Installed Torque Shift Prop today...

[cecho]

I love it!

Engine goes right up to about 4K RPM and slowly goes to 4400 RPM by full throttle. Getting out at the hole at full throttle while at a high RPM is really a great feeling. The prop is also allowing me to plane about 5 MPH slower than my 17 pitch prop did. The prop works amazingly well at full throttle. It also feels like running an automatic transmission in a cruise. Giving it throttle speeds it up, once I get to the speed I want I lower the throttle. Odd feeling.


My questions is about partial throttle use. If I give it just enough gas to plane it seems to never want to cruise at anything but 20 - 25 MPH. I have to give it quite a bit of gas to get it to shift it seems... one trip to full throttle seems to fix the problem every time, but I'm hoping to figure out what I can do, if anything, to get it to shift at cruise speed without getting up to 4K RPM. If this is how the prop works than that's fine, but I thought I'd at least ask about it.

 

[steelespike]

Re: Installed Torque Shift Prop today...

I'm no Torque Shift expert but from my reading over the years I do believe the shift point is adjustable ,I think with a part change,
It does take a certain rpm to shift.Kind of like od on an automatic transmission.It won't go into od until about 40.
Your prop is apparently set for 4000.Once there it will stay until you lower the rpm to a down shift point I'm thinking that you could note that point if you gradually slow until it shifts.

 

[cecho]

Re: Installed Torque Shift Prop today...

I'm looking into it more. It looks like if you have a rough diffuser ring it can cause the symptoms I'm describing. I hit a bit 'o mud at the dock while in reverse yesterday and broke a small piece off the diffuser ring. I'm guessing a new one will solve the issue.


Why doesn't anyone make a shifting prop anymore? Acceleration + Top end and efficiency all in one package seems like a pretty sweet deal.

 

[arks]

Re: Installed Torque Shift Prop today...

I used a Torque Shift prop for awhile on a 23 foot I/O. The shift point can be changed by changing springs, cams and/or blades. I found it difficult to find the 'sweet spot', but it did work pretty well.

Here's a site that sells replacement parts (not cheap BTW): Torque Shift Propeller Exchange

Why doesn't anyone make a shifting prop anymore? Acceleration + Top end and efficiency all in one package seems like a pretty sweet deal.

Because they were a LOT more expensive to build and buy (about $900 in the late 80's) compared to fixed props.

 

[Bondo]

Re: Installed Torque Shift Prop today...

Ayuh,.... I've managed to pick up 4 of 'em over the years,....

1 is ready to go,... 2 are serviceable, 'n 1 is parts are this point,...

1 of the SSteel adjustin' screws is seized in the aluminum hub,...
I've been tryin' different "Tricks" on it for a few years now,....
It sits by the drill press, soakin' in whatever penetratin' oil I sprayed it with last...

Bob's got some nice archives at his website to learn 'bout tunin' yer prop,...
I've chatted with 'im a few times,...
Glad he came outa retirement to carry on the Torque-Shift tradition, myself.....

I love mine for Trollin' purposes,... 11" pitch helps Alot to keep my speeds down, but rpms up abit,...
I'm runnin' the extra heavy springs to hold it in a lower gear, longer...
If it don't shift up, I just over trim the drive to blow it out abit, 'n ya hear it Up shift, then trim back down...

 

[wire2]

Re: Installed Torque Shift Prop today...

I used one for a couple of seasons, mostly out of curiosity. Hole shots are incredible due to the high initial rpm, but my top end didn't change much b/c I have a high hp/weight boat. The major drawback was that when the blades extend at high rpm, it creates a gap between the hub and blades. If you're in a weedy lake it grabs lots of 'em. And they don't all come out when you reverse, like a traditional prop.