B3 question
 

Wasn't sure to post here or on the drive forum

not an issue yet, but my current cruiser has a B-3 /1.8 turning a 22p at 4700rpm the drive housing is pretty corroded from poor maint by last owner and prob on it's last year of svc. I picked up a newer B3 with a 2.2 ratio. Would you run this drive on a 9klb cruiser and if so what props? I have some 24" but thinking i'm going to need 26". Or, have the new drive lower fitted to 1.8 ratio? I already replaced the transom assy fyi.

What engine are you running?

And what is your speed?(GPS)
Is it the 3+3 blade or the 4+3 blade setup?
Is it the type with or without cup?

Anyway.

If you are fx. running 46.5 mph with 14% slip @ 4700 you will need to go up to a 27 to stay close to the 4700 rpm's. If you run a 26" you will run about 4850 rpms. The 24" will put you at more than 5200 so that sounds like an incorrect choise.

Gps speed is 46mph on full tank 4 people. Motor is a gen6 330 with a mag cam/ valvetrain and ecu cal by Mark at PME. It is a 3+3 with cup setup currently

BIII cases corrode quickly and badly, especially in salt water. It's possible the internals are fine on yours and you could simply swap the gears.
If you simply install the 2.2 try the 24's. It's likely you'll have to have them worked. If you find yourself within 300-400 rpms the props can be altered to work well for you.

I will give the 2.2 x 24"/3 a try. What performance issues good or bad usually result from a change like this? does it change my torque profile? Planing rmp change? Just curious

The lower gears will aid in stronger throttle response even with taller propellers.
Test 24's but I think you will need the 26's.

Brett

thanks