Thread: Impeller pitch ??
04-05-2009, 06:41 PM #1
Impeller pitch ??
OK guys/gals, I understand very basics of the pitch numbers, etc.
Looking for some kind of comparison/explantion of the
numbers themselves and how they relate to top speed, acceleration,
out of hole, etc.
the larger the number on the pitch = less rpm, more top speed (assuming
you have the power to turn it)..
How is the 1st number on pitch compared to , like, gear ratios in a car.
Does a 14/19 and 15/19 have same top speed, but diff. bottom end??
Going from a 13/18 to 13/19 would just bring down rpm at top only?? as
compared to gong from a 13/18 to 14/18 does what??
These are just numbers I'm throwing out.. iknow specific skis, power combos
would react diff. in diff situations, But if all else werer equal and
we added/subtracted from each number, what is result.. Thanks
04-05-2009, 08:22 PM #2
- Join Date
- Jul 2007
- PDX - Oregon
I know for sure that the leading edge effects hole shot and the trailing edge effect top RPMs.
Pretty sure they each overlap the other... interested to see what others have to say.
04-06-2009, 11:19 AM #3
So if my rpms on top were ok and I wanted to get
a better holeshot then I should change
my pitch from 13/18.5 to a 14/18.5 ???
Would this keep my top speed and top rpms the same, but
just give me a better holeshot
04-06-2009, 11:59 AM #4
04-06-2009, 06:43 PM #5
04-06-2009, 07:15 PM #6
- Join Date
- Jul 2007
- PDX - Oregon
Shouldn't there be that fine line with the leading edge. If it's too steep and you pin it from stopped your boat will feel like it's working too hard. Where as if it isn't steep enough you will get prop spin... easy to tell because your RPMS will shoot straight up. It's how long the RPMs stay high before you start to fly that you want to pay attention to... I think?? HAHA...
These pros will chime in...
04-06-2009, 08:23 PM #7
I tried a 14/19 and was a little too tall in the heat anyway..
then I munched it in rocks.
So I bought a 13/18 and was on the limiter, but out of the hole was
Then I munched it with debri
I sent both to impros to repair and repitch.
He did them both similar (I think anyway).
I put in the 13/18.5 (added pitch to 13/1.
I'm fairly satisfied with results. Just thought I'd have
a little more top speed. rpms are 8080 in heat. But at
end of season, I added the ppg power pipe & deleted resonator
for shits and grins. I was very close to limiter.. got 8160 pretty
consistently at 69.x mph.
From what i've seen with other's mods, I really should be over
70 mph. I know I could put in an external I/C, but just
shy on funds now (wife losing job this month-16 yrs+).
I am getting my rpm's into the sweet spot, just not
getting the mph I think I should have/want.
So I though about putting in the other prop. It's a 14/19
with pitch taken out , so now is 14/18.5.
Just wondering what net effect would be in my situation, or
should I just F it for now and wait til I get an ext. i/c and
then repitch.. it would be summer in the heat at least.
04-06-2009, 08:30 PM #8
Steve, I was also "thinking' of the ecm reflash service.
That would bring my rpms up 100+ or so.
Would I just use the same impeller that's hitting 8160+ in
the cooler weather?? would it just keep revving to its' 8300+ ??
It would end up a little cheaper overall then doing an ext. i/c.
I just dont want to keep doing the same crap over and over..
getting pricey !!
I am for sure going to fill my ride plate holes this month, but i'd
like to get best bang for buck (if buck available)
04-06-2009, 09:53 PM #9
04-06-2009, 10:00 PM #10
What do you think the net difference between
a 13/18.5 and a 14/18.5 would be..
Holeshot, top, mid, etc top rpms, speed ??
Users Browsing this Thread
There are currently 1 users browsing this thread. (0 members and 1 guests)
By 1FastTrespiper in forum Sea Doo How To & FAQsReplies: 117Last Post: 08-02-2016, 12:23 PM
By Piney in forum 4-Tec PerformanceReplies: 5Last Post: 07-02-2010, 08:42 AM
By Vern in forum 4-Tec PerformanceReplies: 21Last Post: 02-10-2007, 11:35 PM
By Alaska05RXT in forum 4-Tec PerformanceReplies: 3Last Post: 04-19-2006, 08:52 AM
By 1FastTrespiper in forum 4-Tec PerformanceReplies: 43Last Post: 01-04-2006, 10:28 AM