Transmissions
 

Hi
very interesting and informative site, have learnt a lot and still need to learn more, so I can keep the mistakes to a minimum

I have a budget project that I'm working on
502" with twin turbos, aiming for 750 hp, 10-15 psi
arneson 1720 drive
V hull 22ft

need to install transmission/gearbox.
I undertand many of you run BAM/Huber Velvet drives, was original looking for 73C velvet, however understand these wont handle the torque Im looking at

I have 2 x crash boxes that just need bellbousing/drive plates, or a opportunity for DNE (Doug Nash) Transmission.
Cant find much on the DNE.
Understand the DNE would be better suited in docking at ramp
What sort of power can these transmission take?
and how user friendly is the crash box, as it doesnt seem to have a longer enough front spline/shaft to use a soft clutch on, so its on/off to change gear, although I was informed in you could get idel down below 800 rpm youre okay to change gear. With turbo's camshaft are not that raticle, around 0.630", and 250 duration, 114 lobe centres, so should have a reasonable tame idle

sorry for questions but still getting my sea legs, and figured I would ask for some feedback from those that know

cheers
Brett

I had a 516ci twin turbo set up in a 28' Aeromarine. I ran a B&M 2-speed and it was perfect. B&M no longer make this trans, but I have seen them out there for sale. I got mine from Brummett Marine in Cali.

Brett,

Are you using a v-drive?

You need to pay attention to your longitudinal CG placement.
"Doug Nash", do you mean the 5 speed or the 4 speed with overdrive unit like the 80's Corvette?

Jeff

Hallj
The boat originally had a leg in it; but its toast
I have arneson 1720 surface drive (older style) here was think of using this, after all have it. This is straight connection, and not drop box, so need to get motor,trans, low in boat
The Doug Nash looks like a beefed up velvet drive with a large sump capacity, (F-N-R), this I would have to buy, but going at reasonable price, or run the crash box I have, but not sure it will work with shifting without turning ignition off, these came out of larger 42' boat
This DNE transmission doesnt resemble any auto Doug Nash trans Ive seen, not sure whether they still make them of not........ just wantiung to know if anyone has run them successful as cant find anything about them, perhaps Im located in wrong part of the world
any help or comments would be apprechiated
cheers

Huber offers a trans with 1550 lb.-ft. capacity.
Are you planning on making more than that?

I have converted my 20 ft. Donzi to an Arneson.
If you install a Velvet drive without the standoff box, you may not be able to get the bow lift you're looking for. You may be able to set up an ignition cut to get the crash box in and out of gear. A multi plate clutch may be an option as well.

Jeff

Jeff

The DNE was an "aluminum" housing transmission that was similar in size to the Velvet drive. Came and went..

As Jeff pointed out you might want to consider finding a "V Drive" so that you can keep things compact and rearward in the boat.

You turn your engine 180 degrees, install the V drive with a velvet drive trans or similar to it on the v-drive and this will give you reduction which your boat will desperately need as well as reverse propeller rotation from the engine.