Technical Hydramatic\Hydro-Stick Torus differances

Ok hydro gurus lets have a discussion about torus styles. I'm the lucky owner of a B&M Hydro-Stick and from what Ive been told it will have a very high stall speed due to the torus in it (Picture s-l1602). So i started going down the rabbet hole of how to manipulate stall speeds by mix and matching drive & driven torus as stated in the B&M literature (Picture 1943) thanks willys36.

From what I understand the height of the fins in the torus dictates stall speed and apparently per B&M literature that is true for both the drive & driven torus. My plan was to use the stock driven torus (picture Torus 3) and keep the B&M modified drive torus(Picture s-l1602) to lower the stall speed.

Now for what has thrown me for a loop and prompted this post, while watching a rebuild video, the gentleman (John Dodd) working on a hydro that when he pulls the torus apart they both have shaved fins in the center just like my driven torus (picture torus 1 & 2). So what gives?? if I understand he concept of how the fluid coupling work and I believe I do. wouldn't this unit have an unbelievable high stall. I have also seen these no center finned torus in other videos and believe there are stock units.

Please help me understand whats going on here and how this magic works.

Thanks in advance

 

That thing will not couple very quickly and so it seems to me it would be a very high "Stall" unit. Not a Hydro expert but I am just speculating based on torque converter experiences.

 

Very interesting. My torus wheels don’t have three distinct sections like the ones shown they both have full blades like this.

This is where we need a transmission guy who actually built these things to chime in.

 

That excerpt from the B&M catalog in the first post tells what stall speed you can expect from trimmed tori. The page also warns caution in using anything but a stock set of wheels on a street driven vehicle. Hydros don't need cooling due to the efficiency of their tori design but when you tron them, the stall goes up as listed due to lots of slippage and concurrent fluid heating. Definitely don't ust two trimmed tori on anything but a race car.

The tori with the 3 sections are from Olds, Pontiac, and othe passenger cars. The torus shown above with plain fins is from the Chevy tranny. The latter is the most desirable since it is a bit smaller diameter yielding a bit more stall speed without having to trim the vanes.