Transmission for a Jet Drive

[cyclone]

Has anyone ever tried or considered trying to install a Gear Vendors overdrive/underdrive unit in front of a jet pump? I was looking at a boat that had a setback Berkely pump the other day and it looked like there would be enough room to do it. Its only about the size of a football. Having 3 gears would be so cool. I can't believe that no one ever came up with something similar to this by now. Seems like it would be the hot ticket for a jetboat-excellent acceleration and top end capability. Oh yeah, I have an OFFENHAUSER TUNNEL RAM FOR AN OLDS MOTOR FOR SALE.

[superdave013]

I have seen a few with a Casale Z-drives. It's like a v-drive but the shafts are parallel to each other and the top shaft sticks out of the front case.

[pgf127rt]

cyclone, Steve Brule who used to drive the Pro Gas Jet, Head Over Heels ran one with so much success that it was banned from the class, I think he is in California now working for a hi-po engine guru.

[Ghighway]

I also know of a PGJ running a reduction gear so motor stays in optimum rpm range (8000rpm) and pump stays in its optimum range. I don't think there is much use for a tranny on a jet. Need more acceleration = load the pump better, need more rpm = build more hp. Need more speed = load the pump, kick up the hp & free up the boat all of these things work just cost $$$$$$$$$$$

[cyclone]

Thanks for the info guys! I'm going to call up Steve and see what he did. If case you need to know, he now works at Westech Performance in Norco, dynoing and building hi-dollar engines.

[greg shoemaker]

Not aware of any trans that has been banned from racing. The problem has always been to much power losts thru the trans. Carrera built a boat for gear venders and Ispent a lot of time trying different combinations but was never able to generate the same perf without the trans. Kieth Zellmer currently runs an overdrive or underdrive it i just depends on how you interpet the installation. In Kieths case it has been quite sucessful. Greg Shoemaker