Sick Stinger

I posted in General Q&A about 3 problems. I have a lot of prop blow out. With the old motor 650 h.p 509 CI 250 blown. Had a lot of prop blow out and stern lift. It was a Hydromotive QIV 28P on a bravo1 1.5(i think) ratio. Woould this be an incorrect set up wrong prop the X dimention is right from Velocity. MikeS i know you said the blow out is common but how much and is there anyway to take care of it? The blow out and lift, Does it cause handling problmes cruise and top speed issues fuel consumption or plaining ease and time?

My other question woould be I now have a 572 SC 10-71 about 900HP, what prop to use. Anyone else with a se up similar to this if so what do you have. I want to have a max of 6K i have a 34P labbed Bravo1 to put on to start from. I heard 36 when i bought the motor and 32 from another guy who said he has a similar set up
-Mike

LAKESIDE RESTORATIONS

Sometimes lowering the drive height with a spacer, using a caitation plate or going to a larger diameter or 5 blade prop can help.. Jamie / Lakeside

velocitykid

sick, where is your x-dim? do you have a nosecone? what type? i run a 540ci 10-71sc 1000+hp with a 34p bravo and 1.35 gear. i am twisting the engine about 6800rpm. i would start with a 36p and back up if necessary to get the rpms. i know that velocity likes the hydromotive props but every one i have tried had handling issues past 95mph. it could be i have not tried the right hydromotive yet , i run a high x-dim on my boat and the bravo prop just works better for me. with that power i also recomend a gear change to keep the engine in the torque range longer and better curising. just my .02

1HYPER1

Hey Sick,
Try running a Bravo,on my 280 I would experience alot of prop blow out and switched and it performed alot better.Also on my 320,the Hydro while it pulled a little harder it became almost impossible to control at higher speeds so I switched to the 34 Bravos and picked handling as well as top end stability as well as a much better cruising speed.The Hydros are good props but I think in your aplication a different prop will help you.Try to borrow props to come up with the best set up and then purchase what you need because you will need to try several different ones until you find the correct one and they get very expensive,I found out the hardway and have a wall full of props to get rid of.Good luck.Also do things in small incroments so you can see what works and what does not,that way you can keep track of it and not get lost while trying different things.Good luck,
Bill

RaggedEdge

What have you got on the wall to git rid of? Let me know.

Sick Stinger

I have a nose cone on the drive and also the X is at the stock location that Steve Stepp put it. There is no shorty on the drive. Also it did handle like sh!t around 75 it would chine like a mofo. I heard that the braov was much better. I have a 34P labbed 4 blade i hate to run a 5 blade and wreck the drive. Its a bravo 1 and imco's and i dont wanna blow it.
-Mike
Hyper im going to try the 34P if i need to can i borrow any of yours ill pay the shipping here and there if you sont mind and if it works out ill buy it off you,- dependong onw whats props you have left
Thanks Mike

Shore Thing

x2 on using the bravo. My hydro would blow out all the time if i wasn't careful. no problems when i switched to the bravo blades.

Sick Stinger

Thatnks Shore im gonna run the bravo hopefully that eliminates it if not then ill look ing to it futher but info and suggestions please keep them coming

velocitykid

sick, 75 -85mph seems to be the ruff spot in my opinion, i usually try to blow into the 90s pretty quickly. as for the factory set x-dim, i'm not sure they have one, i've have had 14 or so velocitys grace my shop and the x-dim was different on at least 6 of them. also to get top speed from the bravo prop it will probley need some work

Sick Stinger

it was labbed from b blades