Hi,

I was wondering if the new (2007) Bravo X drive is faster then the old Bravo one?

Will my boat go faster with a X drive compared to One drive?

I know that the X drive is a stonger and improved version of the One drive. But is it faster?

Simply - No

What is the max HP that an X drive can handle??

Mercury say's 425hp

Wow!!!! Really?? So if I add anymore power I need a new drive?? That sucks

425 hp!

Why did they put B1's behind HP500EFI's?

Yea I know,to insure a steady flow of repair money,,,,,,,,,,,,,,,,,,,,,,

I thought I read that X's or XR's would be slower than a standard bravo because there is more resistance with the straight cut gears.

Last I remember reading on this in Merc literature:
Bravo 1 - 400hp rating. Used on engines that make less than 400hp (496mag, 8.2mag, etc)
Bravo 1X - 450hp rating. Used on engines that make less than 450hp (496mag HO, 8.2mag HO, etc)
Bravo XR - 600hp rating. offered on engines up to 600SCi

There were 2 major differences in the 1 and the 1X. The gears in the 1X were shot peened or heat treated (can't remember which) to resist chipping and pitting under the additional power with the HO engines. Also, the top cap of the 1X is finned for increased resistance to deflection and to a lesser extent, better cooling. I cannot imagine there would be any difference in speed between these 2 drives.

The XR has the straight cut gears and larger shafts. There is slightly more parasitic loss with the straight cut gears. I do not have any experience to be able to say how much loss of speed that would relate to. The top cap of the XR is finned the same as the 1X.

Previous to the design and release of the XR, the Bravo 1 was the only merc bravo type drive. Then the XR was released but was more expensive obviously than the Bravo 1. The XZ was short lived and fit in the mix between the Bravo 1 and the XR. It had a short market life offered with the 500. The 525 got the XR. There must have been issues with testing on the Bravo 1 behind the HO engines. Rather than go to the expensive XR, Merc changed the problematic components and released the 1X.

The time line may not be exactly correct with the XR - XZ. Not sure which came first.

Hope this helps some.

Here is a link to Bam Marine's site with a chart showing all the differences between the different Bravo drives...

http://www.go-fast.com/mercruiser_bravo_sterndrives.htm



Doug