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Old 04 February 2011, 04:32   #21
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Mmm, I noticed that as well. I think that torque figures are generally (turbos possibly not included) simply a mathematical calculation based on the hp figure.
Unfortunately not. Torque is related to stroke & a host of other things, whioch can be mucked about with even more with on an EFI engine. Grab any car brochure - the torque curve is always roughtly "hill" shaped (i.e as revs increase, torque will peak & eventually drop off a bit), the power curve is a straight-ish line going up as revs increase.
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Old 04 February 2011, 09:25   #22
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Mmm, I noticed that as well. I think that torque figures are generally (turbos possibly not included) simply a mathematical calculation based on the hp figure.
AFAIK isn't it the other way round. Ie. KWs are calculated from the torque figure and then converted to hp?

Of course that only works for a set amount of the unit "work done" whereas what you are talking about is the line graph showing output/revs which is completely different. Similar though because on the rolling roads the hp figure is calculated as the car winds to a stop isn't it, using the rolling resistance of the wheels or something like that in an equation with the torque figure produced during the running up of the engine.
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Old 04 February 2011, 09:40   #23
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Power and torque are not inseparable. Torque is simply a turning force...so taking the turning force and RPM power can be calculated. Therefore the converse is true, if you know the power and RPM you can calculate the torque.

What is generally meant by a torquey engine is an engine which produces good power at lowish RPM.
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Old 04 February 2011, 10:43   #24
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Power and torque are not inseparable. Torque is simply a turning force...so taking the turning force and RPM power can be calculated.
HP = Torque x RPM 5252
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Old 04 February 2011, 10:51   #25
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Power and torque are not inseparable. Torque is simply a turning force...so taking the turning force and RPM power can be calculated. Therefore the converse is true, if you know the power and RPM you can calculate the torque.
Well obviously. You just re-arrange the formula.......Not exactly rocket science!! But what I was saying that on rolling roads and dynos etc they calculate the HP from the torque figure not the other way round.
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HP = Torque x RPM 5252
So keeping Jeff happy (HPx5252)/RPM = Torque. All I'm saying is that in practical applications Matt's formula is used

Incidentally for that equation what would the units of torque be? Pounds/foot? Surely it would be easier to use the simpler metric equation using NM and KW and negating the need for the 5252 division
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Old 04 February 2011, 11:00   #26
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Incidentally for that equation what would the units of torque be? Pounds/foot? Surely it would be easier to use the simpler metric equation using NM and KW and negating the need for the 5252 division
ft/lbs. Only U18's and french people use anything else
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Old 04 February 2011, 11:32   #27
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I presume these simple formulas only work at the flywheel and not after the effects of the gearbox are added in. The losses must vary at different rpm's and therefore affect torque too.
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Old 04 February 2011, 16:13   #28
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1. Gotchiguy chill. My post was nothing to do with your post... so sensitive.

2. My understanding is that outboard power figures are given at the prop.
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Old 04 February 2011, 16:53   #29
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2. An engine of the correct size cannot be found i.e. a single 400hp outboard = 2x200hp
the Harrell Engineering 580HP 6.2L Chevy V8 Outboard
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Old 04 February 2011, 17:00   #30
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the Harrell Engineering 580HP 6.2L Chevy V8 Outboard
Kleenex anyone?
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