For any automotive application, BHP (Brake Power) is considered key to a vehicle’s performance in the eyes of many people.
While this is technically true, it is relative to the weight of the vehicle. To illustrate this, I will show you the specs for a Lotus Elise and a Vauxhall Astra VXR.
– Lotus Elise 1.8ltr / 120HP engine weight 756Kg
– Power / weight ratio = 158.73 Hp (per ton)
– Engine weight Vauxhall Astra VXR 2.0ltr turbo / 240HP 1318Kg
– Power / weight ratio = 182.09 Hp (per ton)
Even though the Astra VXR has twice the available horsepower in its engine, the weight of the Lotus Elise reduces that power from 120HP to 23.36HP.
And to illustrate the point even more clearly, let’s take a Kawasaki Ninja 250R motorcycle:
– Kawasaki Ninja 250R 0.250ltr / 32.18HP engine weight 169Kg – Power / weight ratio = 190.41 Hp (per ton)
The motorcycle has almost 7.5 times less hp compared to the VXR, but it levels out and actually outperforms the car in terms of HP / Ton due to its weight. This HP / Ton idea works the same for torque. If you take a lighter vehicle and a heavier one with the same HP, the lighter model will accelerate better (since everything between the two vehicles is the same apart from the weight)
But it also becomes an advantage in steering, suspension, braking and economy. A lighter vehicle will have a better change of direction than a heavy one. The suspension performs better with less load and allows for greater adjustability. Stopping distances can be significantly reduced and fuel economy can be increased because the engine has less to haul. Most performance-oriented parts can perform better because they have less to pull, stop, and suspend.
So there you have it, in my opinion, weight is the key factor for a good performance machine, in the next part I will discuss how to reduce the weight of your vehicle economically, expensively, but most importantly safely.