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al nunley
Joined: 13 Nov 2006
Posts: 3027
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 Posted: Fri Nov 02, 2012 1:12 pm Post subject: |
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I just amazes me how few understand the torque/HP connection.
You get no HP from the engine to the rear axle. You only get torque. You then calculate the HP at the rear axle. The more torque, (the work) the more HP you can calculate. I don’t understand why nobody understands this.
Torque is what does the wrok, not the HP, the HP is a calcultion.
Look at it this way, the more torque you get to the rear axle, the more HP you can calculate at the rear axle. Seems beyond simple to me.
Look it up In any book you can, Or go to wikipedia
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If the data does not support the theory, get a new theory. (Al Nunley)
All else being equal; Compression is the Holy Grail.
45 years, in and around karting |
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Tim Salvino
Joined: 20 Nov 2010
Posts: 257
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| Posted: Fri Nov 02, 2012 1:48 pm Post subject: |
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Torque is also a calculation.
Distance x Force. |
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Brian Degulis
Joined: 13 Aug 2012
Posts: 412
Location: United States, Florida,
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| Posted: Fri Nov 02, 2012 4:59 pm Post subject: |
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| al nunley wrote: | I just amazes me how few understand the torque/HP connection.
You get no HP from the engine to the rear axle. You only get torque. You then calculate the HP at the rear axle. The more torque, (the work) the more HP you can calculate. I don’t understand why nobody understands this.
Torque is what does the wrok, not the HP, the HP is a calcultion.
Look at it this way, the more torque you get to the rear axle, the more HP you can calculate at the rear axle. Seems beyond simple to me.
Look it up In any book you can, Or go to wikipedia |
This is what I love about physics there is no argument. We could argue all day about who should be president or wether or not global warming is reall but with physics as expressed earlier it is the law.
If you had only torqe to the rear axle your vehicle couldn't move an inch. You must have some torque and some RPM. With those you can calculate HP a total measurement of available power which is what drives everything.
It's much like electricity. You can have a million volts and no power or you could have a million amps and still no power. You must have some voltage and some amperage to have power. With that you can calculate Watts a total measurment of available power.
Watts is to electricity what HP is to mechanical power. You must have both ingredients to have power which is then expressed as Watts for electricity and HP for mechanical power.
Brian |
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Virgil Tripp
Joined: 10 Feb 2009
Posts: 7
Location: United States, Texas, Bastrop
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| Posted: Fri Nov 02, 2012 5:07 pm Post subject: |
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| Torque and RPM are measured. HP is calculated. |
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Mike Goebel
Joined: 28 Jul 2001
Posts: 5763
Location: United States, California, Winnetka
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| Posted: Fri Nov 02, 2012 8:07 pm Post subject: |
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| Virgil Tripp wrote: | | Torque and RPM are measured. HP is calculated. |
Wrong!!!
You can measure force at a distance then calculate torque 
Mike G.
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Mike Goebel
Joined: 28 Jul 2001
Posts: 5763
Location: United States, California, Winnetka
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| Posted: Fri Nov 02, 2012 8:13 pm Post subject: |
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There are a lot of things that are calculated
Lets see
Speed. But who cares about that.
Power. But who cares about that.
bfsc. But who cares about that.
BMEP. But who cares about that.
lateral G. But who cares about that.
Braking G. But who cares about that.
Acceleration G. But who cares about that.
Jerk. Yes it's real and used in camshaft design
Torque is nothing without power. Ever seen an 18 wheeler out accelerate a 3 cyl car. Why??? because it has tons of torque and very low power.
Mike G.
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Virgil Tripp
Joined: 10 Feb 2009
Posts: 7
Location: United States, Texas, Bastrop
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| Posted: Fri Nov 02, 2012 8:21 pm Post subject: |
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Point taken.  |
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Brian Degulis
Joined: 13 Aug 2012
Posts: 412
Location: United States, Florida,
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| Posted: Fri Nov 02, 2012 8:38 pm Post subject: |
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You can calculate torque if you know HP and RPM. The point is that HP is what we use to determine available over all power. Then you can gear to create the precentage of RPM and torque to do whatever job you need to do within the HP limitations but the power you get from that will be the same as what you started with minus transmission loses and will still be expressed in HP.
Brian |
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Mike Goebel
Joined: 28 Jul 2001
Posts: 5763
Location: United States, California, Winnetka
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| Posted: Fri Nov 02, 2012 8:58 pm Post subject: |
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Thats the great thing about Power. It doesn't matter where you want to calculate it, it's the same every where. Unlike crappy old Torque that changes from one place to another.
Mike G.
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Joe Ricard
Joined: 23 Jun 2009
Posts: 864
Location: United States, Mississippi,
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| Posted: Sat Nov 03, 2012 4:36 am Post subject: |
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Now that there are 3 pages of KZ loving.
What is the general consensus on HP numbers for a new KZ motor.
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Mike Goebel
Joined: 28 Jul 2001
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Location: United States, California, Winnetka
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| Posted: Sat Nov 03, 2012 7:07 am Post subject: |
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I don't know but I bet it's huge!!
Mike G.
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Tim Salvino
Joined: 20 Nov 2010
Posts: 257
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| Posted: Sat Nov 03, 2012 7:57 am Post subject: |
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| Joe Ricard wrote: | Now that there are 3 pages of KZ loving.
What is the general consensus on HP numbers for a new KZ motor. |
What numbers are you looking for???
Every dyno is going to show a different #. The people who sell and rebuild them will have a dyno that shows higher #'s. It makes business sense, because there are waayyyy too many people who just look at the peak hp # and make their buying decision based purely on that.
A new KZ should make somewhere in the high-30's to low 40's. And that's a real world guesstimate.  |
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Mike Goebel
Joined: 28 Jul 2001
Posts: 5763
Location: United States, California, Winnetka
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| Posted: Sat Nov 03, 2012 8:32 am Post subject: |
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| Brian Degulis wrote: | On the other hand is it really possible to apply this in reall world driving? You'd have to be pretty focused on the tach.
Brian |
Yes!! The best way to do this is to use your data acquisition system and look to see what RPM you are shifting and then use that to get a feel of what you need to change to get to the correct shift points. Best would be to do a bunch of straight line acceleration tests, use 2 beacons, and try different shift points to see if there is any difference. No one will do this because its too easy. I never did it either
Mike G.
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Brian Degulis
Joined: 13 Aug 2012
Posts: 412
Location: United States, Florida,
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| Posted: Sat Nov 03, 2012 9:00 am Post subject: |
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Yes trying to change the trend makes good sense.
Brian |
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Erik Maxfield
Joined: 16 May 2004
Posts: 1068
Location: United States, California, Vacaville
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| Posted: Sat Nov 03, 2012 11:30 pm Post subject: |
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somebody could take the HP or torque curve, figure out the RPM drop for each gear change, and then integrate (or crunch numbers in Excel) to figure out how to maximize the amount of HP under the curve so as to determine shift points.....
Off topic but pertinent to the discussion.... and hinted at by Mr. Schumachers closest buddy.
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