Alpha1 Gen2 outdrive ratio question

[Wrfd306]

I'm sure this topic has been discussed but I cant seem to find an answer. I have a Maxum 2400SC3 that I want to replace the outdrive on. It currently has a 5.0 mpi engine with a 1.61 ratio Alpha1 gen2. I am replacing the outdrive this year. Problem is that I plan to replace the motor within a year or two. When I do I am gonna upgrade to a 5.7 mpi. The 5.7 calls for a 1.47 ratio outdrive. My question is, can I get away with running a 1.47 ratio drive on the 5.0 for a couple seasons. Is it possible to make it work with the correct prop?

 

[Scott06]

I would think if you buy the 1.47 ratio drive and get a prop 2" lower pitch you will have about the same rpm and performance that you do now assuming it is properly pitched and hitting the correct WOT RPM.

I repowered a 4.3 V6 boat (21 ft searay bowrider) with a 5.0 carbed engine, kept the 1.81 ratio and works fine by stepping from a 19" to 21" pitch. I dont think you can prop around all drive ratio mis-matches but in my epxerince one ratio step can be proped around.

 

[Wrfd306]

Thanks, that is what I was hoping to hear.

 

[Rick Stephens]

Agree with Scott. Either ratio is going to work fine. Just need to prop accordingly.

 

[achris]

I'm sure this topic has been discussed but I cant seem to find an answer. I have a Maxum 2400SC3 that I want to replace the outdrive on. It currently has a 5.0 mpi engine with a 1.61 ratio Alpha1 gen2. I am replacing the outdrive this year. Problem is that I plan to replace the motor within a year or two. When I do I am gonna upgrade to a 5.7 mpi. The 5.7 calls for a 1.47 ratio outdrive. My question is, can I get away with running a 1.47 ratio drive on the 5.0 for a couple seasons. Is it possible to make it work with the correct prop?

Keep the existing drive ratio (1.61) and prop up to keep the right rpm at WOT. Higher pitch props tend to be slightly more efficient. The difference is only 9.5%. I suspect you're already running a fairly low pitch given a 5L in a 24' boat. Running the same ratio with the 5.7 engine will get you up a couple of inches (in pitch), and that is only a good thing.

Chris....

 

[dan t.]

As achris said stick with the 1.6. I repowered from a 5.0 l to a 5.7l and kept the 1.65 ratio leg, just piched up from a 16x16 to a15.5 x18, worked great.