Sx to dps ratio`s

[BRICH1260]

I am contemplating a swap out of my `02 VP SX-M to a DPS lower unit. My current sx-m gear ratio is a 1.60. What DPS gear ratio should I look for to be a close equivilant. Thanks.

 

[HalfFish5087]

Re: Sx to dps ratio`s

I have 1.95 which is turned by a 5.7GS, not sure if it would be the same for EFI or larger motors.

 

[Walt T]

Re: Sx to dps ratio`s

What engine? Are you at altitude? What boat? I too have 1.95 with a 5.7 Running C7 steel props at 5000 feet, modified engine. 22 foot Cuddy.

 

[billbayliner]

Re: Sx to dps ratio`s

Walt, if you are running "C" props, you have an AQ series drive (main suspension fork & pivot tube geometry)
The OP is asking about a DP-S (gimbal system) drive.
I agree, the ratio will be very similar if not the same.

BRICH, *short of an extremely lightweight and nimble hull, your engine will determine the final and overall drive ratio.
If this is a very typical 24 footer, the 1.95:1 is going to be correct for a 5.7L engine.

You will need to test an array of propeller sets, and perform your WOT RPM testing just as you would with your single prop drive.

 

[BRICH1260]

Re: Sx to dps ratio`s

I have the 5.0 270 hp engine if that is needed to make a determination.

 

[saintlee]

Re: Sx to dps ratio`s

I switched my 24 glastron powered by 5.0 gl carbed engine, sx drive to a 1.95 dps.
Don s recommended it. I run F5 ss props. Best move ever.

 

[saintlee]

Re: Sx to dps ratio`s

-You will plane out faster and at lower rpms
-hold plane at lower rps
-backing into slip easier
-zero prop walk
-better mpg
-and you only have to swap out the lower end
not the whole drive

 

[Walt T]

Re: Sx to dps ratio`s

Well worth the cost, you'll love it.

 

[BRICH1260]

Re: Sx to dps ratio`s

In my shopping around for used lower DPS units, I see where some units are marked Helical splines and some are straight. Can someone inform me if the Helical cuts are preferred over straight. It seems like it would be harder to find props to fit the Helical cut.