Dallas speedcal questions

[LaserRed_Snake]

Hey everyone, so I recently bought a Dallas speedcal. So the reason for buying it was I have a newer t45(oss) In my cobra. What dip settings should it be set at? I have stock rear end gears(3.27) and stock tire size(245/45/17)


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[scottydsntknow]

Is it the extended range one? If not you won't be able to use it. If you got it new from Dallas then its not. If you got it secondhand from someone and its like 3 or 4 years old+ there's a good chance it is.

 

[LaserRed_Snake]

Man tbh I wouldn’t know it’s new with no badging on it


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[LaserRed_Snake]

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[LaserRed_Snake]

What the board looks like


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[scottydsntknow]

You can't tell by looking at them... I can dig into my old posts and try to find the calculator that does the extended switch settings. If it works great, if not you are gonna have to go find an older used one.

 

[scottydsntknow]

Found the calculator. Stock tire size and 3.27s the switch setting is 1000000000. 1 is up and 0 is down so the 1st switch up and the rest down. If it works great, if not then you've got a standard range one.

And so you can DIY next time here is the calculator.

https://accutach.com/speedcal-calculator

Math is revolutions per mile times gear ratio times pulse count. You can find tire revolutions per mile on tirerack or discounttiredirect for whatever size. Stock 25.7" tires are 815 revolutions per mile. 3650 OSS pulse count is 12. 4R70W is 6, 4R75W is 24.

So for you it is 815x3.27x12=31,980.6 VSS pulses being sent to the computer. It needs to be getting 8,000 to be accurate. So the extended range switch setting takes that 31,980.6 and scales it down to 8,000. The standard one doesn't have the range to take a number that big down to 8,000.

 

[LaserRed_Snake]

What the board looks like


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[LaserRed_Snake]

Scottydsntknow thanks man really appreciate you! Well only one way to find out is to instal and try it out. Hopefully here in the next week or 2 I have some time to mess with it!


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[jman37]

You can't tell by looking at them... I can dig into my old posts and try to find the calculator that does the extended switch settings. If it works great, if not you are gonna have to go find an older used one.

What is the difference between the 2? And if only the extended range one works, then why was there another model that doesn't do anything?

 

[Tabres]

What is the difference between the 2? And if only the extended range one works, then why was there another model that doesn't do anything?

I'm not going to regurgitate it all here, but if you're interested forum member mwolson wrote a great article regarding the differences between VSS and OSS and how to handle them, which leads to why there is a standard speedcal and an extended range version.

https://img1.wsimg.com/blobby/go/1975f84f-4935-4131-8404-5a914da1afb7/downloads/1brke6aet_808115.pdf

If you ever have electrical questions on these cars, Mark (mwolson) is a retried EE and a national treasure of this forum. He owns and runs accutach. He's a great guy to reach out to. Accutach Company

 

[scottydsntknow]

What is the difference between the 2? And if only the extended range one works, then why was there another model that doesn't do anything?

TBTH I think it was cost... That company is kinda meh regardless... they had a good speedcal for a few years... that was about it.