Breaking down the basics HP and Torque, Whats Your Debate?
10-09-2007, 10:46 PM
#1
Breaking down the basics HP and Torque, Whats Your Debate?
I remember years ago I use to think that Torque was the byproduct of HP. Come to find out that is only partially right which makes my whole statement wrong (for those of you that know what an OXI moron is) as neither of the 2 inertia related forces can exist without one or the other.
Breaking down the mathematical calculation to get torque we simply use the calculation.
Torque = 5,252 x hp/RPM
Now in order to get related HP the equation must involve torque as well as the equation is as stated.
Hp = rpm x torque/5,252
Now I didn't make any of this up these are the calculations used by the dynometers to calculate HP over torque.
The all relevant question that people don't understand is the never ending debate of a high HP engines VS. Torquey engines.. "Come on guy's" we are seriously on 2 different levels if you can't decipher the right answers for your self, and the tuning you prefer for your engine.
Lets take for an example a High End HP 350z , VS. a Low End Torque Nissan Titan Truck. Now lets pit these 2 competitors against each other going up hill. Lets say we factor the grade of a hill could be about 7% incline. Which one would win in an uphill 1/4mile?
The Titan would for reasons that basic fundamentals in physics presents. Torque is a power unlike HP, it is slow.Never the less torque is provided from the weighted inertia of the crank throwing itself, gathering momentum to make HP which is slow in it's linearity to build up. Torque provides true power under load, unlike HP it thrives off of the least of load that is left from momentum (which in all cases you won't see any peak HP till after that 5252 curve when torque begins to plateau)
Why are there so many Honda freaks out there that get off on HP? Plain and simply none of these guys truly understand, where the placement of power is made.
What do you think the heaviest Honda car weighs to it's competitor? Does a Honda need torque with such a light chassis? Such people that admire the linearity of HP with out the thrill of whip your head back torque, have truly lost the thrill of racing, or motorsports in general.
Now I believe Caroll Shelby hit it on the bulls eye when he stated "Horsepower sells cars; torque wins races". Which is true in any aspect. Look at all the powerful sports cars of today Corvette's, 350Z's, Dodge Vipers, and the list can go on to the most exotic sports cars that you would prefer. What is the one thing that most race tuned performance engines have in common? (cars that are factory made of coarse)
Well just to let you know it is an even proportioned balance between HP and Torque. Where the engines happy place is in the midrange, not the high end and not the low. this makes a great track car, posing for power and balance.
Now I'm not here to put Honda owners down. I was just here to set an example. High end has it's place in the 1/4 mile time, but that is about all it's good for. Reason being small torque bands are good for launch, No skidding , and more grip is a good thing for a light cahssis car. After 1st gear it's nothing but high end, in a range that is shifting at a point at 4000+ RPM every other gear. Now where did I state the torque plateaus... (OHHH thats right 5252RPM, now I see why Honda guy's like HP only, for the 1/4 mile (sarcasim))....
The reason why I started this is because most of you new guys talk all this jive about Honda this, and Honda that, high HP Honda everything. Really a lot of you are reading to many super tuner magazines and follow to much hype on commercialized products which sell HP (or fake power, because I don't see much for torque gains), which in fact the people that put together these articles for magazines none the less come from commercialized businesses selling a product to you the consumer. Once again coming back to Carrol Shelby's statement "Horsepower sells cars; torque wins races", HP is what sells for you younger guy's not realizing your not thinking out side the box. The big picture is to find an engine with a wide range of power (not HP), but HP and Torque, and learn to find that happy medium. If you want to wait 7500RPM's for that peak power you will get left behind on the race track with people that selected engines that make torque power as low as 3000RPM (thats power you don't have to wait for). It's time for people to start thinking about basic fundamentals not just the gimmicks that come with selling HP.
Now I've opened this up for debate since I see a lot of you new guys posting about high HP Honda's. Bring your knowledge or what you think, you think is knowledge and bring it to the table. Or just tell me what is on the top of your head about the subject.
Breaking down the mathematical calculation to get torque we simply use the calculation.
Torque = 5,252 x hp/RPM
Now in order to get related HP the equation must involve torque as well as the equation is as stated.
Hp = rpm x torque/5,252
Now I didn't make any of this up these are the calculations used by the dynometers to calculate HP over torque.
