Ok, everybody talks about wanting shorter gearing, a lower final drive, all this stuff intended to make the gear ratios shorter. Instead of just buying into this, I tried thinking about it and only confused myself. Can someone please explain to me how this actually makes the car faster?

The way I see it, yeah the car will go through the gears faster, making it feel like the car is accelerating quicker. It will also get the car from a stop into the powerband faster. But wouldn't this also effectively shorten the powerband and lower the overall power? I'm thinking, because you shift more and rev faster, it feels like you are going faster, but you are shifting at lower points so in the end it all comes out in the wash without much of a difference.

If it is painfully obvious that I have no clue what I'm talking about, please enlighten me because I would like to know why this works how it does. Thank you in advance for any and all help.

 

Shorter gears trade RPM's for more effective torque. More torque = more acceleration. The upper limit to this being that you reduce your top speed as you shorten the gears and you're still subject to the limits of your tires.

My car's currently geared so, I'm problably going 150 in 5th at redline. If I shortened the gears so my top speed is 130 but, increased effective torque, well it might be worth it.

 

Oooh ok, that makes a lot of sense. So basically the car accelerates faster because the car gets into the more powerful torque areas of the powerband quicker? I think this makes sense but I would also like to hear some more people chime in. Thank you MasterKwan for your help

 

Ask "Bense" he's the transmission guru

 

Bense, where you at? You are about to be PM'ed so be ready!

 

stock civic ex trans (92-95)

1st gear = 3.250
2nd gear = 1.900
3rd gear = 1.250
4th gear = 0.909
5th gear = 0.702
final drive = 4.25

multipying 1-5 gears by final drive
1st = 3.250 * 4.25 = 13.8125
2nd = 1.900 * 4.25 = 8.075
3rd = 1.250 * 4.25 = 5.3125
4th = 0.909 * 4.25 = 3.86325
5th = 0.702 * 4.25 = 2.9835

the higher the number, the more torque multiplication. 1st throws you to the seat more than 5th does, because the number is higher.

change the 4.25 to a 4.7 or 4.9 and see what you get.

good luck

 

Thank you again Bense for your help. I will read your write-up closely and see how much I can understand now.

 

you never played gran turismo did you... play itm buy a fully customised tranny (in the game) and play with the numbers, see what happens...

 

Wow bense, i didnt know how that equation worked. thanks.

One question tho, how do you figure out which is the best gearing for the application? Is it just playing around until you get a good set up or is there a science behind it?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by sasser43 &raquo;</TD></TR><TR><TD CLASS="quote">how do you figure out which is the best gearing for the application? Is it just playing around until you get a good set up or is there a science behind it?</TD></TR></TABLE>

There are a lot of factors that are involved. Usually you want to have 4th gear end a few mph higher than your trap speed in the 1/4th So if I am going to trap near 110mph, I want to have 4th end at 113mph or something. But then there's other things to be mindful of. Some people what a short 1-4 gears with a super tall 5th for cruising. I personally can't stand it, because then you have a huge gap between 4th and 5th.

Some of the guys on gassavers.org are using vx transmissions. IMO that 5th is too long. But What you do with the vx trans is you cruise in 4th, but on the longgg flats you can move it over to 5th gear.

Tire size, maximum engine rpm, and gear ratios all have a role in selecting your setup. If you want to read further additional information the FAQ in the tech / misc points to further explanations, calculators, gear ratios, etc. Don't take this as a "OMG SEARCH n00b" post, because it's not. I'm glad to answer your questions, but I am becoming more and more busy these days and I don't have time to find everyones transmission question and assist them.