Cartest software.....

[RacingManiac]

Ok, I think this software is pretty fun, but one part that's really hard to do is gear ratio.

Can someone explained briefly how gear ratio works and how to set it up correctly, and what different thing should I do to a small high revving engine to a bigger engine or a Turbo engine?

[Scott85]

Basics...
a 2.73 gear would br more for top speed VS say a 4.10 gear for a "quick" (0-60, 1/4 mile) run. A good all around gear would be a 3.55 or 3.73 final gear ratios.

[RacingManiac]

I kinda figure out that part, but what about the each gears' ratio? What relation should they be in with each other and with the final gear ratio?

[hondakiller]

if you have say a 6 speed. you should have them go in descending order from 1 to 6 highest numbers in the lowest gears. start with around a 3. something first gear and a two something 2 and a high 1 something third. fourth should be around 1.00 and fifth and sixth should be overdrive gears i.e. less than 1.00. the final drive should be around 3 depending on the hp you have. ive got 800 and 800 and my final is around 3 but that program is weird on the gears. if it were any lower id go over 300 mph and if it were higher id top out at like 150. you have to finely tune it it takes a while. a .1 drop or raise in your final drive will result in about a twenty mph change in your top speed.

[tigeraid]

Not to burst your bubble or anything, but CarTest is incredibly inaccurate and unreliable for performance data. If you want a really good program, try Performance Trends Engine Analyzer/Drag Strip Analyzer package, or Desktop Dyno 2000--both far more realistc.