WaveJammer 701/144 Project

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I have not been able to sell my old WaveJammer, so I am going to embark on something that I have repeatedly stated is totally stupid -- mod it for better performance.

I've already got the necessary 650LX motor plates to put a 701 in it, but since the 500 Yamahas' 133mm mixed-flow pump really can't make use of a 701's horsepower, and since the biggest technical headache is fitting a better pump, I want to start there first.

My intitial prospect for a new pump is the WRIII. It's the only ski that used the 144mm pump (a la SuperJet and others) but mated it to the same style 1-piece cast intake duct as the 133 pump. Unfortunately, the dimensions are totally different from the 133 all the way around. The WRIII is much bigger.

I've found a complete WRIII driveline and pump that should be here in a couple of weeks. I am going to play with the dimensions and see if the two ducts can be creatively cut and rewelded together to make use of the Jammer's original intake grate and ride plate, but mated to the 144 pump's wider opening. This may be impossible, or more work than its worth. The 133's duct opening may simply be too small to draw enough water to keep the 144 pump from cavitating, even if I can make the transition between the two duct sections smooth and wide enough (a major challenge in itself). The pump itself may also not fit above the ride plate, even with some creating gouging of the WJ's pump tunnel.

If I have to give up on the cast pump duct idea, my next approach will be to reshape the bottom of the Jammer hull to work with an integral fiberglass duct and intake shoe, Superjet/B1 style...which would require a different intake grate and ride plate...which wouldn't be much less work than just glassing in the whole pump section from a 144-equipped ski. You can see how the needed changes just keep multiplying until I'd almost be building a custom boat, which is kinda crazy, when you're starting with a pig like the 'jammer. Which is why I want to start with just modding the aluminum duct first. And why I've said so many times that modding a Jammer makes no sense--but I guess I'm getting nuttier as I get older.

Of course, if anybody knows of a junk Superjet or B1 hull that's ready to be cut up, I would willingly jump right to buying the pump section and going from there!

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Got the WRIII pump (from Grayw0lf over at PWCToday) on Friday and only had a few minutes over a very busy weekend to examine it. Dang, that thing's big. I am not totally sure yet, but I think my idea of a custom intake housing is worth nearly zip. I'm thinking glass mods are a whole lot easier than modifying aluminum castings. We'll see. I'll post some comparision photos sometime this week.

My next move is to flip the hull over on its shop stand for a better look at the pump area. That means I'll need to pull the fuel tank, engine and battery, along with the steering tower.

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No pics yet, and I have not started disassembly yet, but I did do a fair bit of gauging with the measuring tape and square ruler.

The WRIII pump actually looks like it will fit more easily than I imagined.

PUMP & INTAKE POSITION (FORE/AFT):
The WRIII pump seemed to extend much farther to the front of the pump, but I remembered when I crawled under the Jammer that the intake grate on the 500s has a big metal extension to the front. The distance from the end of driveshaft to where the hull meets the front of the intake is exactly the same. The duct on the 144mm pump is actually slightly shorter, by maybe 1/2" or 3/4". The big pump is longer, however, so rear of the pump nozzle will be located about 1-1/2" – 2" farther to the rear when installed.

INTAKE WIDTH:
More good news. The WRIII duct is wider, but only by 1/2" per side. Both the 500 and WRIII intake ducts have parallel side edges with a similarly shaped lip. It will take some cutting and glassing, but making it fit won't be major surgery.

PUMP HEIGHT & MOUNTING POINTS:
Again, not as bad as I had feared. Some custom fabricating will be done, but I don't think I'll have any problem fitting the pump behind the ride plate.

DRIVESHAFT CONNECTION:
Eeew. Here's where things get icky. The driveshaft angle and height are less on the WRIII pump, and it's all one cast unit, so it can't be changed. And since the face of the cast intake duct must remain parallel to the underside of the hull, my hopes of using the 650LX bedplates to easily mount a 701 to the stock mounts are gone. The intermediate shaft and motor will have to be shifted, which means a custom motor install and some bulkhead work to move the intermediate shaft bearing support.

Overall, though, I'm more comfortable with that end of the project than totally re-sculpting the hull, which it what several people told me would be necessary.

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Before you all scream "pics!", give me a few days and I'll have some preliminary photos uploaded.

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I wanted a clever name for this project that told people what it was, playing off the "WaveJammer" name. After considering SuperJammer and WaveHammer, I finally decided on "WaveGlamour." I thought it was a neat phonetic play, and it tells people exactly what this is all about - glamorizing the lowly Jammer. I've added a little graphic to my sig that will hopefully encourage folks to check out this thread.

[w/rpm500]

ok what about grafting the whole intake /pump mount out of your pumps original donner ski ? cut out the whole thing and graft in ... the motor mountings could be shaved on the aluminum cradle, both at the engine plate mounting top and the underside of the outer ears,also the mounts bottom side ... let me know what you may think to these...( i have extra 500 cradle's)

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ok what about grafting the whole intake /pump mount out of your pumps original donner ski ? cut out the whole thing and graft in ... the motor mountings could be shaved on the aluminum cradle, both at the engine plate mounting top and the underside of the outer ears,also the mounts bottom side ... let me know what you may think to these...( i have extra 500 cradle's)

I might have gone that way if I had access to the whole hull, but I bought the WRIII pump from a guy in Florida for 100 bucks. Besides, this may actually end up being less work. I won't know until I get into it. We'll have to see.

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On another note, I might take the WJ out to the local lake Saturday and get some baseline top speed and 0-20 GPS numbers before I start modding it. Not really necessary, but it would be fun to compare. It depends on how crazy the weekend gets; I might also look at a 300SX for sale locally.

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I've tried to size up the differences in the WJ500 and WRIII pumps as much as possible without disassembling my 'Jammer, first to make sure it's feasible, and secondly, I hope to get the stock machine out on the water one last time before ripping into it. Fortunately, I'd previously picked up a spare WJ/WR500 intake duct.

Here are some pics showing the two pieces. The first shows the underside of the stock 'Jammer, with the dimensions noted. The other two photos show the WRIII pump with the WJ intake duct alongside, with the front of the driveshaft housings aligned. On the WJ pump, the funky intake grate extends all the way forward to the same point where the housing ends, which is the same arrangement as the WRIII pump. So there's not really an issue with matching the new pump assy to the hull at the front. The WRIII duct is about 1.5" longer, so I'll need to make a cutout at the front of the ride plate, but that should be no big deal.

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Here's a photo of the two pump ducts, showing the difference in width. The new pump is 1" wider (1/2" per side), which is a reasonable modification to accomodate.

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Measuring from the duct/stator joint of the new pump, the rear of the hull will be at about the 12.5" point. The Rend rideplate on my jammer extends about an additional 2.5" back from the end of the hull, so the new nozzle will stick out about 1" beyond the end of my ride plate when installed. Anybody have any idea what effect having the nozzle so far to the rear will have on steering and/or thrust characteristics?

The other photos are of my ski with the stock pump in place, for comparision.