L
lecroy
Guest
After talking about kill times and air pressure I decided to measure my old bike for fun. I took an LVDT and an oscilloscope to the garage. I was very surprised by the results.
The LVDT was setup to measure the full travel of the shift arm. I triggered the scope using the output signal from the Command Center. This way I could measure the time from when the Command Center signaled the air shift solenoid to turn on, to when the arm was in it's full travel position. I filled the tank to 160 psig and ran the shift as normal. I use an air clutch that dropped the pressure to 150 psig right from the start. The first shift took only 25mS! Yes, that's right, 0.025 seconds! The pressure dropped to 140 psig. Shift 2 was 27mS and the pressure dropped to 130. Third shift was 29mS and the pressure dropped to 125. The fourth and final shift was 31mS and the final pressure was 120psig.
I then set the Command Center to allow more shifts and took a few more points. The time stayed about the same all the way down to 90 psig. At 80 psig it was 35mS. At 70psig it was 40mS. At 60 it was 46ms. At 50 it was at 48mS. At 40psig it started really slowing down to 60mS. At 30psig it did not have enough force to shift.
The next time you drive your street bike, when you start to accel try and move the shifter. You can't (assuming you have angle cut gears). Keep the pressure on the shift arm and then blip the throttle just enough to unload the engine and the bike should shift. I have seen autos setup where they delay the kill until the arm moves into the load position and then kill. I agree that this is a better way to shift, but I drive the ignition kill at the same time I turn on the air.
I had heard of people running sub 50mS of kill time. The Dyna would not let you go below this but I can set it to 0.001 seconds with my new software in the Command Center.
So, if you want to shave everything out of the shift, high pressure is good. Fast vales are a must. Closed loop kill time is a must if you need kill at all
:twisted: Keep the lines as large and short as possible. Use the right cylinder for the job and the right air tank size.
Now that your all tired of my blabbing......
The LVDT was setup to measure the full travel of the shift arm. I triggered the scope using the output signal from the Command Center. This way I could measure the time from when the Command Center signaled the air shift solenoid to turn on, to when the arm was in it's full travel position. I filled the tank to 160 psig and ran the shift as normal. I use an air clutch that dropped the pressure to 150 psig right from the start. The first shift took only 25mS! Yes, that's right, 0.025 seconds! The pressure dropped to 140 psig. Shift 2 was 27mS and the pressure dropped to 130. Third shift was 29mS and the pressure dropped to 125. The fourth and final shift was 31mS and the final pressure was 120psig.
I then set the Command Center to allow more shifts and took a few more points. The time stayed about the same all the way down to 90 psig. At 80 psig it was 35mS. At 70psig it was 40mS. At 60 it was 46ms. At 50 it was at 48mS. At 40psig it started really slowing down to 60mS. At 30psig it did not have enough force to shift.
The next time you drive your street bike, when you start to accel try and move the shifter. You can't (assuming you have angle cut gears). Keep the pressure on the shift arm and then blip the throttle just enough to unload the engine and the bike should shift. I have seen autos setup where they delay the kill until the arm moves into the load position and then kill. I agree that this is a better way to shift, but I drive the ignition kill at the same time I turn on the air.
I had heard of people running sub 50mS of kill time. The Dyna would not let you go below this but I can set it to 0.001 seconds with my new software in the Command Center.
So, if you want to shave everything out of the shift, high pressure is good. Fast vales are a must. Closed loop kill time is a must if you need kill at all
:twisted: Keep the lines as large and short as possible. Use the right cylinder for the job and the right air tank size.
Now that your all tired of my blabbing......
