hi all, got an xe faly with a au2 4lt 6cylinder in it bout to finish another 650hp turbod motor au again, i have a t5 out of an ed xr6 i have been running behind this quiet motor and its great when i put the big motor and tune its gonna crap the bed pretty quick, not really looking at 5-6 speed man as they are rather expensive and not the best for the strip.... was looking at a c4 with shift kit and a 2500 stall, but i have heard of ppl tricking up 4 speeds el au ba , to handle that much hp and torque, problem is that everyone i have talked to has no idea or cant help, anybody got theres tricked or know someone that does do these boxes up? cheers

altho it will be better than the t5, they need to be kept cool as possible, and need the shift firmness turned up for starters, less slip between gears means les heat and less wear on the box, not aure about actually building them up to handle 650hp though, would probably be better off bolting in a c4 in my opinion,

AFAIK the EB V8 box is pretty much the most over engineered BTR around, I have also read that the EF/EL/AU pump is pretty much ideally suited for the BTR.

If I had to (and the money to), I would get an AU six box, get it rebuilt using the V8 box parts and using kevlar bands and clutch plates, run a big fat cooler and a CAPA alloy finned pan and use an aftermarket transmission controller.

Of course the C4 is always a reliably strong option, it depends on what it is you want to do with the car really.

Here's some info that might help from an earlier thread:

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