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Thread: HP or Torque ? for lower lap time ?

  1. #21
    Senior Member robburgoon's Avatar
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    Quote Originally Posted by J. Tyler View Post
    Power = Work / Time

    What part of that are you having trouble with?
    +1. More Power, more faster.

  2. #22
    Smack-Talkin' Member J. Tyler's Avatar
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    Quote Originally Posted by robburgoon View Post
    +1. More Power, more faster.
    Why did I read that in Jeremy Clarkson's voice?

  3. #23
    Senior Member robburgoon's Avatar
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    Quote Originally Posted by J. Tyler View Post
    Why did I read that in Jeremy Clarkson's voice?
    The boffins at 949 Racing recently discovered that if you make moor powah, you go moor fasta. Oh dearh. *makes face* I'll need two bravery pills to drive this.

  4. #24
    http://www.trackhq.com/Banners/yellowsitesponsor.gif Chris@Xtremespeed's Avatar
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    Who said, "HP is for winning races, TQ is if you want to do burn outs" ???

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    Senior Member bellwilliam's Avatar
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    Quote Originally Posted by J. Tyler View Post
    Power = Work / Time

    What part of that are you having trouble with?

    *Edit: The gas engine performs more work per unit time, which is why it's HP number is higher. More work done = car goes further down the track (accelerates faster).
    So say s2000 with 200hp 150ft/LB will be faster than 199hp 199ft/LB s2000 ? It can't be that simPle
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  6. #26
    Senior Member robburgoon's Avatar
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    Quote Originally Posted by bellwilliam View Post
    So say s2000 with 200hp 150ft/LB will be faster than 199hp 199ft/LB s2000 ? It can't be that simPle
    It's not. read what I said above about peak numbers not mattering. It's a portion of the area under the hp curve that matters.

  7. #27
    Senior Member robburgoon's Avatar
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    For example, the Race Engineering engine in my spec miata doesn't make terribly amazing peak horsepower in my car (admittedly I need to do a few cheats to get that higher), but what it does have is a freaking amazing midrange. I won't be catching the guy ahead, then I'll shift gears and eat him alive.

    Compared to other SMs, my hp curve isn't tall, it's WIDE.
    Last edited by robburgoon; 08-25-2011 at 11:11 AM.

  8. #28
    Smack-Talkin' Member J. Tyler's Avatar
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    Quote Originally Posted by bellwilliam View Post
    So say s2000 with 200hp 150ft/LB will be faster than 199hp 199ft/LB s2000 ? It can't be that simPle
    If they both rev to the same redline RPM, yes; the 200hp would theoretically be faster. Again, Power is a measure of Work performed. 200hp does more Work than 199hp. Force (torque) is just an arbitrary number that is only a part of the equation for Work performed.

    Work = Force x Distance. Force = torque, Distance = RPM. Increase the RPM and you increase the work done. You can even decrease the Force and still perform more Work as long as you increase the RPM enough.

    *BUT, in reality, engines do not work the way you imagined in your scenario. To make an S2000 have 199lb/ft of torque, you'd have to greatly change the shape/design of the engine, and in doing so you would be forced to greatly reduce the redline RPM and thus the HP. You'd end up with a car with 100hp and 199lb/ft of torque (basically a deisel).

  9. #29
    Senior Member robburgoon's Avatar
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    Quote Originally Posted by J. Tyler View Post
    If they both rev to the same redline RPM, yes; the 200hp would theoretically be faster.

    BUT, in reality, engines do not work that way. To make an S2000 have 199lb/ft of torque, you'd have to greatly change the shape/design of the engine, and in doing so you would be forced to greatly reduce the redline RPM and thus the HP. You'd end up with a car with 100hp and 199lb/ft of torque (basically a deisel).
    Shame on you Jeff, you know better. Give me a wider curve with a 199hp and I'll beat that peak 200hp car. When he's making 190hp after his shift, I'll make 195hp. He can have his 1 hp at 8,700rpm if I get 5hp at 7,000 to 8,000.


    Also, no reason to complicate this discussion with what's physically possible yet. Let's get William sorted out just using curves and theory for now if that's ok.

  10. #30
    Smack-Talkin' Member J. Tyler's Avatar
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    Quote Originally Posted by robburgoon View Post
    Shame on you Jeff, you know better. Give me a wider curve with a 199hp and I'll beat that peak 200hp car. When he's making 190hp after his shift, I'll make 195hp. He can have his 1 hp at 8,700rpm if I get 5hp at 7,000 to 8,000.


    Also, no reason to complicate this discussion with what's physically possible yet. Let's get William sorted out just using curves and theory for now if that's ok.
    Give me closer gear ratios and I'll keep it at that 200hp and beat you

    Seriously though, I am not talking about curve shapes or anything else. All else being equal, 200hp beats 199hp, period; which is what William asked. It's a totally unrealistic & pointless question to ask, though.

  11. #31
    Senior Member robburgoon's Avatar
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    Quote Originally Posted by J. Tyler View Post
    Give me closer gear ratios and I'll keep it at that 200hp and beat you
    No you won't. If I have a fatter curve and you have a dinky little peak you'll need a magic gearbox or CVT to do it.

    But yes, 200hp from 7,000rpm to 9,000 rpm will beat 199hp from 7,000 to 9,000 regardless of what the torque curve does below 7,000rpm.
    J. Tyler likes this.

