Physics Based Performance Modeling/Simulation - 0-60, 1/4 mi, Top Speed

[BigMeatsBronco]

the difference in our logic is that the contest here is the to accelerate to legal speed limit...and to do that, lower gearing has the leverage advantage . If there was a contest to accelerate to vehicles top speed that it is capable of, then taller gearing wins.

for me, most roads, speed limits and hills don't allow top speed, so taller gearing is less efficient on hills and slower speeds (like the speed limit)

so lower gearing works best when your goal (for the contest) is NOT ultimate top speed but instead to accelerate quickly to the about HALF of the vehicles top speed. Normal roads are better suited for lower gearing.


all those racers over the past 100yrs that bring several ratios to track day did that for a gearing acceleration advantage....they chose to use a ratio that matched the track ( because the top speed of the track may not be the same as the top speed the car can muster in a straight line) ...so correct lower gearing allowed them to accelerate quicker and win ...

the problem with your computer model is that all vehicles have an end of acceleration. it ends at the top speed the vehicle can produce. BUT, this is irrelevant because 99% of folks don't drive at top speed or even want to accelerate to that speed. By making the goal a speed that is about half of the top speed, the gearing that is superior for acceleration, to that desired speed, is lower.

so for our roads with speed limits, a lower gearset does accelerate quicker to the speed limit.

Another example is if I only want to go 90 miles an hour, even though the truck is capable theoretically of 130 miles an hour, Then I only need gearing that allows the truck to reach maximum RPMs in the tallest gear at 90 miles an hour. That's set up is going to out accelerate a similar vehicle with taller 130 mpg gearing.


As I've said before I'll gladly sacrifice top speed for better acceleration.

let us know when you get yer Raptor!

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[BigMeatsBronco]

Nope, I never said that and do not believe it. Pure rubbish, prove it or cork it.



We already hashed out this debate somewhat thoroughly here in your thread.

In this "wonderfully elucidating" bicycle example above, choosing the incorrect gear for an acceleration contest (essentially forcing the "engine" to output way less than its peak power) and then not permitting shifting "proves" something about which gear(s) is better for acceleration? Hardly. It's really simple, get your engine (or body) at/near peak power and keep it there as long as possible, this is obviously done by gear choice and shift points. What you are doing is maximizing the time integrated power.

As, I demonstrated, conclusively, in the other thread, a regeared FD does not provide performance benefits across the board and across gears, it helps here and hurts there and is highly dependent on the contest. I showed you a 5.38 and then a 6 and surprise, surprise, no overall improvements. Also, over in that thread you first claimed, essentially that physics is wrong and then went on to accept the physics and completely misinterpret the results as opposite as possible.

Again, across multiple gears, regearing provides NOTHING for overall performance. Why of course, simple, the engine power output is all that matters.

That wasnt my thread. someone elses...

Tall gearing does to the engine the same as yer pedal bike...it forces the engine to operate in less than ideal RPMs! duh

Why do you think semi trucks have 18 or more gears? It's because of a gearing advantage and allowing the engine with a extremely small RPM range to operate in this range all the time.


Even if you take the shifting out of the equation like with a CCV transmission the overall results will be the same tall gearing works good to get to the absolute maximum top speed of the vehicle and acceleration will suffer compared to lower gearing that achieves a lesser top speed.

 

[swamp2]

Maybe not your thread but we took it over...

I already demonstrated with 3 possible regears for the Bronco Raptor (of course the conclusion is vehicle independent...) that overall acceleration across gears is not improved. Babble all you want about semis of bikes, the same physics apply. Real (across the board) performance gains only come from adding power (not torque, not gearing, etc.).

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