The all relevant question that people don't understand is the never ending debate of a high HP engines VS. Torquey engines.. "Come on guy's" we are seriously on 2 different levels if you can't decipher the right answers for your self, and the tuning you prefer for your engine.
Lets take for an example a High End HP 350z , VS. a Low End Torque Nissan Titan Truck. Now lets pit these 2 competitors against each other going up hill. Lets say we factor the grade of a hill could be about 7% incline. Which one would win in an uphill 1/4mile?
The Titan would for reasons that basic fundamentals in physics presents. Torque is a power unlike HP, it is slow.Never the less torque is provided from the weighted inertia of the crank throwing itself, gathering momentum to make HP which is slow in it's linearity to build up. Torque provides true power under load, unlike HP it thrives off of the least of load that is left from momentum (which in all cases you won't see any peak HP till after that 5252 curve when torque begins to plateau)
Why are there so many Honda freaks out there that get off on HP? Plain and simply none of these guys truly understand, where the placement of power is made.
What do you think the heaviest Honda car weighs to it's competitor? Does a Honda need torque with such a light chassis? Such people that admire the linearity of HP with out the thrill of whip your head back torque, have truly lost the thrill of racing, or motorsports in general.
Now I believe Caroll Shelby hit it on the bulls eye when he stated "Horsepower sells cars; torque wins races". Which is true in any aspect. Look at all the powerful sports cars of today Corvette's, 350Z's, Dodge Vipers, and the list can go on to the most exotic sports cars that you would prefer. What is the one thing that most race tuned performance engines have in common? (cars that are factory made of coarse)
Well just to let you know it is an even proportioned balance between HP and Torque. Where the engines happy place is in the midrange, not the high end and not the low. this makes a great track car, posing for power and balance.
Now I'm not here to put Honda owners down. I was just here to set an example. High end has it's place in the 1/4 mile time, but that is about all it's good for. Reason being small torque bands are good for launch, No skidding , and more grip is a good thing for a light cahssis car. After 1st gear it's nothing but high end, in a range that is shifting at a point at 4000+ RPM every other gear. Now where did I state the torque plateaus... (OHHH thats right 5252RPM, now I see why Honda guy's like HP only, for the 1/4 mile (sarcasim))....
The reason why I started this is because most of you new guys talk all this jive about Honda this, and Honda that, high HP Honda everything. Really a lot of you are reading to many super tuner magazines and follow to much hype on commercialized products which sell HP (or fake power, because I don't see much for torque gains), which in fact the people that put together these articles for magazines none the less come from commercialized businesses selling a product to you the consumer. Once again coming back to Carrol Shelby's statement "Horsepower sells cars; torque wins races", HP is what sells for you younger guy's not realizing your not thinking out side the box. The big picture is to find an engine with a wide range of power (not HP), but HP and Torque, and learn to find that happy medium. If you want to wait 7500RPM's for that peak power you will get left behind on the race track with people that selected engines that make torque power as low as 3000RPM (thats power you don't have to wait for). It's time for people to start thinking about basic fundamentals not just the gimmicks that come with selling HP.
Now I've opened this up for debate since I see a lot of you new guys posting about high HP Honda's. Bring your knowledge or what you think, you think is knowledge and bring it to the table. Or just tell me what is on the top of your head about the subject.
Last edited by BigVinnie; 10-09-2007 at 10:56 PM.
10-10-2007, 02:35 AM
#2
Hehe, I see you read the "questions about the ka24de" thread in the newbies forum.
I'll post this here for reference
P = Power, hp
N = Rotational shaft speed, rpm
T = Torque, lb-ft
I'll post this here for reference
P = Power, hp
N = Rotational shaft speed, rpm
T = Torque, lb-ft
10-10-2007, 05:46 AM
#3
Registered User
Join Date: Dec 2006
Location: VA
Posts: 434
In the spirit of good debate... I"m going to approach this in a different matter. Let's talk car. A good car is more than just engine. It's suspension, chassis, gearing, and tires (quick sum up). Now I do agree with you, torque is important. As you stated one needs the other. I am a fan of Honda. I want an s2k over my 240 (I just can't afford to modify an s2k yet). I also want an NSX over an S2k. Obviously none are torque monsters. But both very capable cars, on and off the track. Both have a good chassis, good suspension setups, and good motors.
