joestud

Does anyone know of a company that makes a more aggresive final drive gear for the 1996-98 Civic tranny? I know for B-series people upgrade to the JDM type R final drive but what is there for the D-series?

SkyeC

SRR, y0.

Search...

B18C5-EH2

http://www.exospeed.com sells them I believe.

SRR 4.78 and 4.929 Final drives.

TheAutoboxer

anyone wanna clue me in ona final drive, how does the last gear modify the rest of the gearing.. i assume that the gearing is closer.. making top speed less, and pick-up more.. anyone ?

Happyman

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by menkio &raquo;</TD></TR><TR><TD CLASS="quote">anyone wanna clue me in ona final drive, how does the last gear modify the rest of the gearing.. i assume that the gearing is closer.. making top speed less, and pick-up more.. anyone ?</TD></TR></TABLE>

I'm not too sure but I don't think the final drive is the last gear. I believe that its how short the gearing is. And the final drive is just the gearing for 5th gear but it shortens every gear. I'm probbaly wrong though. Just call me a post *****.

BauleyCivic

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B18C5-EH2 &raquo;</TD></TR><TR><TD CLASS="quote">http://www.exospeed.com sells them I believe.

SRR 4.78 and 4.929 Final drives.</TD></TR></TABLE>

yep

the final drive is the gear that runs every other gear...if you modify the final drive...it is the equivalent of changing the ratio of every gear by itself equally...so in effect by changing the final drive...you are changing the ratios of every gear...instead of replacing every gear by itself

B18C5-EH2

I'll break it down as easy as I can:
The final drive determines what the max speed in each gear the tranny will go, and also how quickly you will rip through the gears.

Example?

I had a 4.929 final drive in my ITR tranny for a while. The stock unit is a 4.400. With the 4.929 FD the mph in each gear was lower, meaning I'd hit the redline quicker in each gear and also it lowered the max top speed in 5th gear as well.

When you reach the redline quicker in each gear basically the car accelerates quicker.

With the 4.929 FD I'd rip through the gears quicker, but the rpm were the same when upshifting...

That brings me to gear ratios.

Gear ratios basically effect how far the rpm drop between shifts.

Example?

If you have a tranny with closer gearing the rpm will stay higher when shifting into each successive gear. This means the engine stays in it's powerband more so than a taller geared tranny.

That's the simplest way I can explain it really.

Zer0DazE

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BauleyCivic &raquo;</TD></TR><TR><TD CLASS="quote">

yep

the final drive is the gear that runs every other gear...if you modify the final drive...it is the equivalent of changing the ratio of every gear by itself equally...so in effect by changing the final drive...you are changing the ratios of every gear...instead of replacing every gear by itself</TD></TR></TABLE>

yes sir, and i can say that the SRR 4.7 fd was probably the best mod i have made to the sohc.

BauleyCivic

so was i right too tom?

B18C5-EH2

Let me add this:

Changing the final drive ratio will NOT keep the revs any higher when you upshift into the next gear - only changing actual gears will do that.

As I mentioned before, changing the Fd will allow you to rip through the gears quicker, but the rpm drops between shifts will remain the same.

Example?

Before the FD install you hit the 7200rpm redline in first gear on your S20 D Series Si tranny and you're at 36mph.

You shift into second gear quickly, and the rpm drops to 5000rpm (just a guess, not the actual numbers).

So after the FD install it'd be more like this:

You go to the 7200rpm rev limit in first gear and you're at only 28mph (just a guess to illustrate the difference again) and you get there quicker.

You still land at the 5000rpm when you upshift into 2nd, but the difference again is how quickly you rip through second, then third, etc.

Ekizzle

Damn Tom, I just wanted to say thank you for all your helpfull and vital information that you share with us.

BauleyCivic

well said tom how come you don't post useful info in my threads

joestud

Thanks guys for the info

IDriveHonda

So how is highway cruising with a 4.7 final drive in the Y8 tranny? Does it keep the rpms too high or is it OK?

Evs-One

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by IDriveHonda &raquo;</TD></TR><TR><TD CLASS="quote">So how is highway cruising with a 4.7 final drive in the Y8 tranny? Does it keep the rpms too high or is it OK?</TD></TR></TABLE>
depends on tire size also.

