Who has experiance with twin screw impellers?

[FSH 210 Sport]

Thanks!

Your density altitude was 2878’. I had to make some assumptions since I didn’t know the other parameters of altimeter and dew point. I don’t have a good feel for a SC engine and how it would be affected by that 2900’ elevation but I’m sure there is some affect, maybe 5% or 25 hp loss.



I don’t know the conditions when you tested the oem impellers.

I’m assuming you already have the 12/18’s, if not you could have Dave at leading edge take some pitch out of the ones you have, much less $$$ to do it that way.

If it was me, I’d try the 12/18’s or repitched first and see what rpms and performance you get out of those. I’m sure you will gain rpms, it will be interesting to see if the 12/18’s get you back up to the oem impeller rpms range / speed or closer to the rated max rpm of 8000 and should get you back up to the oem top speed?

If I remember correctly, the tuner will only give about 5 hp at the stock rev limit of 8000 rpm, raising the rev limit to 8500 is where the 25 hp gain would be seen, but that requires a lower pitch impeller to get that many rpm.

 

[jacoviii]

Well I just pulled the L13 cones off and went to stock. It revs much quicker. Now port is 7600 and Starboard is 7500 much better acceleration (punchy). Top speed 52-53mph. Before with the L13 I felt like the power and take off was very linear... I will still try the 12/18. With each cone. But we are heading to lake of the ozarks next week to watch the races. I know the impeller tuners have their value. But I'm looking to do as much in house as possible.

 

[F.M.]

Looking forward to the results of the 12/18 vs the 12/20. I hate that you had to pull the L13 cones to raise the RPMs. I fell like the L13s provided a noticeable difference in holehsot and acceleration on my '17 242X, but it seems like on the new 160mm pump they don't provide as good of results.

 

[jacoviii]

Looking forward to the results of the 12/18 vs the 12/20. I hate that you had to pull the L13 cones to raise the RPMs. I fell like the L13s provided a noticeable difference in holehsot and acceleration on my '17 242X, but it seems like on the new 160mm pump they don't provide as good of results.

They do in the wave runners and in a stock 160mm impeller boat. But I belive the L13 is a bit much with the twin prop. And factory nozzle size. Don't be put off with my top speeds 54mph was my best brand new. Maybe 55mph ish once.

 

[F.M.]

I would’ve thought your top speed would have been much closer to mine stock since we’re only at about 300’ of elevation difference. My top speed, unmodified, 2 people, half tank of fuel, roughly 75 degree temp, was 58mph. Fully loaded, full fuel, 4-5 people, 56 mph. Now in 90-95 degree temps I’m only getting 54mph.