Re-pitching an impeller

[watersled]

I'm currently running a swirl 12/17 but I don't think I am getting the RPM's and speed out of my ski. My set up is:

62t/61x
dual 38's jetted 135 main, 70 pilot, stock needle and seat, stock spring
Factory limited pipe
rear waterbox and rear outlet
Flow control valve
dual cooling
MSD enhancer

With this setup I was only pulling 6550 RPM and 48-49 MPH. I'd like to just re-pitch the impeller I have but what would I want to pitch it to for racing? Also, feel free to critique my current set up as well. Thanks!

[88kawi5fiddy]

Re: Re-pitching an impeller

is jetting spot on? how fresh are your rings? whats your squish band at and whats your compression? thats a low RPM for having a pipe on it.

PM scotty mac or he will probably see it here soon enough.

[Wet Wolf]

Re: Re-pitching an impeller

Yeah, somethings wrong, It should be able to spin that prop to the sky with no problem.

[Rod Peters]

Re: Re-pitching an impeller

Contact Impros, I am sure they can help you out www impros.com/store or 515 N Smith Ave Ste 102, Corona, CA 92880 · (951) 737-2900

[tshank123]

Re: Re-pitching an impeller

49 seems kinda high for such low RPM. Im wondering if your pitch is too high, or higher than you think.

[watersled]

Re: Re-pitching an impeller

It's supposedly a 12/17 but never checked it myself. As far as the jetting goes, it's close, I've only messed with it for about an hour on the water but if I turned in the main, the RPM would fall off. If I turned it out the RPM wouldn't reach over 6500.

[watersled]

Re: Re-pitching an impeller

I'm running the stock head right now, roughly 145/145 compression.

[HXLOCO]

Re: Re-pitching an impeller

49 seems kinda high for such low RPM. Im wondering if your pitch is too high, or higher than you think.

Right on Tim 49 my blaster with more stuff than you have barely turns 48 49 mph at 7250 rpm but the acceleration is decent it could be r the prop too tall or maybe the pipe too cold

[tshank123]

Re: Re-pitching an impeller

Right on Tim 49 my blaster with more stuff than you have barely turns 48 49 mph at 7250 rpm but the acceleration is decent it could be r the prop too tall or maybe the pipe too cold

Hoping to get on the line with you at some point this season. I'm in the middle of a sport spec blaster build. I want to have fun in sport again.

[tshank123]

Re: Re-pitching an impeller

I'm currently running a swirl 12/17 but I don't think I am getting the RPM's and speed out of my ski. My set up is:

62t/61x
dual 38's jetted 135 main, 70 pilot, stock needle and seat, stock spring
Factory limited pipe
rear waterbox and rear outlet
Flow control valve
dual cooling
MSD enhancer

With this setup I was only pulling 6550 RPM and 48-49 MPH. I'd like to just re-pitch the impeller I have but what would I want to pitch it to for racing? Also, feel free to critique my current set up as well. Thanks!

I'm running the stock head right now, roughly 145/145 compression.

With what you have I wouldn't expect much more out of it. Stock head, stock 38s, 61x cylinder with a limited chamber, those are your limiting factors here. Still its not bad top speed wise, I just wonder how the acceleration out of corners is.

[watersled]

Re: Re-pitching an impeller

For the races I plan on running ad ADA head. But I'm cheap and don't want to spend the extra cash on higher octane fuel when I'm just playing around. But the bottom end on the ski is great and the hookup is great. It beats my brothers 62t/61x with 44s, red pipe, msd, with a concord 13/17 out of the hole for the first 100-150 ft but it's a couple MPH slower on the top