If you're running a 20 inch overall diamater tire AND the 4.7 final drive...your revs will be VERY high at 70 mph.

But with stock size tire diameter, you will be fine.

Rhythm Racer

for tom i know learned somthing new today

BauleyCivic

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by IDriveHonda &raquo;</TD></TR><TR><TD CLASS="quote">So how is highway cruising with a 4.7 final drive in the Y8 tranny? Does it keep the rpms too high or is it OK?</TD></TR></TABLE>

Figure it out yourself:

http://www.f-body.org/gears/

D1678 Gears:
Axle Ratio(FD): 4.250
1st: 3.250
2nd: 1.900
3rd: 1.250
4th: 0.909
5th: 0.702

Stock tire size: 195/50/15
Redline: 7000

IDriveHonda

Thanks for the info guys, I have a J1 tranny in my crx right now and on the highway it runs at or above 5k rpms and that is too much for me, but it is so much fun on the streets. On the D series I would like it to be a bit lower than that for everyday commutes. I usually run a 195/50/15 tire.

The Internet Tough Guy

hrm... one of these should fit with a quaife right? anybody know?

OnebadJdmEg6

YaY Tom's the man , i though it was something about the last gear also but guess not i just learn'd something about it and made me know something of it more yeaH!!! So now somebody buy something from me so I can get a order on a SRR FD for my sohc tranny

ExospeedAMcrx

Tom for the great answers

Evs-One

think of it as a bicycle....

the gears by the pedals being the final drive and the gears by the rear wheel being the 1-5 gears on the car...relatively speaking.

exciv2000

So do you have to crack open the tranny to replace the final drive?

B18C5-EH2

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by exciv2000 &raquo;</TD></TR><TR><TD CLASS="quote">So do you have to crack open the tranny to replace the final drive?</TD></TR></TABLE>

Yes.

It is a pretty envolved process. The final drive is made up of two parts:

The ring gear
The countershaft

The ring gear is bolted to the differential itself, so you must remove the diff just to get it swapped.

The countershaft houses one half of your tranny's gears, so you have to remove both your mainshaft and countershaft and then unstack one half of your gears and synchros in order to swap out the countershaft.

In a nutshell you might as well rebuild the tranny whiule you're swapping a final drive.

BauleyCivic

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AzCivicCpe &raquo;</TD></TR><TR><TD CLASS="quote">so does anyone have before/after 1/4mile times and 60ft times with the 4.7FD???</TD></TR></TABLE>

Heres the closest thing I can give you.

I put 20" tires on my car...having them makes my gearing similar to a having a 4.7 FD in my DX tranny(Transmission is S20 93 DX, 4.058 final drive, 7200 RPM redline)

Shift Points-

Stock:
37 - 68 - 102 - 132

20" Tires:
32 - 60 - 90 - 115

4.7 Final Drive:
32 - 59 - 88 - 114

I only ran once with the 15" pirellis (16.4 w/ 2.4 60ft)...with the 13" sumis, I immediately dropped 3 tenths (16.1 w/ 2.3 60ft) and eventually got my best run in with them (15.9 w/ 2.2 60ft). They are actually pretty damn sticky, I had to cook em before each run though...it was awesome!

Here is an interesting comparo of the sumi's vs the pirelli's with similar 60fts-

195/50/15 (23") Pirelli P700-Z on Integra LS wheels:
60ft: 2.400
1/8: 10.531
MPH: 68.00
1/4: 16.407
MPH: 84.08

175/50/13 (20") Sumitomo HTR200 on Civic VX Wheels:
60ft: 2.451
1/8: 10.594
MPH: 66.53
1/4: 16.406
MPH: 85.09

You can see the difference...with the civic VX wheels at the 1/8 mile I was .06 seconds behind and 1.5 MPH behind my other run, and at the 1/4 mile I was .01 seconds ahead and 1 MPH ahead of my original run. So, in the second half of the run, I gained almost a tenth of a second, however I did gain 2.5 MPH with the VX wheels, and I had an overall better run with a worse 60ft...not bad at all