Only moderately pleased with my 16/21 impeller...report.....

[shockerfd]

I have a 97 Challenger and blew out my wear ring at the end of last summer. I called Dave at Impros and told him I wanted to maintain top speed as best as possible with a tad more grunt. He recommended the 14.5/22.5 then but i ended up not getting back out on the boat. Called him this spring and he recommended the 16/21. In choppy, aerated water there is decent improvement. The boat holds it's low end torque well. It doesn't seem to plane too much different but it did well before w the stock impeller. Now the gripe. I lost an honest 4-5 mph off my top end. (Gps) I expected maybe 1-2 but 4-5 is significant and the seat of the pants feel is noticeable. I'm getting just under 7000 rpms at full throttle. Everything else on the boat is up to par as far as mechanical.


Just wanted to report since impeller choice is a commt topic. Anyone else running the 16/21?

 

[JJinSC]

You could probably get some RPMs back as well as some speed if you tune/hone the nozzle a little. Not recommending this, just an idea.

 

[shockerfd]

Tune and hone as in bore it out? Never heard of this.

 

[Dr Honda]

A swirl 16/21 in a challenger?? That's not enough impeller for that boat. I ran a 16/21 in my sportster. Yes... my engine and pump were massaged a bit... but I wasn't near the 110 HP your 800 has.


As far as opening the pump... that's not the solution in this case. if you open it... you will be bouncing off the rev-limiter.

If it was my Boat... I would add one degree of pitch to the trailing edge of the impeller.

 

[Dr Honda]

Yep... I just checked, and the "Recommended" impeller would have been the 17/22. (more pitch front and back)

The guy at impros sold you the wrong impeller. This is the second time this summer that Impros sold people the wrong stuff.

 

[shockerfd]

Ugh!!! Guess there isn't much I can do now, except maybe put the stock one back on which wasn't in too bad of a condition. I had a local shop do it and not really looking to do it myself or fork out another $190.00 for them to do it. Dave comes highly recommended and I'm a bit surprised at the drop in performance with this impeller, with the exception of choppy water.

As far as adding a degree, does this mean altering the pitch by grinding it out? Who does that? Machine shops?

 

[Dr Honda]

You can re-pitch it yourself. It's not that hard. Basically, you just measure, and bend. No grinding, or machine work required.