alter ego

How common is this question??? These things are never fast enough... I have a 1994 stryker equalizer with a 502 mpi. I have build sheets from Dingler racing engines and a dyno sheet showing 603 hp but its at a high rpm. About 5600... I have a Mirage plus that Darin worked for me last year...it was a 23 pitch, now its 24 pitch and modified into an acelerater. This prop tops out at 58.6 mph not biting in at full trim with the motor turning about 5300 rpm. My spare prop is a 24" pitch Ballistic. It turns 60.4 top with no bite in the mid if I am in chop just trying to cruise. thats why its the spare. I was expecting the mirage to be faster than that but the midrange is great. I think the mirage blows out too soon with trim and the ballistic grips ok at speed but this is a fairly light boat....4500lbs+/- with a lot of power. Something isn't making sense. I was told a 4 blade is the answer but i heard that slows you down even more. I run in Narragansett Bay up in the northeast....Mostly light chop but 2-3' waves are not uncommon. that 60.4 came on a 70 degree day with lots of cloud cover. Any suggestions?

throttleup

At what rpm is peak torque and peak horsepower produced? It's important to get the WOT rpm right.

What is your drive gear ratio? With the drive at neutral trim how far below the hull is the center of the propshaft? Is there a notch or extension box?

Depending on the set up a 4 blade can be faster than a 3 blade, a 5 blade can be faster than a 4 blade, etc.

Matt

mwdill

600hp and only 60 mph? that definatly don't sound right.

alter ego

Definitely something not right there... now its becoming an obsession trying to figure it out. Its hard to test too because the conditions change so rapidly... Heres the numbers I was given after I contacted the builder. Peak hp was at 5600rpm. I think the torque peak is in the 4200rpm range I'll call the builder again for the sheets. I have a Bravo 1 with a 1.5:1 ratio. There are no steps in the hull and no extension box. This hull mold is the same sleekcraft used on their 28' through last year. It seems like a shallow v compared to some of the other performance boats that are 27-29 feet. My boat has to stay in for the season so I'll have to go for a swim to get that measurement for you on the prop shaft/ transom.. Water temp is in the mid 50's right now so I'll have to wait a bit on that one. In theory this boat should run upper 60's at least so these numbers I'm getting seem way off. I hope some of this info helps. thanks.

bbladesprops

Deciding your untimate goals will allow us to best suggest the appropriate propeller. Your hull has certain characteristics that will react to certain props.

alter ego

I'd like to get the boat in the mid 60's for top end and still have the ability to cruise in the low 40's. Part of the problem is that I know it should go faster than it does. I've spoken with other owners of this same boat with stock power that have the same or faster top end speed. One of the other guys swithced to a Bravo one prop with a higher pitch and he said it made a huge difference. His boat is the same as mine with 580hp and he runs at about 70mph. He switched from a Mirage plus and he said it made his boat much better in corners and he picked up a lot of top end. Does that make sense? He figures it picked up about 5mph. I'd like to get that but I've never heard of a prop change doing that much....

bbladesprops

Your slip % is high. Your hull design may run its fastest with a 3BL, but not with it's current set up. Your high slip % requires some dialing in and a Bravo 1 may help. You may need to adjust drive height. Do you know your X dimention? Can you get a baseline with a box stock Bravo 1 propeller.

I have some 24's on loan now. We can lend one to you when they become available. I believe a Labbed 24P will help you out.

alter ego

Thanks Brett.... I don't know the X dimension on my boat but I could try to measure the distance the prop is below the boat from the dock tomorrow. I think my mirage plus has been worked too much.... When I got the boat I had the prop redone to smooth out some dings it had in it and get it cleaned up...then it was labbed , the blades were tweaked and the pitch was raised to 24" from 23". I'm sure you've seen the design Houston prop uses on the Mirage. Darin was really good to work with and I think its just time to try something different. It surprised me how little bite that prop had when trimmed up. Maybe there just isn't enough diameter left to push the water. Thanks for offering to lend me a Bravo 1. That would help me figure this out and then I could just buy it from you if it works out... I'll call you at the shop to get some details together.

robyw1

I have had great results with the Accelerator but at least to me it sounds like you're pitched too low. Mine is a 22' Scarab 3100-lbs modified 454 MPI. I hit 73.5 top speed with a 1.36 B1 at 4700. Many have asked why I use a 1.36 but being the 2nd owner that is what was on there. I know it didn't come with that drive ratio.

alter ego

I am the second owner too...I am learning the boat as I go. I know that boat should go faster than it does with that motor. I am getting ready to swap a Ballistic onto the boat to do some testing....then I'll work on testing a 4 blade. I think that may be the answer. What pitch do you have on your prop now?