BigVinnie

iTrader: (2)

Tired of the inevetable slow 5th gear? Tired of slow 1/4mile times?
Well I've been doing some research and have found out that the KA transmission is the 4th generation transmission made since some of Lseries engines back in the mid 1970's. Any transmission that has the begining I.D reference of (FS) is compatible to that of the KA, all bellhousings share the same bolt pattern from engine to transmission. Most of which are also the same length transmission's as well. I decided to research this project because no matter how much juice(HP) I put into my KA the 5th gear, which I call the lazy 5th is still too slow. It was purposelly devised this way from Nissan of America to be more of a fuel conserver. (well what ever in my mind is conserving fuel obviously isn't delivering me the power I want to the wheels.)

So lets start by exploring the 240sx transmission gear ratio's. Pay attention to the I.D reference numbers.

Nissan 240sx 1989-1998 Transmission number FS5W71C
1st: 3.321, 2nd: 1.902, 3rd: 1.308, 4th: 1, 5th: 0.759

Now take a look at the 3rd generation transmission that came from the 1981-1983 200sx.

Z20s transmission 1981 ONLY
1st: 3.321, 2nd: 2.077, 3rd: 1.308, 4th: 1, 5th: 0.864
Z22s transmission 1981-83 Transmission number FS5W71B
1st: 3.592, 2nd: 2.246, 3rd: 1.415, 4th: 1, 5th: 0.813

Even the Nissan truck (frontier) came with a better 5th gear.......
Nissan Frontier 1997 Transmission number FS5W71C
1st: 3.321, 2nd: 1.902, 3rd: 1.308, 4th: 1, 5th: 0.838

Personally I have selected the z20s transmission, although I will lose a little bit of my top speed numbers, my car will make up for even faster accelerated numbers at the wheels. We will find out soon enough what kind of numbers we will be dealing with once installed, and I have removed the rev limiter speed functions and sensors.
In order to use these older generation transmissions you will need to remove all sensors from the transmission, and reprogram the ECU for no limiter (speed govenor) these older transmissions didn't come with the ports to support speed sensors. Which in my mind are retarded to begin with.

Here are my sources and where I recieved my info......... Gracieland.org is an excellent web site that tells you the percentage of power that is moved in the up shift. Tells you the slight differences that came with the (FS) transmissions. Hope you enjoyed.

http://www.gracieland.org/cars/techtalk/gearing2.html

http://vibratesoftware.com/html_help...nsmissions.htm

pooptown

if it works go for it!!!!............lol

nsn240

nice, let us know how it works for ya

Sieji

For track purposes... any extra edge you can get, go for it. But for those of us who use our 240sx as daily grinds... and don't wanna go thru the hassle of reconfiguring our -o-meters and ECU... seems a bit too much for a lil extra gain.

Aren't their easier methods like: rebuilding the trans and using gears from other transmissions... , I bet some re-machineing will be needed... just an idea.

~eji

BigVinnie

iTrader: (2)

Just incase you guys don't go to the gracieland.org web site this is what each I.D number (suffix) stands for.
First number or letter: F - Type of control F=Floor (direct) R= Remote
second number or letter: Abreviations S - Tranny style S=special overdrive top gear (no letter indicates direct drive top gear)
3rd number or letter: C/R=close ratio 5 - Number of forward gears 3 spd, 4 spd, or 5 spd
4th number or letter: W/R=wide ratio C - Drive/Synchro type F=front wheel drive R= rear wheel drive W= Warner synchros C=servo synchros
5th and 6th number or letter: OD=overdrive 71 - Gear-pair center-to-center spacing in mm (distance between mainshaft and countershaft)
DD=Direct drive A - Sequential model version suffix (alphabetical)
7th number or letter: "A" type - shifters are rubber mounted (infamous monkey motion) "B" type - shifters have a solid cross pin "C" type - shifters are retained in a top cover plate by a circlip (called a "top loader" in American trannys)

BigVinnie

iTrader: (2)

You can use any of the gears that come from the (FS) platform of transmissions. So you can still keep your KA transmission, and swap a gear from the z20 or z22 transmissions, even the ones from the 280z or early 80's 300zx up until 89 if you wanted too, just as long as you use the corresponding transmission I.D's they are compatible gears.
If the FS I.D has the numbers 71 in it then you can do it.The I.D reference also has a w which means that it uses warner synchros system you can do it.

Nissan240Lover

that sounds kewl, You made a good decision on doing that.. good job dude!!!

BigVinnie

iTrader: (2)

Failed to mention that the 1997 KA truck tranny will work as a direct fit with all the necessary sensors.

It's 5th: 0.838
compared to the KA's super too long ratio of 5th: 0.759
All the other gears between the 2 transmissions are EXACTLY the same so if you already like the gearing of the KA and just want more speed in the 5th gear the 1997 frontier transmission would be a wise choice.

EDIT: said that before checking the transmission lengths. Truck tranny's are a few inches too long, and won't bolt diretly up to the 240sx drive shaft.......

Bryan

have you tried this out Big V? Still curious about this

BigVinnie

iTrader: (2)

Still curious, just havent had anytime yet. Need to do it soon to probably replace all the synchros, my second pops out, and the previous owner ran my transmission into the ground without changing the fluids.
Along with all the R&D I have done. I figured that it would be cheaper and easier to either use the frontier transmission 5th gear (86-97) with the same (FS) coding, it uses all the same gears as the CA18det.
Found one small draw back, took some time a while ago to measure transmission lengths. I can confirm that the bell housing bolt patterns are the same, but many of the lengths to the transmissions can be different (anywhere from 4" to11"). So in this instance it is probably better to keep your transmission and just do the gear swap. Looked into if they are swapable all I can find is that the (NAPSZ 720) pickup transmission 5th and the (napsz~kae/kade D21) 1987-97 transmission 5th are the same ratio of the CA18det 5th. The wernor syncros system between the sr and the ka are the same but the bell housings changed, (probably due to differences between the clutch systems and engine type).
So you can order the the 5th gear and probably just take whatever hours it would take you to install it, this gear is also called the nismo 5th, you can probably save some money ordering it direct as the ca18det 5th gear, or the frontier 5th gear. Nismo just rebagged with there name and a higher price.....

Bryan

thanks Vinnie will have to give this a try sometime in the future

xam

will the sr tranny bolt up to the ka24de engine without problems?
liek i just dont like the feel of the shifter of the truck tranny. u think if i get a upgraded bushing and short shifter it will feel more like a sports car? also how does the sr shifter feel, smooth/short?

BigVinnie

iTrader: (2)

I havent seen a gear box to the sr yet, but I do know the bell housings are different. I would have to get back to you on that one. Secondly it isn't a truck tranny many cars have used this werner syncros gear box besides the 240sx. sr and ka use the same gearing ratio's, why would shifting be different?

dread

has aynone heard of the rumar, that the G35 or 350z tranny works on our motors?

sav180

now how tru is the rumor g35& 350z trans work on the ka??