snapmorgan

iTrader: (2)

Thinking of putting on a 2" shorty, but not sure if it will help enough to make it worth it.

27' Advantage V hull
540ci 575hp
63 mph with labbed bravo1 24p at 5200 rpm
prop shaft is 6.5" below bottom of V

I have tried some other props with no improvement in speed or planing. Looking for opinions on whether a shorty will pick me up and also any negative effects. Boat gets on plane easily now. I have a new XR upper on the way, which lower should I get for it?

Thanks

ToMorrow44

On my 27 the -2 shorty helped quite a bit. It is now ~4.5" below the keel, so it sounds like our boats were set up the exact same. Mine could probably benefit from a -3 shorty. If you're ordering a new drive, go ahead and get the -2. It is always easier and much cheaper to put a spacer in it if it doesn't work.

When my 27 had a 620hp motor in it, with the -2 lower it ran 73-74 with a 26lab so I think you have some speed to gain too.

Let me know if you have any questions, I've done quite a bit of testing with props on mine.
-Tom

snapmorgan

iTrader: (2)

I am looking for 70mph. I thought the new 540 would get me there, but I am not even close. I can change intakes and gain another 50hp or so, but I intentionally kept it mild to try and save my bravo drive. And 50hp will gain me maybe 2mph.

How fast are you running with 800hp and how does the boat handle at speed?

Thanks

ToMorrow44

With 575hp you should get close to 70. Is yours an open or closed bow? With a -2 lower and a 5-blade prop, the boat jumps up onto plane and has a great cruise speed but the 5-blades do not like to be deep in the water.

My boat is running mid-80s right now. Likes to chinewalk at that speed so we're having the bottom looked at right now, maybe have it blueprinted as it is not straight. If it is full of fuel, the boat will handle great and run faster than when it's empty. Did the same thing with the 620 too.

snapmorgan

iTrader: (2)

Mine is an open bow. I don't know why it is so slow. Advantage and the original owner said this boat would run 61mph when it was new with the original 454mag. I have a hard time believing that. The fastest I ever had it with the 454 was 54mph. What 5 blade are you running?

snapmorgan

iTrader: (2)

Maybe I should remove the built-in blender.

ToMorrow44

The open bow will slow it down 3-5mph versus a closed bow. I have run both a Hydromotive P-5X and a Maximus. Both work about the same, they roll the boat over on plane at about 1/4 throttle. Cruise speed is about the same with both, ~5mph faster than a Bravo. Now just testing different sizes. FYI the Maximus tends to be labeled about 4" undersize so a 28p acts like a 32p.

Does your boat take a lot of trim to get it running fast?

snapmorgan

iTrader: (2)

I can trim it all the way up as soon as i get it on plane, and it likes it

ToMorrow44

Thats usually a sign that the drive is too deep. Shouldn't take that much trim to get it running. Try the shorty, I don't think you'll be disappointed.

snapmorgan

iTrader: (2)

Thanks, I will start looking for a deal.