Cruise control speed limits and 180km/h limit
Long read....... sorry.
There was a discussion going during NG about cruise control and how it was limited to 110km/h in the AUDM cars and the JDM cars but there is no limit on the USDM cars. I have looked into the cruise control part numbers and they are the same so it's not the computers. My suspicious was the actual speedo its self but I'm not sure about this. It can only be the speedo PCB or the main ECU. So.... has anyone modified their speedo as per my how-to thread and tested their cruise control [above 110]? or has anyone cut the wire to pin 66 on their ECU [disables the 180km/h speed limit] and tested cruise control above 110km/h?
Also might as well keep it to the one thread. The 180km/h limit can be circumvented but cutting pin 66. However our ECU's also use pin 66 to detect if the vehicle is moving and adjusts the idle accordingly. IE stop at lights the idle is raised. So if the signal is not received then the car doesn't compensate and it could idle out or very low when stationary. This can be avoided by simply manually raising the idle. However there was also discussion about this signal also being used [on 2nd gens] to control cooling fan speeds. Fan speed increases etc when stationary. So there is a device by HKS designed to get around all of these. A member on here has one fitted to get around the 180km/h limit.
So to finally get to the point, I suspect the speed conversion chips we used to first create the 280km/h speedo can be used in the same way. This chip converts the signal and turns the speedo from a 180km/h speedo to a 180mph speedo. This also changes the speed limit to 180mph instead of km/h. Everything else works the same and the ECU still compensates for the idle etc. What I suspect is possible is to cut the wire to pin 66 in put the converter chip inline here instead of at the speed sensor on the gearbox. That way all other devices that use the speed sensor's signal would not be effected [cruise control, AA, ECS & speedo] and simply trick the ECU into moving the speed limit from 180km/h to 180mph. If the ECU controls the cruise control then it should also in theory increase the cruise control limit to 110mph instead of 110km/h.
1990 JDM GTO TT, oohnoo fuel loop & rail adapters, K&N FIPK, Vi-PEC plug-in V44 EMS, Iridium plugs, Turbo XS racing BOV, ARC SMIC's
"Work in progress"
Last edited by GTOJOE; 02-13-2013 at 06:09 AM.