justincase
Well-known member
hmmm, Matt thats what the speedo is showin is 54
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prop question for an o/b guru
- Thread starter justincase
- Start date
ross
Well-known member
matt is on the right track...... but i WILL say that when you start playing w/ prop-shaft heights and props you have to watch your rpm-slip #'s! this can get a lil complicated and pricey as you buy lots of props
also when you buy the jackplate/ setback i would advise you to buy water intake scoops!!!!!!! pm me i you want the info or google search them for mercs
they work AWESOME!!!!! and keep your water pressure where it needs to be
also when you buy the jackplate/ setback i would advise you to buy water intake scoops!!!!!!! pm me i you want the info or google search them for mercs
they work AWESOME!!!!! and keep your water pressure where it needs to be
justincase
Well-known member
Ross, when i get the jp ill get the scoops ive been looking and saw a big price swing but if i remember you got them cheap, ill pm you later. thanks everyone!matt is on the right track...... but i WILL say that when you start playing w/ prop-shaft heights and props you have to watch your rpm-slip #'s! this can get a lil complicated and pricey as you buy lots of props
also when you buy the jackplate/ setback i would advise you to buy water intake scoops!!!!!!! pm me i you want the info or google search them for mercs
illMATTic
Well-known member
justincase
Well-known member
actually with no jp and 23p prop with 8.085 slip it would be 59.1 mph
illMATTic
Well-known member
actually with no jp and 23p prop with 8.085 slip it would be 59.1 mph
If you have the power to turn it with this setup. If not. You will lose some rpm.
justincase
Well-known member
well thats kinda what i want to know, i have excellent holeshot and up on plane in seconds, just wondered how much hole i will lose
justincase
Well-known member
Drink a red one for me, i just opened a blue moon
Sam I am
Well-known member
OK, you MUST geta GPS reading this season.
My best guess at your speed right now is 54 mph. How did I arrive at this speed? I will tell you.
5900 rpm, 2-1 gears, 21P, 8% slip, nets you 54MPH.
You may even be turning higher rpms at times since the tach could be maxed out and not even know it.
Jackplate + 23P prop = MORE SPEED
I hate to ask a dumb question, but is that for all 21P set ups? So I'm only pushing 54 mph on my pulse?! Oh no...can my speedo really be 10 mph off? Man...
ross
Well-known member
depends on your gears in the lower, prop slip, and rpm's.......
go to mercury racing's website and use there prop slip calculator.........
http://www.mercuryracing.com/propellers/propslipcalculator.php
Vandalizer
Well-known member
This thread exploded!!
justincase- Since you're running almost at 6k, I'm sure you can gain some significant speed by going to a 23p and pushing the motor back and up. A bunch of the other Exciter guys are finding that they like 8-10" setback- just make sure you give that transom a good look first.
Sam- The calculators are only good for one specific setup- hull, motor, prop, setback, height. If you use your WOT engine speed, gear ratio, and prop pitch you can guess the slip to be between 5-10% and see how close your speedo is. GPS is much better though!!
justincase- Since you're running almost at 6k, I'm sure you can gain some significant speed by going to a 23p and pushing the motor back and up. A bunch of the other Exciter guys are finding that they like 8-10" setback- just make sure you give that transom a good look first.
Sam- The calculators are only good for one specific setup- hull, motor, prop, setback, height. If you use your WOT engine speed, gear ratio, and prop pitch you can guess the slip to be between 5-10% and see how close your speedo is. GPS is much better though!!