Peterbilt 389 Exhaust Kits

Frequently Asked Questions About Peterbilt 389 Exhaust Kits

Will these exhaust kits fit my specific year Peterbilt 389, and what about aftermarket modifications?

Our Peterbilt 389 exhaust kits are designed to fit model years 2008 through current production. However, fitment can vary based on your truck's configuration, including wheelbase, sleeper size, and any aftermarket modifications. Extended hood models may require different pipe lengths. If your truck has an aftermarket air ride suspension or lifted configuration, you may need to adjust pipe hangers or brackets. We recommend checking your specific truck measurements or calling our tech support team with your OEM for exact fitment confirmation.

What's the difference between aluminized and stainless steel options, and which should I choose?

Aluminized steel exhaust kits offer good corrosion resistance at a lower price point and typically last 3-5 years depending on your operating conditions. They're ideal for drivers in moderate climates or those who regularly wash their trucks. Stainless steel kits, particularly 409 or 304 grade, provide superior longevity (7-10+ years) and maintain their appearance better, making them worth the investment for trucks operating in harsh winters with road salt or coastal areas. Stainless steel also handles extreme heat cycles better, making it preferable for heavy-haul applications.

How difficult is the installation, and what tools or additional parts will I need?

Most exhaust kit installations can be completed in 2-4 hours with basic hand tools. You'll need standard wrenches, a reciprocating saw or pipe cutter for removing old exhaust, and potentially a jack and stands. Some installations require new exhaust clamps (typically 5-inch), hangers, and possibly flex pipe if your old components are worn. Turbo-back systems are more complex and may require removing the turbo heat shield. Many customers report the hardest part is removing corroded factory bolts, so having penetrating oil and possibly a torch on hand is recommended.

What diameter exhaust should I choose, and will a larger diameter improve performance?

Most Peterbilt 389s come factory with 5-inch exhaust systems, which is optimal for stock engines. Upgrading to 6-inch or 7-inch systems can reduce back pressure and potentially improve fuel economy by 1-3%, but the gains are most noticeable on modified engines producing over 500 horsepower. Larger diameters also provide a deeper exhaust note. However, going too large on a stock engine can actually hurt low-end torque. Straight pipes will be louder than muffled systems, so consider local noise ordinances if you frequently deliver to residential areas.

Are chrome stacks included, and how do I maintain the finish?

Chrome stacks are typically sold separately from exhaust kits unless specifically noted as a complete package. When selecting stacks, ensure they match your exhaust outlet diameter and consider features like built-in rain caps or turn-out styles. Chrome requires regular maintenance to prevent pitting and discoloration from exhaust heat. Clean chrome stacks weekly with chrome polish and a microfiber cloth, paying special attention to the area where exhaust gases exit. For trucks that idle extensively, consider heat shields or stainless steel alternatives that require less maintenance.