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Discussion Starter #1
I've just been thinking about this for a day or two, and this stuff never seems to work intuitively, so I'm probably wrong...but doesn't it seem odd that the drivetrain loss is a percentage? I mean, if the loss comes from the rotational inertia (resistance to motive torque, in this case), wouldn't that stay the same? The mass of the drive train components doesn't increase when you make more power. If the loss is based on a percentage of power you make, when you make more power, more power is lost overcoming the drivetrain. But, wouldn't it take the same amount of power all the time? For example, if flywheel hp on the wrx is 227, and whp is 168, then that's a 26% loss, or a loss of 59hp. Now if you're making 460 flywheel, with a 26% loss, you'd have 340whp, for a difference of 120hp. So why would it take 120hp to move the drivetrain components one time, but only 60hp when you're stock?

I'm sure it's something obvious that I'm just not seeing, but any insight would help me out a bunch.
 

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right, but with a given mass, it takes MORE power to spin that drive train weight FASTER.
 

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Discussion Starter #6
ALT+F4 said:

Whoa, good article! Very appreciative. So basically, the drivetrain loss goes up because as power goes up, it doesn't become easier to turn the drivetrain components, or spin them at a faster speed. It just gets them up to speed more quickly(read: acceleration), and just as with a car going down a drag strip, it takes more power to increase acceleration. So the drivetrain takes more power in the form of drivetrain loss, to get up to the same rotational speed more quickly.

Kind of like if someone does good at work, things don't get easier for them. Someone notices them doing good, so they give that guy the stuff that's harder to do. So even though things are easier for them, they aren't any easier cause he's asked to do more. The better he does things, his task difficulty moves up appropriately, just like drivetrain losses move up according to how easily an engine turns the components.

Thanks for the good link!!:D
 

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OffRoadWagon said:

Kind of like if someone does good at work, things don't get easier for them. Someone notices them doing good, so they give that guy the stuff that's harder to do. So even though things are easier for them, they aren't any easier cause he's asked to do more. The better he does things, his task difficulty moves up appropriately, just like drivetrain losses move up according to how easily an engine turns the components.

haha!

how much wood could a woochuck chuck..

good article!
 

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Discussion Starter #8
I guess if it the drivetrain didn't pull more power to itself based on the power you make with the engine, people would be just as likely to strip gears at 168awhp as 555awhp. Funny how the stuff that's already obvioius always makes even more sense after looking at it from different directions.
 

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Dear god, you're right! 26% driveline loss! ugh.. The AWD system really takes its toll. My TA had only a 15% loss.

Though the good news is that, looking at the dyno numbers around here, my target of 350+ hp at the flywheel is very doable.
 
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