Which prop for altitude?

[hkunz]

We are going to Powell in a few days, and I seem to remember someone saying that they had two different props for Powell and Havasu. Is there a big difference? Is it worth the $600 or so to get another prop? Mine accelerates great at Havasu, but does not have all the top end it could. Will this trait be exagerated or diminished at higher altitudes. I have no idea what the pitch, or cup, or diameter, or anything else is, although it is a four blade.

[panic button]

Rule of thumb- Go down 2 for the altitude at Powell. Top end will be even worse at Powell and will run on the rich side so watch your plugs.

[BADAXE]

I would not spend the money. I just got back from my first trip to Powell and used the same prop I use at Mead. It was a little slower to plane and was noticebly down on power just a bit but not enough to buy a special prop for.

[OnlyMoney]

On our DCB we changed props, down 2 sizes. But, we were just there in the Skater when BADAXE was and we didn't change ours either. We lost some top end, but we didn't mind doing the slow cruise up there.

We'll be there this weekend as well, running with a smaller DCB. Don't be shy if you see us!!!!!!!!

[titties and beer]

i have a new 28 4b/ss in the garage

[hkunz]

Are you in Page? We won't get there until Monday, Labor Day.

[titties and beer]

15 MINS AWAY ,i'm in bigwater

[Wild Horses]

Your running the 600 sci, I do believe they are set up to deliver 600 horse regardless of the altitude. If that is the case don't change a thing.:thumb:

[hkunz]

Talking with Advantage, they're checking the prop taht is on it, and said something about a loaner if they think we need it, i.e. if we damage it, we bought it, but otherwise we can return it after the trip - how cool is that?:party:

[hkunz]

OK, Advantage just called, I have a 24, and they will loan me a 22 for the trip. Should that work?

[hkunz]

i have a new 28 4b/ss in the garage

For sale, rent, or loan? If for sale, how much?:thumbs_up:

[Rude]

i ususally run a 28 at mead. i ran a 28 at powell last year with full and a boatload of people and the boat would not come on plane. this i ran a 26 with full fuel and just two people and it came on plane but was no dragster. i HAVE to step down at least one size at powell.

[Liquid Courage]

OK, Advantage just called, I have a 24, and they will loan me a 22 for the trip. Should that work?

WOW, what gears do you have in the outdrive? I run a 26p prop here and 24 at Powell, but I only have a 310hp motor. I would think you would be running in the 28p range give or take. Unless you have really high gears in the outdrive.

[hkunz]

The outdrive is 1.5:1. I am wondering if advantage deliverd it with a "short" prop so a) we didn't kill ourselves, or b) the boat showed very well with great acceleration. At Havasu we pop up on plane almost immediately with this prop. I'll bring the 22 to Powell, we'll just have to mess with it a bit.

[Akamatsu]

The outdrive is 1.5:1. I am wondering if advantage deliverd it with a "short" prop so a) we didn't kill ourselves, or b) the boat showed very well with great acceleration. At Havasu we pop up on plane almost immediately with this prop. I'll bring the 22 to Powell, we'll just have to mess with it a bit.

Sounds like the 24 might be right for Powell already and you may consider a 26 for Havasu based on what I am reading....

[kevnmcd]

I ran the same prop (26p) that I always do in Havasu and didn't have any problems with my motor (EFI). I even was able to wakeboard behind it just fine.

[roln 20s]

I ran the same prop I ran in Havasu as well - 26 pitch stock. I run about 500 rpm less at powell, but am ok with that because I am cruising at 60mph for under 4000rpm :D Fuel efficiency :D With 100 gallons of gas and four of us on board- I ran to the bow to get the bad boy to come onto plane. The best prop would be a 24 for me, but as much as we cruise, I will give up the hole shot for less fuel consumption.

Too bad we missed you hkunz.

Roln 20s

[hkunz]

The 24 worked just fine on Powell. Err, except for the cavitation. It seems that the mistakes we made with the boat the first day (numerous, and ugly) have had longer term effects. As for the mistake that fits this thread - I thought I had the drive in the trailer position (the "offshore controls" were new to me, which caused more than one mistake) and we drug the prop and skag up the ramp at Windsor. This put a nick in the prop the very first day. With our jet, no prop, no nicks, thus no experience. The Cheetah only has a 320 HP 6.2 SBC, so the small scratches on that prop didn't make a big difference. Er, and we never drug it on the ramp, just caught a few reeds, etc.:smashfreak:

We took it to one of the two prop places in Havasu and got the nick ground out. Unfortunately, they also ground out the "cup" in the prop. After Advantage and Mercury Racing tested it extensively, they swapped props, and the problems went away. We then took the prop to the OTHER shop (Gibbs) and he put the cup back in, balanced it, and got it ready for next year. We took the boat down to the ramp the day after Thanksgiving, but it was blowing 15 knots or so, so we just put the boat away. I'll know in the spring how the prop works, or if we'll need to buy one.:crying:

[hkunz]

I love reopening ancient threads:laugh:

Now it is spring, and we've tried the balanced 24. We got up on plane fast, and got some great top end, with the engine hitting the rev limiter at half throttle around 65 -70. This would equate to lower gears than needed, so we popped for the 26. Out of the box it cavitated like crazy, but got better top end and more efficiency, (70 MPH on GPS at full throttle 200 RPM below reve limiter) so we took it to Gibbs for more work. I thought we'd get it balanced, but instead we got it labbed. I'd been cautioned on here about the sharpness of labbing, but this prop is not sharp, although it is thinner than it was.:dunno:

[kevnmcd]

That is the down side to labbing a prop is that they basically "thin" the blades making it better (or lighter) for top end speeds. The other down side is that sometimes the blades being thin tend to get a crack in them and break off. Be careful around the shallow areas cuz you don't want to ding them...very expensive to fix. just my .02 on labbed props.

[hkunz]

After talking with Merc Racing, I also found out that cavitating the prop can cause "burning", in which case the ears will fall off. They are getting about 12 hours out of a prop on the bigger motors, like the 1100's and 1200's.

I've been pulling back on acceleration to prevent burn. Now I just have to figure out how not to catch the wind and let it take me into the dock.:puke:

[Rude]

i'm surprised merc told you to use a different prop at powell. i've read numerous times that the 600 and 700 sci motors are supposed to have 600 and 700hp no matter what the conditions. that means you shouldn't have to prop down regardless of altitude or lake.

as far as the 1200 only getting 12 hours per prop.......guess i'll have to cancel my order for that motor. those props would just get too expensive :)

[TooMuchFun]

I lost almost 20mph from Mead to Powell with my Party Cat ... your setup and hp seems similar from what I can tell ... I would change 2 prop pitches when on Powell.

All the computer controlled EFI big hp engines say they compensate for altitude, but they only try. They don't.

TooMuchFun

[kevnmcd]

...as far as the 1200 only getting 12 hours per prop.......guess i'll have to cancel my order for that motor. those props would just get too expensive :)

Those that can afford a 1200 aren't worried about having to buy a prop every 12 hours or so! :insane:

[kevnmcd]

I lost almost 20mph from Mead to Powell with my Party Cat ... your setup and hp seems similar from what I can tell ... I would change 2 prop pitches when on Powell.

All the computer controlled EFI big hp engines say they compensate for altitude, but they only try. They don't.

TooMuchFun

I was very surprised last August when we went to Powell. I stayed with the same 26p prop that I use on Havasu and only saw a slight difference in plane time and top end. Either Gary built me one very "torquey" engine or my gps was lying to me! :dunno: Either way I was very surprised how little I really lost at that altitude and we did a lot of wakeboard on my boat, too.