Currently the longest standing diesel engine, the 6.7 Cummins produces 420hp and 1,075lb-ft. of horsepower. Initially launched in 2007.5, the 6.7 Cummins produced 350hp and 610-650lb-ft. of torque. While earlier years had stout power numbers for their time, it doesn’t quite compare to the 4-digit torque numbers modern diesels produce.
Whether you have an earlier model Cummins, or four-digits of torque, you might still be searching for additional power. Upgrading the 6.7 Cummins with a cold air intake system is one of the best performance modifications you can make.
In addition to increasing air flow and adding horsepower, a cold air intake reduces stress on the turbo, improves efficiency, provides better throttle response, and even improves gas mileage.
Our 6.7 Cummins cold air intake upgrade will cover the performance benefits of upgrading the stock intake system, differences between open and closed intakes, and provide recommendations on our favorite intake systems.
Looking for additional intake upgrades? Check out our 6.7 Cummins Intake Horn Upgrade guide.
6.7 Cummins Cold Air Intake Benefits
The purpose of a true cold air intake is to draw colder air into the engine. However, on diesel engines the intake air temperature actually matters less than the increases in overall airflow. 6.7 Cummins intakes are actually mostly ram air intakes technically. Cold air intakes usually re-route the air filter to a location where the air is colder, usually inside the lower part of the front bumper. Ram air intakes use the stock intake location and focus on removing restriction and increased airflow rather than lowering air intake temps.
The benefit of upgrading the 6.7 Cummins intake is in the increased air flow. More air reduces stress on the turbo which allows it to spool more quickly. Additionally, it increases the turbo efficiency which therefore increases horsepower.
Adding a cold air intake to a completely stock 6.7 Cummins will provide power gains. However, it will not provide near as much gains as adding an intake to a tuned Cummins. Tunes increase power by increasing boost. When boost is increased, air is compressed even more which requires more intake air to supply enough compressed air to the combustion chamber.
When tuned with a stock intake system, the stock intake becomes restrictive as it can’t supply enough air to the turbocharger, putting extra stress on the turbo and reducing efficiency. Benefits of a 6.7 Cummins cold air intake include:
- 5-10whp and 20-30wtq power gains
- Significant air flow increases (30%-50%+)
- Quicker turbo spool
- Better throttle response
- Slight mpg increases (1-2 mpg)
- Cool engine intake noises
6.7 Cummins Intake and Tune Horsepower Gains
As mentioned above, an intake is more powerful when its combined with a tune. The stock intake system is adequate at stock boost levels, which limits power gains on a completely stock 6.7 Cummins. However, it is restrictive when boost levels increase.
When you are completely stock you should expect to get closer to 3-5whp and 10-12wtq gains. However, when tuned you can see closer to 10whp and 30wtq gains depending on the tune you are running.
You don’t technically have to upgrade your intake if you are tuned but we highly recommend it. Using the stock intake puts unnecessary stress on the turbo which reduces its reliability. An intake will allow the engine to breathe better making the engine feel a lot more alive and open.
Choosing the Best 6.7 Cummins Intake
Option A when it comes to increasing airflow is to opt for a drop-in filter. The gains from this are so minimal that we don’t recommend it and are going to skip past it. Upgrade the full intake system, not just the filter.
A second note I want to make is that intake systems have various names. As discussed above, 6.7 Cummins intake upgrades are technically ram air intakes. However, the term “cold air intake” is still popular as it’s the most well-known intake term. You’ll see intakes called performance intakes, ram air, cold air, etc. They are really all the same. However, there are two important distinctions as we’ll discuss next.
Next, you have two options: open intakes or closed intakes.
Open vs. Closed 6.7 Cummins Intake Systems
As the names suggest, an open intake has the air filter directly exposed to the engine bay. Closed intakes house the filter within a box, therefore protecting it from sucking in hot engine bay air. You will also see open intakes that come with heat shields. Heat shield supposedly protect the intake from the hot engine air, although we call bull on some of this.
