Quote:
Originally Posted by Dusten
they dont even sell a tru speed for our trucks. and all the other reprogram style only correct to 35" tires.
i would love to elaborate, as in essence, you are not doing anything close
it isnt the same, because much like a mass air flow extender on high horsepower cars it doesnt reprogram the computer to understand what is going on, it changes the signal to the computer, so the computer is happy.
Its an interpreter for lack of a better word. instead of you learning spanish to talk to your neighbor, you hired someone to stand on the fence and shout back and forth between the two of you.
you are correct, ford does not change the calibration based on what tires are on the truck.
2% is an acceptable error, that means when your speedo reads 60mph you are going *gasp* 61.2.... or for every 100,000 miles, you are really going 102....
My speedo with 37's is only off by 10%. But, i have stopped using it, and just use my gps for speed anyways
they arent fooling anything. the computer knows that your tires makes X revolutions per mile, so you tell it that now, they take Y revolutions. that isnt fooling anything, that is telling it the parameters have changed.
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Good post dusten, I appreciate your in depth description
I will say however, since the programmers do not do over 35, then isn't the only option an inline device?
I thought Truspeed did make them for the 08, I know speed wizard is on many 08's and no problems.
From my experience, I have a 2003 F250 5.4L gas engine, my computer was programmed from the factory with 31.7" tires (stock ones) i never had the computer re-programmed EVER, other then me using my tuner to change tire size (which did nothing by the way)
The engine or tranny on my truck does not use "speed" from the ABS module, and as a matter of fact (i have spent a lot of time researching this), based on my research, the only ford engine / tranny from 99 04 that does use the speed signal is the 7.3L, but when you correct the signal in the right spot (before it gets to the engine/tranny) then the engine/tranny will use the correct value.
What about on the older trucks, when no computers were even involved... the speedometer was corrected by a speedometer gear, this method has worked well for many years, to me an inline device is doing in essence the same thing.
It is changing the amount of pulses PER revolution, and that is what the reprogramming of the computer is doing.
Sure I have to agree that when you use a programmer the computer knows how many pulses per revolution it is getting, and it is the right value. But is there any functional difference between that and just sending the computer a modified value?
When you put larger tires on you the same pulses per revolution as before but you will travel more distance (therefore 30mph as indicated is actually more)
change from 31.7" to 35.5" thats a multiply factor of 1.1198 lets call that 1.12
So what the inline device does essentially is where it used to be 100pulses/sec for 100mph actual, it will will make it 112 pulses per second at 100 mph - this makes the speedometer read correctly.
It sounds to me like you have something against in line devices?
they do the job just as well as changing the program in the computer, they do not cost anything if you want to change the value, and you can change it as many times as you want, or go to stock all in the luxury of your own driveway, cant do that with a ABS module flash
sorry if i am coming across blunt or ignorant, I just do not understand why anybody would be against inline devices where actually there is nothing else that WILL work...?
Thanks for the quick response
Kenny