Duramax LMM Cold Air Intake Upgrade Guide
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Outside of ECM tuning, a cold air intake is one of the best upgrades for the Duramax LMM. The factory intake box is restrictive which leads to power gains, improved efficiency, some fuel economy improvements, and better throttle response when it is upgraded to a more free flowing intake system.
We’ve been manufacturing cold air intakes for Duramax engines via our Boosted Performance brand for years now. In this article we’re going to cover the performance benefits, considerations between open and closed intakes, and mention a few of our favorite intakes available for the LMM.
Benefits of Duramax LMM Cold Air Intake Upgrade
- +5–15 horsepower
- +10–25 lb-ft of torque
- Increased fuel economy
- Increased engine sounds
- Increased throttle response
For most people, the biggest benefit of a Duramax LMM cold air intake is the increase in power. With just an intake alone, the Duramax LMM can pick up 5-15 horsepower and 10–25 lb-ft of torque. While most intakes do not require a supplemental tuning solution, with a tune you will see as much as 30 horsepower and 50 lb-ft of torque in gains.
In addition, you may also see a slight bump in fuel economy. Usually, the difference is only around 0.5–1.5 mpg, but over several tanks it can definitely add up to some good savings. With the larger air filter you will also hear an increase in the engine sounds. The stock airbox does a good job of deafening the intake sound, but aftermarket ones really let you hear it.
The final noticeable benefit will be overall better throttle response. Not only does a cold air intake add peak gains of 15 horsepower and 25 lb-ft of torque, they also improve the entire power band. This means that the car will feel faster even when you are not going wide-open-throttle, and you will also notice towing gets easier, too.
Open vs Closed Airboxes
We recommend open intakes over closed-box intakes. Open intakes usually outflow closed intakes by about 20%. The increased air flow leads to bigger power gains and better performance benefits.
While an open intake will draw in air that is 1-3 degrees warmer the LMM has a good intercooler on it so the IATs entering the engine are virtually the same as those on a closed intake.
Closed intakes do serve a purpose – if you don’t want to add too much noise from intake induction sounds then a closed box is good for this. We love the sound an open intake makes, but if you prefer something more quiet then a closed intake is a good bet.
The factory intake is pretty good so the increase in flow from an open intake is really only important if you are pushing for big power numbers.
Best Duramax LMM Cold Air Intakes
- Pusher, HSP, WCF
- S&B, Banks Power
Open Intakes: Pusher, HSP , WCF
We don’t have a huge brand preference here – there are a lot of good options from brands like Pusher, HSP, and WCFab. We’re working on developing our own but until it’s available you can stick with another quality brand.
Closed Intakes: Banks or S&B
When it comes to closed intakes the only two options to consider are Banks Power or S&B. The Banks intake comes in about $100 more expensive but the S&B ones are known to have a few issues with the see-thru screens cracking so we tend to favor Banks, but S&B is still a great option and comes in at a solid price.
