I've read that the fj20e and et do not share the same clutch/flywheel combo one is 9 and the other 9.5",so the question is if the factory dr30 transmission(of the fj20et)is compatible or comparable to the c or b trans and if it fits to the s12 tunnel without mods?

As far as I know, the FJ's trans is a FS5W71B trans just like the S12's, and should fit the S12 just the same.

correct.

there is a subtle difference between the turbo and non turbo boxes, but they will both fit the same. i ran a non turbo box behind an fj20et for 2 years with no problems...

I have the non-turbo FJ trans, so what are the subtle differences you mentioned? Gearing? Parts strength?

I would think just gear ratios, strength almost never changes in a single trans model. Don't see why it would anyhow.

rumour has it that the turbo gears are slightly wider, but not having to ever put one of the gearboxes apart , i couldnt tell you for sure.

the turbo box also has slightly different castings for the bell/tailshaft housings. the turbo ones having a few small extra webs and reinforcing...

i dont believe that the ratios are any different turbo to NA either.



youd be surprised at just how many tiny little things were changed for no apparent reason all over my rs-x s12 and motor etc. sometimes i wonder if mine was a parts bin special/prototype made with the previous years leftovers

The FJ ratios are different to the CA20 ratios (shorter 1-2-3). The front housings of the CA & FJ are interchangeable.

You've got it right with the different clutch sizes. The FJ20E & Gazelle CA20E clutches are interchangeable, but the R31 CA20E clutch isn't (bigger bolts & different spacing).

fyi ka transmissions bolt on no bell housing swap and if you slot the top holes rb transmissions do as well..

Which means i can use the bigger fs5r30a, i'm dropping an rb26/z32 hybrid box behind my r30's fj and the shifter pops up right where it needs to

Thankfully the r30 has tons of space to fit this transmission, on an s12 i would imagine an fs5r30a would never fit without alot of "coaxing" via a sledge

Was going to go with the Ka's fs5w71c, but i had the space soo...