Speedometer
08-28-2002, 11:33 AM
#1
Charter Member #34
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Join Date: Oct 2000
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Speedometer
Guys,
What brand Speedo do you have and how accurate is it.
With my 272 and now with my 36 I find that both of my speedos are VERY accurate compared to GPS readings.
I talk with guys that their speedo reads 10 MPH over the GPS readings?
Actually I wish my speedo read high just to mess with those passengers that do not know any better.
I had the standard Graffrig on the 272 and it was dead nuts on until about 60 MPH and at that point the speedo read about one mile an hour slower than the GPS.
On the new 36, it is dead nuts on till about 55 MPH and reads about one to two MPH faster than the GPS.
For what it is worth, a lot of the ones that read faster are on Fountains. I was told some time back that Fountain ordered speedo's that read fast. Anyone know the truth on this?
Can you order a speedo that is calibrated to read high? I wouldn't mind my reading low 80's. LOL
Mark
What brand Speedo do you have and how accurate is it.
With my 272 and now with my 36 I find that both of my speedos are VERY accurate compared to GPS readings.
I talk with guys that their speedo reads 10 MPH over the GPS readings?
Actually I wish my speedo read high just to mess with those passengers that do not know any better.
I had the standard Graffrig on the 272 and it was dead nuts on until about 60 MPH and at that point the speedo read about one mile an hour slower than the GPS.
On the new 36, it is dead nuts on till about 55 MPH and reads about one to two MPH faster than the GPS.
For what it is worth, a lot of the ones that read faster are on Fountains. I was told some time back that Fountain ordered speedo's that read fast. Anyone know the truth on this?
Can you order a speedo that is calibrated to read high? I wouldn't mind my reading low 80's. LOL
Mark
08-28-2002, 11:49 AM
#2
Platinum Member
Platinum Member
Hey Mark,
My experiences are very similar. I have the Gaffrig(Livorsi Marine) Liquid-filled speedo and I find that it is no more than 1-1.5mph off at my top speed of about 67. At lower speeds, 60 and under, it is right on.
The speedos can be easily calibrated by adjusting spring pressure or diaphram pre-load(many different mechanisms in different brand speedos) to indicate higher or lower than actual. Speedos are nothing more than fancy pressure gauges.
My experiences are very similar. I have the Gaffrig(Livorsi Marine) Liquid-filled speedo and I find that it is no more than 1-1.5mph off at my top speed of about 67. At lower speeds, 60 and under, it is right on.
The speedos can be easily calibrated by adjusting spring pressure or diaphram pre-load(many different mechanisms in different brand speedos) to indicate higher or lower than actual. Speedos are nothing more than fancy pressure gauges.
08-28-2002, 11:58 AM
#3
Registered
Originally posted by Baja Daze
Hey Mark,
My experiences are very similar. I have the Gaffrig(Livorsi Marine) Liquid-filled speedo and I find that it is no more than 1-1.5mph off at my top speed of about 67. At lower speeds, 60 and under, it is right on.
The speedos can be easily calibrated by adjusting spring pressure or diaphram pre-load(many different mechanisms in different brand speedos) to indicate higher or lower than actual. Speedos are nothing more than fancy pressure gauges.
Hey Mark,
My experiences are very similar. I have the Gaffrig(Livorsi Marine) Liquid-filled speedo and I find that it is no more than 1-1.5mph off at my top speed of about 67. At lower speeds, 60 and under, it is right on.
The speedos can be easily calibrated by adjusting spring pressure or diaphram pre-load(many different mechanisms in different brand speedos) to indicate higher or lower than actual. Speedos are nothing more than fancy pressure gauges.
08-28-2002, 12:40 PM
#6
Thanks for the Kudos Doc.
The pickups (called a pitot tube) for the bravo is a little hole just above 'bullet" (output shaft lower housing). As you change the angle of your drives the water flows differently and thusly indicated speed.
I put nose cones on mine and blocked this area, so I have a separate j-tube on the lower right portion of the drive. The problem is when the hull clears the speedo jumps around like my kids on the bed.
http://community.webshots.com/photo/...48521418iyyrzT
I'm more apt to tell someone I'm doing 70 when really I'm around 80. They don't feel as scared.
The pickups (called a pitot tube) for the bravo is a little hole just above 'bullet" (output shaft lower housing). As you change the angle of your drives the water flows differently and thusly indicated speed.
I put nose cones on mine and blocked this area, so I have a separate j-tube on the lower right portion of the drive. The problem is when the hull clears the speedo jumps around like my kids on the bed.
http://community.webshots.com/photo/...48521418iyyrzT
I'm more apt to tell someone I'm doing 70 when really I'm around 80. They don't feel as scared.
