28 Real Mph Numbers
 

Dont post if ya aint tellin the truth Albert says uper 90S Mine 780 hp notched transom 83-84 30 pitch bravo 5900 rpm if all you were telling the truth Im way slow for my hp ?

The prop slippage is too high if the gages are accurate. For a bravo 1 prop the slippage should be 10 to 15 percent for optimum efficiency. I am at 10 percent on my 24' with a 26p prop with a conservative X. Try to borrow some spacers 1 and 2" and experiment to get the prop loaded more and the slip down. speed should come up .
Good luck....

Mr B-Stubb, Are you refering to me??? If you are, would you please tell me where I am not telling the truth? I guess "all of us are not telling the thruth" Have you weighted your 94/95? Have you tried to space the drive, like we suggested? which prop are you running @ what rpm? The only person that suggested Jo's numbers were questionable was you in the other thread, and since Jo is my son, when you accuse him of questionable ### you touch a wrong spot on me. Anyway, our invitation to bring your boat to Miami, still stands, Jo would be delighted to spend time w/ you and your boat, just like he spent w/ you before you bought your pre-owned Pantera. Like you say, "if you all are telling the thruth" Please do not forget, I have nothing to gain for lying to you, just like I gained nothing from you when you bought your pre-owned, all we did was get you a trailer @ cost! I think you should take us on our offer of coming to Miami and take Albert's boat and try different props on your boat, maybe a spacer or two, our shop doors are open to any Pantera owners, specially since you are a couple hours away! Pepe 2 pantera.

B-STUBB
 

I RAN 86 WITH 540 NA 650 HP AT 5900 RPM 28 LABBED
I RAN 98 WITH 540 BLOWER 8-71 850 HP AT 5900 32 PITCH BRAVO ONE.IF YOU DONT BELEIVE IT BRING YOUR GPS AND DONT TELL ME TO SLOW DOWN WHEN I PASS 95 ON THE CHOP.I`LL BE IN FT LAUDERDALE AT THE APBA RACES IF NOT I WILL AT DEERFIELD THE FOLLOWING WEEK.

PS:WHO DYNOED YOUR MOTOR OR THOSE HP NUMBERS ARE WITHOUT A DYNO RUN.

ALBERT

I'll be playing with mine this weekend, fresh water, 1120 ft, mid 70's air temp, have a nice lake x tuned 28 to try and a 1/2" spacer if i get real ambitious.

Over the winter (or next few weeks)my 575 will be getting some Help From Dustin- he's going to help with a non intercooled kit for my 575:D

I'll be running with no tabs, I marked my indicators to neutral with drives and tabs measured neutral. I've got no notch but 7" of ITS setback- anyone have a starting point for how many "ticks" off neutral on the drive for best effiencies?

Sorry to be a newb- been driving a cat too many yrs. Gotta get used to this v-hull thing. Love the boat and my wife REALLY loves the boat!

with regard to true speeds- I care more about a decent rpm/cruise speed because that's where I log the hrs.- A big top number is just gravy.

I learned with my cat along time ago- there is my best GPS number where all the planets are in alignment, the air and water temp Gods are smiling and you've got a 18" chop and the right wind. (99.0 gps)

Then you've got everyday, sticky water, plenty of fuel, a few buddies, hotter air and water realistic speeds- Mid 80's to low 90's depending on all those variables.

It would be a mistake to tell all my buddies I've got a 99.0 mph cat and think that I'd be able to prove it to them.:D

Re: 28 Real Mph Numbers
 

I dunno but your way slow at that. Merc 575sci, about 75 degrees with 3 adults and 1 young man and all the normal boat crap on a relativly flat water day I think we ran 72.3 when Cat demoed my old 28 and that was at 4900 rpm and a 28 labbed bravo one. I have talked to DK a couple of times and I think he is seeing your numbers with less than 650HP.

You have some tuning to do it looks like.

Re: Re: 28 Real Mph Numbers
 

Branden will be happy you referred to him as a young man (He's nine):D

83-84 may be reasonable for everyday numbers- could be there is some setup to be gained. I don't where you run B-stubb but we are not all in salt water at sea level.

Then again- seems like 200+ ponies would get you more than 11-12 mph? Or is that about right for a stout but non stepped 24 degree hull in calm waters? (Forgive me again- I'm used to Cat numbers and Cat Gains)

Just went back and read this "83-84 30 pitch bravo 5900 rpm"- Isn't that a whole bunch of slip? With a 1.5 ratio that would be good for high 90's in my cat- maybe triple digits. What is the X dimension? Did the factory set the drive height or someone else? Have you tried different props are are you putting blind faith in the one you have?

Not trying to poo-poo your boat or setup but if you want and think you should have more then you need to look at these issues.

Hey Catitude...
just outa curiosity, where is your PROP shaft with relation to the bottom of the boat? Ive tried several drive heights and found the best results around 4.5" below the bottom with 12 imco Ext box. The best that Ive seen with just me on the boat light chop and 30 gal. fuel. 79 - 82 mph 540ci/approx 650 hp (not Dynoed) at 5900rpm. turning a labbed 26.

Jo Pepe...I plan on having the boat down there for the St Pete race and Deerfield Race. It would be nice if you guys could do your magic. If you have the time

Bruce- thank you for that valuable info- cause I've been wondering myslf where the sweet spot is. I know salt water has more buoyancy- does it also have more bite at the prop?? (therefore can run a little less drive in the water?)

