I would think 793lbs of Torque is too much for an XR? I am looking at engines for a 12,200 lb. boat with triple XRs.

Unless you babied it you'd probably start playing the bravo switch game on a regular basis.I have broken upgraded xr's in a boat 1/3 the weight of yours with similar torque,Smitty

B-max Only Go's To 800 Foot Pounds & 800hp If That Tells You Anything.

What kind of torque do you get out of Whippled HP 500's and will twin XZ's last a season on a 9,000 pound boat with this set-up??

One of our customers has a 43 Black Thunder that must be getting up there in weight. He used BMax drives behind supercharged engines that made 875 HP. Torque was just over 800 ft-lbs. He had to show his dyno sheets to Bmax to get warranty. He used Vortech blowers so did not have this big torque at low RPM. This may also help the drive life.

Various sources of modified XR drives claim that 800 HP is no problem, but how hard and fast the torque comes on has to be considered. This is where centrifugal blowers have an advantage over positive displacement blowers, but articfriends is using a centrifgual blower and he broke too. It's hard to stay out of the throttle when you've got boost...

Craig, If you boat is 9000# I'm Mary Poppins!

Charly here has a whipple on his single 525 EFI and has had no problem with his "XR" on a Fountain 29 that has to be 6700#

I blew one this summer but I blame it more on not tighthening the top cap (my fault) than the weakness of the drive. My rig dry is 9800# and your has to weight at least that.

GL

Hi Mary, how you been?

You aren't running the XR drives are you?