Baggers Torque and HP question
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Grand HDF Member
Joined: Jun 2007
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From: Lansing mi
Baggers Torque and HP question
I did a Search but way to much info to read as I'm looking for a quick answer. On just about all Dyno charts the Torque is higher then the HP. Now over the last day or so I have been looking at a lot of charts and just about all of them show more Torque then HP, but but maybe 1 in 10 will show more HP then Torque.
So, why so few with higher HP then Torque? a problem, or just one of them odd normal things.
So, why so few with higher HP then Torque? a problem, or just one of them odd normal things.
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Joined: Sep 2010
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From: Phoenix '53, '88, '09 Big Twins
the V twin is a torque motor.
produces torque at lower(er) rpms than most 4 cylinder. this is related to number of cylinder, configuration, bore and stroke.
cam choice and changing other parameters will change how the motor makes power and in which rpm ranges.
the key is to select the type of build that produces usable power in the rpm range in which you ride ( for most of us between 2600~3200 rpms 90% of the time) as opposed to a drag bike motor which is turning 6 to 9000 rpms on the track but can barely idle
as noted below, the 2 lines always cross at 5250 rpms
mike
produces torque at lower(er) rpms than most 4 cylinder. this is related to number of cylinder, configuration, bore and stroke.
cam choice and changing other parameters will change how the motor makes power and in which rpm ranges.
the key is to select the type of build that produces usable power in the rpm range in which you ride ( for most of us between 2600~3200 rpms 90% of the time) as opposed to a drag bike motor which is turning 6 to 9000 rpms on the track but can barely idle
as noted below, the 2 lines always cross at 5250 rpms
mike
Last edited by mkguitar; Jan 2, 2013 at 05:22 PM.
Elite HDF Member
Joined: Nov 2006
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From: Stockbridge, GA (Atlanta)
for a bagger you want torque
I did a Search but way to much info to read as I'm looking for a quick answer. On just about all Dyno charts the Torque is higher then the HP. Now over the last day or so I have been looking at a lot of charts and just about all of them show more Torque then HP, but but maybe 1 in 10 will show more HP then Torque.
So, why so few with higher HP then Torque? a problem, or just one of them odd normal things.
So, why so few with higher HP then Torque? a problem, or just one of them odd normal things.
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Grand HDF Member
Joined: Jun 2007
Posts: 4,599
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From: Lansing mi
Could be, My Brother has a Big Dog with a S&S 107 and his HP is higher then his Torque and we felt that was odd, so that's why I was looking at the Harley numbers. So must be the S&S and the Evo 1200 have something in commend.
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From: Santa Cruz
As an example, Sportbikes make a lot more HP than tq. It just matters on engine design and use. As a general rule long stroke engines like the harley V-twin make more Tq and short stroke engines like in sportbikes make more HP. Tq is a measurement of force, a steam engine makes maximum torque at 0 rpm. HP is a measurement of work over time so engines that can produce torque at high rpm make more HP. There are sportbikes that make maximum TQ over 6000 rpm (after a stock harley hits the rev limiter) and maximum HP over 10,000 rpm.
Its a matter of building and tuning.
Its a matter of building and tuning.
Last edited by 0ldhippie; Jan 3, 2013 at 12:04 AM.
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roomate has a Ninja 600-thing...he loves it, i hate it. good ting he's buying a bagger
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From: Bedford UK
As a sweeping generalisation, for our big twins, the two numbers are fairly close. My S&S 107 gives 101HP and 107TQ, which seems to be typical. It does seem to me that cam designers are getting better TQ results with some of their designs these days, so we may be going through a fresh surge of development that swings TQ figures higher than HP, especially for our dressers.
A further thought is that Harley themselves are chasing changing EPA regulations and one solution is to increase TQ at low engine speeds, in an attempt to reduce noise and exhaust emissions at the levels they are measured. Modern cars are doing the same and pulling low rpms we would not have thought of trying to use, only a few years ago.