Dialing In
#1
Guest
Posts: n/a
Dialing In
I just got through the break in perod on my motor and I finally got to open it up and see what it will do. It ran 69.5 @ 5500 rpm. Just to give you a little back ground on the motor it is a 454 that was bored and stroked .30 over running a wieand 177 blower. I called hydromotive to find out what kind of prop I should be using and the told me to stick with my 15 by 22 pitch 4 blade bravo. That just doesnt sound right to me. The guy who built my motor told me to prop it to 5200 rpm's. I dont know anyone who has a prop I can borrow so I was hoping someone might have a suggestion. By the way this is on a 26 Checkmate Persuader. Any help would be appreciated.
#2
Charter Member # 55
Charter Member
From your WOT RPM readings with the current prop, I would think that you should go to a 24 Bravo. Will probably drop the rpms by 400+/-. If it drops too much you get the prop labbed.
#3
Guest
Posts: n/a
From several conversations with the tech guy at Hydromotive, they have always recommended running at the very top, if not beyond, of the power rpm range. If your mechanic said to prop it to 5200, it must have made power near there. Did you have it dyno'd? I doubt there is any problem with running it 5500, but it's the wrong season. If it were doing it in cool weather and dropping down to 5200 this time of year, you would have a good all around choice. If it's got a blower, chances are that it's got plenty of torque to pull a wheel that's a little large in the summer. Over propping a NA motor turns it into a dog. I'd try a prop 2" more pitch, but stick with the same type for apple to apples comparison purposes.
#4
Platinum Member
Platinum Member
Be carefull with the Hydromotives. I twisted the splines on my prop shafts with them. I went from 25p Mirage to 28p Q-IV Hydromotives. If you are close to South Haven, Michigan you can try the 25p Mirage. I can't get them back on. The guy at Hydromotive told me to stay with my 25p Mirage since I put on Whipples. It didn't make sense to me eather at first but its becoming clear. The splines in the Hydromotives are set further away from the thrust plate.
#5
I hate the winter!!
Platinum Member
Join Date: Jul 2001
Location: long island, new york
Posts: 2,707
Likes: 0
Received 0 Likes
on
0 Posts
Just a little information here, if you don't already know this. A 24 Bravo actually measures 22.5 pitch. Mercury measures their Bravo wheels at the highest pitch, where Hydromotive measures at the average pitch. Bravo wheels have a 3" pitch progression. So, if you are to compare Hydromotive to Bravo remember to subtract 1 1/2" of pitch from the Bravo to get a correct comparison.
#6
Offshoreonly Advertiser
Offshoreonly Advertiser
I would try a 23" Revolution, should drop you 300 RPM, and should be faster than a non-labbed Bravo 1. Of course the only way to know for sure is to try it.
__________________
Marc
www.mercruiserparts.com
www.go-fast.com
www.bammarine.com
www.cyborgtransmissions.com
It's not alive -www.BoatStuffExpress.com - temporarily retired
Marc
www.mercruiserparts.com
www.go-fast.com
www.bammarine.com
www.cyborgtransmissions.com
It's not alive -www.BoatStuffExpress.com - temporarily retired
#7
Guest
Posts: n/a
I noticed you're running a Persuader hull. So am I except in the 219 flavor. When I called Checkmate asking about props Mike indicated that all the Persuaders ran similarly and that they recommended Laser props. I believe the Ballistics act similar to Lasers.
I've tried 23" Mirage Plus on mine and the hull felt "dead", not the usual responsiveness to trim that Checkmate gives and likes. My current and best so far is a 22" ??? no name stamp. The 23 MP dropped 300 rpm to 4600, gained 1 mph, with poor holeshot. Gave it back. 23" non-cupped Mirage might have worked better.
Check out the thread on "Mirage vs. Ballistic". Those guys are running older Formulas. Another thread talks about Ballistic working real well for the 25 Sunsation (which I haven't driven, but sounds like it responds like the Checkmate), and Chaparall hulls. I'm REALLY interested in trying one of these. Might be a real sleeper.
Mbam's comment on the Merc Revolution 4 is on too. Seems like it acts sort of half way between a 3 blade and the Bravo's and Hydromotive 4 blades. Works on many hulls and gets good speed at less price.
My 2 cents.
Scott
I've tried 23" Mirage Plus on mine and the hull felt "dead", not the usual responsiveness to trim that Checkmate gives and likes. My current and best so far is a 22" ??? no name stamp. The 23 MP dropped 300 rpm to 4600, gained 1 mph, with poor holeshot. Gave it back. 23" non-cupped Mirage might have worked better.
Check out the thread on "Mirage vs. Ballistic". Those guys are running older Formulas. Another thread talks about Ballistic working real well for the 25 Sunsation (which I haven't driven, but sounds like it responds like the Checkmate), and Chaparall hulls. I'm REALLY interested in trying one of these. Might be a real sleeper.
Mbam's comment on the Merc Revolution 4 is on too. Seems like it acts sort of half way between a 3 blade and the Bravo's and Hydromotive 4 blades. Works on many hulls and gets good speed at less price.
My 2 cents.
Scott
#8
Guest
Posts: n/a
Thanks for all of the responses I think I am going to try a 24 pitch or 25 pitch bravo and see what happens. I figure I am going to ask around this weekend to see if anyone has one that I can borrow and try before I go buy one, unfortunatley there arent to many prop retailers up this way that will let you try a few different ones. If anyone has one of these props for sale let me know mayby we can work something out. Thanks again.