Competition Super-nice AWD Dyno in Georgia!!!!!

[jetenginedoctor]

So, tractive effort and gearing are related in that a change of gear can help you gain or loose a certain amount of tractive effort... am I following you right? You have a given amount of tractive effort depending on horsepower produced and depending on what sort of gearing ratio etc. you use, you are either using it or losing it through your drivetrain. Indirectly it is a reflection of torque?



Scott

Exactly. You can increase tractive effort by increasing HP, or by torque multiplication. If you increase torque without torque multiplication, you'll automatically make more HP (remember the formula. ) An increase in torque without an increase in HP will yield an increase in tractive effort, but across a smaller range of vehicle ground speed. The trick is to choose gears so that as the vehicle accelerates and the transmission is shifted, that the engine falls into it's range of highest HP, thus its highest tractive effort and acceleration.



I'll test a car on Monday so that I can better illustrate this concept. When you plot tractive effort over wheel speed, you can see where each arc overlaps the one before and after it. The idea is to choose your shift points at the point where the corresponding arcs are at their highest overlapping points. It'll make a lot more sense when I can put it on the screen for you.



BK