PROPPING AN OLD HULL AND A NEW MOTOR - PLEASE HELP

[captmatt3311]

Hey all, been a while since I reached out for some advice.

I repowered my 1997 518svs with a 2021 v8 pro xs. I originally had a 2001 200 efi. So far ....its amazing, but I'm having a little trouble dialing it in.

I broke ththe motor in with what I had for props - I used my 25p trophy plus from my last motor just to get some engine time in.
I achieved 5400 rpm @67 mph (after my initial 2hr break in). I had only 94% throttle demand verified at the time.

I dropped down to a 23p trophy plus, put the new seastar foot pedal in and verified 100% linear demand. I now achieve 5800 rpm at 65 mph.

The numbers seem consistent with what you would expect rpm wise. My concern is I'm not reaching 6200 rpm at all. Prop to pad is 3.25 inches - playing with my plate didnt change anything. And trimming is limited as I'm on the edge of wicked chine walk.

I know the boat will run 68-69. - I just dont know where to go from here .

I'm very bow heavy ( ultrex and 3 graphs) so that's why I run a 4 blade. I assume i can gain a little speed with a temepst plus, but the bow lift is embarrassing compared to the trophy. The fury line up seems appealing. .... but the stats dont seem to sell me on bow lift with a heavy load.

Has anyone propped a similar setup as I have ? If so .... what prop and what numbers are you seeing.

I just want to get the vest speed and efficiency out of the boat/motor that it offers - and running 400 rpm shy of recommended WOT rpm has me wondering.

I know 5600-6200 is considered WOT. Does that me I'm okay at 5800 ? Will I gain anything good by dropping to a 21p to get those from back ? Will my top end just suffer more??

My hole shot is completely out of the question- regardless of prop I have a 0-20 hole shot of 3.0 seconds on the vessel view app.

So.... my multi part question .... ends with WWYD to consider this rig "set-up" and ready to roll.

TIA.

[Jgp32]

I just repowered my 2007 519vx with a 200 pro xs 4stroke. I ran the same 25p tempest that I ran on my 2stroke. I am running consistent 67-69 with 2 people and a tourney load. have had it up to 70.6 by myself. I am only turning 5500 rpm at WOT, I am happy with how it performs now... Don't see the need to spend more money in props to get to the 6200 rpm mark.

[Rip Bass]

If you want to get the most out of that rig,you’ll need to learn how to control the chine walk. Meaning prevent it from starting,you can not drive through it.Trying to prop it for no chine walk is costing you speed.

[captmatt3311]

I would have kept my 25p 4 blade as well .... great speed out of it. But it's not allowing the motor to run the recommended rpm range- which if I'm not mistaken is like driving around town always in 5th gear. While it seemingly makes sense to stay with the top performing prop .... I think there are some cautions to be weary of with over propping.

[captmatt3311]

So, you think I can get the rpm out of this prop- but I just need to drive the boat - not relax at the wheel like I've always gotten to?

I dont have a problem trying that method out. Makes sense. I am concerned that its unneeded though - only because I've gotten full range of rpm and full range of speed to 69 mph with my last 3 motors and never once played with chine walk

[captmatt3311]

I have found the perfect balance of trim and it rides perfect I just cant get the rpm up a little more

[mikesxpress]

To get the full performance benifts across the entire power band the V8's need to be at that 6200 rpms WOT. The V8 drinks more fuel than the Opti did and based on me monitoring the V8 fuel consumption with the Level 1 Merc monitor, it drinks less when propped correctly. My 250 V8 will be 3 years old in July.

[captmatt3311]

Thanks! That was my initial thought. Looks like I need to try a 23 tempest or a 22 trophy now.