Okay, so this is gonna sound really newbish...but what can i say? Im a newb...

What exactly is the Final Drive ratio? Ratio of what to what...

Also, there are final Drives that are high and low, im guessing one is good for one purpose and the other for another purpose... or maybe one i just better? Explain the difference please???

Thank you

edit: oh, and yes i did a search, but couldnt find a clear answer

 

First, the engine drives the main gears. Each one is expressed as a reduction ratio, like this ('95 GSR):
1st = 3.23:1
2nd = 1.90:1
3rd = 1.36:1
4th = 1.034:1
5th = 0.787:1

So for example if you're in 2nd gear, the output spins slower than the input by a factor of 1.90. But then there's one more gearset, called the final drive. That's the gearset that drives the differential. Mine is 4.40:1, you multiply that reduction ratio. So in 2nd gear, 1.90 x 4.40 = 8.36, so for every 8.36 revolutions of the crankshaft, the axle makes one revolution.

Higher numerical ratio means a 'lower' gear. So if you want to have lower rpms at the same road speed, you look for a lower FD, like 4.0:1 or whatever.

 

why do people get final drives that are high?

 

In simple terms - to get higher rpms, for example faster launching or faster 1/4 mile times. Or even in road racing you would pick your gear ratios & final drive ratio to allow you to stay up in high rpms where your engine makes more power.

 

read this:
http://www.team-integra.net/se...D=707

 

so basically, for acceleration and power you would get higher final drive ratios and for better gas milage and top speed u would go for lower final drive ratios?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by variablevalve &raquo;</TD></TR><TR><TD CLASS="quote">so basically, for acceleration and power you would get higher final drive ratios and for better gas milage and top speed u would go for lower final drive ratios?</TD></TR></TABLE>

yes, more or less..