Power or Torque

Power or Torque - Which do you think is most important?



It's a simple question, but the terms power and torque are two of the most misunderstood and misused in our industry. When it comes to tuning, often we hear the request ‘I want maximum torque’, or ‘I want a tune for maximum power’, suggesting that the two terms are mutually exclusive. The reality is that torque and power are inextricably linked by a simple formula: Power (HP) = Torque (lbft) x RPM ÷ 5252. This formula means that provided there is RPM, we can’t have torque without power.

When we tune a car on a dyno, the dyno measures the torque being produced by the engine and then the power is calculated from the torque and the rpm at which the torque was produced. If we look at a dyno sheet showing torque (in lbft) and power (in hp), we will see that the two lines always cross at exactly 5252 rpm - At this point the RPM cancels out the constant of 5252 in the equation, and torque is equal to power. If we understand the relationship, it should be clear that torque and power go hand in hand, and if we optimise the torque produced at each rpm, we must also achieve maximum power at each rpm - We can’t have one without the other.

EFI tuning isn’t magic, and the engine’s ability to produce torque is an aspect of it’s mechanical design, not how good we are on the laptop. If the engine is provided the correct amount of fuel and ignition advance, it will make the torque it was designed to. Changing the actual shape of the torque curve, or where in the rev range peak torque is achieved requires mechanical changes to be made to the engine (cam timing for example).