RomRaider

I am going to play around with this and see if it also is an output to the Dash.

Anybody else looked into this? Supposedly it can't be done...

Where might you see this?

It's quite easy to find. I found it by tracing the vehicle speed parameter from where it pulls from the atu. Just before it loads the parameter it's multiplied by a float value of 1.0. Change that to whatever your new ratio is and you've got a calibrated ecu.

Subroutine 10dd0 in a8dh20xx

Definitely does not directly effect dashboard. Didn't have enough time to scan to see its full effect, but mph matched rpms from prior. Tried 1.5 as the multiplier so it would have been obvious.

VSS signal goes directly to combination meter in 06-07wrx, but in CAN vehicles, same modifier most likely will affect speedo output

If somebody has a can rom and wants me to dig it out to see let me know which Rom and you can be the first.

In CAN vehicles speed info comes from the ABS unit (wheel sensors) and transmission via CAN.
I doubt the ECU can do anything to the value as the combo meter will most likely pick the value off the CAN bus.

Except that in 08+ ABS and Combination meter connected to different CAN lines, so speedo gets signal indirectly either through BIU or ECU -> BIU, so it's still worth investigating