MikeScarab28XLT

Hello,

I'm from Germany and a need your help !!

Nobody can help me in Germany !!

I have a setup:

Boat 28"
twin 502EFI and Bravo One Drives (1,50 ratio) spinning 26" Bravo@ 5000RPM oder 27" Mirage lap @ 5000RPM

now my Question:

if i swap to a 1,36 gear, what make my RPM and what prop i need ???
What speed do you think ???

Thank you for all answers !!

audacity

nothing justifies a gear change in this application...hull size/x-dim/hp/props...

z.zuperboat

With A 1;36 Gear You Will Need A 24 Bravo Or 25 Mirage.top End Should Be The Same Or Alittle Slower And The Acceleration Will Be Slower.1.50 And 28,s Are Perfect For A 28 Foot.if You Want To Go Faster Have The Props Redone To Spin In Not Out And Swap The Drives.that Should Give You More Bow Lift And More Speed.alittle Less Control.that Worked On My 28 Pantera.new Gears And Props Should Cost About 5k For No Reason To Change Or $600 To Have Props Re Worked And Swap Drives. Good Luck

audacity

why would he need to swap drives???

MESABALANCING

SOME ELSE HAD ASKED SIMILAR QUESTION ABOUT A COUPLE OF WEEKS AGO AND I GAVE THE SAME OPINION THEN IF THE ENGINE DOES NOT MAKE OVER 750 TO 800 FT LBS OF TORQUE WE HAVEN'T SEEN ANY PERFORMANCE GAINS BECAUSE YOUR SIMPLY GOING TO NEED TO TURN A SMALLER DIA. PROP AND THAT ULTIMATELY WILL MOST LIKELY HURT THE PERFORMANCE AS FAR AS MANEUVERABILITY AND POSSIBLY TOP SPEED . WE EVAN TESTED 5 BLADE PROPS WITH THAT RATIO IN A 28 WE RACE AND DID NOT SEE ANY IMPROVEMENT .I THINK IF YOUR LOOKING FOR SPEED THE BEST WAY IS MORE POWER WITH THE SET UP YOU HAVE.GOOD LUCK LAZ MESA WWW.MESABALANCING.COM

z.zuperboat

I Guess You Could Run Them In Reverse But I Was Told It Puts Alot Of Pressure On The Top Cap.so I Prefer To Swap Drives

MikeScarab28XLT

@ audacity

OK that means i have to littel HP !!

@ z.zuperboat

Drive swap ?? Oh you mean change props from left to right !!

I have make it !! That are 2-3 km/h only !!

Props re work in germany are 1200$ for one Prop !!

I have 2 Mirage 27" from Mike J. this are lap props and they run 2 km/h more than the Bravos 26". But i like the acceleration more from the Bravos !!






Another question !!

I have a Data link wire from 1. engine to 2. engine !!! And i have the Rinda Diacom Software on it !! At WOT the engine with the sterring makes 300 rpm les then the other !!! only diffrent i can see are the IAC data !! Idle air control bypass !!! At WOT shout it be open ore closed ???

I have attached the data file from the engines, can anybody read a wrong thing out of it ???

MikeScarab28XLT

@ MESA BALANCING

you mean too, i have to less HP !! I mean it too !!

Do you now at twin setup how many RPM i go down with 1" more ??
At singel 300 RPM down, at twin the same ???

If i drive 28" Bravo with 4700 RPM that only 2 kmh but at 4800 that 4 kmh more !!

my prop rotation on the picture:

audacity

"I Guess You Could Run Them In Reverse But I Was Told It Puts Alot Of Pressure On The Top Cap.so I Prefer To Swap Drives"

dude...you swap the drives and all your going to do is turn the other side of the gear....switching your drive side to side and changing your props will still result in having to run in reverse!!!

"I Guess You Could Run Them In Reverse But I Was Told It Puts Alot Of Pressure On The Top Cap."....what r u talking about!??...if you have counter rotating props....one side uses the top gear(load) and the other the bottom...maybe you have counter rotating engines?LOL

MadMat

Propeller Revolutions in the UK might be able to help you, they do a lot of blue printing work, and it should be fairly cheap to send the props to them from germany. http://www.proprevs.com/
Cheers
Matt