Results with the new Rotax Racing SC Impeller

[Jarrett]

I had some not so great results with the new Rotax Racing SC Impeller today. Here is some background on my ski:

Date April 2th 2006
Mods:
Reflashed Rotax Racing ECU
Rotax Racing IC
Riva Grate
PPG Opas blockoffs
Worx sponsons(down)
Vortech SC Impeller
PPG Power Pipe
Bruce's SS Wear Ring
Jerry's Air Mod
Jerry's Ride Plate mod (sucked out)
Jerry's Reverse Bucket mod
Altitude 530 ft.
Air temp 90
Water temp 70
Humidity 60%
Fuel 2 bars
Oil 3/4 on notch
Prop Impros repitch Solas 14/20
Max RPM 8150
Boost Unknown
Peak Speed 73.6

[Jarrett]

Today Frank and I did the follow mods to it:

Refilled the ride plate and intake grate holes
Redid the air intake where it uses the stock elbow and 4 inch hose with K&N in the front of the hull.
Installed the new Rotax Racing SC impeller
Installed 42lb injectors

First run today:

Date May 20th 2006
Mods:
Rotax Racing ECU & IC
Riva Grate
PPG Opas blockoffs
Worx sponsons(down)
Rotax Racing SC Impeller
PPG Power Pipe
Bruce's SS Wear Ring
4inch / K&N air setup
Jerry's Ride Plate mod (replaced and sucked out again)
Jerry's Reverse Bucket mod
42lb injectors
Altitude 530 ft.
Air temp 91
Water temp 80
Humidity 60%
Fuel 5 bars
Oil 1/2 on notch
Prop Impros repitch Solas 14/20
Max RPM 8150
Boost 8.5
Peak Speed 73.7

[Jarrett]

We thought the injectors were possibly making it too rich, so we reinstalled the stock injectors. We went out for some more runs on the warm engine and I got this:

Date May 20th 2006
Mods Rotax Racing ECU & IC
Riva Grate
PPG Opas blockoffs
Worx sponsons(down)
Rotax Racing SC Impeller
PPG Power Pipe
Bruce's SS Wear Ring
4inch / K&N air setup
Jerry's Ride Plate mod (replaced and sucked out again)
Jerry's Reverse Bucket mod
38lb injectors
Altitude 530 ft.
Air temp 91
Water temp 80
Humidity 60%
Fuel 4 bars
Oil 1/2 on notch
Prop Impros repitch Solas 14/20
Max RPM 8100
Boost 8.0
Peak Speed 73.6

[Jarrett]

So the questions I have are:

Is that the right amount of boost for this SC impeller at 8100-8150 RPM?
Is something wrong or is the heat just killing me?

It seems I have a problem or the impeller isn't adding anything to my setup. Anyone got any ideas on potential probs? Thanks.

[Tennessee]

I put mine on today and got 10.2 at 8350. May have a little leak or something.

[psycho rxp]

your Rpms low. the boost will rise as you gain rpms. Sounds like you need a re pitch. You should be at least 8400rpms. If you lighten your valve train you should pitch your prop to 8500. that will get you more speed for sure.

[Water4fire]

Jarret just for info. My ski runs the same as yours with the same stuff in your first post.
73.5mph at 8100
8p.si. boost.

DO you think all your boost is getting to the motor??
No leaks?

.

[HOSS]

I`d deffinately throw some gauges on it just for insurance. But it does seem as though you have a boost leak.

[ramnj]

Jerry's Air Mod
Jerry's Ride Plate mod (sucked out)
Jerry's Reverse Bucket mod

Jarrett,

Don't mean to hijack the thread, but what are the above??

Thanks,

[shhr]

this is interesting

I wonder if the difference between the Riva and RR is only felt if you run a RR ECU and turn more than 8100 RPM`s