Prop question
 

I just put a brand new 454/330 in my 260 Stinger. It's a complete roller motor w/Holley 650, Stainless Marine 4" exhaust and a Bravo 1 outdrive. I understand the RPM range should be in the 4400-4600 range. I have three props 21, 23 & 25 pitch all three blade. What would be the proper prop to use. I think my 260 wieghs approx. 6000 lbs. The boat originally had twin SBC 350/260's in it and I converted it to a single BBC 454/330. Lost about 800 lbs in wieght and 260 Hp. Any help would be greatly appreciated, Thanks

The 3 props I have are: Laser II 48/25P, Laser II 48/21P and a Quicksilver Mirage 48/23P. I hope this helps you help me...

http://www.rbbi.com/folders/prop/propcalc.htm Click on the web site, it's a prop calculator. Hope this helps ya!

Not very good speeds out of the above formula. What can I do to at least get into the 50 mph range. Would it help to get a four blade prop or what. Any help is appreciated.

You will need the blade area of the Mirage propeller. Try that first. Get some base line info and we can offer test propellers determined off the info you supply.
Because this is a major adjustment to the boat, a beginning baseline is the first step. Everything else is speculation.

Let us know, this is a interesting project!

Brett

Brett, Thank you for your time & response. I will be putting SHOWTIME in the water this weekend. I'll put the 23P Mirage on before I head out to get the baseline stats and foward the results to you. Thanks for the advise on where to start. You're right this has been an interesting project to say the least. I ran a thread on my budget restoration project in the classic section, "Stinger 260 Facelift" check it out. Thanks again. Gator

Gator I agree about the blade surface of that Mirage 23P, but I'm thinking with a full roller motor, shouldn't you be more like 4600-4800 rpm range? Just curious. Hope the test goes well

Mac I would like to get those rpm's and may. But I only have about an hour on this motor and want to break it in. I definately don't want to build another engine unless I go bigger and all out. Which I may do over the winter...

Makes sense gator. Easy on the throttle :evilb: and you'll get those rpm's! I think that 23P is the right call.

Here she is running in the boat.

[YOUTUBE]http://www.youtube.com/watch?v=KkzpmKCssv0&feature=g-upl[/YOUTUBE]

Brett, I ran the 23P Mirage today, 42 mph (GPS) @ 4400 rpm's, full fuel (120 Gals.) and 4 adults. Boat ran awesome just has no speed. If I could get 50 mph and I would be happy...

What rpm at WOT are we looking for?

Brett

im no prop expert,but try half fuel and 2 adults,as you'll never get best top speed with the boat loaded....jmo

Brett is that speed right for a stock 454 roller motor? I was hoping to get closer to 50 MPH at 4800 rpm's if it is possible.

pqjack, I realize that I have the boat loaded to the hilt but trying to see what I'm going to get for top speed with this new motor.

Multiple issues and more testing required.

Too much weight for testing but most important is the high slip % you are achiving at over 30%. You need to cut that in half. If the propeller was reworked or even repaired prior, some of that could be a issue.

Also, if we harness the slip number we will be using a smaller pitch propeller in order to get the rpm up to what ever number you are searching for.

13 hour day is up! Talk to you later.............

Brett

nice motor...looks like a few intake manifold bolts are missing?

Though my sold boat a bit differnt last month, a baja 260, brett and I discussed a rev 4 when i had so much cavitation and slip. The 4 blade gave me a solid 9mph more with best performance at all curves (holeshot, top and, etc) it was labbed too...but locally. I beleive Brett could have done better lab job then my oldtimer, but he was down the street and took one day. I'm sending my next job to brett...twins 292 formula with stock 330's. have the Mirage and the bravo ones alreay stock and ready to be tweaked. Broke some ribs so cant boat for a few days while in ICU ...

Dtile, I have no idea what those holes are for there are no matching holes behind them . There aren't any intake bolts missing though. Are you telling me you gained 9 mph with a four blade prop. Were you running a single 454 or twins? I would buy a four blade prop for the extra MPH no problem. I wish I knew where I could borrow one to test out. I'll have to see if anyone has one I can borrow. Thanks for the info...

Brett would a 23P 4 blade Bravo 1 give me more speed and lower slip without over reving the motor?

ya, was a single stock non mag bottom painted baja...It came with a mirage, not the plus. I first had the non mirage cupped and it gave me more lift and speed, about 4 mph...then used the 4 blade, gave me another 3-4 (eliminated cavitation at all speeds) then the lab gave me the rest...Though again, Baja hull...they are made a bit different and he might just use a mirage tweaked. I like the quick acceleration and better cruise speed now, though the top end is nice was still too slow for me. I could still use more bow lift I think..boat is sold...http://www.youtube.com/watch?v=zl6iCl0dufk&feature=plcp

Gator,
Bravo one props only come in even numbers, 22, 24,26 etc. I PMd you back a few minutes ago. I will let ya know ASAP as soon as I hear back from the other gentlemen.

Dtile, Thanks for the info .

Matthew, let me know whats up when you can, Thanks...

Talked with Brett (BBlades) yesturday. He's got two different style props on their way to me for testing. Hopefully going to get this 30% slippage under control and my speed up to where it should be. Will keep you posted on the results. Thanks Brett