4 Blade switch to 5 Blade ? Your experience

[LFarr]

I'm hearing good things from two guys who switched from Bravo1 4 blade to 5 Blade.

Better hole shot & improved stability.

One person with twins went faster, the other single engine application did not lose top speed.

Both guys were 500 + inch supercharged.

I'm running HP500, Progharged at 9psi, 5500 rpm 26p bravo1 prop, IMCO 2" shortie.

If you've switched 4 blade to 5 blade or know of someone who has.......I'd be real interested to know your experience....before & after.

Thanks......

[Hydrocruiser]

Originally Posted by LFarr

I'm hearing good things from two guys who switched from Bravo1 4 blade to 5 Blade.

Better hole shot & improved stability.

One person with twins went faster, the other single engine application did not lose top speed.

Both guys were 500 + inch supercharged.

I'm running HP500, Progharged at 9psi, 5500 rpm 26p bravo1 prop, IMCO 2" shortie.

If you've switched 4 blade to 5 blade or know of someone who has.......I'd be real interested to know your experience....before & after.

Thanks......

I saw a 38' Scarab...with a 5 blade gain some efficiency at cruise speeds and get on plane with a bit less strain on the engines. They went from a Mirage 3blade to a 5 blade...it was probably worth the money. The were not happy as top end was the same...they need more power.

[Pure Energy]

I went from 4 to 5 and picked up 6 mph at cruise. Due to engine problems I have not had the chance to run WOT. Single 30' superboat

[RLW]

Originally Posted by Pure Energy

I went from 4 to 5 and picked up 6 mph at cruise. Due to engine problems I have not had the chance to run WOT. Single 30' superboat

Pure Energy,
Would like to know your X dimension?
4 Blade prop make and pitch?
5 Blade prop make and pitch?
What power are you running in the Superboat?

I tried a 25P P-5X and had good take off/holeshot. Cruise was slower by 1 mph, than my 26P Bravo. Top speed was also slower with P-5X.
It seems that most people have good results going to a 5 blade from a 4 blade prop. I seem to be the exception with my 1989 27' Activator. Also, propshaft is 5.25" below keel.
Have to try one (or two) to find out.

[Pure Energy]

X dim is 1.5" higher than factory. Sorry that doesn't help but that's all I know

4 blade was a 26
5 blade is a 25
Hp was probably high 5s, but has just been rebuilt and dynoed 610 hp and 635 torque

Boat will be done this week so I will give better details next Monday. Shoot me a PM and remind me.

Also you might want to PM Titan. I think he had a 27 Activator and he may have some tips for you.

[RLW]

Thanks for the feedback!

[zt260]

From my experience you need big HP and a higher X-dim to make a 5 blade work better than a 4 blade.

I went from a bravo to a maximus and added a 2" shorty. I'm running 1300HP in a 26' checkmate and I like everything about this 5 blade. Hole shot is good the cruise is better and I gained 2mph WOT. My prop shaft is now only 3 1/2" below the hull.

BTW Blades labbed it to get these results.

I would give it a try, based on your info. Good Luck!

[RLW]

ZT260,
What 5 blade are you running?
What numbers are you seeing, as in RPM and speed?
Russ

[zt260]

It's a 26" Mercury Maximus. 1.3 ratio at 6200rpm I was running 103mph with the 2" shorty Bmax drive. Works out to be about 12% slip. With a standard length drive I was at 9% slip, but it was 3 mph slower.

I've since increased boost and labbed the prop again for more rpm. The new top speed is still under wrap. I still have a smart azz by me that needs to go down.

In a week or two, I can give you all the new numbers.

[Prowler]

hmmmmm i wonder who that smart azz is ?