R33 GTR Speedo in G4+ Posted April 9 · Report reply Hi, Thanks for the replies and information. I want to have accurate control of the Speedometer, currently it uses a converter chip to adjust it from KPH to MPH and this keeps dropping out intermittently. There is a way of converting it to MPH inside the speedo head but you have to cut and bridge certain jumpers between 1 and 9 and each one of them tweaks the speed reading slightly so would involve a lot of removing the head, soldering the jumpers then road test against GPS and then adjust again and there is no real information about which jumpers control the reading by how much so could be very time consuming. I originally thought just feed the signal to the ECU and let the ECU control the speedo, then I remembered the speedo receives the signal from a VR so I just thought if the speedo is driven by the square wave after the VR signal has been conditioned I could bypass the conditioning chip and drive it directly. This would mean I could ditch the converter chip, make speedo adjustments easy and also, it does bug me a little that I can have RPM sweep but not Speedometer sweep. It isn't critical as I can carry out the mods to the speedometer but really would like to use the ECU to control it. Thanks again, Edward.