39TG prop selection
 

Hey guys, need some input.
Looking to prop a 39 with 700s and XR drives. Some are saying to try Bravo 33s but speaking with someone else they recommended trying a set Maximus but I'm not sure what pitch. Any help would be greatly appreciated.

700sci’s and XRs?

A 565 39 TG uses 32 Bravo's.https://www.performanceboatcenter.co...=xAllInventory
Most likely you would need at least 34's and probably 36's.I would say 5 blades in 33-34 range would be you best bet assuming 1.5 ratio drives.

Its gotta be the Red 39 that came out of Ohio.

That is correct.

I'm going to try a set of Bravo 34s first to see how that goes. I'm being told that the Maximus tear up the drives a lot quicker....

Using playing cards for props will tear up an xr when hooked to 700’s. Good luck. Be gentle on the throttles.

:party-smiley-004:

.....let us know how the 34's work Im looking for a set

I'm betting the 34s are horrible. Run six blades spinning in. Diameter will depend on how much weight you have in the nose, excetera. Cabin. If it's a full cabin, I might consider pulling the padding out of the nose, and any other weight that's easy to remove. Otherwise, 6 blade will probably not work. Not sure who owns my old boat now, but it's the same set up, 600 turned up to 700s - on a light layup, 1/2 cabin with the high X dimension.

I did give my friend who owned the Finish Line boat at the timthe set of my 5 blade Maximus that were worked quite a bit. Carried the nose too much on my light boat, and worked well on his full cabin. Hope that helps!

How much HP are you running thru your xr’s?

Tooo much, Whipples website says around 780 with my configuration...........Boos tuned ECM's

Your TG is lighter than most, right? I just finished a pair of relatively mild na 615’s thinking they would land in the mid 600 range. They just dynoed 728 with big tq. They are going in a 34 Phantom which I’m guessing is around 8000#. The boat has new ITS XR’s with drive guardians and is rigged and heading out west in a couple weeks, so no time for a plan B.

no high jack DawgMode.............7800# hoodoo

Yes and my apologies to the op, carry on.

time for SCXs

I bought a 39 TG last year that has 600 SCI's with XRs. When I bought the boat the ECUs had a 700 tune (was told the engines were converted to 700s) and would always set off the alarm due to still having 600 cams. Over the winter, the correct cams went in as well as SCX drives.

With that said, I have no clue what hp my engines were making last year, for arguments sake, lets say 650 hp. 32 pitch bravos were a joke. At half throttle I was on the limiters at 90 mph. I then bought a new set of 34p Bravos. The 34's were better but still on the limiter at 3/4 throttle but now 93 mph. Then I tried a new set of Bravo 36 props. TERRIBLE, anything over 50 and they would blow out. I ended up with a set of factory labbed Maximus ST 34 props. These worked well but still on limiters at 3/4 throttle and now 96 mph. New drives lasted 12 hours and my port drive broke a tooth and destroyed the upper. I didn't even bother to fix it, as I knew the drive would just blow again. Bravos are too weak for a 39 with 600 plus hp.

I'm about to have my boat back in the water and test new props. The refreshed endings now have the right cams, and a stage 2 tune from Boos, so 800 hp now, full SCX drives and Drive Guardians. Props I have to test are Merc Racing 16.75 x 35 hering labbed 4 blades, 16" x 34 Merc Racing 5 blades, and a pair of 35 Hydromotive P5X props. The nice thing with with the 1 7/16" shaft is you can run bravo and SSM 6 props.

With your set up, if your rev limiter is turned up to 6k, you may be able to find enough prop. If you are stock, there is no way any bravo style prop will work. I tested them all last year, and none would keep me under 5400. Your best bet is going to be sell your XR uppers and run SCX uppers and use your sport master lowers. If you go that route though, you will need to re-gear the lower unless you bump the limiter.

I'll report back on my set up hopefully next weekend. I feel your prop pain, as I went through it all on my boat last summer.

Yes it is!

The limiters are at 6300 so I will see what happens. I know that I am playing with fire with the XRs but will "try" to take it easy on them and when they blow, I will upgrade to the IMCOs.

If you can swing it, upgrade now. When my drive blew, and I babied them, the entire upper was junk. It was not rebuildable in the slightest. You can probably get $10k for your uppers, and put that towards the SCX uppers. Once they blow, and they will, you wil get nothing for it. Either way, the 39 is an awesome boat, and you will love it! With 6300 RPM limiter, you have a lot of room for standard props.

Yes- Sell NOW before you eat them. I rebuild my XRs 4-5-6 times- Total waste of $$. Get out Now lol

Just came back from seatrial and she did 97mph hitting the rev limiters with the 34 Bravo's so I'm thinking of trying a pair of 36's. Let me know your thoughts.

My everyday props ran 97/98 MPH and the fast ones ran 101 MPH on stock 600 Mercs. 6 blades and never a drive failure.
https://cimg1.ibsrv.net/gimg/www.off...4c8423ffcc.jpg
https://cimg3.ibsrv.net/gimg/www.off...679ef6204a.jpg

What are the specs of your 6 blade props?