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View Full Version : Bravo XR / XZ drives



Freak
07-25-2002, 11:17 AM
What exactly is the difference?

Havasu Hangin'
07-25-2002, 01:49 PM
Straight cut gears on the XR- stronger, but robs around 25 more HP...

Trash
07-25-2002, 08:07 PM
Where is everybody getting that the straight cut XR gears rob 25 more HP? That just doesn't make sense. It is my understanding that straight cut gears are more efficient than helical cut gears, thus less HP loss. The only down side is the noise (if that can be considered a downer). I haven't seen Merc downrate their HP rating for like motors behind different drives since they are all based on PSHP. Anyone want to shed some light here?

rustyk
08-06-2002, 07:59 PM
Trash:
Where is everybody getting that the straight cut XR gears rob 25 more HP? That just doesn't make sense. It is my understanding that straight cut gears are more efficient than helical cut gears, thus less HP loss. The only down side is the noise (if that can be considered a downer). I haven't seen Merc downrate their HP rating for like motors behind different drives since they are all based on PSHP. Anyone want to shed some light here?Thats right, an angle cut gear is most likely to walk and cause drag and a straight cut gear will be noisy but will not walk and cause resistance against an apposing surface.
rustyk