DRAC, RPM/VSS ratio or both?

[Stokes1114]

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!

[1project2many]

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.

[Stokes1114]

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?

[1project2many]

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.

[Stokes1114]

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.