39TG prop selection
05-31-2021 | 12:51 PM
#11
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From: Midwest & T-Rock
05-31-2021 | 01:32 PM
#12
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From: Sarasota FL. Priest River ID
06-01-2021 | 06:03 AM
#16
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From: Chicago, IL; Onekama, MI
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.
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.
Last edited by endeavour32; 06-02-2021 at 06:37 AM.
06-01-2021 | 08:42 AM
#18
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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 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.
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 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.
06-01-2021 | 09:30 AM
#19
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Joined: May 2009
Posts: 3,895
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From: Chicago, IL; Onekama, MI
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.
Last edited by endeavour32; 06-02-2021 at 06:31 AM.
