Already went through the search button and can't find a solid answer on calibrating speedometer on a 2011 f150 3.7 with 33" tires. Already tried everything, diff gear ratio, diff tire circumference, disabled vid, nothing works. Is this even do-able? VCM Scanner does not have the tire calibration option.. not even latest BETA. Thanks.
https://forum.hptuners.com/showthrea...50+speedometer
This is all I could find.
did that and nothing
This is manual transmission ? can you post your base file ?
follow these steps: disable VID, enter the proper rear end gear ratio, Under " VSS Tire Revs Per" enter 611.15, Then for N/V base use this formula to calculate that value (611.15*60)(gear ratio) and divide that by 3600. Your speedo will be accurate within a .1 mph if you do all of this
Could somebody clarify for me/us some of these parameters? Am I understanding correctly that when the original file is read, the "final drive ratio" that is listed may not be the actual axle gear ratio since by default the PCM is "learning from BCM"? I have a value of "3.31" listed as final drive ratio, but truck has 3.55 gear ratio. Is it the same with the "driven tire circ"? I am changing out the gears and tire size on a 2011 F-150 5.0 auto. If I'm reading these threads right, I'll need to change both gear and tire size things from "learn from BCM" to "calibration. Change MIN and MAX tire to a range that will allow my tire size, enter my actual tire size, and then for "final drive ratio", enter the axle gear ratio I'm using? I primarily need the speedo to read correct, will just doing those things make it correct? Or do I need to also change the "N/V Base" value, Disable "VID" and change the "VSS Pulses Per Rev - Trans"(I do not have a "VSS Tire Revs Per" box and assume thats what this is)? In the post prior to this one, there are some maths. I assume the 611.15 is revs per mile of a 33" tire. My "VSS Pulses Per Rev - Trans" value is currently 40.0000 and my "N/V Base" is also 40.0000. If "VID" is enabled, does it disregard these values? And what is the 3600 value derived from in that formula? And I keep seeing posts about changing gear/tire size using VCM scanner, but I've tried 3 software versions and none had that option in "special functions". Should I be seeing that option? Sorry for all the questions, I'm just trying to figure what is doing what! So thanks in advance for any help! I'm currently using vers. 4.9.359betaOriginally Posted by aaronson
That?s just a constant I?m not sure where the 3600 come from that?s really just how I learned it. I believe there?s a thread I may be miss quoting but N- engine speed(rpm) and V- vehicle speed(mph). If you for sure know the vehicle has 3.55 then that value would need to be changed from 3.31-3.55 for the gear ratio. I?ll look at the tune here in a minute.
Ok so I looked at yours all you would change is the ?NV base?which uses the formula I posted. The max driver circle which is the circumference of your tire and then Change the gear ratio to 3.55 if that?s what you have. That should fix your speedo
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