Megasquirt values for launch and traction control on 3G swap
I'll try to get a picture the next time I pull the cover off to work on things to show it actually installed, but the short version is I have a potentiometer attached to the pedal with a string and a spring on the other end to keep tension on the setup. It's a similar idea to a string pot for measuring distances, just a bit more homemade and short throw.
Here's a nice 3d model I put together when I printed the pieces mixed with horrible MS paint to fill in the blanks, lol:
I had the pot left over from a motion platform I built for racing in VR. It's hall effect, not a wiper, so it doesn't drag or wear out over time and has really clean output. My clutch master has a 1.2" stroke, so I designed the arm on the pot to match that and targeted ~120 of rotation over that travel (the pot is only a 180 deg variety). Currently I appear to only use about 75% of the travel before my pedal hits the floor according to TunerStudio at least. The whole idea behind this was I could set an virtual variable in the computer that would toggle on and off based on the voltage coming from the potentiometer. That way I can tune when I want the switch to "open" or "close" electronically instead of having to constantly tweak a bracket for a physical switch. I still need to do some more logging with that as well to see where my clutch is starting to engage/disengage maybe before I even set a launch rpm.
Front wheel speed is reading the heads of the lugs inside the rotor on the front right wheel, rear wheel speed is the factory speed sensor in the T56 trans I'm using. I checked them in TunerStudio and did some logs and they seem to agree quite well, though there is obviously a resolution issue at super low speed since the front only has 5 teeth per rotation while the transmission sensor is 10 teeth multiplied by the rear end ratio (so effectively 35.5 teeth for me). I tried putting an indicator on my digital dash for when traction control is pulling timing, but I'm not sure if it actually works or not. I know you can set an indicator light output on the computer, but I don't have the output channels to spare at the moment. I've thought about trying to fake it out by running on jackstands and manually turning the front wheel or something, but I don't think that would really work that well with all the other threshold values that the computer looks for. I think I know what you mean about the low speed issue though. My current setup has the minimum TPS at 40%, minimum MAP at 60 kpa, and minimum speed at 4.9 mph. I think I instinctively let off when the wheels start spinning, so guessing I drop under the TPS and MAP thresholds fairly quickly instead of riding it out and letting the computer pick up the slack. I think the 4.9 mph was the lowest I thought the front sensors could read smoothly from logs I'd done before. It has a bit of a stairstep effect due to the low tooth count. I'm also seriously rethinking my launch rpm. I tried looking up what factory settings Dodge uses on the cars that come with it. They typically run pretty low, like 1600 rpm or something like that, but I think a lot of them are automatics as well and may not be able to launch any higher due to converter stall speeds. I'm a stick shift so not a problem there, but I don't think my car has the suspension to actually do anything with a hard launch anyway.
I'll try to get a picture the next time I pull the cover off to work on things to show it actually installed, but the short version is I have a potentiometer attached to the pedal with a string and a spring on the other end to keep tension on the setup. It's a similar idea to a string pot for measuring distances, just a bit more homemade and short throw.
Here's a nice 3d model I put together when I printed the pieces mixed with horrible MS paint to fill in the blanks, lol:
I had the pot left over from a motion platform I built for racing in VR. It's hall effect, not a wiper, so it doesn't drag or wear out over time and has really clean output. My clutch master has a 1.2" stroke, so I designed the arm on the pot to match that and targeted ~120 of rotation over that travel (the pot is only a 180 deg variety). Currently I appear to only use about 75% of the travel before my pedal hits the floor according to TunerStudio at least. The whole idea behind this was I could set an virtual variable in the computer that would toggle on and off based on the voltage coming from the potentiometer. That way I can tune when I want the switch to "open" or "close" electronically instead of having to constantly tweak a bracket for a physical switch. I still need to do some more logging with that as well to see where my clutch is starting to engage/disengage maybe before I even set a launch rpm.
Front wheel speed is reading the heads of the lugs inside the rotor on the front right wheel, rear wheel speed is the factory speed sensor in the T56 trans I'm using. I checked them in TunerStudio and did some logs and they seem to agree quite well, though there is obviously a resolution issue at super low speed since the front only has 5 teeth per rotation while the transmission sensor is 10 teeth multiplied by the rear end ratio (so effectively 35.5 teeth for me). I tried putting an indicator on my digital dash for when traction control is pulling timing, but I'm not sure if it actually works or not. I know you can set an indicator light output on the computer, but I don't have the output channels to spare at the moment. I've thought about trying to fake it out by running on jackstands and manually turning the front wheel or something, but I don't think that would really work that well with all the other threshold values that the computer looks for. I think I know what you mean about the low speed issue though. My current setup has the minimum TPS at 40%, minimum MAP at 60 kpa, and minimum speed at 4.9 mph. I think I instinctively let off when the wheels start spinning, so guessing I drop under the TPS and MAP thresholds fairly quickly instead of riding it out and letting the computer pick up the slack. I think the 4.9 mph was the lowest I thought the front sensors could read smoothly from logs I'd done before. It has a bit of a stairstep effect due to the low tooth count. I'm also seriously rethinking my launch rpm. I tried looking up what factory settings Dodge uses on the cars that come with it. They typically run pretty low, like 1600 rpm or something like that, but I think a lot of them are automatics as well and may not be able to launch any higher due to converter stall speeds. I'm a stick shift so not a problem there, but I don't think my car has the suspension to actually do anything with a hard launch anyway.
