Just wondering where a turbo gearbox usually fails in 400+ applications and whether an OS Giken 3 speed gearset would be a solution.
The ratios look really nice, Get to keep helical gear cut and syncros, and it seems to be about the cheapest and easiest option without re-engineering everything for a bigger more expensive gearbox with fat and lazy v8 ratios.

 

the case is the weak point, not the gears.

at about 600whp+ in third gear doing hard drag pulls, the case tends to grenade. have never seen one break below 500whp though.

 

Ok thanks. That sounds like pretty catastrophic failure though. Does an aftermarket bottom plate help with case longevity?
I keep hearing that above 400 (but below +600!!) they last for a while depending on circumstances but give a bit of warning. As i wont be running much more than 400 was wondering if a better gear set and a rebuild would be a viable option.

 

if you're running less than 500 and dont track or drag race often i wouldn't worry much about it. perhaps a bearing rebuild for preventative maintenance.

 

I don't know about the t2 transmission, but the FD one blows up 3rd gear because the shafts actually push apart when a lot of power is applied and loose gear tooth engagement. FD guys have experimented with different shaft materials, but it didn't really seem to help.

From what I've read if you have enough power to be blowing up an FD transmission there isn't a lot to be done to strengthen it, you just have to upgrade. I imagine the t2 is pretty much the same.

also... most "lazy v8 gear ratios" can be fixed with a different final drive.

 

yep, you can go with a T56 and change the rear end if you start running into issues with the stock turbo transmission. once the tranny goes the diff is being pushed to its limits too.

the TII is virtually identical to the FD in how much abuse it can take.