was wanting to go down? High comp pistons etc?
What power could you achieve realistically if you had the money, sticking with the 2.0l lump? For eg, what would 5k get you if you had money coming out of your ears, excluding things like an exhaust and basic mods which most people already have?
Is boost really the only way to go?
What power could you achieve realistically if you had the money, sticking with the 2.0l lump? For eg, what would 5k get you if you had money coming out of your ears, excluding things like an exhaust and basic mods which most people already have?
Is boost really the only way to go?
5K is a pretty basic spec still, you are nowhere near pushing the boundaries on that sort of modest budget
230 ish BHP you could get for that if you were doing all the work yourself.
Approaching 300 would be possible if you dont care about reliability and dont mind spending 50K for it to work for a few hours use.
Boost is therefore basically the only way to get 300 which is what I think the clio chassis particularly works well with, unless you are a works touring car team!
It would be nice to have money to burn
Although 230bhp would feel pretty good in an n/a clio, although you can boost it to that for almost half the price.
It would be nice to have money to burn
Although 230bhp would feel pretty good in an n/a clio, although you can boost it to that for almost half the price.
TBH doing 230bhp N/A for 5K is cutting a whole load of corners as well IMHO, id budget nearer to double that to do it properly including a bit of labour and a diff and a box rebuild and an uprated clutch and a decent flywheel etc.
Why would grown ups not want power or torque?
I think there is a mentality of "Cars that win races are N/A so N/A must be better" but the reality is that turbo cars only ever dont win if they are banned or heavily restricted by the rules, there isnt an N/A racecar anywhere on the planet IMHO that wouldnt be faster round a track if a decent turbo setup was used.
Chuff that then lol.
If i was as good as some people on here with a spanner, then it might be something i would consider.
Knuckles
ClioSport Admin
The thing I heard, and won't forget is
torque is how hard you pedal your bikes pedals, power is how fast you spin them
torque is how hard you pedal your bikes pedals, power is how fast you spin them
NA is more cultured.
I loved racing a turbo car, rolling starts were so easy to make places up lights out and booooooooost. I'm an NA boy though through and through, I think its because of the simplicity and character over what can often feel benign and fake. It's horses for courses.
We all know engines don't win races, chassis's do.
Not a bad way of thinking of it.
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