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rlivingood
08-16-2004, 06:03 PM
Folks,

I have a 2004 Prostar 209 and have installed a GPS which gives speedometer indication.

My question is that the speedometer and the GPS don't match and can be off as much as 10-15 MPH. I do the same thing in my car and the speedometer is almost exactly the same as my odometer.

The GPS is the Meridian Sporttrack Pro Marine with BlueNav charts. Used in the Sacramento Delta of California.

Any ideas or others having this same problem.

Regards,

Rod

DanC
08-16-2004, 06:14 PM
10-15 mph, wow that is a lot. There is a little lag to the reaction time on the speedos. Is that much offset present only on acceleration or all the time? My 2003 209 was off by 2-3 mph when I bought it. It has two dashboard toggle switches to adjust the offset on the speedos. I brought my boat up to 28 mph on a GPS, waited to make sure everything was settled down and driving a straight line, and then pushed the toggles until the boat speedos matched the GPS.
10-15 mph sounds like something else is the problem. Do both of the boat speedos read the same? Maybe check your paddle wheel, it's near the drain hole in the bottom of the hull.

bradamerry
08-16-2004, 06:14 PM
Rod, mine gets off from time to time, but not that much. I always believe the GPS and change the speedo to match it. But I believe you have the paddlewheels and I don't. Somebody here always has the answers!! :D Great info on the board, not always BS talk.

rlivingood
08-16-2004, 06:50 PM
Thanks for the quick inputs.

I did a little more seaching and found that the top speed for the boat is suppose to be around 44 Mph with the 310.

Now I have even more evidence that the speedos are off since as much as I'd like to believe it my OT speed isn't going to be 50 Mph or 49 Mph which the speedos reflected this last weekend. (I am just finishing off the initial breakin for this new boat and working the top end only occasionally).

Both speedos show the same speed (no perfect pass).

The RPM is almost equal to the GPS speed on this 1:1 boat in my tests. I will try some of the staight line speed runs as suggested earlier and get a better indication of the difference.

I'm not too familiar with the new switch type speedo adjustments (my old prostar had little knobs) and will look into that.

I wonder if the speed can be adjusted that dramatically using these switches.

Regards,

Rod

DanC
08-16-2004, 07:08 PM
Good info on top end and rpm to gps speeds. Sounds to me like everything is working ok except the offset. No way should you get more than 45 mph with a factory setup.

Yes the switches should be able to adjust the speedos that much but it will take some pushing, they make pretty small adjustments with each push. I was able to change mine 5 mph, didn't try any more.

Both speedos should show the same. I find it humorous that MC installs two speedos in this configuration because there is only one paddle wheel and one computer feeding two different gauges. It's like having two different tachometers. Two different gauges used to be fed by two different sensors (pitot systems). Clearly they are just filling the dashboard hole for PerfectPass.

H20skeefreek
08-16-2004, 07:24 PM
Good info on top end and rpm to gps speeds. Sounds to me like everything is working ok except the offset. No way should you get more than 45 mph with a factory setup.

Yes the switches should be able to adjust the speedos that much but it will take some pushing, they make pretty small adjustments with each push. I was able to change mine 5 mph, didn't try any more.

Both speedos should show the same. I find it humorous that MC installs two speedos in this configuration because there is only one paddle wheel and one computer feeding two different gauges. It's like having two different tachometers. Two different gauges used to be fed by two different sensors (pitot systems). Clearly they are just filling the dashboard hole for PerfectPass.

I'm sure it has something to do with tradition as well.

rlivingood
08-23-2004, 11:44 PM
Folks,

Took the advice and using the GPS I changed the speedos to match the GPS. One thing I found is that the speedos vary as the speed changes. I've set the speedos to be most aligned at about 32 MPH which gives the best range for low end and ski pull, don't do much for the barefoot speeds since it's off almost 3 MPH at the top end.

For now I'll use the GPS when I want the correct speed.

FYI for those interested.

Regards,

Rod

H20skeefreek
08-24-2004, 07:11 AM
Folks,

Took the advice and using the GPS I changed the speedos to match the GPS. One thing I found is that the speedos vary as the speed changes. I've set the speedos to be most aligned at about 32 MPH which gives the best range for low end and ski pull, don't do much for the barefoot speeds since it's off almost 3 MPH at the top end.

For now I'll use the GPS when I want the correct speed.

FYI for those interested.

Regards,

Rod

I'm using a GPS for speed, my 2 speedos NEVER match, and my tach can't be right, but i know from using it in my car that my GPS always is. when i finally break down and get PP, i'm going to go with a paddle wheel version, and replace one of my speedos witht he large faced PP, and there is a company that makes a GPS powered speedo in the 4" face, so i'm going to swap that one in for the other speedo. They even told me that they could put the old MC on the face in place of thier logo. I'm going to do some checking to see if the PP can read MPH's off of a GPS.

chris.willman
08-24-2004, 09:07 AM
H20skeefreek,

Could you post your source for the GPS 4" speedo.

Thanks.

G-man
08-24-2004, 09:47 AM
Perfect Pass can't control speed by GPS. Perfect Pass best controls speeds faster than 24 mph by rpm's off a sensor to the tach. Once you get your baseline rpms set then simple input of crew weight, skier weight, and wind you'll have great speed control.

H20skeefreek
08-24-2004, 10:05 AM
H20skeefreek,

Could you post your source for the GPS 4" speedo.

Thanks.

I just talked to the manufacturer again, and evedently they CANNOT put a MC on the gauge face (someone was full of it when i talked to them before). The manufacturer is Nordskog. they have a digital face (up to 200mph+++!!!), an analog up to 60mph and an analog up to 90mph. Overtons sells for 389.99. Unfortunatly West Marine does not deal with them YET. Oh and they are 3 3/8", but that's the standard size.

NeilM
08-24-2004, 10:06 AM
I already asked PP if they had any intent of making a unit that used GPS for speed. Their answer was 'no' - that GPS was way too slow to be used for feedback to the throttle (makes sense). I also think that adding in GPS circuits to make PP self-calibrating would be cool, but it'd probably add $300 or so to the cost of the unit. Would YOU pay that premium when you probably already own or have access to a GPS? Not me.

Livorsi makes some great looking GPS speedos..
http://www.livorsi.com/catalog/gps.htm#GPS

Jorski
08-24-2004, 10:11 AM
Could you post your source for the GPS 4" speedo.

www.livorsi.com