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Mech. to Electric Speedo

Discussion in 'The Garage' started by zcarczar, May 18, 2005.

  1. zcarczar

    zcarczar 1/2 ton status

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    I want to swap my mechanical speedo over to electronic. What do I need for this swap? Dyeager or anybody done this swap or know what is needed? I plan on running an autometer speedo if it matters, but still want the VSS signal for the computer.
     
  2. sled_dog

    sled_dog 1 ton status

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    You read my mind, I meant to ask this last night. I know int he Doubler article the boss man claimed no one was making one, just wondering if that still the same. I need VSS to go with my Doubler using a Ford 205.
     
  3. dyeager535

    dyeager535 1 ton status Premium Member

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    I've done the swap, but the truck doesn't move, so the only thing that says I did it right is the gauge "zeroing" when I turn the key. :)

    (here's my DRAC post

    Really only need to know what pulse the speedometer operates at. There are enough outputs on the DRAC to run both the speedo and ECM, so that isn't a concern.

    Only problem with DRAC is that you need the 40 tooth reluctor setup. That reluctor is pretty hard to retrofit, otherwise your "stuck" with the later 241 or 205. I really like the DRAC/electric speedo setup (easy to modify for gearing, tire size, and accurate) but that's also because I have the 205 to work with it.

    jagsthatrun has a bunch of different options for VSS, perhaps they have an adapter that has two electric outputs that you could use.
     
  4. zcarczar

    zcarczar 1/2 ton status

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    Sweet, I have the later version 241 in my truck so that will work perfect.
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

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    As long as you have the VSS on the case, DRAC swap is a no-brainer. Only concern then is what the aftermarket speedo uses as input.
     
  6. sled_dog

    sled_dog 1 ton status

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  7. dyeager535

    dyeager535 1 ton status Premium Member

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    I was just reading somewhere else (thirdgen probably) about an inline jeep VSS "generator". I think it was some other "pulse" though.

    All the ECM needs/wants is 2000PPM. I KNOW jagsthatrun has ones that will work for that.

    jagsthatrun's VSS section (excerpt from the book online!) shows pretty much all of the options, another one is VSS driven off the speedometer gear, think that was a police/taxi thing on some applications. No idea if any of those will work with a transfercase.
     
  8. sled_dog

    sled_dog 1 ton status

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    Yes I just read through the JTR book on their site and mentioned exactly the one I think I need. According to them you are incorrect about the 2000PPM. It says 90-92 TPI is looking for 4000PPM, need a 4 pulse sensor. The one I found there (page 5, #4) is a speedo cable that threads in and has a VSS sensor on the end of it(10" length of cable). Looks like that should be perfect. I will give them a call or email.
     
  9. K5MONSTERCHEV

    K5MONSTERCHEV 1/2 ton status

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    I have a electric speedo in my blazer. I love that its accurate and I can recalibrate it whenever.
     
  10. zcarczar

    zcarczar 1/2 ton status

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    Ok, so it looks like im going to need a DRAC from a '90 Blazer that is for the 2000PPM setup like I have, and I can get the wiring diagrams for it at work and set it up accordingly im geussing unless someone knows something I dont.
     
  11. dyeager535

    dyeager535 1 ton status Premium Member

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    For 90-92 TPI that's probably right...I was talking about the '747 (TBI) and '165 (MAF) ECM inputs.

    As to DRAC donors, Astro's, S10's, and the R/V '90-91 are donors, probably others. But the Astro's are so easy to find...
     
  12. zcarczar

    zcarczar 1/2 ton status

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    I got a DRAC coming, I was lazy and just had the parts guys order me one. It was $50, now I just need to make it adjustable.
     

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