ca gearbox ratios

[CNHSS1]

my car had an S12 mk2 box originally fitted. after breaking a couple i bought an s13 and s14 box. the s13 box, and s14box when fitted with the s13 CA bellhousing, are 50mm longer overall (in the tailhousing section actually), than teh S12 Mk2 boxes. it required the prop shortening by 50mm, but the gearbox mounting points on the box are in the same place and take the same mount as the Mk2 so its only the prop that you need to get shortened (cost me £40 inc balancing iirc).

the gearlever position is moved back 65mm though so the tunnel will need modifying too.

S14 ratios are better for my car anyway, and the latest s14 box i have has the anti surge trapdoor design too to stop the oil rushing away from the gearset asnd filling the tailshaft section.

[30psi]

Is there a difference in length to the S13 box and an S14/13 bellhousing combo?

ie, if I fit the S13 box will I need the prop shortened when I eventually get an S14/13 combo?

Have you considered going for an os giken gearset?

[CNHSS1]

certainly the 3 s13 boxes and two s14 boxes (when fitted with CA bellhousings) i have had, are all the same length, so you will need to shrten the prop anyway to fit s13 or S13/14 hybrid.

i have considered the OS Giken stuff, but my gerabox failures (to date ) have been selectors rather than gear sets. In my opinion, i could run 20-30% MORE horsepower than a 200SX and not break the gear sets or tailshafts due to the lower weight of the car. Its torque that kills the gear sets and bearings and im not dragging a 1200kg tin car about, but 750kg of plastic pig instead! so the loads are less, and the box is subjected to those loads for less time due to the quicker acceleration of a much lighter car. Trouble is by the time you have a Giken box built up, its nigh on 2 grand and it uses stock selectors and H pattern.

I toyed with a Quaife sequential box for a while, but i just couldnt justify £6k for a box, even if i could afford it. The more i looked into it, it wouldnt fit anyway as theres a dirty great lump on the drivers side of the box that just wouldnt go into the chassis (see Brens pics of his S14 monster build). The HKS sequential box that i saw at the Autosport show would fit however as its all in a std size casing

If i do buy a race box, and it wont be in the next 18months as it would probably require a class change, i would probably go for the HKS or more likely the PPG dog box with possibly an Ikeya shifter.

[30psi]

Cheers Craig, I'll prob try to fit the S13 box first off then going for an S14 combo as and when.

What is it you do to break the lever arms (selectors) then, are you just too heavy handed with the box?

[CNHSS1]

id like to say its a design weakness, but i suspect its because im a heavy handed mutha funker
i tend to stamp on the clutch and slam the lever into gear which breaks the cast 5th/reverse selector. Proper usage i reckon theyd last forever!

[Beany-s12]

i'm not 100?% sure on this one but i thought if u got an early s13 box it was shorter than the later ones! i'll be able to tell ya for sure tommorow coz gonna try fitting a Greg s13 box into my mk2!

[CNHSS1]

i have heard that too but all mine were longer than mk2 silvia. i suspect that the earlier s13 boxes are the same as the mk2 s12s anyway (they share the same FW part number accoring to FAST iirc.
why not measure the overall length from bell housing face to end of box, not including tin cup shit shield thingy? I have mk2 s12 box here from a mate that i can then measure up.

[PukkaSilvia]

below is a pic of the neutral lever position of a s14 gearbox in a mk2 s12.