dip switches on a speedcal

[crash549]

my brother and i just had a failed attempt at putting my speedcal in. i'm wondering what to set the dip switches at on my speedcal with 4.30 gears and 285/35/18 tires. i'm going to jack it up again tomorrow but we just ran out of daylight and my speedcal didn't come with any instructions. any info would be appreciated. thanks.

 

[SVT CAMR]

I would just call Dallas Mustang and get the info and be done. If you some general install info check out american muscle they have install directions on their site with some general dip switch setting.

 

[mwolson]

I wrote a couple of calculators that can help you.

First, you need to know if it is an old standard range Speedcal or the new extended range Speedcal. All they are selling now is the extended range unit.

From the tire size calculator here: Tire Size Calculator - Discount Tire Direct, you can see that your tire revs per mile are 780.07.

Based on my VSS calculator here: Ford VSS Calculator, you can see that your VSS signal is now at 9886.360842105263 pulses per mile.

Putting that into my Speedcal calculator: Recalibrator & Speedcal Calculator, you can see that your speedcal switch settings need to be 1001111001 for the standard range Speedcal or 0010011110 for the extended range Speedcal.

 

[mwolson]

BTW, this assumes you have not changed your stock speedometer gears. If you have changed them, then you need to put the correct teeth counts into the calculator.

 

[94svtford]

0010101000 is the 3.27 to 4.30 dip switch setting as for tire height im running same size tire in rear shouldnt even be noticable difference the 18's are only 4.40 mil. or so taller from stock so that would be a -0.34 mph at 50 mph. so you wouldnt even notice.
heres a link to a nice little tire calc. i always use. It allows you to compare
www.dakota-truck.net/TIRECALC/tirecalc.html

 

[crash549]

thanks everyone. i'll try to get it working today.

 

[mwolson]

0010011110 gives you a speedcal multiplier of 1.234375
0010101000 gives you a speedcal multiplier of 1.3125

0010101000 will be off by about 6% with your setup. It is up to you what you want to use.

 

[Dirtbikes4fun02]

The speed cal crash as is a lil confusing since it only came with the first page of direction. His speedcal has 2 sets of dip switches a row of 10 and a row of 8... I gather that the numbers yall r giving him is for the set of 10. But what do we set the row of 8 at?

 

[mwolson]

You are not supposed to mess with the settings on the other switch bank. I am pretty sure I have seen photos that show those switches set on the internet on pages that say how to install Speedcals...

 

[94svtford]

supposed to have just the number 1 activated on row of 8

 

[94svtford]

0010011110 gives you a speedcal multiplier of 1.234375
0010101000 gives you a speedcal multiplier of 1.3125

0010101000 will be off by about 6% with your setup. It is up to you what you want to use.

i used my 4.10 dip setting with the same size tire and i had my friend ride aside of me, my speedo was dead on.

 

[Dirtbikes4fun02]

So just the first switch on for the bank of 8... I think they r all turned off right now.
That may be y the speedometer stayed at 0mph... Or I might have a wire crossed, I gotta look under his car again tonight. I put the colored wire from his stock vss in the new speedcal harness and mated it to the grey wire from the speedcal plug. Is that right? Cause I have read if they r reversed it will also cayse ur speedo to read 0mph

 

[mwolson]

i used my 4.10 dip setting with the same size tire and i had my friend ride aside of me, my speedo was dead on.

That doesn't make sense given the math. I wonder if 6% error is too small a difference to notice given that kind of a road test.

I'm not trying to put your results down, but I have the math down cold. :shrug:

 

[Dirtbikes4fun02]

0010011110 gives you a speedcal multiplier of 1.234375

So that is the code I need to put in for 4.30 gears and a 285 35 18 tire? And that's as close to perfect as possible, right?

And assuming crash's speedcal may be the extended range, is that the right code for that?

 

[mwolson]

0010011110 gives you a speedcal multiplier of 1.234375

So that is the code I need to put in for 4.30 gears and a 285 35 18 tire? And that's as close to perfect as possible, right?

And assuming crash's speedcal may be the extended range, is that the right code for that?

That is the correct code for crash's setup, assuming he has an extended range speedcal and stock speedo gears.

The best way to test it is to find a place where they have accurately marked out up to 5 miles. If you drive those miles at exactly 60 MPH on the speedo and time yourself, you should take exactly one minute per each mile. Where I grew up, they had a section road every mile so it was easy back there.

You guys can all check my math because I posted it on the calculator pages below the calculators.

For those of you who are into math, the speedcal switch setting is a 10 bit, fixed-point number with a 3.7 format. The first digit represents 4, the second 2, the third 1, the fourth 0.5, the 5th 0.25, the 6th 0.125, the 7th 0.0625, the 8th 0.03125, the 9th 0.015625 and the tenth 0.0078125. Just add up the numbers corresponding to the bits that are 1, and you have your multiplier.

 

[94svtford]

That doesn't make sense given the math. I wonder if 6% error is too small a difference to notice given that kind of a road test.

I'm not trying to put your results down, but I have the math down cold. :shrug:

road all the way up to 80 mph "fast as we went" and still was dead on with a 05 navigator speedo, of course the speedo is never gonna be dead on but i think 6% is gonna be hardly noticable.

 

[crash549]

i sware i'm going not going to put this off like most projects. it's so ****ing loud driving my car with the shifter plate off. maybe this weekend.:shrug: