An aftermarket intake, exhaust or tuner adds horsepower and torque to most diesel and gas engines
Performance equipment isn’t just for hot rods anymore. Adding aftermarket performance parts to a tow rig might be just the thing you need to get over that hill at a comfortable 55 mph, even when you’ve loaded down the trailer for a long trip. Or perhaps you’d appreciate an improvement in fuel economy. In any case, passing other vehicles and entering busy highways shouldn’t be a white-knuckle experience. A little more power can inspire confidence and make your travels a lot more enjoyable.
You may have considered performance parts before but were leery of the claims of increased horsepower and torque, better mileage and no warranty concerns. We’re here to clear this up for you. First, we’ve gathered a bunch of performance parts that you might want to consider for your rig, plus we’ve talked to multiple sources about what you can expect to achieve. And we even met with the industry association SEMA (Specialty Equipment Market Association) to learn more about government regulations and how manufacturers are complying with them.
For many years, performance enthusiasts have been increasing the horsepower and torque of their engines by adding an aftermarket intake, exhaust and tuner. The trifecta package was practically a given if someone was interested in going beyond stock.
The easiest, least expensive performance enhancer is a cold-air intake. Cooler air is denser and packs more punch in the combustion chamber than warmer air and can even lower exhaust gas temperature (EGT) a few degrees, according to some manufacturers. Cold-air intakes often change where the air is drawn from (in the front rather than inside the fender, for example) and include less-restrictive air filters.
Next, factory settings can be reset so that the engine puts out more power with a so-called tuner. Tuners run the gamut from simple plug-and-play units to elaborate color touch screens that can display gauges that keep you informed of parameters such as transmission temperature and boost levels. Most tuners have several settings, so you can select the power level you’d like to run. Some have a tow setting, while others are safe for towing no matter which level you choose.
Most of the tuners simply plug into the under-dash connector (known as the OBDII port), and after answering some prompts (year, make, model, engine, tire size, etc.), the tuner reprograms the Power Control Module (PCM) or Engine Control Module (ECM), depending on the year of the vehicle. Some allow you to adjust the automatic transmission shift points and firmness, some let you read, diagnose and clear diagnostic trouble codes (that Check Engine light on your dash), and some even let you adjust the cooling fan on/off temperatures.
A performance exhaust system is also a viable option for gasoline and diesel-powered vehicles. These so-called cat-back exhaust systems (which bolt on after the catalytic converter) often offer bigger, mandrel-bent tubing and a less restrictive muffler (or mufflers) that help reduce backpressure and can improve both performance and mileage. This upgrade typically comes with an improvement in sound, and even appearance. Aside from a polished chrome or stainless-steel tip, different configurations are offered by manufacturers, such as a split side or split rear exit. And some even offer a choice of material, such as galvanized, aluminized steel or stainless steel.
Unfortunately, there isn’t a lot you can do to the exhaust of 2008 to current diesel trucks, which are equipped with a diesel particulate filter, or DPF. Polished tips or a “DPF-back” exhaust kit is about it, but earlier trucks can still take advantage of improvements with a cat-back exhaust or even a turbo-back exhaust system in states with 49-state guidelines.
Changing Diesel Regulations
In 2008, the EPA started requiring a DPF on heavy-duty trucks (three-quarter-ton and up), and biannual smog tests required the original exhaust parts to be intact when the truck was inspected. This threw the aftermarket performance parts world for a loop, and many are still trying to figure out where they fit in. When some companies offered “DPF Delete” options, the EPA cracked down, and now nearly all companies are towing the line. But you can still find power and torque for your rig. Many companies have taken the time and expense to get their products approved by the EPA, and they get what’s called an Exemption Order (EO). By using parts blessed with an EO, you can enjoy improved performance and still pass a smog test.