The motor are peaky in nature, but they've been geared to match their peaky motors. I'm not sure if you've every driven an NSX, but it's an amazing car. Low torque output, and the horsepower isn't that high by todays standards, but the car is so incredibly well geared it's very quick for what little it has. It's also light weight and the suspension is spot on. S2k is along the same lines but not as beautiful or as fun to drive as the nsx.
Perhaps I didn't debate you properly on the engine thing, but I think looking at only hp or torque is only looking at 1/10 of the whole picture. I too am not a fan of the whole Honda Civic thing (I've onwed one and poured tons into it) but I do have to respect Honda for their engine choices and not doing what everyone is doing. To name some fast cars without a lot of torque: NSX, S2k, Elise/Exige (S?), F1 cars.
The other reason why I tend not to worry so much about power is, I think the ONLY real sports cars is a light weight one. 350z, Vipers aren't light by any means out of the factory. Light weight cars require less motor and less power to do be as efficient obviously. Feather weight > heavy weight.
The motor are peaky in nature, but they've been geared to match their peaky motors. I'm not sure if you've every driven an NSX, but it's an amazing car. Low torque output, and the horsepower isn't that high by todays standards, but the car is so incredibly well geared it's very quick for what little it has. It's also light weight and the suspension is spot on. S2k is along the same lines but not as beautiful or as fun to drive as the nsx.
Perhaps I didn't debate you properly on the engine thing, but I think looking at only hp or torque is only looking at 1/10 of the whole picture. I too am not a fan of the whole Honda Civic thing (I've onwed one and poured tons into it) but I do have to respect Honda for their engine choices and not doing what everyone is doing. To name some fast cars without a lot of torque: NSX, S2k, Elise/Exige (S?), F1 cars.
The other reason why I tend not to worry so much about power is, I think the ONLY real sports cars is a light weight one. 350z, Vipers aren't light by any means out of the factory. Light weight cars require less motor and less power to do be as efficient obviously. Feather weight > heavy weight.
10-10-2007, 07:58 AM
#4
Club240 Staff
Join Date: Jun 2004
Location: tampa, fl
Posts: 483
I will add in my view I guess. There is no absolute to this argument/debate.
I loved my STI for its light switch tq that kicked in at 3k and the Grip to put it down. Really launched it out of corners which gave it a great advantage on track. However, I would not feel the same about my mr2 in the respect as that same light switch tq was a liability that had a tenancy to put you *** over end. So low end tq is great when you can utilize it. I disagree with what shelby says in the light that most people will read into it which is that low end power matters more in a race. This leaves people think a big TQ number is important. It is and isn't as from your equation, TQ involves RPM. Now, the spirit of what Shelby said is true, TQ matters more, but not as a number.
To explain my point, I bring you the typical 20k RPM F1 engine which ,makes crap for TQ since they make their power over 10k rpm. If you have a motor that winds out further, that TQ number becomes misleading. No one will argue that an F1 cant whip out of a corner because relative to the RPM....it is making a lot of tq. But since the Tq number is so low, its easier to look at the HP over the power band
In summation , you cannot look at any one number and say thats what matters. The important things are redline, length of power band, and power itself. You could also simply look at the area under the (hp) curve. One key to getting any car with a seemingly low tq motor to be faster is get more RPM.
I loved my STI for its light switch tq that kicked in at 3k and the Grip to put it down. Really launched it out of corners which gave it a great advantage on track. However, I would not feel the same about my mr2 in the respect as that same light switch tq was a liability that had a tenancy to put you *** over end. So low end tq is great when you can utilize it. I disagree with what shelby says in the light that most people will read into it which is that low end power matters more in a race. This leaves people think a big TQ number is important. It is and isn't as from your equation, TQ involves RPM. Now, the spirit of what Shelby said is true, TQ matters more, but not as a number.
To explain my point, I bring you the typical 20k RPM F1 engine which ,makes crap for TQ since they make their power over 10k rpm. If you have a motor that winds out further, that TQ number becomes misleading. No one will argue that an F1 cant whip out of a corner because relative to the RPM....it is making a lot of tq. But since the Tq number is so low, its easier to look at the HP over the power band
In summation , you cannot look at any one number and say thats what matters. The important things are redline, length of power band, and power itself. You could also simply look at the area under the (hp) curve. One key to getting any car with a seemingly low tq motor to be faster is get more RPM.
