Upgrading 395 Gearbox with Shorter Ratios & Limited Slip Diff

[GavinT]

G'day Stefan,

That sure sounds like a lot of money.
This might be going full circle but I'm wondering how difficult it might be to find a R-12 365 gearbox in the EU. I recall Australia only imported four of them to contest the Australian rally championship but there must be oodles of them in Europe by comparison.

Sometimes the rally crowd are a good place to fish. Didn't the rally boys have access to a shorter diff ratio in Europe - I thought they had a 4.125 (33/8) option available from the factory.
Have you talked to Salv Sacco? - he likely has lots of contacts on the rally scene.

[jbcollier]

Bit out there, but could you change your final drive by just fitting smaller diameter wheels and tires?

[Mecky]

Thanks for your input guys. I researched a bit and read that a complete 365 gearbox costs around 4 - 5 k € here in Europe and that's the same ball park as my new diff. With the new diff, I have no risk of used parts, which may be damaged without me or even the seller knowing. That's why I prefer the new parts, even if the 365 gearbox could save me a few Euros.

Regarding the wheels, I'm already at the absolute limit of my race series' rules. I went from Kumho tyres (235/45R13) to Pirelli (225/45R13) and the Pirellis have the smallest allowable diameter. That reduced my top speed from 236 to 232 kph. Even if it would be legal, I'm not even sure, if there are 13" semi-slick tyres available, which fit on my 9" wide rims and have a smaller diameter compared to the Pirellis.

[Mecky]

Finally, my 395 with 4.125 ratio and Quaife ATB is ready. Great craftsmanship from the gear factory. Installation worked great. I only had to exchange one shim with a slightly thinner one (difference: 0.06 mm). Thus, the manufacturing quality is great. Installation of the gearbox is tomorrow. Dyno run in about 1.5 weeks, test on track in 2 weeks time.

 

[jbcollier]

Sweet!

I have all the bits to do my 395/365/352 fusion.  Just been tied up with other projects.  This year for sure!

[Fotog]

I hope you have success with that change.  It's interesting to hear what you're doing with the car and especially gearing, in pursuit of racing success.  Thanks for posting!

Vince