Now before people begin bashing me, let me first say I tried a search and I'm still just a newbie so go easy.

I've seen alot of people advertising "final drives", and I've seen alot of people installing them as well. What does a "better" final drive do for you? What makes one better than the other? What sort of drive is better suited for daily driving? How necessary is an improved final drive? Sorry for the beginner questions, but transmissions and gearing is something that I've never really gotten into.

Thanks for any help.

 

The final gear affects the gearing of the other gears. So if you make the final shorter/longer
then you effectively make all the other gears shorter/longer.
Making the gear ratios shorter gives better acceleration at the expense of lower top speed.
How necessary? Depends. Some setups can benefit from changes in gear ratio
so whether or not you NEED it or not is really dependant on the setup.

 

can you explain to me more of what that means. I sorta get it but not really....

I'm not really a newbi but understanding gearing is somthing i didn't really reaserch on. I always though that the final drive was the the 5th gear...then i would also see a measurement for the 5th gear and get confused.

can you give me an example of trannys that most commonly have this 4.91 final drive swaped in? who makes them too?

 

Basically the trans is setup as follows:

1
2
3
4
5
R

Final

Each of the above gears must go through the final before finally turning the wheels.

The two common upgrades for the B-series transmission are 4.785 and 4.929. The
stock gear being 4.40. Honda makes the 4.785 and ATS makes the 4.929.

Here is a chart of a us spec ITR transmission with the stock Final with speed shown
in mph at 8000rpm:

1st - 3.2310 - 38.55
2nd - 2.1050 - 59.17
3rd - 1.4580 - 85.42
4th - 1.1070 - 112.50
5th - 0.8480 - 146.87

Here is another chart with the ATS 4.929 at 8000 rpm, you can see how the top
speed is reduced in comparison to the stock transmission.

1st - 3.2310 - 34.41
2nd - 2.1050 - 52.82
3rd - 1.4580 - 76.25
4th - 1.1070 - 100.43
5th - 0.8480 - 131.10

 

Think of your transmission gears as torque multipliers. So torque in any selected gear is multiplied by the final drive = drive wheel torque. Final drive is the gear on the differential and is the final multiplier.
I have a 4.929 from ATS in an LS tranny, you can also get them for GSR/Type R/B16A.

 

I also was considering the TAS FD....I have a '00 Si.....anyone run one in a SI tranny? I was wondering if I should change out the 5th gear to GSR or LS to make freeway driving tolerable....

 

wow sgT
thanks for the well put data and explanation. I do have a better idea of how it all comes into play now. Do you have a link to ATS 4.929?

honda makes a 4.785 final too? is that in the ITR tranny?
How much does it cost for parts and labor?

 

a slight piece of technical info that was seems to be forgetten is wheel & tire size combination, in regards to top speeds...

In Japan, the 98+ Type-R integra's all have a 4.785 fd and 16" wheels with either a 40 or 45 series tire (can't remember exactly), unlike the pre 98's that use a 15" wheel. Reason why is the wheel spin/mph factor. If Honda used a 15" wheel w/50 series tire on a JDM 98 ITR, the car would lose MPH because of the 4.7 fd and wheel size dynamics. So to correct that, they used a 16" wheel and a 40 or 45 series tire. They coulda used a 55 series tire w/the 15" wheel to correct the MPH loss, but I guess they didn't want to stick with the older 4x114 wheel style that the 97 ITR had.

So, if you plan to change your current FD to something of higher ratio (4.7 or higher) and are **** about it, don't forget the wheel/tire combination technicality.

And of course it also depends on the type of racing you're into.

A 4.40 FD is just right for a 14-15 wheel w/50-60 series tire, though.

Actually, you can make your own shorter final drive for free, by using smaller wheels (13" wheels, but I forgot what tire size to use). I'm not sure what chassis & motor you have, but if you're able to fit on some 13" wheels, try some out and drive around. A noteable increase in acceleration will be experienced.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NAEBP00Si &raquo;</TD></TR><TR><TD CLASS="quote">I also was considering the TAS FD....I have a '00 Si.....anyone run one in a SI tranny? I was wondering if I should change out the 5th gear to GSR or LS to make freeway driving tolerable....</TD></TR></TABLE>

Im assuming you meant ATS. ATS makes 4.929 FD for the B series. we dont have much information on it on our site.. but you can check out our GEARING section on our website wwww.exospeed.com to see your choices for the gear set.

 

hear is an easy explanation of a final drive
think of a 10 speed bike
the final drive would be th gear in the front
the 1-10 in the back are the gears
the gear int the front sets the tone for the 1-10 gears in the rear
the shorter or longer the gear in the front will in turn affect all of th 1-10 gers in the rear making them shorter or longer.