Discussion => The No Wake Zone => Topic started by: countryboyaustin on July 07, 2010, 07:10:34 PM
Title: Using a transmission with a pump?
Post by: countryboyaustin on July 07, 2010, 07:10:34 PM
Ok My question is If I designed my motor to fit further forward and my pump further back on a 21' daycruiser and put a 2 speed powerglide between the two wouldnt I be able to get a TREMENDOUS amount more top end out of a relative standard big block?
Title: Re: Using a transmission with a pump?
Post by: beerjet on July 07, 2010, 07:34:01 PM
You would have to stick the pump WAAAAAAAY back to offset the off balance the weight of the motor. If it was that easy, someone would have done it yeas ago.
-beerjet-
Title: Re: Using a transmission with a pump?
Post by: propless on July 07, 2010, 07:38:41 PM
Just curious, but why do you think you would get an increase in speed.
Title: Re: Using a transmission with a pump?
Post by: mash on it on July 07, 2010, 07:42:22 PM
Powerglide is 1:1 ratio 5000 rpm= 5000 rpm More weight in boat = slower boat
Title: Re: Using a transmission with a pump?
Post by: Brendella Pickle on July 07, 2010, 08:08:27 PM
You could have GV make you an overdrive... and just like it says above... if that was so easy, we'd all already have one.
Title: Re: Using a transmission with a pump?
Post by: countryboyaustin on July 07, 2010, 08:14:42 PM
My mistake A Powerglide was a poor example
Title: Re: Using a transmission with a pump?
Post by: beerjet on July 07, 2010, 08:16:38 PM
The reason V-Drives use them is because they have the option to over drive the final gear ratio through the gear box. Option we dont have.
-beerjet-
Title: Re: Using a transmission with a pump?
Post by: Oldsquirt on July 07, 2010, 08:48:36 PM
Ok My question is If I designed my motor to fit further forward and my pump further back on a 21' daycruiser and put a 2 speed powerglide between the two wouldnt I be able to get a TREMENDOUS amount more top end out of a relative standard big block?
Nope. You need to remember that transmissions don't multiply power. They do multiply force, in this case torque, at the expense of rpm(think LOW GEAR). They can also multiply rpm at the expense of torque(think OVERDRIVE). In each case , HP available at the output shaft is the same as the engine's HP at the crank MINUS the HP lost in the transmission.
Title: Re: Using a transmission with a pump?
Post by: HDriderTH on July 07, 2010, 09:05:05 PM
I just run the powerglide in low in the no wake zone, otherwise the boat'l idle like 15 MPH. Anywa, thats why I use one in a v-drive, otherwise drive is 1:1
Title: Re: Using a transmission with a pump?
Post by: stc315 on July 08, 2010, 07:35:50 AM
I looked into going with a Lenco single speed so that I would have a neutral for use out of water, but a Jet-a-way is cheaper. Still can't afford a Jetaway :banghead:
Title: Re: Using a transmission with a pump?
Post by: fast fred on July 08, 2010, 08:33:12 AM
In the case of a jetboat you dont want to overdrive it you want to underdrive it. By underdriving the pump it allows the motor to spin more RPM. Its only used in race applications. There is a Z-drive setup and theres one old racer i know that has is own contraption. I havent played with it yet but soon I hope to test with one in the new boat. Matt
Title: Re: Using a transmission with a pump?
Post by: GT Jets on July 08, 2010, 05:14:47 PM
FWIW, the pump curve for most Berkeley type pump impellers puts the optimum RPM at bout 5200 RPM, easily obtainable with any V8 internal combustion engine...(well almost any) ;)
Now when you are running a turbine that spins 26,000 RPM, then I would expect to see some sort of gear reduction...
The Z drive deal has been around for a while, I will still have to wait and see if the benefits out way the drawbacks....KISS.... :sly:
Perhaps the biggest performance gains that can be realized is with impeller design, you don't see much because the engineering is stupid expensive, as is the R and D phase...Just to sell a few hundred impellers a year would be an exercise in frustration because your design would be copied before you recouped your engineering costs....nature of the beast... :mad:
And yes....Been there and done that. :banghead: :banghead: :banghead: