LLY Duramax Cold Air Intake Ultimate Guide
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General Motors/Chevrolet produced the Duramax LLY 6.6L diesel V8 engine from 2004–2006. Depending on the mode, it produced 210–310 horsepower and 520–605 lb-ft of torque. It was the replacement for the LB7 V8 diesel engine, and was soon succeeded by the LBZ V8 diesel engine. While at the time, its 210–310 horsepower figure was decent, modern turbo-diesels can more than double the output. That’s why a LLY Duramax cold air intake is one of the top mods LLY owners. Read on to find out which LLY duramax cold air intake makes the most power at the best cost.
What is a LLY Duramax Cold Air Intake?
An LLY Duramax cold air intake is a type of performance intake. They are one of the most popular upgrades for the LLY, and are on our top LLY Duramax upgrade guide. Air intakes are the very first part of the intake system. They connect directly to the turbocharger on the turbo-diesels like the LLY, and are located in the engine bay. They consist of two parts, an air filter and tubing, and some systems include an airbox to enclose the filter.
Compared with the OEM intake, a performance intake will increase the volume and velocity of air flowing into the turbocharger. They do this by having bigger cone-style filters and larger diameter and less restrictive tubing. For many people, a cold air intake is the first mod they do on the LLY Duramax. You can expect to gain 10-15 horsepower and 10-15 lb-ft of torque.
Short Ram vs Cold Air Intakes
For the most part, LLY Duramax intakes can be broadly divided into two categories: Either short ram air intakes or cold air intakes. Both of them are very similar to each other, and both generally produce about the same amount of performance. Short rams are often less expensive than cold air intakes, but that is not always the case.
The difference between an LLY Duramax cold air intake and a short ram air intake is the location and placement of the filter. On a cold air intake, the air filter is located as far away from the engine as possible. Usually, this means putting it near the fender or wheel-well, where it can draw in colder and cleaner air than from the engine bay. The stock LLY Duramax intake is technically considered a cold air intake, but it is more restrictive than most aftermarket products, which is why most people upgrade.
In comparison, a short ram air intake places the filter as close to the turbo as possible. This means that the tubing is usually much smaller on a short ram vs a cold air intake. The reason for the small-length tubing is because short rams operate under the principle of allowing the least space between the air filter and turbo. In theory, this means the least amount of restriction. The air takes very little time to reach the turbo, so airflow velocity is exceptional.
Which Intake is Better?
Most people opt for a cold air intake over a short ram intake on naturally aspirated engines due to the lower intake temperatures (IAT) they produce. However, on a turbocharged engine like the Duramax LLY, both short ram and cold air intakes work about the same. This is because the LLY has an intercooler which cools down the turbocharged air before it reaches the engine. The IATs are not as important on turbo-diesels for this reason, making short rams and cold air intakes perform similarly.
For these reasons, when picking out an intake, you should prioritize something that is going to deliver the best flow and the most volume. Sometimes, this means a short ram over a cold air intake, though they both usually perform within a few horsepower of each other. If you really want to improve cooling on your LB7 Duramax, investing in a larger intercooler is the best way to go.
Open vs Closed Airboxes
Another consideration to make when upgrading the LLY intake is whether to have an open or closed box system. For the most part, cold air intakes will almost always have the option for an airbox, whereas on short rams it depends on the specific brand. The stock Duramax LB7 intake itself comes with an airbox. The purpose of the airbox is to seal off the filter from the engine bay to improve cooling and longevity. It shields the filter from the engine bay heat, and also stops it from sucking in as much debris.
One downside is that many people claim that airboxes can impede airflow by adding a restriction on the filter’s ability to take in air. In addition, they are also more expensive, as sometimes just the airbox can add as much as $100 to an intake kit. Also, on turbo-diesels like we mentioned, intake temperatures are not nearly as important as the intercooler. So you might be paying a significant amount extra for an airbox that doesn’t help with cooling.
Typically, we recommend using open box intakes, but airboxes can be beneficial, too. Besides price, there is not much of a downsize to them, other than sometimes fitment.
Dry vs Oiled Air Filters
Your final consideration when picking out a Duramax LLY cold air intake or short ram air intake is the filter media. Most systems give the option of using either a dry filter or oiled filter. Most oiled filters are reusable and most dry filters are disposable. People opt for oiled filters because they can catch more dirt and debris due to the oil and stop it from getting sucked into the engine. But there can also be some serious downsides to them.
While the oil can be helpful at picking up dirt without impeding flow, many people have issues with oil getting into the mass airflow meter (MAF) housing. What happens is the oil drips down off the filter at high speeds. Due to the location of the MAF, it is unfortunately a good candidate to take on the oil.