10-10-2007, 11:20 AM
#6
i'd just like to direct everyones attention to the opening statement made by charles, "There is no absolute to this argument/debate". what some missed on the other thread was that the discussion was about a ka.
10-10-2007, 05:48 PM
#9
To explain my point, I bring you the typical 20k RPM F1 engine which ,makes crap for TQ since they make their power over 10k rpm. If you have a motor that winds out further, that TQ number becomes misleading. No one will argue that an F1 cant whip out of a corner because relative to the RPM....it is making a lot of tq. But since the Tq number is so low, its easier to look at the HP over the power band
In summation , you cannot look at any one number and say thats what matters. The important things are redline, length of power band, and power itself. You could also simply look at the area under the (hp) curve. One key to getting any car with a seemingly low tq motor to be faster is get more RPM.
One key reason I set the example of a 350z VS. a Nissan Titan truck in an uphill 1/4mile. A Titan is far heavier in chassis weight than the 350z, yet makes more torque and close to the same HP as the 350z.
In the spirit of good debate... I"m going to approach this in a different matter. Let's talk car. A good car is more than just engine. It's suspension, chassis, gearing, and tires (quick sum up). Now I do agree with you, torque is important. As you stated one needs the other. I am a fan of Honda. I want an s2k over my 240 (I just can't afford to modify an s2k yet). I also want an NSX over an S2k. Obviously none are torque monsters. But both very capable cars, on and off the track. Both have a good chassis, good suspension setups, and good motors.
The motor are peaky in nature, but they've been geared to match their peaky motors. I'm not sure if you've every driven an NSX, but it's an amazing car. Low torque output, and the horsepower isn't that high by todays standards, but the car is so incredibly well geared it's very quick for what little it has. It's also light weight and the suspension is spot on. S2k is along the same lines but not as beautiful or as fun to drive as the nsx.
Perhaps I didn't debate you properly on the engine thing, but I think looking at only hp or torque is only looking at 1/10 of the whole picture. I too am not a fan of the whole Honda Civic thing (I've onwed one and poured tons into it) but I do have to respect Honda for their engine choices and not doing what everyone is doing. To name some fast cars without a lot of torque: NSX, S2k, Elise/Exige (S?), F1 cars.
The other reason why I tend not to worry so much about power is, I think the ONLY real sports cars is a light weight one. 350z, Vipers aren't light by any means out of the factory. Light weight cars require less motor and less power to do be as efficient obviously. Feather weight > heavy weight.
The motor are peaky in nature, but they've been geared to match their peaky motors. I'm not sure if you've every driven an NSX, but it's an amazing car. Low torque output, and the horsepower isn't that high by todays standards, but the car is so incredibly well geared it's very quick for what little it has. It's also light weight and the suspension is spot on. S2k is along the same lines but not as beautiful or as fun to drive as the nsx.
Perhaps I didn't debate you properly on the engine thing, but I think looking at only hp or torque is only looking at 1/10 of the whole picture. I too am not a fan of the whole Honda Civic thing (I've onwed one and poured tons into it) but I do have to respect Honda for their engine choices and not doing what everyone is doing. To name some fast cars without a lot of torque: NSX, S2k, Elise/Exige (S?), F1 cars.
The other reason why I tend not to worry so much about power is, I think the ONLY real sports cars is a light weight one. 350z, Vipers aren't light by any means out of the factory. Light weight cars require less motor and less power to do be as efficient obviously. Feather weight > heavy weight.
Look at the chassis size and weight of the s2000. Honda is very good at perfecting and engineering an engine class to work with it's chassis weight class not to mention front to rear distribution when it comes down to the liking of the s2000 or the NSX for that matter.
But looking at s2000 dyno charts the engine is designed for high end and a light chassis as the torque curve falls far below what the KA engine or SR make as 4 bangers.
