what prop to try next
 

Just picked up my 2010 heat last weekend with a 600sci, it came with a labbed 15x28 maximus 5 blade and it ran right on 80 on both the in dash gps and my hand held at 5400rpm and hitting the rev limiter. The water was glass and air temp was only 68 deg. on havasu that day. I know I will loose some speed and rpm when the weather gets hotter this summer so I am trying to deside if this is the right prop or if I should exchange it for something else. I also tried a stock 28 bravo and it ran 78 on glass and 80 with alittle chop at 5400. What would be the next prop to try?
John

That is the same speed and rpm my boat ran when stock.

I was spinning a 27 pitch, Hydromotive P5x

Chris

P.S. Merc props are generally about 1-2 pitches smaller than they are marked.

John, congratulations on your new Heat, and welcome to the Nordic Forum.
The Maximus will run on these boats, but is far from the most efficient design. It is a large diameter, thick bladed windmill.
The Hydromotive P-5X, and Herring 5BL props are faster out of the box, and worked to your boat's specific requirements are way faster. The Bravo 1 can work if it is custom worked (usually more cup for starters), but may require a spacer to lift a full load of people, gas and gear.
I'm with Chris, the P5-X is hard to beat.
Hydromotive has an exchange program, if your local prop man or dealer doesn't have them in stock for testing.
Here's a link www.hydromotive.com
Show us some pics of the new ride...........
Best Regards,
Steve

The maximus is a labbed prop cut down to 15" with the defuser cut off, I would have thought that it would have had more bite then the stock 28 bravo but it did not, they where almost identical at 3000 36 mph, 3500 46 mph, 4000 55mph and wot. Would a stock p5x have more bite in the midrange and be faster then this maximus?
John

p.s. could not get the pics to post don,t know why

John,

I dont know if the P5-x would be faster than the reduced diameter Maximus, but it would definately be quicker. They hook up like glue on the bottom end, and have great acceleration. My guess would be that the P5-x would equal your top end speed on the Maximus, and be 1-2 mph faster than the Bravo. At least that has been my experience.

The fastest prop I have had on my boat was a 15" diameter, 5 bladed Hering. Beat out the other props on top end by a couple of mph, but sucked getting on plane with the drive height I was using, and was not quick in the midrange like the P5-x.

After trying literally 30+ props on my boat, I setteled on the P5-x as my everyday usage prop, with the Hering being my poker-run prop.

Chris

Hi John,
That mod (reduced dia.) should definitely help. I ran a nicely modified (BBlades) Maximus, and it was the worst handling prop I've ever had on the boat. Kited and chinewalked all over the place. A friend had it built for his tunnel which obviously requires different mods.
With the P-5X on my boat in smooth water I can take my hands off the wheel at 90. Yes they are efficient in the midrange. I'm surprised the Maximus wasn't. The one I tried was.
Not sure, but you may have to be a paying member to post pics.
Regards,
Steve

Thanks for the info Chris and Steve
It's going to be a month or so before I get back to Havasu so I will try to get a p5x to try before I go. So do you think a 27 pitch is the place to start?
Thanks John

Hi John,
It's easier to compare stock to stock, and your 28 Maximus was evidently heavily worked by someone who knows their way around a grinder.
The 28 B1 gives us something more consistent to go by. It's really a 27" on a pitch block. Even though the P5s are really efficient (you'll get lower slip %s across the RPM band), they are also harder to turn, because of the added blade area of the 5th blade. A 27" P-5 should pull your Rs down 100-200 vs
the 28" B1, but should increase your speed 1-2 MPH by lowering your slip %. You are correct to consider favorable weather conditions now, and probably a light load (gas, people, gear) vs summer, which will knock off some RPM too.
And Chris had your setup using a 27", so a stock 27" P5-X is a good starting point.
I had Merc Lab 30", further modified here (more cup), on my Heat (at the time lightly modified 575). An out of the box 28" P-5X ran with it on top, was better out of the hole, and was more efficient in the middle.
I'm running a blueprinted 29" P5-X now @ 5800/5900, and it does everything well.
Regards,
Steve

Yup,

Steve is correct.

When my 600sci was stock... the stock 27 pitch p5x was the way to go. labbing it will get you about another 150 rpm if needed.

With the old Whipple stage II, I spin a 30 p5x to between 5600-5700 rpm at 91-93 mph.

The new stage II produces right at 800 hp, or about 55 more horsepower than my current stage II setup.

prop shaft centerline is at 3.5 inches below the keel.

Hope all this helps,

Chris