Porsche Enthusiasts Club Forum

got 2 boxes here. one is a 7q (016j) from 82-85 2.5 944.

the other is AOS (083f) from 89-91 s2

the 7q box has an lsd fitted from an audi v8 (torsen diff)

i have checked the ratios and the 2 boxes are not far about. the final drives are also very similar and make almost next to no difference. 7q is 3.889, and s2 is 3.875 (about 0.004% difference) which at 160mph is about 1mph lol.

so the in gear ratios are also not massively different.

based on a 17inch wheel, with sidewalls of approx 90mm each side. and redline of 7krpm the following speeds would apply

7q box

1st- 36mph
2nd-61mph
3rd-89mph
4th-121mph
5th-156mph

the s2 box as follows

1st-37mph
2nd-63mph
3rd-92mph
4th-126mph
5th-167mph

the only real difference is 5th is a bit longer and so you get approx 10mph better top speed at 7krpm, the rest of the gears are almost close enough to make no noticeable difference

so my question is regards to the actual gear set strengths

does the s2 box have any actual benefits in strength or design?

as if not then i can just use the 7q box as it already has the lsd diff fitted.

if the s2 is substantially stronger for any reason, then it may be worth transferring the lsd over. but if not then the ratios are close enough for me to be happy using the 7q box.

kind regards

my next question, is that if the 2 above boxes have little differences when it comes to strength, then what are the options for stronger boxes that will take the power/(torque) better, if these boxes end up in pieces. i know some turbo boxes have hardened 1st/2nd gears i think? but does that really help when on track and doing normal 3/4/5 gear speeds.

968 6 speed? any other options or ideas?

still toying with the idea of sticking with 924t engine and going for approx 400bhp, or if the costs just dont mount up, then possibly a v8 ls series engine swap which will have more torque than the 924t engine.

regards