KA transmission swappers

[BigVinnie]

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. Well I will see if I can keep the speed sensor in order to use my speedo.
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.

The 1997 frontier transmission has all the sensor ports needed, and has all the same gear ratio's up untill 5th, 5th believe it or not for the truck is more aggressive than it is for the 240sx..... I wonder why Nissan would do such a thing???????

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_hel...ansmissions.htm

[TheSnail]

If your realy interested. Why not get a Ca18det rwd tranny since it has the gear ratios that you want. You would not have to deal with the sensor crap.

Here are the ratio's;

1st- 3.321
2nd- 1.902
3rd- 1.308
4th- 1
5th- .838

[BigVinnie]

If your realy interested. Why not get a Ca18det rwd tranny since it has the gear ratios that you want. You would not have to deal with the sensor crap.

Here are the ratio's;

1st- 3.321
2nd- 1.902
3rd- 1.308
4th- 1
5th- .838

Those are the same gear ratio's that are in the ka frontier transmission..
What is the transmission I.D number for the CA?

[TheSnail]

I would have to see in tommarow, but if you are wondering about the tranny bolting strait up to the ka, it will not work. But a simple bellhousing swap between your tranny and the rwd ca18det (not s12 ca18et), and you have the gears you want.

[drift freaq]

SR and KA trannies are the same as well, just different bell housings. Also you should realize, the ratios in your KA trans are closer together than the ratios in the Z series trans. If your looking for a stronger 5th then the truck trans would probably be the way to go.
P.S. you have to remember that these trannies gear ratios are matched to final drive ratio of the particular cars rear end. Before you go employing a Z series trans look at the rear ratios of the 200sx. You may find, that though the 1st, 2nd and 5th gears of the Z series FS5C71B trans are lower, they may not work as well with the 4:08 final drive ratio in your car.

[ryan hagen]

ca18det had a 4.4 ratio rear end so that might throw their tranney gearing off?

[TheSnail]

Like the frontier and the ca18det, the ratios are the same with the ca18et. The problem with the ca18et tranny, is it is too short in length for for use in a 240sx and it also uses a shift linkage like those found on the 300zx's. So if you want the gears on this side of the pond, then it will take more work. If you got 2-300 spare $, then go with the ca18det.

[orion::S14]

^^^ Same with the Frontier trans...it's ~10-12" shorter than a 240SX trans, so to use the gears, you'll need to swap the guts into a 240SX transmission housing (if that's possible).

- Brian

[BigVinnie]

^^^ Same with the Frontier trans...it's ~10-12" shorter than a 240SX trans, so to use the gears, you'll need to swap the guts into a 240SX transmission housing (if that's possible).

- Brian

Well what about just swapping out the gears? They are all spaced @71mm from center, and they all use the Warner Synchros system, so all gears and components should be interchangeable and be compatible. Technically I was reading up on the transmissions and if it is labelled with the W71 in the I.D they are the same size gear boxes, more than likely just the bell housing's are shorter or longer.

[CKAMC]

http://www.nismoparts.com/catalog/?section=241

The 240SX was originally equipped with a .759 ration 5th gear. An alternate .838 ratio gear set is available as a direct replacment for the OE set

[BigVinnie]

http://www.nismoparts.com/catalog/?section=241

FU%K what Nismo is charging I'll just rip it out of a wrecked 97 frontier for pennies on the dollar......