What it is!!!!
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Senior Member
Joined: Sep 2006
Posts: 544
From: Flemington, NJ
What it is!!!!
Hey guys,
Help me out here.
I have 3000 miles on my new engine but my speedo is off by 7 mph to fast.
So if I am going 60mph I am really going 53mph.
So the question is how many miles do I really have on my new engine.
Thanks in advance,
Schoon
Help me out here.
I have 3000 miles on my new engine but my speedo is off by 7 mph to fast.
So if I am going 60mph I am really going 53mph.
So the question is how many miles do I really have on my new engine.
Thanks in advance,
Schoon
Super Moderator
Joined: Jul 2006
Posts: 5,244
From: Reno, Nv.
RE: What it is!!!!
I'm not sure on this,........but I'll take a shot.
53 is roughly 88% of 60.
I took the remaining 12% X 3000 and came up with 360 miles, subtract this from 3000,
.... I figure 2640 total miles.
(corrections appreciated
)
53 is roughly 88% of 60.
I took the remaining 12% X 3000 and came up with 360 miles, subtract this from 3000,
.... I figure 2640 total miles.
(corrections appreciated
)
Joined: Aug 2006
Posts: 753
From:
RE: What it is!!!!
I believe, that would be correct, or I should say is correct if you were traveling 60mph ALL the time. However, you'll find that your speedometer is off less the slower you go. So when your doing 35 it may be only 3 mph off, or less. in other words if you drive 7 mph it's not reading "0" is it?
Hey this would be a good one to present to my Engineering department,
Hey this would be a good one to present to my Engineering department,
Super Moderator
Joined: Jul 2006
Posts: 5,244
From: Reno, Nv.
RE: What it is!!!!
ORIGINAL: Doctor K
Gorich is correct. However, if you divide 3000 by 1.07 you arrive at 2803.7383 miles, if you ALWAYS drove @ 60 mph[8D]
Gorich is correct. However, if you divide 3000 by 1.07 you arrive at 2803.7383 miles, if you ALWAYS drove @ 60 mph[8D]
Where did ya get the 1.07?
Senior Member
Joined: Jul 2005
Posts: 2,105
From: Central North Carolina
RE: What it is!!!!
I compute 13% error - the actual speed is 53 mph and the error is 7 mph. 7/53 = 13%.
Speedometers are often a bit optimistic, but this is rather extreme.
But regardless, I would not assume that, because the speedometer needle is that far off, the odometer is also that far off. This much error could be because of some mis-assembly or malfunction or miscalibrationin the speedo or its needle.
If it were my car, I would test the odometer. Find a ten mile stretch of highway with mile markers. Note the mileage to the tenth just as you pass a marker and drive at 60 or so (it really should not matter what speed) for ten miles, then note as you pass mile marker #10 how far your odometer says you have gone, if it has the same 13% over error it will say around 11.3 miles traveled rather than 10.
A thought, not knowing the details of the car: if an automatic transmission vette had the ECM programmed for the wrong axle ratio, for 2.73 while the car actually had the 3.15 rear axle ratio, it would have a bit over a 14% error: showing 60 mph when actually doing just under 52 -- just a bit more error than you have measured -- it would be easy to be off by that small difference and not know it. If your odometer test shows you are off that much, I would look at whether the ECM (if this is a newer vette) or the speedometer cable gear (if older), is incorrect for the axle ratio.
Speedometers are often a bit optimistic, but this is rather extreme.
But regardless, I would not assume that, because the speedometer needle is that far off, the odometer is also that far off. This much error could be because of some mis-assembly or malfunction or miscalibrationin the speedo or its needle.
If it were my car, I would test the odometer. Find a ten mile stretch of highway with mile markers. Note the mileage to the tenth just as you pass a marker and drive at 60 or so (it really should not matter what speed) for ten miles, then note as you pass mile marker #10 how far your odometer says you have gone, if it has the same 13% over error it will say around 11.3 miles traveled rather than 10.
A thought, not knowing the details of the car: if an automatic transmission vette had the ECM programmed for the wrong axle ratio, for 2.73 while the car actually had the 3.15 rear axle ratio, it would have a bit over a 14% error: showing 60 mph when actually doing just under 52 -- just a bit more error than you have measured -- it would be easy to be off by that small difference and not know it. If your odometer test shows you are off that much, I would look at whether the ECM (if this is a newer vette) or the speedometer cable gear (if older), is incorrect for the axle ratio.
Super Moderator
Joined: Jul 2006
Posts: 2,328
From: Dickson, TN.
RE: What it is!!!!
In addition to what Lee pointed out it could have something to do with tire size also or a comination of things. hope you figure it out. do the Highway patrole still check speedos for people or have a shop that does their cars?