Gear Change and RPM ????

[Brazos River Rat]

Changing from 22 gears to 15 gears, How much RPM will this increase me.
Currently running 22% gears and 11x 16 two blade prop .
Thanks for the help...

[Carnivalride]

Depending on set up and engine rpm approx 400rpm

[Brazos River Rat]

Currently running 5500 RPM with 22% gear and 11x16 prop in a cole TR4.

[superdave013]

That's a HUGE jump in gears. Sounds like the right direction to go.
22%, 20% (very rare and I don't know why), 18% and then the 15's
You will have a totaly different boat when you drop the gear that much. That jet boat that get's ya off the line will have a supprise the next time!

[Brazos River Rat]

That's a HUGE jump in gears. Sounds like the right direction to go.
22%, 20% (very rare and I don't know why), 18% and then the 15's
You will have a totaly different boat when you drop the gear that much. That jet boat that get's ya off the line will have a supprise the next time!
Thanks :
15 gears is what J.J reecommend. I think it will really wake the boat up.
Just don't want to turn more that 6200 RPM.
J.J pulled it apart this morning and it does have 22 in it..

[beaverfab]

SUPERDave cole runner,lake layup. :: 454 30 over 475, 525 hp. will start with 15's then if he pulls them to far then 18's, with the 22's puled 5500rpm, this should get 600 to 700 more r's. What do you think?

[superdave013]

I think some 12's and get R in the 7,000 range.
Hey, you are the expert, not me for sure. Sounds like you have him on the right track though. Just my $-0.01

[beaverfab]

How is your boat coming? Miss all the nice pictures. Thanks for the nice words but I am no expert just a gas mokeny. j.j.

[Carnivalride]

Let me know what you get without knowing cam and engine set up I can't guess for sure but using the math (5500x1.22)/1.15 and 'gut feel' I'm sticking with my original guess at 400rpm increase and maybe 500rpm. I ran a similar sounding set up and went from 1.18s to 1.09s it picked up 4/10th at the drags on the first 1/8th
Good luck!

[Brazos River Rat]

I don't think my poor motor would handle 7000., no way. That is why I want it around 6200, It just a lake boat..
Thanks J.J.
Will pick it up Thursday around 3:00