While electronic engine controls have enabled engineers to create more powerful and fuel-efficient cars, they’ve also created a barrier between automotive technology and the home mechanic. Two decades back it was still possible to modify an on-board computer by replacing the chip or PROM (programmable read-only memory), but thanks to tightening emissions controls, that is no longer the case.
If the engine control module (ECM) is essentially a sealed unit, what can the mechanically-inclined car enthusiast do to boost horsepower and enhance performance? As it turns out, quite a lot.
The traditional approach to boosting horsepower was to raise the volume of combustibles by installing a higher capacity carburetor, high-rise intake manifold, and open exhaust. In the days before federally mandated emissions controls, richening the fuel mixture to produce a mild power boost was as easy as turning an adjustment screw on a carburetor.
Old school is to push more fuel through the engine. New school is to reduce inefficiencies by flowing more air through it. In other words, the newer and equally valid approach is to make the engine more efficient, because internal combustion engines lose nearly half their energy through inefficient combustion and internal pumping losses.
While computerized engine controls, direct injection, and variable valve timing have increased engine efficiency significantly versus cars built 50 years ago, there’s still a big margin for improvement. By boosting the volume of air going through the engine, the tuner gets more power out of the same gallon of gasoline. Spark plugs designed for racing applications are more resistant to corrosion and can produce a hotter spark for more efficient combustion.
Borla 14834 S-Type Cat-Back Exhaust System
High performance air filters, cold air kits, less restrictive cat back exhausts and high performance spark plugs can all add significant horsepower to a vehicle without affecting emissions compliance.
If your vehicle didn’t come equipped from the factory with a stainless steel exhaust system, installing one is an important first step. Since exhaust pipes tend to corrode from the inside out, you might not be aware of restrictions in the exhaust due to the build-up of corrosion.
An example of plus sizing using a large diameter alloy wheel and low-profile summer performance tire.
Those who want to push the envelope further should consider a supercharger or turbocharger that can boost engine horsepower by as much as 45 percent under wide open throttle.
Whether you decide to do the job yourself or hire a tuner, the first step should always be a baseline chassis dyno test to get a real-world assessment of how much power is going to the wheels. When planning your tuning project, remember that power to the wheels is the only power that matters, so your suspension, wheels, and tires will need to accommodate whatever you are adding under the hood.
Plus-size wheels and tires increase the size of the tires’ contact patches with the ground for better traction and make the wheel and tire package stiffer. Those willing to put up with a firmer ride will enjoy better control during cornering. In addition to enhancing performance, some wheel designs can also reduce a car’s aerodynamic drag, making the vehicle slipperier in the wind. Performance summer and winter tires also improve performance because they are optimized for hot and cold temperatures respectively, as opposed to all-season tires that are more of a compromise.
Consider swapping existing suspension components for higher performance shocks and coil-over springs, adding a strut tower brace and/or adjustable strut mounts in place of the vehicle’s fixed rubber mounts.
Adding power under the hood means that the braking system will have to work harder, so consider upgrading that as well with bigger rotors, multi-piston calipers and higher temperature brake pads.
