Solas Concord 15/23 impellers on 98 sportster

[LawnDart]

Thought it might be helpful to post this. I installed Solas Concord 15/23 impellers on my 1998 sportster twin 717s. Top speed was almost a wash.......about 46-47 mph same as before. Engine speed dropped about 600 rpm when topped out. It pulls slightly harder out of the hole and is much easier to tow a wakeboarder at a steady speed. With the stock impellers I was constantly modulating the throttles. It also stays more hooked up when cornering the boat where I would scrub a bunch of speed with the stock impellers. I'm a bit disappointed it didn't gain top speed but overall the boat feels better.

 

[ialonso]

Did you mean 600 RPM drop at full throttle? What was your max RPM before? and what is it now?

Thanks for sharing!

 

[racerxxx]

Those impellers powered by a pair of 787 is ideal, never rode in a 717 powered boat. I think thy're the same hull just a different engine package and seat config. With 787's they will plant you in your seat out of the hole.

 

[LawnDart]

Did you mean 600 RPM drop at full throttle? What was your max RPM before? and what is it now?

Thanks for sharing!

Yes, it was full throttle cruising at about 6600 rpm both engines with stock impellers, now it is about 6000.

 

[LawnDart]

Those impellers powered by a pair of 787 is ideal, never rode in a 717 powered boat. I think thy're the same hull just a different engine package and seat config. With 787's they will plant you in your seat out of the hole.

Yeah it seemed kinda like the pumps were loaded more than with the stock impellers and the boat needed more juice to pull them.

Edit - I'm also at 4200ft elevation with stock motors. I'd be willing to bet the performance would be better different at sea level. These impellers might be pitched too steep for my elevation.

 

[Dr Honda]

That's exactly what I would expect.


The boats have a lot of drag... and unless you find more HP... you don't go faster. Personally... I like the Skat-Trak impellers for the boats. They bite even harder, and don't disrupt the top RPM too much.


The is one thing you can try. If you take a degree or so out of them... you will get that 500 RPM back, and you MAY pickup 1~2 mph. But with that said... what is your peak RPM? and what is your compression right now?

 

[LawnDart]

That's exactly what I would expect.


The boats have a lot of drag... and unless you find more HP... you don't go faster. Personally... I like the Skat-Trak impellers for the boats. They bite even harder, and don't disrupt the top RPM too much.


The is one thing you can try. If you take a degree or so out of them... you will get that 500 RPM back, and you MAY pickup 1~2 mph. But with that said... what is your peak RPM? and what is your compression right now?

Peak is around 7000 on the tachs. I haven't had a need to put a comp gauge on it yet (knock on wood). Both engines run strong and crisp, trouble free with good plug reads.

I don't have any expectation to do 50+ anyway. I wanted to replace my stock impellers which had excessive clearance on the nozzle side and found a smoking deal for the Concord 15/23s.......was hoping for some top end speed but I think this shows these impellers may not be the optimal choice for 717s and my elevation.

 

[Dr Honda]

Well.... Spec top RPM is 7000, and your limiter will kick in at 7200. So, I'm not sure how you lost 500 RPM.

But with that said... sounds like your engines are fine, and running well. So, just go enjoy it. :cheers: