Vehicle performance will have an impact on every trip you take. Anyone who has spent time behind the wheel of a heavily-laden Vanagon has a story to tell about being passed by an old lady on a Hoveround during a routine hill climb. Conversely, those of you with keys to a burly full-size pickup know that you’ll never really need to tow the Space Shuttle.
Like everything else we’ve discussed in this series, balance is the key. Combining what you know about the type of terrain you’ll be traversing with your own driving style and the loads you’ll be carrying will permit you to shop for the proper vehicle to meet your needs.
Horsepower & Torque
To grossly oversimplify things, torque gets your movement started before horsepower takes over to accelerate and sustain the pace.
As we mentioned in a previous article, torque is a force that creates rotation. In this case, it’s the power of your engine being distributed to the drive wheels. Horsepower is nothing more than a byproduct of torque and engine speed (aka RPMs). Think of it like this: torque measures the ability for an engine to do work, and horsepower measures the rate at which that work can be done.
Together, they determine how much force your vehicle can supply with a specific load at specific speed and under specific operating conditions such as grade and resistance. The steepness of a hill, the type of surface, the weight of the vehicle, the size of its tires, and the aerodynamic drag, among other factors, all play a role in the effective and efficient transition of torque and horsepower from the engine to the ground. The more force your engine can provide, the more likely your vehicle is to overcome these parasitic draws.
So why does this matter to us? Because we overlanders love to bolt all sorts of crap onto our vehicles. The more of that you do – large tires, bull bar, fridge, a second battery, driving lights, roof rack, tents, awnings, and myriad other widgets – the more likely you are to desire extra torque and horsepower. But like anything else, you’ll pay for that in both purchase price and out of pocket economy.
There are a number of aftermarket products available which claim to increase the power output of your vehicle – cold air intakes, re-programmed computer chips, and larger diameter exhaust systems – and in some cases they are effective. I strongly encourage you to not go down this route. Today’s modern motors are finely tuned by factory engineers with lots of university degrees on their wall. In many cases, modifying any part can create unbalances in the engine’s systems and only serve to create long-term reliability issues. Some modifications may even void your factory warranty. The golden rule of engines is to change as little as possible.