Building Horsepower: the Pros and Cons of Turbochargers
“Turbo” is one of the most abused words in the English language. It’s used by marketers as a catch-all term for anything that’s supposed to act fast, from software to cold remedies. In reality, however, a turbo can seriously boost the amount of power an engine can turn out. The cost may or may not be worth the gains though, depending on the factors that we’ll look at in this article. What Does a Turbocharger Do? As we discussed in the last article on performance, internal combustion engines rely on a steady supply of air in order to ignite fuel. The more air molecules that can be squeezed into the cylinders, the larger the resulting explosion will be. Production vehicles are designed to supply less than the maximum amount of air the engine can handle, resulting in sub-premium performance. Turbochargers use a turbine driven by the exhaust system, which in turn operates a compressor that forces more oxygen into the cylinder. The results can be amazing; a turbocharged engine can easily be 30-40% more powerful than a standard motor. PHOTOS: See More of the 2013 Hyundai Veloster Turbo
PHOTOS: See More of the 2014 Porsche 911 Turbo S
Sound good? Well it is. But, as with all things in life, the benefits comes with drawbacks and possible pitfalls. Let’s examine those for a minute, so you’ll know what you’re getting into before laying down your hard-earned cash.
Factor #1: Lag
Turbochargers run at a rate that is set by the gas flowing through the exhaust manifold. Because of this, you shouldn’t expect immediate response when you step on the pedal; it will take a moment for the effect to kick in (though this can be pretty awesome).
Some models try to compensate for this with lighter blades or by using two turbines, a smaller one that kicks in quickly and a bigger one for sustained high-speed driving. This, of course, represents an added expense, one that may affect how easily your spouse approves funding for the project.
Factor #2: Knocking
Turbochargers can create so much pressure within the cylinder that the fuel/air mix detonates before the plug fires. When this happens, it causes knocking, a common complaint among vehicle owners. This problem degrades performance and can harm the engine, a concern that you or the technician who installs the turbo will need to deal with if and when it occurs.
PHOTOS: See More of the 2005 Saleen S7 Twin Turbo
Factor #3: Diminished Results
When properly installed and configured, a turbocharger can give a car or truck tremendous boost. I use the qualifier “properly installed and configured” to point out some pitfalls you may run into. For example, while a turbo puts a greater volume of air into the cylinders, its may not add more actual air molecules, which is the point of the whole project. This problem can be countered by cooling the air flowing into the cylinders, but, again, this will add to the price tag.
Another potential issue you might run into applies to more recent vehicles with computer-controlled components. When the turbine adds air to the mix, the engine will also require added fuel, otherwise it will run too lean. The problem is that some chips are programmed to inject only a set amount of gas into the cylinders.
PHOTOS: See More of the 2012 Pagani Huayra
This can often be overcome by reprogramming or replacing the control module, but this is another possible expense to consider. This is rarely a problem with carbureted systems, though every now and then a turbo requires the owner to install a new carb, in order to enjoy the maximum return on investment.
Adding a turbocharger is one of the easiest and most effective ways to give your vehicle more gumption. Keep in mind, though, that installing one comes with possible drawbacks. These are factors you will need to consider before making the jump to turbocharged power. Properly planned and well-installed, however, you’ll probably find that the challenges are more than made up for by the added power, speed, and sheer fun you will enjoy.