Now swap a KA engine in the s2000 chassis I bet you wouldn't think the KA engine wasn't a slow engine as most people perceive it to be, I mean in reality the s chassis is far heavier than that of the s2000. Better yet I've seen almost bone stock KA's swapped into Datsun 510's running 14.5 seconds ion the 1/4 mile, not to mention that is .20 seconds short of what a 2004 s2000 can run in the 1/4 mile. Looking at the 2 dyno graphs comparing the KA engine to the F22c the KA makes roughly 35ft/lb.s of torque more than the F22c, where as the F22c makes relatively 33HP more than the KA24de in an extended RPM range.
S2000 Dyno Graph
PDM racings Dyno KA24de
Yes I did and a good statement you made as well although the 90% of the rest of that thread was B.S. Reading along the pages of that thread made me laugh and at the same time I almost wanted to cry because so many people went off the subject with crap that is meaning less to the rest of the world that is actually trying to learn.
Last edited by BigVinnie; 10-10-2007 at 09:44 PM.
10-12-2007, 05:37 AM
#11
Registered User
Join Date: Dec 2006
Location: VA
Posts: 434
I think I'm having a hard time debating, because I am not seeing the point of the debate. Are you saying torque is more important than HP, vice versa? Or are you stating information on torque VS HP.
I never really focus too much on power when looking at cars primarily because all manufacturers now can make lots of horsepower from relatively small engines. You can pretty much choose the type of power you want. I myself prefer small displacement motors that are slightly peaky in nature (I love the s2k motor). I also love my sr20det, it makes great power through out the rev band. I know I'm at opposite ends...
You stated earlier that the ka24de and the sr20 make significantly more power earlier in the power band than the s2k motor. It's not that Honda couldn't make a motor with more low end torque they just chose not to.
Bore X Stroke of the 3 motors (quick google for the info, could be wrong):
(Bore X Stroke)
KA24DE:
89 x 96
Sr20DET:
86 X 86
S2000 (F20):
87 x 84
The sr20 makes more power because it's FI, no surprises there.
The KA24DE makes more power because of the 12 MM extra stroke. The motor was obviously designed for low end torque. *couhg* truck motor *cough*.
S2k 84 MM stroke, obviously for the peaky nature the motor was designed for.
I do disagree with your statement on the KA24DE feeling quicker in the s2000 chassis. The weight of the S chassis and the s2k chassis is very similar (2700lbs); give or take a hundred. The rear end gearing of the two motors is similar as well: 4.11 for the s2k, and 4.10 for the stock stock 240sx rear diff. I don't know the gear ratios for the respective transmissions, but I would guess the s2000 transmission is geared shorter since it has the luxury of the 6th gear and smaller displacement. Then you've got the fact that the ka24de makes less power than the s2000 motor. I believe the s2000 chassis with a ka24de would be worse than with the F20 motor.
My friend James and I had a similar debate a while ago (more like me listening him talking). Our conversation started off with mr2 turbo VS NSX. I said "you can up the boost make more power, go faster than the nsx." He replied with "yeah but the nsx would feel better." The nsx has a better chassis, and nicer suspension. Nicer everything. How do you measure the feel of the car? I mean my hopped up 240sx at one point may actually be faster than a stock Lotus Elise, but I may be holding on for dear life in the 240sx while I'm perfectly comfortable in an Elise.
Then we wound up talking about torque and he told something that someone he respected told him. Look at torque like this:
You've got to move 100 lbs from point a to point b. You can pick up 50 lbs at a time and move it taking 2 trips but moving more slowly (large amount of torque), or you can pick up 20 lbs at a time and move it in 5 trips moving more quickly (less torque). In the end you're accomplishing the same thing.
Perhaps my rebuttal wasn't what you were going for but focusing on primarily hp or torque is pointless. So many other factors come into play when making a competent track car or street car.
I never really focus too much on power when looking at cars primarily because all manufacturers now can make lots of horsepower from relatively small engines. You can pretty much choose the type of power you want. I myself prefer small displacement motors that are slightly peaky in nature (I love the s2k motor). I also love my sr20det, it makes great power through out the rev band. I know I'm at opposite ends...
You stated earlier that the ka24de and the sr20 make significantly more power earlier in the power band than the s2k motor. It's not that Honda couldn't make a motor with more low end torque they just chose not to.
Bore X Stroke of the 3 motors (quick google for the info, could be wrong):
(Bore X Stroke)
KA24DE:
89 x 96
Sr20DET:
86 X 86
S2000 (F20):
87 x 84
The sr20 makes more power because it's FI, no surprises there.
