There has been a lot of buzz on the internet lately discussing whether a cold air intake (CAI) is worth the money and work to install. Some of these arguments are based on a performance proposition and it is easy to justify the cost if all you are concerned about is boosting power. But what about the everyday driver? Do you need to install a cold air intake on your daily?
Before we answer that, we must identify the claims made by the manufacturers. What exactly does a cold air intake do? Secondly, we need to figure out what makes a good cold air intake. Of course, we should also discuss what to avoid when shopping for a cold air intake. Finally, we need to dive into what the experts say and put this debate to bed with a simple cost-benefit analysis. To accomplish that, we reached out to Banks Power and Strictly Diesel.
What Does A Cold Air Intake Do?
Let’s quantify a few facts. For starters, the size of each cylinder in your engine is fixed, we can’t make it bigger. To generate more power, we need to burn more fuel. To burn more fuel, efficiently, we need more oxygen, Cold air is denser than warm air and takes up less volume.
In its most basic form, a cold air intake is much like the OE air filtration system — it gathers air for the engine to breathe. However, a CAI is designed to create a smoother path for that air. Some actually gather air from under the hood while others gather air from outside of the vehicle to feed the engine. Since cool air is denser, it delivers more oxygen within the same amount of volume. If you feed your engine with hot air, it takes up more volume and you reduce the amount of oxygen available to burn. That means you burn less fuel which leads to reduced power.
It’s all about airflow and air temp. With the right intake, you can increase both power output and efficiency. — Gary Maschner, Strictly Diesel
Jay Tilles, brand manager for Banks Power, summed it up this way, “It’s not just about power. Fuel economy goes up by reducing the amount of fuel needed to run the engine. Additionally, if you reduce the amount of work the turbo does to increase air density, you see an improvement to overall efficiency.”
Gary Maschner, general manager of Strictly Diesel, echoes Jay’s thoughts, “It’s all about airflow and air temp. With the right intake, you can increase both power output and efficiency.”
Is There Such A Thing As A Bad CAI?
While speaking with both Jay and Gary, we asked about what makes a good cold air intake and what makes a bad intake. It’s no secret that a good intake will increase airflow and reduce the intake air temp, that is a given. However, one that sucks air in from under the hood often reduces the amount of air flowing due to the ducting. Jay calls these configurations “filters on a stick.”
Gary concurs that there are actually several products on the market that reduce the performance of the vehicle. He states, “people often buy a kit without doing any research, and unfortunately, there are products on the market that are actually worse than the stock configuration.”
Both Jay and Gary reference a short video clip by Gale Banks, discussing the issue. In this short clip, Gale discusses the issues with using what they call a filter on a stick.
The Right Kit
Doing research online can be tricky — there is a lot of misinformation out there. While articles that test various intakes on dynos are good entertainment, those tests do not emulate real-world conditions. They are often done with the hood open and sometimes with the filter removed.
Before you start researching, you need to ask yourself, are you looking for an intake to help generate as much power as possible? Manufacturers can make an effective intake that maximizes power, but most of the time, these are only suited to high-performance situations and are not effective for everyday use. It’s easy to solve for one variable. However, for use in our work trucks and everyday drivers, more variables need to be considered.
We do real-world testing. We want to increase power and efficiency while reducing emissions.— Jay Tilles, Banks Power
Most people drive their diesel truck daily and tow occasionally. In this common situation, the driver needs to add equipment to make the truck more effective. We are all looking for improvements in power output, better fuel economy, and lower emissions. If you can get more power, better MPG, and be 50-state compliant, that’s a win.
When looking for a CAI that improves all aspects of performance and is suitable for everyday use, those parameters may increase the cost of the unit as well as create more work to install, but the return on investment will make it worth it over time. Between fuel savings and less strain to do the same work, a quality intake should eventually pay for itself.
Let’s Talk Filters
Intake filters come in all shapes and sizes. Flat, bowed, and cone-style filters are the most common. You want to pick a filter that allows the most airflow while still trapping the most debris possible coming into the intake. There are a couple of factors to keep in mind. First is the filter’s shape. Flat, cone, and bowed filters are common in aftermarket intakes and flat filters are most found in stock configurations. However, cone filters generally flow the most air, primarily due to the increased surface area of the filter. Cone filters have the added benefit of more uniform velocity funneling to the intake tube.
