28 Real Mph Numbers

B-Stubb · 09-19-2003, 12:56 AM

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 ?

IRONMAN · 09-19-2003, 07:50 AM

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....

JO - PANTERABOATS · 09-19-2003, 08:49 AM

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.

MIAMIBOYZ · 09-19-2003, 10:14 AM

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

Cattitude · 09-19-2003, 12:33 PM

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

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.

Von Bongo · 09-19-2003, 01:13 PM

Quote:

Originally posted by B-Stubb
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 ?

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.

Cattitude · 09-19-2003, 01:24 PM

Quote:

Originally posted by Von Bongo
Merc 575sci, about 75 degrees with 3 adults and 1 young man

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

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.

BRUCE SEROFF · 09-19-2003, 03:33 PM

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

Cattitude · 09-19-2003, 03:56 PM

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??

BRUCE SEROFF · 09-19-2003, 04:18 PM

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.