The KA24DE makes more power because of the 12 MM extra stroke. The motor was obviously designed for low end torque. *couhg* truck motor *cough*.
S2k 84 MM stroke, obviously for the peaky nature the motor was designed for.
I do disagree with your statement on the KA24DE feeling quicker in the s2000 chassis. The weight of the S chassis and the s2k chassis is very similar (2700lbs); give or take a hundred. The rear end gearing of the two motors is similar as well: 4.11 for the s2k, and 4.10 for the stock stock 240sx rear diff. I don't know the gear ratios for the respective transmissions, but I would guess the s2000 transmission is geared shorter since it has the luxury of the 6th gear and smaller displacement. Then you've got the fact that the ka24de makes less power than the s2000 motor. I believe the s2000 chassis with a ka24de would be worse than with the F20 motor.
My friend James and I had a similar debate a while ago (more like me listening him talking). Our conversation started off with mr2 turbo VS NSX. I said "you can up the boost make more power, go faster than the nsx." He replied with "yeah but the nsx would feel better." The nsx has a better chassis, and nicer suspension. Nicer everything. How do you measure the feel of the car? I mean my hopped up 240sx at one point may actually be faster than a stock Lotus Elise, but I may be holding on for dear life in the 240sx while I'm perfectly comfortable in an Elise.
Then we wound up talking about torque and he told something that someone he respected told him. Look at torque like this:
You've got to move 100 lbs from point a to point b. You can pick up 50 lbs at a time and move it taking 2 trips but moving more slowly (large amount of torque), or you can pick up 20 lbs at a time and move it in 5 trips moving more quickly (less torque). In the end you're accomplishing the same thing.
Perhaps my rebuttal wasn't what you were going for but focusing on primarily hp or torque is pointless. So many other factors come into play when making a competent track car or street car.
10-12-2007, 06:45 AM
#12
Honda is just good at following the typical rod stroke ratio's, as well as applying a fully counterweighted crank this is a formula that Honda has followed for years , because it keeps a smooth harmonic balance to achieve high HP numbers. But HP is a number that is more relative after momentum is applied, so if you look at HP it isn't as powerful as torque which I believe 1ft/LB tq=3 HP.
10-12-2007, 07:08 AM
#14
Some what, but wouldn't you rather see a 4 banger make 210ft/LB.s torque/210HP to give it that happy medium rather than just seeing an engine that could make 140ft/lb.s of torque, and 210 HP. I would even be willing to own an engine that would make slightly less HP numbers than that as long as the torque HP ratio was well balanced (more of an even number). That is more of the point I am getting at, establishing a well balanced torque/HP ratio engine not just focusing on merely HP figures.
I mean there are Chevy LTZ and Mercedes Benz Diesel engines that thrive on Torque and are some of the fastest engines in the world. I would just like to see in advertising that Toque is as just as important as HP figures.
I mean there are Chevy LTZ and Mercedes Benz Diesel engines that thrive on Torque and are some of the fastest engines in the world. I would just like to see in advertising that Toque is as just as important as HP figures.
10-12-2007, 08:44 AM
#15
I do disagree with your statement on the KA24DE feeling quicker in the s2000 chassis. The weight of the S chassis and the s2k chassis is very similar (2700lbs); give or take a hundred. The rear end gearing of the two motors is similar as well: 4.11 for the s2k, and 4.10 for the stock stock 240sx rear diff. I don't know the gear ratios for the respective transmissions, but I would guess the s2000 transmission is geared shorter since it has the luxury of the 6th gear and smaller displacement. Then you've got the fact that the ka24de makes less power than the s2000 motor. I believe the s2000 chassis with a ka24de would be worse than with the F20 motor.
S2000: Curb weight/2855 LB.s
S2000: Curb Weight without hard top/2765 LB.s
s13: curb weight 2700 LB.s roughly because fast back, and coupe have different distribution factors
s14: curb weight 2753
Datsun 510:curb weight 1980 LB.s
So yeah a KA would defenitely feel faster in the 510, and it would be slower in the s2000 than a 240sx chassis. Just to make the correction. For every 100LB.s there is 1/10th of a second lost in the1/4mile from weight. So a KA in a 510 is roughly .7 to .8 seconds faster than in a 240sx.