What gains should I expect with new 1.62 gears

[RobShaw]

2008 Allison BasSport Pro (2 seater). 2008 Merc 250XS (top speed with the 1.75 gears was 87+).

Props I ran with the 1.75 gears: 28 Hydromotive Quad IV X-OB, 30 Mazco RE-4, 27 Allison Cut Trophy from Performance Propeller.

Im thinking low to mid 90's, any thoughts?

Thanks

[LakeTrash]

If your setup was correct with the 1.75, changing to 1.62 will do nothing except lighten your wallet.

LT

[RBT]

probably have a loss in both top end and acceleration.

[THE HOSER]

probably have a loss in both top end and acceleration.


sorry but hes correct

[ANIMAL]

Big cube, high torque, low rpm motors on a lighter hull like yours love tall gears. You may or may not end up dropping a pitch or so, but you'll be much happier with the end result once you find the right combination. Been there, done that.

[props4u2]

Big cube, high torque, low rpm motors on a lighter hull like yours love tall gears. You may or may not end up dropping a pitch or so, but you'll be much happier with the end result once you find the right combination. Been there, done that.

One correct answer!!!
I must say I'm suprised at the other answers. Any of you ever tried this on the 3.0L engines?
The slower accelleration is correct also.

Lee

[RBT]

played with 1.62's on a 650lb drag rocket chasing top end.... lost
played with 1.62's on a 1200lb Tuff 21 with a 300X, lost top end... I don't have much other than that. I do have some hearsay from friends too though.
Try it, gears are cheap.

RT

[WILDMAN]

If you go with 1.62's and lower your pitch by 2", you'll be the same in the end. Changing props is easier than changing gears.

[props4u2]

Rob,
I have a 1.62 umit we can run on your boat.


Lee

[allyfreak2]

if with those props were on the revlimiter, yes 1.62 gears will help your topend but slow your acce.

[THE HOGG]

One correct answer!!!
I must say I'm suprised at the other answers. Any of you ever tried this on the 3.0L engines?
The slower accelleration is correct also.

Lee

I WENT FROM 1.87'S TO 1.62'S ON A SIMON BUILT 3 LITRE AND 1600 LB. VEGAS. I HAVE HAD SOME FAMILY PROBLEMS SO HAVENT GOT TO RUN IT MUCH YET BUT SO FAR I AM GETTING TO 101MPH 900 RPM'S LOWER THAN WITH THE 1.87'S WICH IS WHERE I WAS HITTING THE LIMITER BEFORE. I DID LOSE MOST ALL OF MY ACCLERATION AND SEAT OF THE PANTS FEEL WHEN I STOMP IT BUT I AM STILL RUNNING THE SAME 30P RE3 AS BEFORE SO IT IS EXPECTED. FUEL MILEAGE SEEMS TO BE A LITTLE BETTER AS WELL.

[hsbob]

if you were running out of prop pitch then going to a taller ratio may be the answer. go to the old land and sea site. they have a write up on the effect5 of ratio changes vs torque.

[beer30]

If you are running a 34" prop with 1.62, how could you go to 1.75 and not hit the limiter??:confused: Chuck

[THE HOGG]

If you are running a 34" prop with 1.62, how could you go to 1.75 and not hit the limiter??:confused: Chuck

???WHO????