06-24-2014, 12:37 PM | #375 | |||||
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I fully agree though, for a constant torque, the absolute power losses increase with RPM. And this is where it becomes interesting, with the broad power plateau of the S55, power losses in absolute terms do not increase much with RPM across the power plateau. It is not me but you that quoted an efficiency formula that drastically varies with RPM. I have been disputing this since. Quote:
Doing a quick exercise, taking the wheel and tire weights from the EAS thread and assuming a dyno run that takes 13s to accelerate from 3000 to 7400rpm in 5th. I figure it takes about 10hp to accelerate only the rear wheels and tires at 7000 engine RPM. Add the discs, hubs, half-shafts, diff, driveshaft, transmission and engine and the overall inertia can have a quite meaningful impact on the output reading. Quote:
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~2-5% Tire losses ~2-5% Inertial impacts ~8-10% Drivetrain efficiency Anything above that has probably more to do with poor heat management of the test environment. Last edited by CanAutM3; 06-24-2014 at 05:24 PM.. |
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06-24-2014, 02:25 PM | #376 | |
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425lb-ft and 265hp vs 295lb-ft and 414hp. Guess which one is faster . Engine torque without gearing means absolutely nothing in terms of vehicle performance. It seems to me you have some fundamental misunderstandings of basic physics . Last edited by CanAutM3; 06-24-2014 at 04:11 PM.. |
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06-24-2014, 03:11 PM | #377 | |
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06-24-2014, 05:13 PM | #378 | |||||||||
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Utter rubbish. Torque and power are like apples to oranges. Much more below. Quote:
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Please show me a basic calculation, the math, formula and result that allows torque alone to compute an instantaneous acceleration value. Surprise, surprise, there isn't one. Here is the trivial math for you using power (makes NO difference what gear you're in - cool isn't it) a = P/(v*m) (all SI units, power is wheel power of course). Do some comparisons vs. real world test data. Wow, what a surprise it actually works. Share your wonderful, powerful insightful method or cork it, really. Quote:
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Welcome to your own personal little island of misperceptions, false beliefs, lack of foundational understanding. It must be a lonely place there. Honestly, it is time to write your own simulator (as I have done) to better understand these subtleties.
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06-24-2014, 05:18 PM | #379 |
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That was clearly an error. What I meant to say/construct through a formula was simply that power losses are a linear function of rpm. Good catch. Not sure how I brain farted that one so badly. It is not from a lack of understanding, just being quick and careless... Sorry this wasn't noted prior.
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06-24-2014, 05:19 PM | #380 |
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Whew, another voice of reason with conclusions supported by the physics...
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06-24-2014, 05:33 PM | #381 | |
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