richardpalinkas Posted November 12, 2018 Share Posted November 12, 2018 What method is best to recalibrate the speedo for different tyre sizes? I can calibrate the instrument cluster, but wondering if there is a better way to do this Quote Link to comment Share on other sites More sharing options...
Roland@pcmtec Posted November 12, 2018 Share Posted November 12, 2018 The best way is to just measure everything and put the values in. Note that the Mk2 FG doesn't use the VID block so any changes you make there will be ignored, they need the cluster to be reprogrammed with IDS. Edit: Instead of measuring you can simply measure the speed error with a GPS speedo, divide the speed measured by the speed actual and use that to multiply the rolling diameter. Quote Link to comment Share on other sites More sharing options...
richardpalinkas Posted November 12, 2018 Author Share Posted November 12, 2018 Haedll8. In vid block editing, just edit tge tyre size figure Quote Link to comment Share on other sites More sharing options...
Roland@pcmtec Posted November 12, 2018 Share Posted November 12, 2018 Correct. Providing the VID block is enabled, if its not enabled then you need to configure the "VIDBlock Calibration Overrides" value instead. Quote Link to comment Share on other sites More sharing options...
richardpalinkas Posted November 12, 2018 Author Share Posted November 12, 2018 Just checked auf0389, vid block has been disabled. Can this just be re enabled and adjust accordingly? Stock value says it should be enabled Quote Link to comment Share on other sites More sharing options...
Roland@pcmtec Posted November 13, 2018 Share Posted November 13, 2018 You can do whatever you want there. There is no real reason to use one over the other, typically other software did not map the VID block so historically a lot of tuners turned it off. The only benefit of disabling the VID is you can set the speed limit higher than 250kph which is useful for dyno tuning. Quote Link to comment Share on other sites More sharing options...
richardpalinkas Posted November 15, 2018 Author Share Posted November 15, 2018 (edited) so if a tyre size is 4% larger diameter, is it as easy as increasing this figure by 4% the current value is 0.7919921875, so the new figure should be 0.823671875? Edited November 15, 2018 by richardpalinkas Quote Link to comment Share on other sites More sharing options...
richardpalinkas Posted November 15, 2018 Author Share Posted November 15, 2018 Ok so for anyone else who wants to know what to do, this is what i did and works a treat. Calculate the difference between your current speed and actual speed. For me, my speedo was at 100, gps was at 102, so a 2% difference due to a larger tyre, ie. 275/35r19 instead of 275/30r19. In vid block scalers, find tyre size, should be 0.78 etc and minus 2% off this value. Reflash, and all good to go. 1 2 Quote Link to comment Share on other sites More sharing options...
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