keep in mind, that the redline is different. this affects the "top end" of each gear by 1000rpm, where the ap1 had that extra rpm to spin in a gear.

use the reverend's gear calculator and change the ap2's redline to 9100 and you'll see what i mean.

 

Yea I set the redline to 9100 with teh ap2 gear ratios and it ends up to be 156 with the 4.44 gear. So I guess that 1100 extra rpm really helps.

 

Only until you run out of rpms. Then you have upshift, and you have less torque. Until the stock car runs out of rpms. Then the stock car has to upshift and you have more torque. Etc. Integrated as a whole: damn near even.

 

Yes, I do, thanks for asking. The acceleration of the car is not determined by the peak force on the car in a particular gear. It is determined by the integrated force on the car over time. In other words, it is limited by power, not torque. Power does not change with the gear ratio.

If you want to do the math, what you need to do is calculate the force on the car as a function of time, including the periods of time when you have to upshift with "gears" before you have to upshift with a stock car. During the time when you are in the same gear, the modified car has the advantage. During the time when the stock car is in a lower gear, the stock car has an advantage.

Overall, time-integrated, it doesn't make much difference.

Consider if the tranny were continously variable. Then it would adjust itself so that no matter what the diff gearing was, the overall final drive ratio would be the same. In our car, the tranny is not continously variable, but as you shift between the gears you do a reasonable approximation of it over the span of the entire run.

 

[QUOTE=Wisconsin S2k,Aug 23 2005, 11:53 AM] think of the 10 speed bike.

 

i give up. if you really think that the correct gears can't make the car faster, then you're quite simply out of your mind. i dont know how much more clear a picture i can paint for you.

4.57 gears on an S2000 WILL MAKE IT ACCELERATE FASTER if you "look at the entire picture". again, this is not a new concept. i guess for the last several decades that people were modifying their mustang, or camaro, or old muscle cars, and putting SHORTER FINAL DRIVE GEARS into their cars, that all this time it really does nothing and you're smarter than all of them.

right, but you yourself said this:
so figure it out. during the entire acceleration range, i have a much more greater "area under the curve" if you were to graph it out. i may have to shift at 39mph to 2nd instead of 43mph like a stock S2000 would, but I have a MASSIVE gearing advantage from 0-39mph. and that's just to START!! am i getting through to you?

 

if it really makes you feel better, i'll post a video of me and ryan racing, then have us switch cars, and then race again. (even though i've already done this with another S2000 owner)

but then you'll come up with some other excuse about how the 4.57 car isn't really faster, and who the hell knows what else.

seriously. people have been doing this for years. it makes the car accelerate faster overall, from ANY speed roll or from a stop. if you want to argue that, you might as well argue that the sky really isn't blue too.

 

You can talk all the science crap you want but lets get down to it...have you ever actually been in an S2000 with 4.57s? Better yet have you driven one? I am sure you will say yes because this is after all the internet and many of us on this site tend to inflate our experiences a bit. I can tell though that the answer for you is no.

I however own an 03 S2k without gearing and have had the pleasure of riding in WisconsinS2k's car MANY times. WisconsinS2k is an excellent driver and an even better shifter. Setting aside this fact, his car tears through the RPMs and the car is without ANY doubt faster than stock. I have also had the opportunity of running Wisconsin's car before and after the setup. It used to be an even match before, now I look slow as hell compared to him. I am extremely tempted on a daily basis to perform the same setup on my car as Wisconsin's but mine is a lease and I do not want to deal with the eventual hassle. I suppose that there will always be doubters, but be sure to actually experience the gears before trying to throw all sorts of interesting theories around. Have a nice day.

Ryan

 

The math is symmetric, Wis2K. It all comes back to power in the end. Torque times velocity is power, so at a given velocity, the torque of the car is determined by the power available. You choose the gears and the gear ratios to keep the engine in the peak power band as much as possible over the range of speeds you expect to operate in.

That's why ideal quarter-mile times can be predicted extremely well by only knowing the power-to-weight ratio. (This is not true of NHRA drag racing, where all the cars have so much power that the limiting factor becomes the tire grip.)

It's certainly possible that you can tweak the ratios just a bit to optimize the car for a given task (like 0-60, or the standing 1/4 mile). But unless you really have a terrible design to start with, you are only talking about small effects.

Obviously we are not going to convince each other here. Hell, I wouldn't have bothered in the first place if I didn't respect your intelligence. But I hope you will realize that you are arguing with an intelligent and experienced engineer. That doesn't mean I can't be wrong, but you should at least consider whether I might know WTF I am talking about.

 

Next time you fly in an airplane, consider whether you care about whether engineers like me have been "talking all that science crap".