Which brings us to the emissions equipment so many people want to remove. It’s important to realize that not all of the smog-related equipment that comes on a modern vehicle is bad. Take the Selective Catalytic Reduction technology that came into prominence to help meet 2010 emissions standards. The system uses Diesel Exhaust Fluid (DEF), which is a combination of urea and deionized water that is sprayed into the exhaust stream of diesel vehicles to break down NOx emissions into harmless nitrogen and water. Because this system deals with the emissions at the tailpipe (often called after-treatment technology), manufacturers were able to more aggressively tune the core engine for more horsepower and better fuel economy. The DEF is stored in a separate tank and typically has a blue filler cap; it never comes into contact with diesel fuel in any way.
After-treatment technology also means that aftermarket companies can boost horsepower and torque without affecting the level of NOx emissions, and that’s good news.
What About Water Injection?
Several companies are now offering water injection as a way of increasing power without affecting the DPF. Water injection has been used for many years, and even diesel engine inventor Rudolph Diesel was purported to have said, “Every diesel should have water injection.” You can think of it as a chemical intercooler, delivering a colder, denser charge into the combustion chamber. The benefits, besides more power, include better fuel economy and lower EGT. In fact, some say you can expect EGT that is 250 degrees cooler.
Snow Performance specializes in water/methanol injection, and, for example, the company claims a 70-horsepower improvement over stock on a 2011 Ford F-350 6.7-liter Power Stroke. Better yet, Snow claims a 1 to 3 percent improvement in fuel economy. A small, steady spray of water is injected across the entire power curve (even at cruising speeds). The increase in combustion efficiency comes with no need to increase the amount of diesel going into the engine. Lower EGT is one of the positive results. Water injection does not leave a “signature” on a truck’s computer, so there should be no concern over warranty issues. Snow Performance has units for diesel-pusher RVs, too. Banks Engineering also markets a water-injection system for diesel engines.
Why can’t gas engines see the same gains as diesels?
Put simply, diesel and gas engines are two different animals — they’re built differently, and they operate differently. Because of the high compression used in the design of a diesel engine, the bottom end and rotating assembly (engine case, crank, rods, pistons) are all far more stout in a diesel than in a gasoline engine. And the direct injection used in diesels is also far easier to tune.
The difference in fuels and the way the two engines burn it is also a big reason they can’t see the same gains. For example, diesels burn hotter and make more power when you add more fuel to them (within reason). One manufacturer we talked to likened tuning a diesel engine to stoking a coal fire in a locomotive. By contrast, gasoline engines are far more sensitive to a correct air/fuel ratio; simply adding more fuel can actually hurt performance.
Gasoline engines used in trucks and SUVs don’t have nearly the compression of a diesel engine and aren’t assisted by a turbocharger. So the only way to create the kind of horsepower gains in a gas engine that you can see in a diesel is to modify it dramatically with more compression, a turbo/supercharger, etc., which costs a lot and requires a higher grade of fuel (premium or better) to keep detonation at bay.
But that doesn’t mean you can’t see improvements in a gasoline engine — it’s just that the gains will not be as dramatic. Cold-air intakes and exhaust systems apply to gasoline engines, too, and a tuner can do more than just increase power. For example, 5-Star Tuning specializes in Ford’s gasoline V-10 Triton engine that shows up in a huge number of pickups and motorhomes. Mike Butler of 5-Star says he uses the SCT tuner to improve fuel economy but also to afford a better driving experience. The shift points can be modified, and driving on cruise control can be greatly improved, as the transmission will no longer hunt endlessly for the right gear at exactly 65 mph. In other words, adding a tuner to a gasoline engine is not just about power increases.
Will It Fit?
Back in the day, aftermarket parts were notorious for questionable fitting issues. In fact, a common expression among performance enthusiasts was, “Bolt-on parts don’t.” But today, with the increased use of sophisticated 3D measuring devices and computer-assisted design, nearly every part on the market bolts right on with no need to get a hammer out of the toolbox. Since SEMA has a bevy of technological tools and shares measurement information with members, there’s really no excuse anymore for bolt holes not to line up.
We hope we’ve cleared up some misconceptions about aftermarket performance tuning parts and spurred you into continuing to research what is available for your specific rig. We’ve included quite a few examples to get you started in your search for just the right parts to make your traveling better, but near-endless combinations are available for your tow vehicle.
Will It Void the Warranty?
Adding any aftermarket part can’t lead to the voiding of the warranty. With that said, however, it can have an affect on the warranty. In 1975, Congress enacted the Magnuson-Moss Warranty Act to protect consumers from manufacturers who were not honest in their warranty rejections. It’s simply not enough to claim that any aftermarket add-on is the cause of a defect in the vehicle; it must be proven. And if proven, everything else that is protected under the warranty is still covered. Obviously, it is prudent to buy good quality parts designed specifically for your vehicle from reputable aftermarket companies. Don’t go for that $69 tuner on eBay.
How SEMA Has Helped
SEMA was founded in 1963 as the Speed Equipment Manufacturers Association, but a lot has changed since then, and the modern SEMA is a trade organization for the automotive
specialty market. The nonprofit organization is headquartered in Diamond Bar, California, where the newest member benefit has unfolded: the SEMA Garage. This garage allows member companies to use nearly $2 million worth of parts, including a full aftermarket-part Executive Order (EO) certification lab, operated in partnership with the Automobile Club of Southern California.
We talked to SEMA’s vice president of OEM and product development programs, Mike Spagnola, for more insight. “People tend to think it’s only California that has laws restricting what you can do to your tow rig’s driveline,” Spagnola told us, “but it’s more accurate to say that only California enforces it. But other states are starting to enforce it.”
So aftermarket manufacturers have to pay attention and make sure their parts are in compliance. To get an EO could take around $30,000, if they were paying a regular lab to do the testing.
Put 40-inch tires on your rig, and then expect the dealer to replace the worn-out ball joints, and you might not be getting your way. That is called “cause and affect.” The burden of proof for the damage, however, lies with the manufacturer. So if you put an aftermarket air intake on the truck, and the transmission later burns up a clutch pack, the dealer can’t get away with saying that the warranty doesn’t apply. One aspect of the Fed’s act is that it helps consumers resolve disputes in a timely and inexpensive way. Many times the Better Business Bureau is used to solve stalemates. Note that leased vehicles might not be covered by the Magnuson-Moss Warranty Act.
We also consulted the SEMA Action Network (SAN) for help with this question, and it’s clear that adding performance parts can’t “void” the warranty, but there’s plenty you should know.
From the SAN website (www.semaactionnetwork.com): “Federal law sets forth requirements for warranties and contains a number of provisions to prevent vehicle manufacturers, dealers and others from unjustly denying warranty coverage. With regard to aftermarket parts, the spirit of the law is that warranty coverage cannot be denied simply because such parts are present on the vehicle or have been used. The warranty coverage can be denied only if the aftermarket part caused the malfunction or damage for which warranty coverage is sought. Disputes in this area usually boil down to arguments over facts and technical opinions, rather than arguments over interpretations of the law.”
SEMA is actively helping aftermarket companies get certified by the California Air Resources Board (CARB) so that their products can be sold in all 50 states. The SEMA Garage is a premier automotive research and testing facility that can measure vehicle fuel efficiency, exhaust emissions, drive-wheel horsepower and other auto-related tests at a reduced cost. One of the core capabilities of the SEMA Garage is emissions testing related to obtaining CARB EO certification. Automobile Club technicians are responsible for all automotive and emissions testing and act as unbiased third-party entities, an essential component of independent automotive tests.
AEM Induction Systems
800-992-3000 | www.aempower.com
(Advanced Flow Engineering)
951-493-7155 | www.afepower.com
800-498-6951 | www.airaid.com
800-601-8072 | www.bankspower.com
800-635-9950 | www.diamondeyeperformance.com
888-360-3343 | www.edgeproducts.com
901-382-8888 | www.hypertech-inc.com
909-839-0706 | www.injen.com
800-858-3333 | www.knfilters.com
888-636-7223 | www.mbrp.com
909-947-0015 | www.sbfilters.com
940-783-9914 | www.bullydog.com
888-227-2447 | www.superchips.com
866-365-2762 | www.snowperformance.net
270-746-9999 | www.tsperformance.com