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      06-11-2013, 09:13 PM   #118
swamp2
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Drives: E92 M3
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Wow, this barely deserves an (ongoing) response but here we go...

Quote:
Originally Posted by flinchy View Post
verifiable via hand

(i worked it out on paper with a calculator first)
Great post it all up, shift point calculations for the F10 M5. With the required curves I keep mentioning and posting.

Quote:
Originally Posted by flinchy View Post
yeah the page i posted with the REALLY GOOD calculator seems to still be down

really saddening, GREAT online tool.
Sounds great,

Quote:
Originally Posted by flinchy View Post
power is torque over an RPM. fact... verified by the conversion formula.
Again no, incorrect. Power is by DEFINITION the product of a force multiplied by a velocity, which is generalized into rotating devices to power = torque x angular velocity (all in SI units of course). You can't escape these, they are the definitions...

Quote:
Originally Posted by flinchy View Post
well, close... the car with the higher AVERAGE of power over the accelerating rev-range will out accelerate... you can have a car that momentarily has WAY (or more realistically, slightly) more power, but throughout the revs has slightly less... if you're talking at specifically 6547 RPM car vs car identical gearing... for that RPM, yeah, of course.
You keep missing the most basic point, INSTANTANEOUS was the point of my first "rule".

Quote:
Originally Posted by flinchy View Post
your second paragraph is inaccurate... if you have peak torque at say... 6000RPM.. redline at 10k... and torque drops by 5% of the peak value linearly to redline.... well, peak acceleration will continue to redline
100% positively, FALSE. The acceleration curve "mirrors" the torque curve and this comes fundamentally from F = ma. You can also grab the more detailed formula 2-9b from the Gillespie text book, Fundamentals of Vehicle Dynamics. Again ignoring the (typically) minor corrections in the second term, the peaks corresponding become obvious. Please stop while you are ahead. You can also spreadsheet up this type of solution as many forum members have done themselves to see this point. Each ongoing post here makes you look all the more incorrect and quite frankly ignorant.

Quote:
Originally Posted by flinchy View Post
so ... i guess previous discussions weren't taking into account how many times the force is applied per timeframe AS WELL as gearing. if you haven't thought about this... well.. think about it.

which of the above RPM's are you going to make peak acceleration gearing taken into account now?
Really, WTF, I can't even understand this gobbeldy-gook


Quote:
Originally Posted by flinchy View Post
HP = Torque (lb/ft) * rpm / 5252
Yes, finally something correct. This is the exact same formula as power = torque x angular velocity (as I keep saying) just using terrible English units instead of the preferred SI units which help keep the concepts simple as the fundamental unit system for physics... Now that being said, yes when working in hp and ft lb the above formula is quite useful.


Quote:
Originally Posted by flinchy View Post
RPM = time in this case... maybe i should say 'over a frequency'
Again no. RPM is in no way equal to or equivalent to time. Yes time must march along in the background, in the same way it does for most simple Newtonian mechanics problems, for something to spin in the first place but that's about it.

Force, torque and power are all both instantaneous and potentially time varying quantities.

Quote:
Originally Posted by flinchy View Post
yes, it's what you're saying (in arbitrarily more complex terms than they need to be)..

for 99% of the population, my explanation is a LOT easier to understand and give them that 'oh' moment haha
No, no, no. I insist on keeping it simple and focusing on concepts, pot meet kettle... Big fat chance on the second point. You language is so imprecise and has been riddled with errors. If you think that begets clarity you've got even more problems.

I'm far from perfect but here on this forum I do have a thrust and a bit of role as one who brings clarity and transparency to aspects of vehicle performance through correct science and math (often statistics or lack thereof). You've got a long way to go to offer any help or clarity here on these particular topics. Please, please for you own education.

Here are some pointers, thank me later for all of the solid materials here. PLEASE, PLEASE, save yourself, do some reading:

Does final drive really matter
Power to weight is the most critical metric in performance (late in the thread an agreement is finally reached)
Another like the above (particularly my post #134)
Peak in gear acceleration is (not quite) at peak torque
Bruce's good old write up on power vs. torque
The lack of low end torque in the E9X M3. #1 and #2
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