The second major debate about filters is whether to use a dry or oil-soaked unit. Dry filters use a thicker medium to clean the air for the engine. Oiled filters use a thinner medium and trust the oil to trap the dirt. There are pros and cons to both filters and in everyday use, it comes down to your specific usage needs — almost.
Oiled filters are excellent in extremely dirty environments. Dusty job sites, farm work, gravel roads, etc. However, the trade-off is you will need to maintain/clean the oiled filter whereas a dry filter is usually discarded and replaced. Both filters work well, but you need to properly maintain your filter to keep it working at peak performance.
One common problem with oiled filters is fouling the MAP sensor. Both Gary and Jay say this is a common issue caused by over-oiling the filter. If you are the type of driver that services your equipment often, then a properly oiled filter is likely your best bet. For the rest of us, get the dry filter.
Also, go to any diesel forum and ask about using an oiled air filter on your turbo diesel and you will get a lot of varied opinions. Some say it is fine while others claim the oiled filter’s oil will get sucked into the turbo. According to Maschner, “as long as you take care of the filter they can be a good thing and improve airflow. Again, the risk comes when filters are over-oiled after cleaning. Some of the oil can be pulled through the filter and develop a film on the mass air flow sensor. This can cause a check engine light, increase emissions output, and other drivability concerns.”
During our interviews with both Jay and Gary, they mentioned how the new factory Duramax setup is extremely efficient. They both said with this application, most aftermarket systems on the market are not much of an improvement over the stock configuration for everyday driving. However, Jay teased about a new product Banks is testing to make sure it improves all aspects of performance.
Jay described the testing process at Banks Power. They use an AVL dyno in the shop for measuring power differences. Additionally, Jay says they use a full suite of sensors to test their intakes. Using a PEMS (Portable Emissions Measurement System) they can test the system while off the dyno and in the real world. All testing at Banks is done to replicate real-world use as much as possible.
“The point is to increase manifold air density,” says Jay. “We are looking for increased flow, reduced intake air temp, and reduced humidity.” Jay continues, “We do real-world testing. We want to increase power and efficiency while reducing emissions.”
New Era Duramax
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“The new Banks Ram-Air ships with the new Banks Air Mass Control Module. This electronic device is connected in line with your stock MAF sensor. It sends a corrected calculation to the truck’s ECM, thereby allowing us to outflow stock without setting a warning light. Many of today’s trucks have MAF calibrations that are so tight, any deviation will result in a warning on your dashboard. The patented Air Mass Control Module frees Banks engineers of these constraints. In other words, we can flow what we want,” says Jay Tilles.
Most truck owners are not SAE-certified mechanics. However, Gary assures everyone, the DIY mechanic can install a cold air intake. “The main advantage is, all the stuff you need to replace is easily accessible.” Continuing, Gary says, “But if you get in over your head, there is always a local shop that can help with installation.”
People often buy the intake that is easier to install and fits in their budget. It is important to understand what your intake will do to the performance of your truck and be sure it is installed correctly. Getting clean cool air to the engine is as important as getting the fuel there.
Is There A Downside to a Cold Air Kit?
Actually, there is, but it is a grey area. Gary wisely points out that some car dealers might try to void your warranty if something goes wrong. If it found your CAI did allow the damage, your warranty will be voided. Fortunately, enthusiasts have the Magnuson-Moss Act on their side.
According to the Magnuson-Moss Act, a vehicle manufacturer cannot automatically cancel your warranty just because you’ve installed aftermarket car parts. It is an illegal practice. That said, if your aftermarket part somehow causes or contributes to a failure in your vehicle, the dealer may be able to deny your warranty claim — as long as they can prove the connection. In these cases, the burden of proof is entirely on the dealership.
“This is more prevalent with extended warranties,” Gary says. “To keep your warranty, you may want to remove your aftermarket intake before you take it to the shop.”
Another concern is associated with the oiled filters fouling the MAF sensor. This issue is mitigated or eliminated by not over-oiling the filter. All other issues usually stem from not installing the intake properly.
Are Cold Air Intakes Really Worth It?
The short answer is yes. Even a “filter on a stick” will usually increase power. However, it is important to maximize your investment and make sure your intake increases overall performance and doesn’t allow damaging dirt and debris into your engine. It’s also very advantageous to stay 50-state-compliant with emissions.
Although a quality CAI can range anywhere from $300 to $600, or more, with the cost of fuel these days, any increase in fuel economy is easy to track and justify.