Results 1 to 5 of 5

Thread: DRAC, RPM/VSS ratio or both?

  1. #1
    Fuel Injected!
    Join Date
    Dec 2016
    Location
    Colorado
    Age
    39
    Posts
    120

    DRAC, RPM/VSS ratio or both?

    My 93K1500 has the normal 7 jumper drac module and I know that I need to change my jumpers to read correctly with the tire size and gear ratio change. However, I can find a clear answer if I need to change the rpm/vss ratio in my bin as well? Or what this scalar is for? Im using $E6. Any info will be appreciated!

  2. #2
    Administrator
    Join Date
    May 2011
    Location
    Lakes Region, NH
    Age
    54
    Posts
    3,862
    Hello,

    The DRAC is in place to convert the transmission speed signal to 2k / 4k / 128k ppm signal for other modules. If it is adjust properly then all connected modules will receive a correct speed signal and no additional adjustments should be needed.

  3. #3
    Fuel Injected!
    Join Date
    Dec 2016
    Location
    Colorado
    Age
    39
    Posts
    120
    Perfect thats exactly the info I have been looking for. I just did the jumpers the way its shown on tbichips.com, and now its reading about 5 miles too fast..gonna have to look for more info on the jumper locations. Any other places to find info on that?

  4. #4
    Administrator
    Join Date
    May 2011
    Location
    Lakes Region, NH
    Age
    54
    Posts
    3,862
    http://gearhead-efi.com/gearhead-efi/doc/DRAC2.pdf

    Best way to determine ratio if calculating it is to get the "rolling circumference." 5mph difference is sometimes too small for DRAC to adjust. Is scantool speed correct? Could be an issue with speedometer reporting.

  5. #5
    Fuel Injected!
    Join Date
    Dec 2016
    Location
    Colorado
    Age
    39
    Posts
    120
    Quote Originally Posted by 1project2many View Post
    http://gearhead-efi.com/gearhead-efi/doc/DRAC2.pdf

    Best way to determine ratio if calculating it is to get the "rolling circumference." 5mph difference is sometimes too small for DRAC to adjust. Is scantool speed correct? Could be an issue with speedometer reporting.
    Tunerpro and speedo are both reading 5 fast. Not a big deal for me at all, I just wanted to get the trans shift points and everything factory like before I start tweaking anything with it. I have my rolling circumference and used the tool on tbichips site.

Similar Threads

  1. DRAC needed?
    By mmigacz in forum GM EFI Systems
    Replies: 1
    Last Post: 03-04-2016, 10:55 PM
  2. Overdrive ratio parameter
    By myburb in forum GM EFI Systems
    Replies: 3
    Last Post: 01-28-2016, 09:26 AM
  3. Rocker arm ratio
    By killface in forum Other EFI systems and related topics
    Replies: 12
    Last Post: 03-23-2015, 10:04 PM
  4. 95 tahoe vss correction via RPM/VSS Ratio?
    By bgwhtahoe in forum GM EFI Systems
    Replies: 0
    Last Post: 10-04-2013, 01:02 AM
  5. arf ratio at idel
    By ony in forum GM EFI Systems
    Replies: 21
    Last Post: 06-09-2013, 04:12 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •