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Gear ratios in alpha one gen 1

87concord

87concord

Regular Contributor
what would be the best gear ra

what would be the best gear ratio for higher top speed in a gen1 aplha one drive and how do you tell what ratio you alredy have
 
it is based on the engine disp

it is based on the engine displacement typically.

small block v8's used 1.5 to 1 on the gen 1's
i am to tired to remember the others.

if you change gear ratios you will have to change the prop pitch and it may become a large changed based on the ratio you use.
 
"You will not get more top end

"You will not get more top end out of a gear change. As long as your current prop gives you book rpm at WOT; that's it; there ain't no more.

The only recipe for more top end is more hp. And you will only get the square root of the power increase in top end increase. Example: If you increase your shaft hp by 50%, you will only get a 22% increase in top end. Nasty, huh?

The ratio should be on the decal top port side of the drive.
1.32/1.29 for big block V-8's
1.50/1.47 for small block V-8's
1.84/1.81 for 4.3 V-6
1.65/1.62 for I-6's
1.98/1.94 for I-4's

Rod"
 
"got ya, kinda like the rearen

"got ya, kinda like the rearend of car. doesnt matter what gears you have if you dont have the ass to back it up"
 
"David;
Kind of like that.
T

"David;
Kind of like that.
The big problem with boats is that the drag of the water increases as the square of the increase in speed. Wind resistance is a lesser factor.

Unlike a car where the rolling resistance does not increase much with speed. Wind resistance does increase with speed, and at the point your power and wind resistance balance, that is your top speed limit for a car, on level ground.

Rod"
 
"Yes, but at the point where y

"Yes, but at the point where your water drag equals your avilable power, that's it, there is no more. And that won't change regardless of drive ratio.

A higher numerical ratio drive can turn a higher pitch prop and produce the same speed, as the prop will be turning slower.

If you try to swing too mcuh prop for your drive ratio and available power, the engine lugs and your hole shot is lousy. Takes a long time to plane out.

Rod"
 
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