The Chevy Duramax from '01 to '04 code-named the "LB7" makes considerable performance numbers. To begin modifying and upgrading the engine, supplying it with clean air should be the first step. An aftermarket intake will provide better performance, fuel economy, and an overall better driving experience.
The Duramax LB7 has an efficient air intake, but if you're looking for incredible performance numbers, we at HeavyWeight Diesel stock air intakes and filters from aFe Power, Banks Power, and S&B. For even greater performance numbers, pair the intake with a quality tuner that will optimize the airflow to your Duramax engine.
Air filters remove particles such as dirt and debris, allowing cleaner oxygen to reach the engine, which will result in better combustions. Keep in mind that if you drive your truck only on pavement, you can opt for an open-air filter, and if you drive on dusty roads, a more closed air filter will keep your engine healthy for longer.