Hull issues
 

Has anyone closed up the notch on a hull to stop over wetting the drive and make the water come off cleaner

The notch gives the drives cleaner water. Similar to putting them on boxes

Boat dragging its ass water coming off notch heading up at a 45 angle wetting the top of the drive causing a lot of drag

What hull? Maybe something else wrong with it. Notches are a good thing and that's why they were added. Lol

27 fever

What power? What speed? Fountains have alway worked well with the notch. I'm not sure what you mean it's dragging other than you think it should be faster. If that's the case give al the info. Power? Drive? Ratio? Prop? Max rpm at wot?

600hp
Bravo 1 with -2 short
24 px5 hydro 71 at 5300
1.50 ratio
Bravo 1 24 5500 73
Bravo 1 26 5100 70

Yup should be faster
2000 hull

Has the motor been dynoed? Where was peak power?

The 24 bravo 1 gives you 12% slip. That's pretty good.

Your slip is good. Sounds like your not making 600hp.

Try putting in 23.2 for the slip calculator, since thats what a 24 bravo measures out to be about. Slips even lower.

I'm with you, I think he's down on power. Whats the build specs?

Yes. That's the direction I was headed is his power is off. Not an issue with the notch.

beat me to it,,my guess,,540-550hp

how about some info on the engine.

5500. 599 hp
4700 592 tq

509 stock gen 6 block
Merlin iron heads 320
Merlin intake single plane
850 qf
243 248 630
Dry risers
Harden exhaust manifolds
9:1 compression
Je mini dome pistons
H beam rods

With that cam, not surprised its going faster with the smaller prop. Try a 22p bravo one.

Where did the HP peak ?

Also is the hull stepped or not?

Then let's go to the dyno. What exhaust on the dyno and what exhaust in the boat. You can easily leave 40 or more from dyno headers to marine manifolds.

Stepped hull
Harden cast aluminum manifolds
Dry risers wet at the tip

Dyno headers. When on dyno

Yea the notch is not a problem. If you do fill it your drive height will be way off also.

Peak hp was at 5500 599. 6000 hp was 592

Was it dynoed with your exhaust or dyno headers? Do you have dyno sheets?

This is a hydraulic motor

Drive is 2.50 below the hull pad

Also with dyno headers to your manifolds is a dramatic loss. Mild thunder will chime in again but I think mer recently did a test on similar power and it was around 40hp from dyno headers to manifolds.

Harden makes a tubed headers called cyclones that will work with my risers that are all stainless

Basically my manifolds are the same manifolds that came
On HP 500s or Gil type manifolds which I read somewhere rated for 500 hp I'm wondering if they're choking me out

Yes. I know the ones you have. GIL replicas. As far as manifolds go the best ones are the ones diamond sells. The old KE design. I'm in the same department. I have gils for my builds and now second guessing myself.

I dont think youll see a gain from the short tube cyclone/gil replacements.

I think the heads are probably your limiting factor from keeping it how a 27 fever should run with 600hp. Legit 600hp.

Okay which heads I run in salt water but flush all the time

That's high. Any trouble planing?

That isn't high with a notch or box. If he can get on plane with the bravo without too much problem than that is the prop he should run. I agree the heads and exhaust are the problem. How about some anodized aluminum heads. I lean toward AFR and Lightning headers.

I run in salt also and went with EQ heads. The are rumored to be the old RHS castings. Not overly well known yet but the people running them have been very happy. Between boat guys and car guys they really like the heads. Dollar for dollar likely the best head on the market. I bought mine bare for like $435 each. They are at the machine shop right now getting cleaned up and ready to go. The model to check out is ch-454-a

even down on power if the boat is running anything over 40 mph the water should not be coming off the notch at a 45 degree angle. that boat with a 525 runs cleaner than that. something else is wrong with the setup or the way he is trimming the drive or the weight distribution or the bottom.

Without pics of what he means it's tough to say how the water is coming off the notch. In theory on an integrated swim platform it would be nearly impossible to see the water coming off a notch. He's not as fast as he things he should be is the main issue and it's likely because he isn't quite making the power he thinks.

24. Bravo 1 4k 52 mph 14 %
26 bravo 1 4k 56 mph 8 %

Do slip at wot. You'll generally have more at cruise due to the fact more hull is wet and therefore more drag.

24 at 5500 73 12%
26 at 5100 70 at 16%

The bottom line is that I am loosing about 75 hp from the exhaust system and once the motor is mounted in the boat

12% is a good number. You're right the exhaust is limiting you. Like I said I'm in the same situation. Contemplating ditching the exhaust before I even dyno. Lol