To answer your questions- 3 and 13/16" below the keel as best I can tell with 7" setback from ITS. This is with an aluminum straightedge on the keel, to a neutral trimmed drive and eyeballing the center of the XR nose as best possible. To check my eyeballs I measured from the cav plate the shaft center in the rear and got the same reading to where I was eyeballing the front of the drive- If I'm off, it's not by more than 1/16"

I'll need the 28" because I can't spin that high. Sounds like a 1" spacer may be optimum for me based on your experience, would put me just barely deeper than you but with 5" less setback- make sense??

Ive tried many heights form 2 3/4" below to 4 3/4 below.

at 4 3/4 below with an Imco lower. I dont think any of the boat was ever in the water. but I hit 78 with three men in flat water and alot of fuel w/ non labbed 26 at 5500. Right now as we speak Im at 3 1/4" below and hitting 80 by myself in the boat. with a standard XR lower. in bay chop. I would start at 4.5 or 4.75" and work down from there.

Thanks Bruce!
 

Cool Photo!!!

I'll probably do the 1/2" spacer first for 4 5/16" because I own one (will have to pull it from my Daytona). I'm pretty sure Chris Martin will let me borrow a 1" if he has one and I'll buy it if it works well (I bought my XZ/Imco lower and 1/2" spacer from Chris)

how does this boat respond to the Imco Lower??

Mr. Awsome, We will be happy to store the boat for you @ no charge, of course! We can try some props on the boat and run it in different water conditionsw/ Jo. But as far as relocating your drive height, we can not do it in that time frame! We are swamped w/ work . That is why i am here Sat 6 AM. So let me know, Regards, Pepe.

Wow all this in one post, Pepe calm down Im not questioing you or Joe U guys have been great to me ,what I am questioning every one does not have a notched transom and my X seems to be a question Im at 4 1/2 on my propshaft I have gone deeper but slowed the boat down Mike from halls did my props ,I will turn a 28 labed 5950 at 82 mph went to a 30 went 83-84 orderd a 32 havent tryed it yet mabe I need to rethink and go deeper again I will take Jo up on comeing to miami and go for a ride I will call, B Stubb

Hey B Stubb,
I run a 95 28 Pantera with 600 HP -
Mike just cut a prop for me -

my std 26 4 blade turns 77 mph @ 5800 RPM ( X @ 17 ")

Mike 28 lab prepped turned 77-78 @ 6000 RPM
All readings are by 2 GPS unit ( on board and hand held )

I need to try a 30 " prepped unit - I will also try to
lower the X by an inch to see how it affects performance . Horsepower peak is 5500 , so I am way over revving - Need to get the prop to bite and get the RPMs' down .

As far as efficiency , the 28 labbed is a 26.5 " unit for the calc .
Efficiency looks to be around 75% .??
Based on .0006249( prop) ( rpm) based on 1.5:1

Jerry

So when you say x is 17", where are you measuring from??

After this weekend I'm going to say I may need a deeper x. I've got 20% slip, get my best at just about a 1/2 a tic above neutral on the drive, 71.6@ 4900, more trim just ups the r's without a speed gain then speed falls off about 2 notches up from neutral.

this is with about 5/8 tank and 3 of us in the boat at 1120 ft of elevation.

Brian...
Your boat is quite a bit heavier than Alberts boat...
His is a full race set up- I think it only weighs 4400lb or so. Your full cabin/pleasure lay out probably weighs 1000lb more, but Pepe would have the better weight difference for ya.
Anyway, your boat runs damn good, and looks good doing it!
Let me know when you're bringing the boat over for Jo and Pepe to look at it. We'll go for a ride, and hit Shooters, Monty's, and Hooters...:D :D :D :D

Tim

Im hopeing to go to the races this weekend good lord willing talked to Joe he said hopefuly after the races we my go for a run

what races????

I guss apba races in ft lauderdale /I will be racin in my mind sitn in the boat

Ft Lauderdale is next weekend Oct 3-5

catitude X is measured from the center of drive shaft very close to where the gimble piviots to botom of boat the v / what pitch prop 28 ?

You found the race gona be there ?

Yeah- 28 labbed, same prop took me to 93+ on my 650 hp daytona at 5400 (1.36 gears)

Cat, I have talked to Jo about X's before and about where yours is at for comparison to mine. Jo said he set the X on your boat at 17 1/2. Normal pleasure versions are at 17" and yours was raised 1/2" for the ITS setback.

Mine is set at 20 1/2" because I have the nothched transom. It came from the factory with a 2" drive spacer. It was still too high and couldn't lift the bow enough. I was getting the same thing as you. Raise the trim and gain rpms and only very little speed. I put in a 3" spacer this year and it helped a bunch.
The speed will also go up when you lighten the fuel load. If I run with only 30-40 gallons and 2 people, I pick up 3-4 mph over running with 3/4+ fuel. Also if the water was flat, that hurts a lot also. A 1-2' wind chop is the best I have found for top speeds and that was even running into the wind.

PS. Sorry I didn't get a chance to give ya a call today. I have just been busier than @*&%. I'l try you tommorow night.

Brian-
I'll be at the races.. But.. I'll be workin' our booth there. Stop by and say Hi. It'll be tough to miss our booth- Just look for the float lift hanging in the display.
Sunstream Boat Lifts.
TIM

Tim call me 239-872-0952 I need to find how to get to a rampI dont know my way around there