Boatally Insane

iTrader: (1)

FINALLY got a chance to run my "new" boat some..


SO thrilled with the ride ! was able to go WOT at the roughest part of the lake on a holiday weekend..
I've had faster boats but none this fast comfortably in the rough... (this currently has the 496 MAG HO)

It currently has a 25 pitch Hydromotive P5X on it and I hit 69.9 mph with a fuel tank of fuel and 3 people on board.. Not sure of exact RPM but looked to be about 5100 RPM...


I see everyone recommends a labbed 28 Bravo I for this hull / engine combo.. just curious what speed / RPM Y'all are seeing with it...




THANKS !







Doug

Ryan00TJ

iTrader: (8)

Bblades labbed 28p Bravo 1 prop, custom labbed for the VR and we kept the hub diffuser on this one to help with blowout planing.

Low 80s, 1100', calm water, 3/4 tank, me, normal lake load.

Boat ran 74 GPS @ 5100 rpms

Bblades labbed 30p Bravo one
High 70's, calm water, 1100 altitude, boat had full fuel 93 oct, me, normal lake load.

Boat ran 75 GPS @ 4875 rpms.

Above numbers are 496HO w Whipple stage 2 tune and stock risers mixing water at transom, turbulator removed.
Gotta love the 496, when maintained it's turn key boating! I've found my stock Velocity Livorsi tach to be roughly 50rpms fast vs Merc scantool.

Congrats on that speed! Sounds like it's dialed in with that prop. No need to rev above that rpm. Limiter is 5150. Just remember that a labbed Bravo one "MIGHT" get you a couple mph on top. More than likely you will lose cruise and midrange speed vs your current prop.

cabin fever

Id say you are where u wanna be.

Padraig

Prop and speed look about right.

Plus, remember,I told you you would love a Velocity. Welcome to the family.

Padraig

Boatally Insane

iTrader: (1)

Wanted to revisit this thread now that I have my new engine installed.....
It Dyno'd at 630 hp @ 5500 N/a....

So with the same 25 pitch P5X I had with the 496 (65mph most days best of 69)
it now ran 76 MPH @ 5500 RPM and accelerated like a rocket...

Tried a couple other props but all seemed to be too big..
With a cutting edge 5 blade 29 (supposedly runs like a 28) it ran 78.5 at 4900 and acceleration was doggy as hell...


What am I missing ? Thought this hull ran in the 80's with a 525 ??

I HAVE added some weight.. now have 3 batteries and a bunch of stuff in the cuddy..
I was also running with a passenger and a full tank of fuel.. Were the speeds with the 525 fudged a bit ??


https://www.youtube.com/watch?v=CfMxjdlrm5U

Padraig

Just a couple of thoughts. As I understand it, the 525 was rated conservatively and it was rated at the prop. I am guessing yours was rated in the dyno without marine exhaust, accessories and drive. The bunch of stuff in the bow also does not help as it is usually considered as the worst place to carry excess weight.

I am sure the boat test was done with a light load and not anywhere near a full tank of gas. Steve knows how to set up aND how to drive a boat for max speed.

Padraig

Ryan00TJ

iTrader: (8)

Yep, those numbers were probably not full fuel and only driver. I believe it ran a custom labbed Hydro QIV. Low 80s is very believable IMO. What kind of weight are we talking up front? The pad hulls are very simple, the less hull in the water the faster you'll go most of the time. Extra weight up front is a no no.

13% slip with the P5X, while not great it's not horrible numbers. Probably planes like a dream and great midrange bite with the 5 blade. The 29p CE has less slip and is faster but too much pitch. At 4900, your way under your peak 5500 range.

You have an easy 5-7mph left on the table with the proper prop. I think a properly labbed Bravo one or QIV will give you the fastest speed. Brett @ Bblades and Kenny H echoed the QIV MIGHT be a tad faster up top vs the B1 but won't plane as well and be down on midrange speed. I really like how my 28 and 30p Bravo one props run. Both are Bblades labbed. If I were in your shoes, I would call Brett and see what he recommends. Their prop trial program is top notch. With his expertise you'll find that missing top speed.

Unlimited jd

iTrader: (5)

So you have a dyno sheet of the motor n/a? I've seen a few 600-650hp engines lately that made less torque than an hp 500

Boatally Insane

iTrader: (1)

My engine WAS dyno'd in FULL MARINE dress...
Made pretty good torque N/A for a low compression small cam blower motor




I spoke with Kenny yesterday.. He has personally driven the boats I've been comparing mine to, and said that the listed speeds ARE correct...
The blue boat with the 525 has a higher X dimension than mine..
My X isn't high enough for a 5 blade to work properly on the top end (3.5" propshaft depth)
He too suggested I go with a labbed Bravo prop for best top speed..


I'm not going to invest that kind of $$ in this stage of tuning tho' as I'll need yet a different prop once I get the blower and a different drive installed (looking like I'll be going with a 1.36:1 ratio )

I was just trying to get a baseline before I make TOO many changes at once


THANKS !


Doug

Ryan00TJ

iTrader: (8)

Dyno looks strong! Kenny H won't steer you wrong. My propshaft is also 3.5" below pad. I don't blame you not wanting to dial in the prop if you are making those changes soon.

Basically sound like you averaged 65mph, added 200hp, gained 11mph, with no prop tuning. Not bad IMO......