As usual, don't expect this to be short ;-)
So to recap what I've learned from you guys here and during your time at wakeworld...
Accuski is the reason for the MMDC computer and the message center. To complete the installation, its a few hundred bucks to add: a servo and linkage back at the engine, a sort of kill switch at the throttle handle and a foot pedal. Accuski's Toyota adaptaption of the MMDC allows only for pressure-based speedo sensors like the two types of transom-mounted pickups our boats came with.
Accuski has since come out with a system that uses the 'much-better-for-wakeboarding-speed' paddlewheel speedo sensors. However, they do not have a way (or do not have the desire) to make the paddlewheel work with our application.
Cyclone has the Accuski setup (sans the paddlewheels) and in MPH-hold, the system is worthless below slalom speeds. However, he does use the system, albeit in RPM-hold mode. Being able to hold an RPM must be an improvement over throttling it, but not close to what a paddlewheel system can do.
Perfect Pass uses a different message center on their top-o-the-line model, and that unit doesn't have as cool a display as the Accuski and likely wouldn't support the other reason we use the message center - display readings from the Lowrance depth finder (which mine has gone on the fritz, by the way.)
Perfect Pass also makes a simpler version which has no display unit, just a 2" round unit installed in the dash with the exact same buttons and functions of a typical automotive cruise control application.
Overall reviews from non-Epic owners is that Accuski has many very cool abilities but that PP pulls a little more reliably.
The options, as I see them (based on what I remember you guys saying) are:
1) Adapt the Accuski to a paddlewheel setup. My impression is that our MMDC can't easily be upgraded to accept paddlewheel sensors. Unless we had some really good insight into the inner workings of the MMDC, we'd be unable to adapt our current boxes to paddlewheel. Accuski might have a better chance at modding one to meet our needs, but I'm sure that they're influenced at least a little bit by the fact that they'd be taking on work for a pretty small sliver of the market. If we knew what was going on inside the MMDC, we'd have a much better chance at figuring out how to hotwire the unit for paddlewheel.
2) Get Accuski to adapt their most current MMDCs (shipping with the other brands of boats) to work with the Toyota, and then replace our MMDCs altogether. Specifically, it seems they'd have to ensure the computer could still read signals coming from the engine and turn them into signals to drive the dash gauges. Also, the unit would need to be able to display depth finder readings. Naturally, this system would accept the paddlewheel speedo, and they've already got the foot pedal/kill switch/actuator dealies all worked out. The bummer for us is that we'd have to replace a couple hundred dollar MMDC. The bummer for them is that the same 'business case' still might keep them less than motivated about taking this on. I'm really curious to see if there's a hardware difference between the Toyota application and the others (as far as engine interfaces, dash outputs, etc.)
3) Add Perfect Pass to our boats. As for me, I'd just get their simplest MPH-based system with the car-like controls (drive to a speed and then engage the cruise.) I'd stick the 2" control dealie in the gunwhale next to the throttle. Did I mention that the simple system is $700? Also, Perfect Pass has unresolved issues with the way our throttle linkage works (don't quite understand this part.) Could it maybe be possible to merge the Accuski linkage/kill switch with the PP speedo and controller and leave the MMDC and message center in there to display depth?
4) Make our own system. Don't laugh. First, the system has to accept input from the paddlewheel (a known signal). Second, it's got to have an interface no more complicated than On/Off, hold and faster/slower. Add a kill switch tied to throttle position. Once armed, the unit will have to 'remember' what the speedo was saying when you hit 'arm'. From that point on, it simply compares desired and indicated speeds and outputs a signal that a model aorplane servo can accept. I've not programmed them myself, but there are chips called PICs that might be able to handle all of this. I think all we'd need is some time to figure the system out, and the benefits would be simplicity and cost - PICs are like a buck, and the means to program them is pretty cheap and accessible too. The other alternative would be to do it old school, with discreet components. Might even be easier to design.
Finally, there's even a possibility we can do it all electronically. Look in your engine manual at page SF-32, step 4. The Throttle Position Sensor looks like it converts mechanical positioning of the throttle cable into an analog electrical signal heading towards the throttle body. What if we inserted something equivalent to an A/B switch and produced the electrical signal ourselves when in cruise control? Engaging the cruise disconnects the signal being generated by the throttle position sensor and replaces it with the control signal generated by our cruise control setup. Pressing off or moving the throttle level places the switch back into the normal position, where throttle position is set by the throttle linkage. The good deal is that there's no servo to fail and no linkage to adjust. It simplifies a home-brew design because we don't have to build the servo interface or the linkage. It does cross some boundary, like 'do you really want to start snipping wires in the engine's electrical?' This approach could be done pretty damn clean, and it could even come into play with getting the Perfect Pass system on our boats.
Pete, I'd really like to know what the Accuski and PP guys told you about their major malfunctions. What exactly is the hangup? What stuff do I have wrong, and what have I missed?
And no, I don't smoke pot or do speed.
