hp500efi

LMAO

car54driver

92 under best conditions.

Guest

I'm going to guess 94.

a friends 35 with procharged 502 will do 97

Roger

Just finished the boat but it now has Troy Dennis 572's with 680 HP and I am a little dissappointed with the results. Just ran it at Fountain with 30 Mercury's and it ran 93 at 5000. We installed 2" imco shorties with 1.34 gears and the boat just does not seem to gain speed after 88 MPH. It will run this at half throttle. We tried 4 blade 29 Hydros and got 5100 and it ran 95, but getting on plane was bad. Also had the bottom checked and it needed blueprinting and it has been done. ANY IDEAS???? I was looking for 102-105 range.

32fever

Have you talked to Hydro? Maybe try their 5 blade? Not sure what range of sizes is avail. I know on the 37 AT AVH's I was reading they tried the Herring 5 blades and had better results. Not the same boat, but maybe the manufacturer of the props can offer assistance.

KAAMA

iTrader: (1)

I'm sure it will FLY!

sauron

Yes talked to Hydromotive and they think that the boat is lifting the tail to much pushing the nose over. I believe them because the boat is very tight, does not chime walk or porpoise. I have ordered a set of 27s and are going to try them. See if RPMS go up and the nose lifts some. Will advise. Roger,

SteveDavid

Hi Roger,

A couple of diagnostic questions:

#1. At speed, what was your water pressure?
#2. Did positive trim make any difference at WOT?
#3. What were your RPMS at 85 MPH?
#4. Was anyone looking at your slip stream? If so, was there a solid directional flow of prop blast, rooster tails, cavitated water, etc?
#5. At what point on the side of the hull were you seeing water spray from?

I aks these because it's easy to prescribe a solution before knowing the prblem, and that just might have you chasing non existent gremlins.

My assumption, (and that's a loaded word) is that you're losing water pressure as you're experiencing prop blow out. When this happens it';s like a clutch slipping, you just don't gain much with higher RPMs, thus the RPM at 85 MPH question. If positive trim does not lift the hull and you're seeing spray ahead of the CG, this would also indicate a lack of leverage on the hull thru the drives.

If that's the problem, and I say IF, then a larger diameter prop, and more blades, such as the P-5 might help. Are you currently running a 15.25 or 15.50 diameter? If so, trying a 15.75 diameter 5 blade, be it a P-5 or Hering, may help. Are you using a diffuser ring on the props you ran your current speed with? If not, you might add them to reduce blow out.

You mentioned you are running the 2" shorties, so I'm guessing your X dimension is pretty high? Are you running a staggered set up? If you are, which way are you rotating the props? There is also the chance that a close stagger may be causing cavitation between the props as they cycle past each other?

Seems I'm asking alot mroe quesitons than giving you answers, sorry Roger, it's a process of elimination. I'm out of town until Sunday evening, let me know what happens over the weekend. Hey, 90 plus is fast, hope you're wearing a life jacket and a kill switch lanyard

See ya Roger,

Steve

Roger

Too Old, I have considered that also. I may not be able to test this weekend due to no water in the lakes around here, but when I do I will post the results. Just recieved the 27s from Hydromotive and hope to test if water permits.

Roger

Steve, thanks for the help. I will let you know the answers after I test the new props from Hydromotive. Give me your phone number if possible. I would rather talk on my dime than type. Roger