When the MAF gets covered in intake oil, the problems can range from faulty or bad readings all the way to completely fouling the sensor. It does not happen on every filter, and most people will say it’s only an issue with excessive oiling. However, considering they offer zero performance benefits and dry filters do just as well at filtering (OEM filters are dry), we recommend a dry media filter if possible.
Benefits of LLY Duramax Cold Air Intake Upgrade
- +5–15 horsepower
- +10–25 lb-ft of torque
- Increased fuel economy
- Increased engine sounds
- Increased throttle response
There are a few benefits to upgrading the stock intake to a cold air or ram air intake, but the most important is the increase in horsepower and torque. With an LLY Duramax cold air intake or short ram air intake, you can see increases of as much as 5-15 horsepower and 10-25 lb-ft of torque. To get the most out of your intake, tuning is recommended. Especially on a MAF based system like the LLY Duramax uses.
In addition to the performance increases, you’ll also notice the throttle is much more responsive whenever you hit the gas. You can also see increases to fuel economy from using a less restrictive and better breathing intake. Usually, it’s only 0.5-1.5 mpg, but it’s better than nothing and is a nice byproduct.
Finally, after installing your new performance intake you will definitely hear it from behind the wheel. Not only does the larger filter make more noise, but even intakes with airboxes are not nearly as insulated as the stock intake system. The new intake will be noticeable from the moment you step on the gas, and can really complement an upgraded exhaust.
Best LLY Duramax Cold Air Intakes
The top 3 Duramax LMM cold air intakes are:
- Banks Power Ram Air Intake
- S&B Cold Air Intake
- HSP Cold Air Intake
There are dozens of LLY cold air intakes and short ram intakes on the market, and these are the top three out of them all. These are widely considered by enthusiasts to be the best performance intakes for the LLY, and they all produce similar amounts of horsepower and torque. We recommend the Banks Power unit if you can afford them, but the S&B and HSP are also solid options. Let’s take a look.
1) LLY Duramax Banks Power Ram Air Intake
As you might have expected, the ultra-popular LLY Duramax Banks Power Ram Air Intake is our first entry on the list. Among turbo-diesel enthusiasts, Banks Power are some of the most popular intake systems available. For many years, Banks have been providing reliable products that are known for delivering solid performance, having excellent fitment, and maintaining fantastic quality control.
The Banks Power LLY intake will allow for maximum gains of 15 horsepower and 25 lb-ft of torque. Compared with the OEM intake, the Banks Power flows a whopping 57% better, which is a significant improvement and the best of all the intakes on our list. The intake is available with either a dry media or oiled filter. Like we talked about before, we definitely recommend the dry filter option.
The Banks Power intake markets itself as a ram air intake. But, if you compare designs it actually locates the filter in the same spot as most cold air intakes. It has a pretty small airbox, and the filter faces downward in the engine bay and is not immediately accessible. Among LLY Duramax drivers, the Banks Power is widely regarded as the top intake on the market. The only downside is the price.
2) LLY Duramax S&B Cold Air Intake
Next on our list is the LLY Duramax S&B Cold Air Intake. It is second only to the Banks Power intake, and delivers very solid performance. The S&B is one of the most popular LLY cold air intake kits on the market, and S&B themselves are quite a reputable company. Not only are they known for their intake systems, but their air filters themselves are some of the most popular and widely used on the market. Many aftermarket intakes use S&B filters over K&N filters on turbo-diesels due to superior performance.
The S&B design is largely similar to the Banks Power intake, but the airbox is much different. On the S&B intake, the airbox is oriented differently and has a see-through cover so you can view the filter. The S&B has both an oiled or dry filter option, and we again suggest the dry version. Compared with OEM, the S&B intake flows 43% better and is much less restrictive.
In addition, the S&B LLY intake is also 50 states legal due to its CARB certification and EO number. This makes it a great choice for those living in strict emissions states, like California, who can only use CARB approved intakes.
3) LLY Duramax HSP Cold Air Intake
Price: $403.75 (optional +$70–145 for powder coating)
The final intake on our list is the LLY Duramax HSP Cold Air Intake. The HSP intake is one of the more popular LLY Duramax intakes on the market, and it’s not hard to see why. HSP makes the product from mandrel bent tubing, and uses CNC machined sensor blocks to help ensure good fitment and seal for the airbox.
The design is relatively similar to both the Banks Power and S&B LLY intakes, but the airbox is open and allows for the air filter to be exposed. In addition, the HSP LLY intake has optional powder coating, which really makes it stand out from the rest. There are nine different powder coat options, including “M&M Orange,” “Illusion Blueberry,” and “Polar White.” They definitely make the HSP intake stand out as one of the most sleek on the market.
The HSP intake is not as well known or popular as either the Banks Power or S&B intakes, but it is still a solid performer. The one downside is the length it takes to produce, as HSP custom builds all their intakes. This can mean more than a month of waiting time, which can be prohibitive for some buyers.