We highly recommend open intake systems. To help you see why, here are the pro’s and con’s:
Open Intake Pro’s
- >20% more air flow than closed intakes
- Better power gains due to greater air flow
- Biggest improvement in turbo efficiency
- Usually slightly cheaper due to less materials and engineering
- Provide more cool intake noises
Open Intake Con’s
- Draws in air that is maybe 1-3 degrees warmer
- This doesn’t really matter
Open intake systems are always our recommendation. They provide better power gains, reduce the most stress on the turbo, and sound cool. Not to mention they provide better bang-for-the-buck since they are cheaper and provide better gains.
The reason we say intake air temps don’t really matter is because turbo diesels are all intercooled. Intake air is passed through the turbocharger. Turbo’s run extremely hot which heats the air up anyways. To cool this air down the air then passes through the intercooler. The air being a few degrees hotter has no impact on the intercooler, so ultimately the air enters the engine at the same temperatures regardless.
The only time we would recommend a closed intake system is when you care about intake noise. Open intakes provide a bit louder of a “whoosh” sound under acceleration. We love the sound, but not everyone does. You really only hear it under acceleration or heavy boost (driving up hills, etc.), so it isn’t terrible for long highway drives, but it is louder.
Open intakes > closed intakes.
Best 6.7 Cummins Cold Air Intakes
We always recommend open intake systems because they provide the most power for the lowest price. Additionally, they reduce the most stress on the turbo and have greater impacts on turbo spool, throttle response, and so on. With that being said, there are some good closed intakes on the market if you want a quieter system. And, at the end of the day, a closed intake still provides ample performance benefits unless you are shooting for aggressive power levels.
Here are a few of our favorite open and closed 6.7 Cummins cold air intake systems:
1) 6.7 Cummins Best Open Intakes: GDP & WCFab
Our two favorite open 6.7 Cummins intakes are the GDP, or Gorilla Performance, and WCFab, or Wherli Custom, intake systems. GDP is the best budget-friendly option at $289, while Wherli Custom is the top-tier option coming in at a pretty price point. Both intakes are true open systems without heat shields. Each also use high-quality S&B filters. The difference between the two is that Wherli custom fabricates their piping in the US whereas we guess GDP sources the piping overseas.
At the end of the day, the piping doesn’t matter much. Both use S&B filters which are the best on the market so we like GDP just for the bang-for-the-buck factor. However, both of these intakes will provide better power gains and efficiency improvements over the closed systems mentioned below.
2) 6.7 Cummins Best Closed Intakes: Banks Power & S&B
If you’re opting for the quieter and slightly less powerful closed intake system, Banks Power and S&B are the two best on the market. S&B is one of the most respected names in the industry and they actually manufacture the air filters used on both GDP and WCFab intakes mentioned above. While S&B tends to focus on intakes and filters, Banks Power is well known for providing a range of diesel performance products from tunes to intercoolers and so on.
If you are looking for a closed intake system these are the only two systems we would personally consider. Both great options for those wanting a quieter intake. Despite providing less air flow and power gains these intakes are good enough for 99% of the people just looking for some slight power increases.
6.7 Cummins Cold Air Intake Upgrade Summary
Stock or tuned a cold air intake system is one of our favorite 6.7 Cummins performance mods. When tuned it can provide up to 10whp and 30wtq power gains. In addition to power gains, an upgraded intake also reduces turbo stress, improves efficiency, increases gas mileage by 1-2mpg, and makes for better engine responsiveness. Outside of the 10whp and 30wtq peak power gains, an intake also has greater increases on low-end power making it an awesome mod for towing and acceleration.
Open intakes are the way to go unless you really want less noise. Open intakes usually flow about 20% better than closed intakes, and 50% better than the stock intake. Therefore power gains are better on open intakes and they are also usually a bit less expensive as well providing better bang-for-the-buck.
What LML intake are you running or considering?