Are the sweptback Bravos faster than the old style?
 

A little back story; I hit a submerged object last fall and trashed my drive and transom assy. over the winter I freshened the engine, replaced the transom assy with a new HP unit and installed a brand new take off XR drive that I bought from Outerlimits. The engine makes 25 more dyno confirmed HP than it did last year, buy my boat is about 6mph slower than it was. The only real change is from going from the sweptback XR to the older style XR. Both are 1.5 ratio. Any help would be appreciated.

Still turning the same 28p Bravo 1 prop about the same rpm

I think they run exactly the same.

Is the new XR low water pick-up? Your 100% sure the ratio is 1:50? I bought a brand new drive last year and was told it was 1:50 and it was LWP, my drives were DWP. So I had a port LWP and a Starboard DWP. Took the boat out and it listed and RPM was off by 400, turns out wrong gear ratio in the new drive although case said 1:50. Switched the lower case to DWP and correct gear, issue solved. It was probably more the gear than the case difference.

The tag is stamped 1.50 and I am still running 5200rpm at WOT. But no, I am not positive. New drive is dual pickup, just like the original

Your RPM's would be down if it was the gear ratio so count that out. You say still running the same prop but did it have to be repaired or did emerge unscathed?

When you freshened the engine, what got changed? Hp is 25 more, but how does the torque compare?

Yes, same prop. It was not damaged. The engine just got bored .030 and a new set of pistons. Same heads and cam. Cam degreed in the same. I doubt the torque curve changed much.

The swept back XR's use the same gears as the earlier square like cases. There shouldn't be a speed difference there. However, if your original sweptback drive had helical gears (non-xr) it would have been faster. XR straight cut gears take more power to turn.

The original was an XR as well. I was just thinking the lowers may be more streamlined on the sweptbacks or something of that nature.

6mph is alot. Either the engine isn't making the power it was or that prop is NOT in the same condition.

All i have is , are you reading off the pitot or gps ? Maybe something got whacked and your losing a pound or 2 of water pressure now. Or your trim sensitive and the limit isnt set where it was .

If you are running same prop, same drive ratio, and are still running same rpm, I'd think it's a setup or trim issue. Not seeing how hp will come into play here

did the bottom of the boat get damaged in any way? If no damage to the boat then the prop did get hit. This is a single engine boat? if not is the drive alignment correct.

There was no damage to the hull at all. I did, however have the bottom of the boat buffed and waxed to help keep the river water stains off. I know that's not optimal for speed, but I wouldn't think it would cost 6mph.

As far as the trim, I can still trim it up enough to blow out the prop just like I could before.

It is a single engine boat, GPS speedometer

Joe, were you running the boat in heat? You were at desert storm correct?

The wrong wax will slow a boat a lot more than you would think. Wax is the wrong thing to put on the bottom of your boat. Wet sand for speed. They used to make a bottom coating that when I used it I would see about 3 MPH gain BUT they stopped making it because it was made with a chemical that was banned in the USA. ( OZONE depleting )

It was only around 90deg. If it is the wax causing it, I guess it will get back to normal after a few more times on the water. No way I would wet sand. The stains in the mud holes that I boat in would never come off.

If you hit something hard enough to trash the outdrive and a transom assembly and you still believe the prop emerged
unscathed you may want to rethink it.

No way a cursory visual inspection by you will find slightly bent ears on the prop. Have it scanned to truly know.
You can perform a pointer test yourself but it requires a bit of set up.