SD
The Torque Converter in any Car/Boat simply takes the place of the clutch. The torque converter is what allows you to have the car in "Drive" while you are stopped at a red light and the engine still runs. If you did this with a "clutch car" the engine would die. Simply put, there are torque converters COUPLED to transmissions (these are the thingys that change gears), the converter has nothing to do with changing gears.

The reason that Automatic trans cars in the old days got worse milage than manual trans was the fact that until they developed "lock-up" devices in the converters, these bad boys slipped all the time (not much slipage, but enough to cost the car a mile-per-gallon or two, compared to identical Manual trans car) when both manual and automatic car had the exact same rear end ratio.

Unless you consider mutliplication by a number less than 1, torque converters don't "multiply" anything. On the other hand, that is one of the primary jobs of a transmission.

I stand corrected after reviewing your link. I didn't know that they typically had a reduction built into them. I thought they were just fluid couplers. You learn something everyday.

John

There isn't a reduction built into them, they are just a fluid coupler. Their design is such that torque is multiplied through the fluid coupling. Fluid mechanics was not my best class in school, so I may not be able to explain it very well, but torque can be multiplied through this fluid coupling.

You do lose POWER through a torque converter. Power is derived from torque and RPM, actually TQ(in ft.lbs) x RPM / 5252 = HP. In the torque converter, you lose RPM but you gain torque. You lose enough RPM, though, that there's a net loss in power.

Some aftermarket torque converter manufacturers advertise a 2.7 torque multiplication ratio, or more.

We are in the process of converting two seperate boats, one is a 42' Sonic SS and the other a 28' Wellcraft St. Tropez. Both will feature twin 6.6 liter Duramax engines, LBZ blocks. The St. Tropez will run a stock 360 hp, the Sonic will be in the neighborhood of 400-500 hp after tuning from PPE.

The cooling systems have been the biggest issues, although when you get down to the basics of how a turbo diesel works, there isn't anything, with the exception of the water cooled manifolds, that hasn't already been designed.

The other issue is the CAN system, which there is stand alone management available from PPE.

Both projects are in the works, I'll let you know how they work out. When you get right down to it, its just a pair of diesel engines in a boat.

Banks had them on display in Miami in the convention center.
They were the 6.6 Liter V-8 Diesel Marine Engine. They looked great the website is banksmarine.com

We have also been speaking with PPE on a Duramax Project. We got a parts list for two builds. One for a 600 hp motor and the other for a 700-850 hp. Both are single turbo applications with a Closed Cooling system ,front mounted intercooler and Dry exhaust manifolds.

Guilderoy,

How much are you going to be in the project for twins? What boat are you planning to put the bigger motors into?

Is this project going anywhere?

Most of the bolt on parts are out there but still isn't happening enough to bring the prices down on the fully built crate motors

It's funny how this has been talked about for a decade now, with lots of promises of components and marinized engines, but nothing ever materializes. I don't think the demand is there at the price point diesels come in at for a smaller recreational boat once everything required is in place, including HD drives, emissions equipment, etc. The only places I see diesels are sailboats and large cruisers. The diesel sailboat engines are small, and not too expensive. Large cruisers are expensive boats to begin with, so the cost is easily buried in the price. Both categories use straight inboard drives, so there is little additional cost to beef up the drive configuration to handle diesel torque.

Example:

Chaparral 225 SSi with Mercruiser 220 hp V6 gasoline engine = $43,105.

Same boat with Volvo 2.4L 200 hp 4 cylinder diesel = $72,707

That's almost $30,000 more! Now consider, most people put less than 100 hours a year on their boat. You'd never get your money back.

Michael