Hey guys, anyone know if it possible to change the final drive.. thus shortening all the ratios in a cheaper way than changing the ratios themselves?

 

A common thing to do. Buy the Motorsport 8:32 final drive. A nice uppgrade but more a bit expensive now a days.

Thomas

 

Thanks Tomas.. but what does it involve? how is it done? and any rough costing?

Basically I got a 993 6 speed for a good price to do a conversion on my C4 to C2. The gearbox was rebilt only a few thousand miles ago so is pretty much new inside. However it is a G50/20 with the longer ratios. Changing to G50/21 spec is simply too expensive.. that is why I wondered on a shorter final drive. However this would have the added disadvantage of making 1st and 2nd probably too short.. so I guess my best bet is still just to keep looking for a G50/21..

 

This pic is from a C4 front diff but just to get the idea. You remove the diff cover on the left side of the tranny. The you replace the final drive parts, No 6, always bought as a pair. I'd say that those parts are €2.500 plus work. Except for removing the tranny from the car it's not a big job for a skilled guy. An important thing is to adjust the setting/clearance.

Thomas

 

thanks. So pretty much totally uneconomical to do.

 

yeah, it's a lot of money. But people regard it as one of the best "power" mods you can do. Compared to spending the same money on the engine for more HP. But still, money is always money....

Thomas

 

It's possible but it doesn't address the real issue, large rpm drops
Here is what a /20 looks like stock


Here is the same box w/ 8:32 cwp


Note that the rpm drops are unchanged by the cwp change

 

Agree, that's why I haven't bought the 8:32. I would like to change the gears instead. The 3rd gear is way to alone in the middle. I'd like to push 3rd and 4th gear down towards 2nd.

Thomas

 

Gearing depends on the particular engines torque curve and the cars aero characteristics
Here's a comparison of 2 different 964 trans and a 993 trans in an RSA
for track use I'd want the stock /03, but it could certainly be improved upon

 

I haven't seen an 8:32 for sale in a couple years. That said, if you find one expect it to be around $3000. And then another $1000 to install it. A lot of labor to spend on a box just rebuilt.

Gears will run you around 1000-1200 each. A common budget approach is 5th in 6th and tighten up 3-5. Expect labor around $600-700. So really a zero sum game with respect to cost.

In recent years the real budget way is to find takeout 3-5 from a GT3. I would expect to pay half of new for the used gears.