Is my speed really that off?
#12
RE: Is my speed really that off?
Hi,
See the speed sensor topic I started a while back.
The Factory MOPAR speed sensor is in the tail shaft of the transfer case.
It counts RPM's and then sends the info back to the computer.
If you increase tire size your speed will be off, further more the sensor will send erroneous info to the computer.
A lot of things come into play at this point.
Things were much easier in the days of carburetors and non computerized wheelers.
Sorry, was having a flash back………….
Any way, the idle/fuel mixture, shift points, hydrocarbons and on and on are effected.
The speed sensor affects a lot of components, not to mention fuel mileage.
I would recommend Super lifts speed sensor, I have one and it works great. (I am running 38.5" Swampers and my speedo is within 1-2 mph).
Summit racing sells it for about $175.00.
It can be adjusted endlessly, gear upgrades and tire size.
You will save the money in the long run.
There is another company that also makes one I don’t remember the name though?
Hope this helps ya out......
Later
See the speed sensor topic I started a while back.
The Factory MOPAR speed sensor is in the tail shaft of the transfer case.
It counts RPM's and then sends the info back to the computer.
If you increase tire size your speed will be off, further more the sensor will send erroneous info to the computer.
A lot of things come into play at this point.
Things were much easier in the days of carburetors and non computerized wheelers.
Sorry, was having a flash back………….
Any way, the idle/fuel mixture, shift points, hydrocarbons and on and on are effected.
The speed sensor affects a lot of components, not to mention fuel mileage.
I would recommend Super lifts speed sensor, I have one and it works great. (I am running 38.5" Swampers and my speedo is within 1-2 mph).
Summit racing sells it for about $175.00.
It can be adjusted endlessly, gear upgrades and tire size.
You will save the money in the long run.
There is another company that also makes one I don’t remember the name though?
Hope this helps ya out......
Later
#13
RE: Is my speed really that off?
I think you can also calibrate your speedo for tire size and gears with the hypertech and super chips' programmers, at least they claim to. One other thing, speedometers have a margin of error that the manufacturers consider acceptable. I used to have a '97 Ram 4x4 that I ran 285/75R16's on, and the speedo was right on whenever I passed one of those radar things AND, when I was following someone I knew somewhere. That's about a 33" tire vs a 29" tall 245/70R16 stock. Now I have a '98 Ram 4x4 that I run 33"s on, and the speedo is 10% off. Meaning that when my speedo says 60 mph, I'm doing 66, at a reading of 70, i'm going 77, etc etc. Here's another good link to a few easy to use calculators:
http://www.tyres1.com/calculators.html
http://www.tyres1.com/calculators.html
#14
RE: Is my speed really that off?
I am trying to put a sensor on my dodge too and I have no white/org wire and there is no plug on the tail shaft of my tarnsfer case. I have on what is a 2 wire that is at the 7:30 position looking up at it from the ground towards the engine. But thats as far back as the plugs go this one is a blue and a green/blk wire. Noone has been able to tell me crap about this issue can you tell me were exactly the plug is and if it is a 2 or 3 or 4 wire plug and what the other wire colors are that go with it. Thanks.
#15
RE: Is my speed really that off?
what yall were sayin about the speedo being off with bigger tires is true but i just learned the other day that your speedometer is only calibrated to be accurate between 55-70 mph with the most accurate readings being in the 60-65 mph zone. when you drive a significant amount slower or faster (not just a few mph) your speedometer will be off by about 2-4 mph...not much, not even enough to matter but i just thought that it was an interesting point.
#16
RE: Is my speed really that off?
Everone should check their speedo and odometer against the mileposts.
It is a simple thing to do.
At a steady 60 mph ten miles of mileposts should go by at exactly 10 minutes.
Every 10 seconds off is a single mph fast or slow.
60 miles in exactly 1 hour (60 minutes)
is an even better test and is long enough to check your odometer accurately.
It is a simple thing to do.
At a steady 60 mph ten miles of mileposts should go by at exactly 10 minutes.
Every 10 seconds off is a single mph fast or slow.
60 miles in exactly 1 hour (60 minutes)
is an even better test and is long enough to check your odometer accurately.
#17
RE: Is my speed really that off?
my godfather siad it depends on the place you take it.. private garage will charge you more then the dealer because its a brand new truck accordin to them.. unless you know the guy.. if you wanna be safe and have some cash left in your pocket... instead of sorry take it to your local dodge dealer to fix it.. and yes the bigger the tires the more the speedometer is off...