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how do dynos work?

davey g-force

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I still stand by my original comment that an engine expels energy (and thus power) - it has to, due to reasons I mentioned above.

I agree that we need to agree to disagree. Any further arguing about this by me would be pointless. :D
 

Not_An_Abba_Fan

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If we extend your logi: if dynos only measure torque and torque wrenches measure torque, then a dyno and a torque wrench are the same thing?
That comment may just prove you spend your days in a labcoat. If rapists all wear blue hats and you wear a blue hat, does that make you a rapist?

A dyno measures the torque of an engine, a torque wrench measures the torque applied to a bolt. It doesn't matter what is exerting the force on the wrench, whatever it is is the thing that is producing the torque, the wrench is just measuring the applied torque. The wrench itself (or the lever) is just multiplying the torque so not as much force is required to get the bolt to the required tightness. Just like the engine is providing the force required to spin the crank shaft.
 

commsirac

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A dyno measures the torque of an engine, a torque wrench measures the torque applied to a bolt..
Once again you have got it only half right, dynos measure torque and RPM
to be able to give a power figure. If they didnt measure the rpm then they wouldnt be able to provide a power figure.....if they only measured torque then as previously it would be a pointless measurement, as pointless as me saying I could get my bicycle to record a reading of 1000Nm on the dyno.....which could easily be achieved.
I gather you havent gone to a physicist or engineer to clarify this...suggest you really do that for you own good...unless you want to be forever ignorant on this issue.
Im finished here.
 

mr LS1350

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burnz

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i got a headache reading that, i wonder how many pills comms had from banging his head.
 

-=ApheX=-

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Figure i'd stick in my 2 cents...

rwkw - think about this word for a moment?
Kilowatts is what we are really talking about here... with me so far?
So the engine creates "Energy" by converting energy! fuel and air + spark = big bang
This energy cause's an effect by moving a piston to which this energy is transferred... This energy remains the same as the effect of this energy whilst it travels through a spinning crank shaft to the axel then axel to wheels... Keeping in mind this is still energy!
now... This energy is measured from a Dyno in Kilowatts because this is the energy output it is creating at a measurable force...

It's is fairly simple to explain when you don't over think what is actually happening here...
The question was asked how do dyno's work? elaborated how does it measure rwkw?

So to summerize rwkw is the transferred energy to the wheels from which the engine has produced. energy equating to that of a measurable force... in effect everyone in there own way is correct, but you are all over thinking the simplisity of cause and effect and how we measure such occurances!
 

-=ApheX=-

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That comment may just prove you spend your days in a labcoat. If rapists all wear blue hats and you wear a blue hat, does that make you a rapist?

A dyno measures the torque of an engine, a torque wrench measures the torque applied to a bolt. It doesn't matter what is exerting the force on the wrench, whatever it is is the thing that is producing the torque, the wrench is just measuring the applied torque. The wrench itself (or the lever) is just multiplying the torque so not as much force is required to get the bolt to the required tightness. Just like the engine is providing the force required to spin the crank shaft.
Ohh I wanted to also mention something in regards to Torque in applications, "Not an abba fan" this is not aimed at you...
Torque from an engine to wheels is similar in essence to that of a torque wrench or driver...
Elaborate... We try and undo a massive bolt with the handel of a small wrench? won't work very well... not enough applied force... we do it with a longer wrench more applied force is driven through the device in question to turn said bolt...
Think about this in an engine scenario, Power is applied to the crank spinning an axel, so if we think about it as the maxium amount of force has been applied in the engine and is being expelled through gears, axel, diff to wheels, to road... Torque is but a by product of energy applied earlier to spin something with mass and or resistence e.g. a road!!!
apologies for double post...
 

Not_An_Abba_Fan

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The point of the whole argument is what do dyno's measure, they can't measure power as power is only a calculation based on what is actually measured, which is torque. There is a thread on LS1 that explains it better.

Whatever applies the force is irrelevant as the dyno can't actually quantify it, it can only measure the torque required to spin the rollers.
 
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