High altitude prop recommendations

[JetboatBrad]

Anyone have any recommendations on high altitude impellers at 6200’ (Lake Tahoe) I have tried to sift through the posts here but are all ultimately recommending local shops and never say what they got put on. I was hoping to swap them out myself and was looking for a good aftermarket brand and most of the after market sites have a elevation calculator. Any advice is much appreciated

 

[FSH 210 Sport]

Anyone have any recommendations on high altitude impellers at 6200’ (Lake Tahoe) I have tried to sift through the posts here but are all ultimately recommending local shops and never say what they got put on. I was hoping to swap them out myself and was looking for a good aftermarket brand and most of the after market sites have a elevation calculator. Any advice is much appreciated

Call Glen at Impros in Southern California. Mine are on the way to me for 5000’ feet. I went with Skat Trak impellers.

 

[JetboatBrad]

Thanks, I’ll give him a shout. He swap them out for you too?

 

[FSH 210 Sport]

Thanks, I’ll give him a shout. He swap them out for you too?

No I will do the R&R on the impellers. Going to keep my OEM ones as spares.

 

[JetboatBrad]

No I will do the R&R on the impellers. Going to keep my OEM ones as spares.

Nice. I’ll probably do the same. Let me know how you like them if you get yours on before I do

 

[Ronnie]

There is at least one member here who keeps his boat in Tahoe. Pretty sure he has gone the repitched impeller route. @sysinu boats at lake Powell and had high altitude impllers for sale a few years ago. If no one with experience chimes in, give impros a call. I think one of the Gaddis (owners/operators of the green Hulk pwc site) brothers runs it now. They won’t steer you / repitch your impellers wrong.

 

[JetboatBrad]

Ok awesome, I will call them too. I’m sure these guys have it down to a science so they will take care of me. Appreciate the reference. I’d like to find someone who does some aftermarket stuff on jet boats

 

[Dave burke]

@Ronnie (and others), I boat at about 1500’. Do you think it’s worthwhile changing my impellers or repitching them? Thx

 

[Ronnie]

I’m not the correct person to ask as I boat at sea level most of the time. A few years back I took my waverunners to union reservoir near placerville, ca, elevation 8,000 feet.

Union Reservoir - in California's spectacular High Sierra

Union Reservoir, located next to Utica Reservoir on Spicer Road is a small, incredibly scenic lake perfect for kayaking and canoeing to small islands.

www.gocalaveras.com

both of them lost 10 mph off their top ends and did not accelerate nearly as fast as they did at sea level. If I always boated at the elevation I would not have noticed the performance losses. I doubt the effects are as bad at 1,500 feet but I don’t know for sure.

 

[Dave burke]

Got it, thx. Based on what I’ve read here ans elsewhere, I don’t think 1500’ has a huge impact but I don’t know for sure.

 

[JBehrens]

I boat at Lake Powell and have an OEM impeller pitched for ~4000 from Impros. It's a massive difference over stock. I would even think that even at 1500 or 2k it would make some difference but not as much as higher elevations. On a side note, density altitude matters a lot, I have seen ~3 to 4mph difference on the same lake just from a 2500ft change in density altitude.

 

[Dave burke]

Interesting, thx. I’m no meteorologist, what is density altitude?

 

[JBehrens]

Density altitude is the altitude relative to standard atmospheric conditions, taking into account physical altitude (atmospheric pressure), temperature and humidity. DA is often used for aviation to calculate engine power loose given current altitude and temperature. For my example, in the summer, Lake Mohave is at about 650ft physical altitude but due to the weather conditions (high heat) the density of the air is equivalent to ~2800ft (making your boat, truck or plane perform as if it was at 2800ft) so power is lost due to lack of air density. But say in the winter when it's really cold the DA could be at or below the physical elevation giving more air for the engine to work with.

 

[rad1026]

I was up at 6,900' last weekend and could only run around 6,100 rpm, 35 mph with full fuel and 5 people. If I was going to do most of my boating at altitude I would have another set of impellers just like I had different pitched propellers.

 

[Dave burke]

Density altitude is the altitude relative to standard atmospheric conditions, taking into account physical altitude (atmospheric pressure), temperature and humidity. DA is often used for aviation to calculate engine power loose given current altitude and temperature. For my example, in the summer, Lake Mohave is at about 650ft physical altitude but due to the weather conditions (high heat) the density of the air is equivalent to ~2800ft (making your boat, truck or plane perform as if it was at 2800ft) so power is lost due to lack of air density. But say in the winter when it's really cold the DA could be at or below the physical elevation giving more air for the engine to work with.

Got it. Thx. Can it be calculated (with elevation and temperature) or do you need some sort of gauge to measure it?

 

[JBehrens]

Got it. Thx. Can it be calculated (with elevation and temperature) or do you need some sort of gauge to measure it?

There are charts (google density altitude chart) but the easiest way to get the current number would be to find the nearest airport and plug that into flight aware, the weather tab METAR section will give the current weather and the DA.

Laughlin/Bullhead Intl Airport Weather (Bullhead City, AZ) [KIFP/IFP] - FlightAware

 

[Dave burke]

Very helpful. I learned something today. Thx

 

[JetboatBrad]

Me too. I pretty much just boat here or at similar altitudes. I will definitely get some new impellers. Are there any worse or better on the aftermarket ones? I know more expensive usually means better but not always.

 

[JBehrens]

Me too. I pretty much just boat here or at similar altitudes. I will definitely get some new impellers. Are there any worse or better on the aftermarket ones? I know more expensive usually means better but not always.

Personally, I would stick to OEM 6CW (meant for the single engine boats) and have them modified. They may not be the best looking but they have the longest blades and seem to be the best middle ground between low end torque and high rpm smoothness. Some say Solas are better but cruise around the jet ski forums and you will find plenty of Solas and Skat Trak's dropping blades and killing pumps. just my .02

 

[Dave burke]

Just checked it. Closest airport is Adirondack Regional which has an elevation of 1600’ and a DA of 2600. So I guess my effective elevation is closer to 2500’. Very cool!