If you want to make the most of the engine you’ve got, maximizing the horsepower by modifying the airflow, exhaust, and overall engine performance can give you the power you’re looking for. You can max the efficiency and the performance of your vehicle with a few alterations and tips. See Step 1 for more information.
Maxing Engine Efficiency
Make the vehicle as light as possible.The simplest and cheapest way you can get the most efficiency and power out of your engine is by giving it the least amount of car to power. Even dropping 20 pounds will help you accelerate faster. Remove excess junk from your trunk and cab, and consider making extra modifications that will lighten your load:
- Remove the rear seats, which can weigh up to a hundred pounds in some models.
- Use lightweight wheels instead of steel, with high performance tires. This can help you drop up to 50 pounds.
- Use carbon fiber or fiberglass body panels instead of the manufacturer panels. This is a more complex modification, but if you’re trying to find your engine’s max and make the vehicle lighter, it’s a possibility.
Install a high-flow air filter and intake system.Changing out the air-filter to a higher performance variety can add a few horsepower cheaply and quickly to your engine. You won’t have to buy new air filters, and you’ll allow your engine to breathe better, adding a small amount of power. For about $40 – $250 for most applications, this is an excellent place to start.
- AEM dryflow air filters never need any oil added and are legal everywhere. K&N Air Filters are good for for 1,000,000 miles (1,600,000 km), and can add five horsepower or more depending on vehicle.
- Cold-air or ram-air intake systems draw in air from a cooler place outside the vehicle. Some cars will benefit greatly, and some will not. Usually, higher-end cars will not be able to benefit from this, as they already have a well-designed air intake system.
- Before making any filter modifications or using a high-performance system you get from the Internet, research the laws in your state regarding filter regulations. Some high-flow filters aren’t legal in all 50 states.
Upgrade to a performance exhaust system with test piping.Ideally, a “header-back” exhaust system will be installed, in which the exhaust goes pretty much straight from the engine to the tailpipe, efficiently and quickly. Kits are available, should you choose to do it yourself, for several hundred dollars, though welding a new exhaust system onto the car requires that you have access to a shop with a hydraulic lift, the replacement system, the welding gear, and the know-how. It’s usually better to have a muffler shop that knows what they’re doing upgrade your exhaust system for a fee.
- I-4 engines should go up to 2.5 exhaust, unless a turbocharger is equipped, then 3″ is acceptable. V6/V8 cars should have 2.5″-3″ exhaust all the way through.
- Exhaust headers are expensive and will add only a small power gain. It’s a good option, but only if you’ve exhausted most other HP-maxing opportunities available.
Maxing Engine Performance
Consider installing a performance camshaft.Performance cams increase the duration and timing of the valve openings during the engine stroke, increasing horsepower and making your car accelerate more quickly. You’ll idle slightly rougher with a performance cam, but get a throaty rumble that’s desirable for some gearheads, depending on your vehicle. They’re on the expensive side, but work well in conjunction with header or exhaust upgrades.
Research your turbocharging and supercharging options.A turbocharger can add up to 25 – 30% power gains. However, turbocharger kits cost about $3,000 for common applications, and go up in price for less common applications. Turbochargers are excellent for any car, anywhere, but can be prohibitively expensive, and are difficult to install for novice mechanics. Research which systems and options would be effective for your model and weigh your options.
- Turbochargers suck air into the engine, increasing boost and horsepower. An intercooler will also need to be installed with a turbocharger to avoid turbo-lag, in which the engine overheats and slows the impeller.
- Superchargers are belt-driven, making them more effective for 6+ cylinder engines. While a turbocharger results in a higher peak of HP, superchargers don’t require the use of an intercooler, and result in fewer heating problems and maintenance issues. They’re available in centrifugal, screw, and roots-type models, depending on the kind of engine.
Install a water-injection or anti-detonant injection kit. For $300, a good water-injection kit increases gas mileage and power while reducing carbon deposits within the combustion chambers, preventing engine pinging. Most of the time, having such a system installed will even let you buy lower-octane fuel. While water-injection kits will have almost no performance gains on naturally-aspirated engines, they can help restore lost power. Turbo or supercharged engines will have massive power gains with water-injection.
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