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View Full Version : Which spedo to trust


2QWICK
04-23-2007, 03:52 PM
So i have roughly 12mph difference between my factory spedo and the one on the PerfectPass. I know that they can both be calibrated and judging by the quality wake at an indicated 21-22mph on the factory spedo I would guess it to be right. I guess my question is which is right? Could the factory spedo be off that much? In concept the calibration is easy… however the execution of doing it will be tough for me to do, i.e. setup start and stop points, friend timing etc.

Thanks in advance for your feed back!

trickskier
04-23-2007, 03:56 PM
They both could be off.........12 MPH difference is HUGE!!! I calibrate mine with a hand held GPS unit.

Andyg
04-23-2007, 03:56 PM
Find a friend with a hand held GPS. I found that is the easiest.

88 PS190
04-23-2007, 03:57 PM
or a course and your magnets.

RobertT
04-23-2007, 04:00 PM
Get a GPS, or borrow a friends. They are as cheap as $50 bucks at Walmart.

I did find that the "curve" between perfect pass and the speedo differs by 3mph. What I mean is....if I calibrate it perfect (Perfect Pass and factory speedo match) at 25mph, they will start to differ at top speed. Perfect pass says its 3mph slower than the factory speedo.

If I calibrate it at top speed, its off slightly at normal speeds.

I dont give a rip, makes no difference to me, but I calibrate mine at 25mph just because thats in the middle of ski/boarding speeds.

The consistent pull is more important than actual speed for us.

I am pretty sure they are both off the same paddlewheel, so it has to be a programing issue.

2QWICK
04-23-2007, 04:02 PM
I'll have to ask around for a GPS... a Garmin GPSMAP is on my to-do list for this summer but hasnt found its way into my budget just yet.

trickskier
04-23-2007, 04:07 PM
I'll have to ask around for a GPS... a Garmin GPSMAP is on my to-do list for this summer but hasnt found its way into my budget just yet.
I'll bring mine if we can hook-up one weekend.

uawaterskier
04-23-2007, 04:26 PM
or a course and a stopwatch

alpine740
04-23-2007, 07:23 PM
If you have 12 mph difference, I have to ask if your factory speedo is an Airguide. If so, use the PerfectPass and cover your Airguide with a piece of tape and draw a smiley face on it. If you have a newer boat with a speedo driven off the paddlewheel, I would still put my money on the PerfectPass display. I have calibrated my PerfectPass at 20 mph and it is dead on at 36 mph as well.

Romanod
04-23-2007, 07:52 PM
Try a GPS most will give you very accurate speed.