Hello
I like to know if i can update an newer sweptback X drive with new gears to an real XR drive! This means in first way the Upper!
For Lower i have ordered the bigger propshaft and new bearing carrier.
My eyes are now on the Upper as i like to know if i can update or must chnage the complett upper! i pretty shure some of you know it 100%!
Thanks for let me know!
Michael

The upper cases on an X and XR are the same

Leave it alone. The X gears are just as strong as XR.

the X is actually "technically" a little faster because of the helical gears. Ever so slightly weaker though . . . .again "technically" lol I would also leave it alone

I have to respectfully disagree from personal experience!

For 2015 the nearly new X drive is strong enough,i think! It gets also next days a Lower with big 1 1/4 Propshaft.
Must work behind an light Baja 232 with newer 8.2 and 500 HP Whipple PCM.!
But in next winter i try to build or buy engine with 600-800 HP and i think the drive need some work then too!
So i like to know if possible to make the X real stronger like an XR drive!
So change the gears from Upper is the work that can made to an X??
thanks for all your meanings!Michael

You can swap the gears from X to XR, but make sure you input shaft has the large yoke splines.. B1 has the smaller yoke, XR and XZ have larger input shafts.
Hope that helps.
Dick

Michael, both versions are still Bravos. Whether or not it will hold up will largely depend on how much air time you get because that is what breaks the gears and no one can be perfect on the throttles. When I put the 525 in my little 22 Donzi I broke the upper gears in about 5 hours. An XR lasted 3 seasons before it broke because the input shaft bearing pre-load nut backed off, so no fault of mine. A new hard shimmed XR upper has lasted 2 seasons so far. Experiences will vary. I'd run it until it breaks and then install an XR upper. JMO, from experience.

Thanks for this note!
I have checked fast the partnumbers from newer X and XR drive and the ones from Yoke parts are exact same! So that look good for me!?
Michael