500hp super charged 86 mph gps
 

Just wondering if 86 mph on gps is a good solid number for a 28ft. boat with a 500hp super charged with 5lbs of boost. Should it be faster or slower? Just looking for honest opionions this is gps not the dreamometer lol. Thanks...

What is the boat, what is the set up? Seems a bit on the high side.

John jr

2000 velocity 30 pitch prop from b-blades

non stepped hull, 86 probably isnt going to happen

Step or no step, seems high

My 28 with a 575sci will run 70. i know it isn't a race boat, but 86 sound high to me unless it is a new OL 29 in disguise.

Well a little more detail would help us. First off, is this a HP500 carburated engine with a super charger installed after and the ACTUAL HP rating is unknown? Or are you saying this engine is 500 HP after the super charger is installed? If it is the the first and the engine is producing 700-800 HP then I think it is very plausible.

Exactly, I should have elaborated as if it was a a 500 HP or 500 horse after the blower. I took it for a 500 hp boat after the blower. :D


John jr

It has to be a 500HP with an SC on top of it and probably making about 650hp.

Its 500hp with a super charger running 5-7 pounds of boost 2. 800 cfm carbs. wimple inner cooler
intake . 30 pitch b-blade prop xr drive aluminium heads. Just wondering if my numbers are close to what theu should be guys thanks for your input. Just wondering if i should be looking for more or if were close..

Is it just me or is 7lbs of boost a lot?? Anyhow 650-700hp with a b-blades prop sounds like a very plausible 85-86mpg combo...

I was running. 5lbs but thought since i put such a efficient inner cooler on i could run a lil more. Any tips to squeeze a couple more mph out if her?

In that case the numbers seem close to where they should be. Is the drive on a box? what kinda prop, bravo-hydro or other? What rpms are you spinning the engine to?


John jr

If it helps I have an 02 Velocity 280 which I'm assuming is what you have but a different year. I have a 496HO 420HP and mine will run 67-69 any day of the week hit the 70 a couple of times early in it's life. If you are at 500 HP with the blower I would think you speeds are great meaning 80 hp got you about 16 MPH sounds like a 500 HP engine with a blower added giving you XXX HP to achieve the speed you stated. How's the chine walking? I know mine runs high on the step when running hard with only about 2-3 feet of the back of the step in the water. With your HP I'd bet the boat is out of the water more than in. sounds like a fun ride. good luck with getting any extra out of it.

I have a 30 pitch bravo 1 done by b-blades and also have msd with a rev box set at 6000 rpm, but generally run it in a normal condition day between 5500 and 5600 give or take the humidity. The best speed ive seen on gps so far is 88 and 97 on the dreamometer lmao. Looks impressive on the speedo not going to lie haha.

A b-blade prop,hydraulic steering and bigger tabs is all you need my boat handles the speed very well with that combo.

sounds about right to me.

I had a 502 supercharged 28 Eliminator step hull and I went 86mh top speed. So I would say the HP500 with blower has a bit more power but you don't have steps so it should equal out.

MP

86 w/600+ HP sounds believable.

I've seen 80 w/ stock 525.

A buddy of mine has a 28 Velocity with a warmed up 525 that will run mid to high 70's . If you know how to run these boats they are fast . Just not for the faint of heart .

speed
 

That speed is about where you should be with that wheel at that rpm with about 650 to 700 hp.
My 26 velocity with my small class 6 engine that is 620 hp will run 90 mph with a labed 30 bravo at 6200 rpm.
With my 510 ci 720 hp it will run 94 mph at 6400 rpm
Thats with a high x and a 1.65 gear
This is a race boat with no cabin but it gives you some idea of what they will run if i put my 1.5 drive on its a little faster.
I also have no nose cone on any of the drives i run im going to test a cone and see how much it helps.
I also just built a 588 ci 14to 1 engine real good heads and a tunnel ram.
The sister engine i built to the engine above made 920 hp at 7200 rpm with a single 4 barrel so i hope this one does a little better that will be our loto engine for the speed record this year sorry got a little off topic but might be usable info that might help you.

Thanks alot gary great info. And good luck. I just want to make sure im in the ball park of were i should be. I prolly could do a lil better if i could get my slip numbers down, im around 14.8 right now but also prolly saving my XR drive lol.

Blown525

Sounds close. Velocity is a fast hull. Pad with no step. There is a 28 around here with apprx 650 hp. That boat has put up 84.

speeds
 

Blown 525 i have also found that my boat has went the fastest with a labbed bravo out of the box hydro was close but sternlift made it handle not as nice .
Tom at hydromotive is going to do up one of my 30 or 31 quad 4 for the loto runs that wont give so much stern lift but for all around use you cant beat the bravo.
I race with a 24 pitch bravo at 70 mph at 5400 rpm on the chip the bravo just hooks up nice we come into the corners at 70 and crank the wheel the boat takes a nice set and turns great.
Here are some runs we made prop testing some more useless info.
24 hydro 6800 rpm 86 mph
28 labbed bravo 6500 rpm 88.9
30 bravo 6500 rpm 92 mph
30 hydro 6400 rpm 91.7 mph
28 hydro 6500 rpm 90.0 mph
32 bravo 6300 rpm 92 mph real lazy
30 bravo labbed 6500 rpm 94.7 real cold day

Indeed V's are a fast strait V hull, infact possibly one of the fastest. Very respectable number. it would also seem that bravo's run better then hydro's in ALOT of different set ups, Hmmmm


John jr

Call Steve or Kenny at Velocity and they should be able to give you a pretty good idea of the boat's capabilities.

What kind of rpm are you turning to see that 86 mph?