Originally Posted by Griff

On my 28 Pantera, it came with lower with a nose cone and standard side water pickups.
I wasn't getting enough bow lift and switched the lower to a DWP. I got slightly more bow lift and picked up 1mph.

Originally Posted by Baja Rooster

Wow. I've heard of losing a mile or two an hour with the XR but 7 is pretty significant. Someone was selling 1.65 units in the swap shop and was selling the fact that the 1.65 were banned in a particular class of racing as they proved to be an advantage. That's just the Internet talking but it did make me wonder about it being an advantage. I'm only getting ~63 out of my 272 Islander and was wondering if the ratio/prop combo was holding it back on top end in trade for the jump out of the hole.

Originally Posted by endeavour32

Did the new lower have a nose cone?

Originally Posted by Ghost24

The efficiency advantage of the 1.65 with a steeper pitch prop I spoke of is with other things being equal, including slip. If the product of the steeper prop pitch and the 1.65 gear drive equals the product of the shallower pitch prop and the 1.5 drive, the two combos are effectively geared the same to the water. Other things being equal, speed would be the same at the same RPM. However, there is a school of thought that not all other things are equal--rather, that the 1.65 with the steeper pitch prop means lower speed of the prop turning and fewer turns of that prop through the water at the same BOAT speed. Thus, the drag of the blades through the water is less with the 1.65 and the steeper pitched prop.

I can't swear this is true, but I would expect it to be true and I know of at least one boat that has suggested it's the case. Again, other things aren't all equal. But this is an argument that one factor of the higher reduction in the drive and the steeper pitch prop means less drag at the same speed, and thus more speed by wasting less power to resistance.


I expect any gear ratio that is further from 1:1 would be harder on the drive. How significantly different I don't know. Given that failures happen, by definition, at the boundary of ruggedness, I would expect it would mean the 1.5 would survive SOME conditions where the 1.65 would fail. But to your point, how large the delta is, and thus whether it would be considered significant, I can't say.

Originally Posted by JaayTeee

. The 1.65 gear helped a marginal engine perform better throughout the entire rpm range, what I failed to mention earlier was that the XR on the original engine was also a pig on acceleration, even dropping to a 24 pitch prop didn't help with the acceleration, I think it is a combination of things, the XR uppers are probably worth 1 or 2 mph, prop efficiency and the ratio and the skeg and possibly the water inlets are the rest

Originally Posted by Vortec Bandit

The 1.65 ratio was banned in SVL class. We swapped out 1.50 because of the rule change. Was a move backwards.