Horse Power and RPM's

[stud_rudd]

Ok so I dont quite get the concept of Horse power and RPM's. Here is what i am wondering. At 6000 RPMs my boat will push 80 MPH. What is moving at 6000 RPM's. Is it the pistons, the drive shaft, or what. Now if I add a blower to the engine, I know it will greatly increase my Horse power, but at 6000 rpm's will i go any faster then 80 mph.

 

[duanehydro]

pardon? :huh:

 

[stud_rudd]

If my driveshaft is spinning at 6000 rpm's and it is making my boat move 80 mph... then whats the difference in having a BBF 533 versus a SBC 350 if 6000 makes it go 80mph

 

[duanehydro]

If you are turning your pump 6,000 (assuming your tach in on)  installing a blower (adding HP) will accelerate faster, but the rpm will increase substantially...upon adding more motor, I'd ad a taller impeller to flow more water @ less RPM.

If my driveshaft is spinning at 6000 rpm's and it is making my boat move 80 mph... then whats the difference in having a BBF 533 versus a SBC 350 if 6000 makes it go 80mph

it's all about torque, and having the top end horsepower to pull past the torque band...

 

[3boatpaul]

:huh: horse power  ?? just a number , torque is the power motivator  with that you are able to run bigger gears , props  or impelers  rpm 's the more you got the faster you go  may be wrong have been before 
:smile23:  that is my DISCLAMER  :smile17:

 

[stud_rudd]

So my jet has an "A" impeller. Is there another impeller i can change it out with and get more.? If so where can i find one? thank you

 

[CorDog009]

 

[3boatpaul]

oop's sorry duana  we were posting at the same time  :smile23: it is still a torque and rpm game . the more r' s you make the faster you go  BUT the motor has got to make  the power to do it big blocks  start off making more torque than a small block

 

[duanehydro]

So my jet has an "A" impeller. Is there another impeller i can change it out with and get more.? If so where can i find one? thank you

AA stainless, and I'd add an inducer, for a blown 533 bbf- < my suggestion. while you are at it, I'd change to a hardened shaft as well. which type loader is in the boat? Shoe? :smile11: Paul, no problem, your input is valuable!

 

[duanehydro]

btw, 80 is damn respectable for a jetboat. :smile15:

 

[badblood]

80 is ok. but to answer your question. If you change motors and keep the same impeller and still turn 6000 you will still go 80.
Math class is just starting. Now if you change to a AA impeller and turn 6000rpm you will be going faster. You dont need a bigger impeller to go faster, just put some more power to it and turn more rpms. A well built big block should have no problem with 7000 rpms.  It just has to make enough power and torque at that rpm range to get there. Are you confused yet? A good power adder is nitrous and it is cheap power. You can pick up 10mph for about 1k. Lets see you do that with any other speed parts. My old gull wing jet ran 86 on the motor and 98 on the spray with a pump gas 468 bbc.