Quest for Speed

I am looking to get a few MPH top end out of the boat (38 Powerquest with 500efi's and ITS) but I do not want to lose the current cruising speeds. I am running 30 pitch Bravo I's that top out at 79mph at 4900 rpm. It will cruise at 60mph at 4,000 and 70mph at 4200. It seems I get a lot out of that 200 rpm right now and not as much near the top end. I would like to get the rest of the rpm's out of the engine's but I'm afraid to lose the cruiseing speed if I lab the prop's. What is the likelyhood of loseing anything if I lab the props? Should I just buy another set of props?

throttleup

If it's in your budget go with two sets of props. A blueptinted set that will run just under the rev limiter for those days when you really want top speed and a nice set of cruise props, with a WOT rpm of 4800, for days when you just want to cruise.

Another option is to have your current props trued to manufacturer specs. We call this service a high performance recondition. The props are pitched to the same specs as a lab finished set, the blades are patterned and in the case of twins the two props are matched. Various other steps are taken in the process but the cup is not reduced. You should see only a minor increase in rpm, due to increased effiicency. Cruise speed should be the same, or better, and the top speed should be a little higher. The results depend on the current condition of your props when they were manufactered.
Since all of the mass produced props are cast they distort through the cooling process. That distortion varies with every prop. Therefore the results vary with every prop.
With your current set up the 30 bravo's you have now are great cruise props. For top speed a set of lab finished/blueprinted Bravo 30's should give you a little more top end. You will lose some of your cruise speed and the props may slip when getting on plane. The lab finished Bravo 30's should get your rpm close to the rev limiter. Boats with the HP 500's seem to get their max speed right around 5250.

Matt
Throttle Up Propellers
www.throttle-up.com
[email protected]
877 842 6855 toll free

HOUSTONPROP

I have a labbed set of 30 pitch bravo one for 1,200.00

Quest for Speed

Thank you for the information throttle up and SOLD to Houston Propellers. Darrin I will call you on Monday, I think I have your number from a post you called me about when I used BMAC 13 as my user name.

Macklin

Quest, I had my props labbed and lost a solid 5mph off my cruise speed.

Matt, the high performance recondition and matching is just what I need, as we discussed. I will be boxing them up soon. Does patterning the blades add the satin finish on the blade edge that we see on a recently reworkeed set from you?

BillR

Quest,
I'll chime in w/ my PQ experience.
I have a 34' PQ and was runnin' stock 28 B1's at 4900 to 5000 depending on the day.
I bought a set of York labbed 28's and ran 5200 all the time. Also tapping the rev limiter alot. I gained 1 mph. Still under 80mph
Then I bought a set of Merc labbed 30's. I am now running 5100 rpm and have broken the 80 mph mark consistently. All of this was done in cold 58 - 64 degree weather. I will sometimes hit the revlimiter, but when the weather warms up, I'm pretty sure I'll be right at 5000. With all labbed props, I have lost cruise speed at same rpm. But all around performance is majorly improved. I may send my labbed 30's off to be fresh'nd up and MAY ask if the can increase cup slightly. BUT not reduce top rpm by more than 100 rpm.

If you want new props for your boat. Use this formula I was told for twin engin apps.
On twin engine boats: Add 2" pitch = 200 rpm less then lab the prop add 300 to 400 rpm. So If you get a set of labbed 32's you should see 5000 to 5100 rpm. On the PQ hull, I'd bet 5100 rpm and around 82 mph!!!



If your boat has ITS, it must be new. How many hours you got? If under 40, You will likely gain more speed as the motors loosen up more. On my 2 PQ's, I never got good top speeds until about 50+ hours.
Post some pics of your 38 over on the PQ forum.

Quest for Speed

Thanks for the info Bill. I am definately going to keep the props I have and likely get them trued like throttled up recommended. I am going to call Houston Propeller on Monday and find out if he added any cup to 30's he has or maybe see if he has some 32's.

throttleup

Macklin,

NO...THE SATIN FINISH is not from patterning the blades. This is just the finish on the leading edges. I will let you know when I receive your props.

Quest for Speed,

Be careful if you purchase used lab finished props. Get the history of the props. Generally we get what we pay for! We have New Bravo I Props for $450.00 including hub (Solid if needed) Lab Finishing is on special for OSO members for $80.00 per blade, includes polishing.

Matt
Throttle Up Propellers
877-842-6855

HOUSTONPROP

All work and props sold are 100% guaranteed!we will re work or replace the prop or props until you are satisfied!

KAAMA

So what you prop guys are essentially saying is that when it comes to Lab Finished props, you CANNOT help the MPH/Speed loss that occurs at cruising speeds---right? Just curious is all. Thanks