Post by 90GTVert on Feb 14, 2010 17:34:11 GMT -5
Torque Driver Modification
Before you begin reading this, if you are unfamiliar with the torque driver or need help removing or installing it, CLICK HERE.
There is a fairly simple modification that can be done to many stock torque drivers to give you a slight increase in gearing potential for more speed. The torque driver has 2 paths cut into it where pins ride. The length and and angles of these paths determine the amount of travel that the rear pulley has and how quickly the pulleys open and close. Other factors, such as clearance with other moving parts and contra spring tension have an affect on pulley function as well, but the torque driver is where it all begins.
Here you see a path in a stock torque driver from a 1E40QMB 2 stroke engine. Notice that the path gets very close to one grease seal, but there is a roughly 2mm left to the grease seal on the other side. The side that has a closer clearance is what controls how far the pulley can close. The side with room to spare controls how far the pulley can open.
This image shows the distance that the maximum distance that the rear pulley can open in stock form.
By lengthening the paths in the torque driver with a dremel or other tool, you can create more potential for travel. I say potential for travel because you may be limited by clearance with other parts of the rear pulley/clutch assembly or roller/spring tuning to allow the pulley to open farther. In this case, I had more room for the pulley to open, but I prefer to leave a little material between the paths and the grease seal.
That is as far as I went with my torque driver modification for now. If you have the patience and the proper tools, you could potentially cut two new paths for the pins to ride in. Changing to greater or lesser bends and angles could help tailor the torque driver to your needs or tastes. The straighter the path, the easier the pulley will be able to change positions. Making a path with no bend would make the rear pulley open and close in a more linear manner. Creating more of a bend would have the opposite effect. You could change the position of the bend as well to suit your preferences. The angle of the paths helps to control how easily the pulley resists opening and closing as well. A path that runs straight up and down would offer little resistance to change, while a path with a great angle would resist change.
Be creative and be careful and you can probably make your stock torque driver function better with no money spent.