  12. #32
    Senior Member robburgoon's Avatar
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    William, are you sorry you asked yet? If so, Jeff, I think our work is done here.
    Last edited by robburgoon; 08-25-2011 at 11:29 AM.

  13. #33
    Corners > Straights JDMxDB8's Avatar
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    I'm learning a lot from this thread. Keep it coming fellas.

  14. #34
    Senior Member psychoazn's Avatar
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    We had a discussion regarding this. The conclusion reached was that area under the curve (AUC) is what ultimately matters, which is a function of both torque and hp.

    The case we used was F20C (AP1) vs F22C (AP2). Although on paper they make the same power, on a dyno, they don't. The F22C consistently makes more torque and more power. However, the F20C revs higher, and uses both sides of the power curve, whereas the F22C only use the "climbing" side of the power curve.

    Real world results (via drag racing) show that the AP1 and AP2 are neck and neck.

    After some crude calculations, we discovered that the AUC is within 1% on the respective cars.

    Thread located here:

    Net power output - S2KI Honda S2000 Forums

    Really relevant discussion starts here:

    Net power output - S2KI Honda S2000 Forums

  15. #35
    Senior Member psychoazn's Avatar
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    Quote Originally Posted by J. Tyler View Post
    Give me closer gear ratios and I'll keep it at that 200hp and beat you

    Seriously though, I am not talking about curve shapes or anything else. All else being equal, 200hp beats 199hp, period; which is what William asked. It's a totally unrealistic & pointless question to ask, though.
    I disagree.

    What if you have a turbo car that makes a "pyramid" power curve that makes 240whp vs a car with a "climbing" power curve that makes 260whp?

    Although the 260whp has a higher peak, the turbo car has a much larger area under the curve, and ultimately, more energy is being expended and more work being done, given a speed and/or RPM range.

    HP is much more directly related to how quickly a car accelerates over a period of time than TQ, but its not the end all say all. AUC is.


    In this case, I'd be comparing a VQ35DE (non-revup) vs EJ25/4G63.

  16. #36
    Senior Member psychoazn's Avatar
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    Quote Originally Posted by J. Tyler View Post
    If they both rev to the same redline RPM, yes; the 200hp would theoretically be faster. Again, Power is a measure of Work performed. 200hp does more Work than 199hp. Force (torque) is just an arbitrary number that is only a part of the equation for Work performed.

    Work = Force x Distance. Force = torque, Distance = RPM. Increase the RPM and you increase the work done. You can even decrease the Force and still perform more Work as long as you increase the RPM enough.

    *BUT, in reality, engines do not work the way you imagined in your scenario. To make an S2000 have 199lb/ft of torque, you'd have to greatly change the shape/design of the engine, and in doing so you would be forced to greatly reduce the redline RPM and thus the HP. You'd end up with a car with 100hp and 199lb/ft of torque (basically a deisel).
    Give the s2k a 2.7L engine, and you'll have your 200 ft/lb. Lower redline to about 5500 (5252) and you'll have 200hp.

    For a production engine for regular consumer use, a NA engine will make 75 ft/lbs of torque +-5, for every liter of displacement. This is accurate from a Ford Focus, to a S2000, 370Z, all the way to a 997 GT3 and LP-670.

    The figure will be between 85 +-5 for the latest direct injection NA engines and the "exotics". Example would be GT3 4.0, 458 Italia, etc.
    Last edited by psychoazn; 08-25-2011 at 12:38 PM.

  17. #37
    Smack-Talkin' Member J. Tyler's Avatar
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    Quote Originally Posted by psychoazn View Post
    I disagree.

    What if you have a turbo car that makes a "pyramid" power curve that makes 240whp vs a car with a "climbing" power curve that makes 260whp?

    Although the 260whp has a higher peak, the turbo car has a much larger area under the curve, and ultimately, more energy is being expended and more work being done, given a speed and/or RPM range.

    HP is much more directly related to how quickly a car accelerates over a period of time than TQ, but its not the end all say all. AUC is.


    In this case, I'd be comparing a VQ35DE (non-revup) vs EJ25/4G63.
    Did you read the part of my post that said "All else being equal"?

    Because in your scenario there, you did not keep all things equal.

  18. #38
    Senior Member psychoazn's Avatar
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    Oops, reading the thread backwards ftl.

    How would you keep everything else equal? relative or absolute gearing? :shrug:

  19. #39
    Smack-Talkin' Member J. Tyler's Avatar
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    Quote Originally Posted by psychoazn View Post
    Oops, reading the thread backwards ftl.

    How would you keep everything else equal? relative or absolute gearing? :shrug:
    Did you read the part where I said it was a "totally unrealistic and pointless question"?


  20. #40
    Senior Member bellwilliam's Avatar
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    not sure why you say it isn't practical.

    cranky old man, Gordon's Miata 4-banger makes ~375whp, 250ft/LB. red line at ~6.5k rpm (assume that's where the rpm cut is)
    say he drops in a stock LS1, which makes ~350whp, 365ft/LB. also red line at ~6.5k rpm.

    his 4-banger would weigh less. so we would drop in additional 100LB in the 4-banger to even out the weight. in this case, everything else would equal.
    which engine will be faster ?

    I am confused between peak hp number and under the area (under hp or torque curve ? )
    am I the only one confused by what Tyler and Burgoon said ?
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