JDogg

Hm, you're right. Let's see what happens, giving the stock car the lower gear advantage, over the range of 37 MPH - 42 MPH. Stock car goes from 8000 - 8900 RPM in first gear. Modified car goes from 5800 - 6200 RPM. Doesn't look too good for the modified car. However, looking at the torque curve, there is a large increase from 5800 - 6200 RPM, and a large decrease from 8000 - 8900, although it's still higher than the starting point at 5800. So yes, there is a torque advantage for the stock car at the crank, but multiplied by the gearing, it could come out even, although I am no way for sure. If it is even, the advantages do outweight those small windows where the stock might have an advantage (37 - 42 MPH, 58 - 65, 82 - 91, 104 - 115, 124 - 138). These windows, from 0 - 150, represent 30% of the ranges of speed you might encounter. For the other 70% of the time, the modified car will definitely win.

Hmm... I guess looking at it, 70% of the time is good, but isn't THAT GREAT. If, during those windows, the cars come out even, it's a worthwhile investment. If the stock car really does have the advantage, even after taking into consideration the gearing advantage, it's not so great.

Edit: Ooh cool, my numbers match the ones on the graph, and it looks like the stock car does indeed have the advantage 30% of the time.

jasonw

[QUOTE=Wisconsin S2k,Aug 24 2005, 12:18 AM]way to dodge the subject.

jasonw

Good work. That is very much in line with what I expected. Do you have a formula or is that based on existing data points?

The point I was trying to make here all along is that there will be intervals in which the 4.57s are not an improvement.

Wisconsin S2k

calculate the gearing advantange the 4.10 car has in say 3rd gear, vs 4th gear in the 4.57. in the short time the 4.10 car has that "advantage", it is probably less than HALF the advantage the other car has. this is why you have to graph it out, to be able to look at the entire picture.

if by the time I'm at 105mph shifting to 5th, and the other car is only at 95mph (since I accelerated faster), I'm already ahead of the game. while he may slow or sustain my accelerating advantage, it's short lived, because soon enough he finds himself having to upshift, and I once again have an advantage that is probaly double what he just had.

again, graph it out and you'll see the whole picture. whether .4 seconds to say 100mph is "small change" to you is your deal.

however, I find it interesting that while you said Force is unaffected by gearing, at the same time you are conceding that gears can give you a small acceleration advantage. however, if that's true, taking the equation F=ma, since you concede a goes up slightly, this means F also went up since mass is constant. yet gearing doesn't affect F? interesting.....

beanolo

so i was interested in getting gears and was wondering if the 4.57's would be faster than stock?

Wisconsin S2k

no one is arguing that. but what you're ignoring is the fact that OVERALL, they are an improvement in acceleration. in the real world, most people will do more than just race in the small window that the 4.10 has the gearing advantage.

Wisconsin S2k

also another article how gearing increases acceleration.

http://www.findarticles.com/p/articles/mi_...308/ai_n9287022

Wisconsin S2k

likewise. remove the drive line and gears, so only the engine is in the car.


now how much force do you have pushing the car forward?

Wisconsin S2k

[QUOTE=CrazyPhuD,Aug 24 2005, 01:47 AM] ok so I as asked to make another one of these graphs showing effective torque as a function of MPH.

Wisconsin S2k

HP is a function of work over time. not acceleration.

acceleration is calculated using mass and force. force does NOT use horsepower anywhere in the equation. as i said, hp is irrelevant in determining a car's acceleration.


and, I said I did not know how to graph it out in a timely manner with an EXCEL spreadsheet. must I be so damn literal with you? sheesh. give me a pencil, paper, and ruler, and i can plot it out.