Your Kenworth W990 already makes a bold statement. Now itâs time to back that up with an aftermarket exhaust system that boosts your performance and turns heads while youâre at it.
4 State Trucks gives you everything you need to upgrade, replace, or customize your W990 exhaust setup. Whether youâre chasing better airflow, reduced emissions, or a classic chrome-stacked lookâthis product lineup has your back.
Why Upgrade Your W990 Exhaust System?
Letâs talk benefits:
- Improve engine performance: Better exhaust flow = more power and better fuel efficiency.
- Upgrade the sound: Dial in that deep, confident Kenworth growl.
- Enhance your rigâs look: Chrome stacks, polished tips, and tight-fitting piping give your W990 that show-stopper finish.
- Keep it compliant: With reliable mufflers and emission-control parts, youâre ready for the road ahead.
What's Available?
- Chrome Exhaust Stacks & Tips: For that polished, professional look that stands out.
- Mufflers & DPF Systems: Quiet down your ride while meeting EPA requirements.
- Exhaust Clamps, Elbows & Mounting Brackets: Keep your system locked in and leak-free.
- Full Exhaust Kits: All-in-one setups for easy installs and maximum results.
Achieve the Total Performance & Style Upgrade
Every part is engineered for heavy-duty, commercial-grade use. Whether youâre pulling loads coast-to-coast or running regional hauls, your W990âs exhaust system needs to keep up. While youâre working on the exhaust, you can swap out your
W990 AC/heating components. These components are durable, corrosion-resistant, and designed to last mile after mile.
Ready to upgrade your Kenworth W990?
Shop exhaust parts now and build a system that performs just as hard as you do. Clean look. Strong sound. Maximum power. Letâs go.
Frequently Asked Questions About Kenworth W990 Exhaust Parts
Will these exhaust stacks fit my specific W990 model year?
Our Kenworth W990 exhaust parts are designed to fit all W990 models from 2018 to present. However, slight variations may exist between model years, particularly in bracket mounting positions. We recommend checking your existing exhaust measurements or contacting our support team with your OEM to ensure proper fitment. Most 5-inch and 6-inch diameter stacks will work universally, but elbow angles and mounting hardware may vary.
What's the difference between 304 and 409 stainless steel exhaust components?
304 stainless steel offers superior corrosion resistance and maintains a brighter finish longer, making it ideal for show trucks or drivers in coastal areas with salt exposure. 409 stainless is more affordable and still provides excellent durability for most applications, though it may develop a slight patina over time. Both materials handle exhaust temperatures well, but 304 typically carries a 5-year warranty while 409 offers a 3-year warranty on most products.
Can I install these exhaust parts myself, or do I need a shop?
Most straight stack replacements can be completed in 2-3 hours with basic tools including wrenches, a sawzall for old pipe removal, and proper clamps. However, full exhaust system overhauls or modifications requiring new mounting brackets typically need professional installation. Common challenges include aligning dual stacks evenly and ensuring proper clearance from cab components. We provide detailed installation guides with each product, but welding may be required for custom applications.
What exhaust tip styles work best for the W990's classic look?
The most popular options for maintaining the W990's traditional appearance are curved top stacks with either chrome or powder-coated black finishes. Bull hauler styles (straight cut) offer maximum flow for performance, while miter cut tips provide a sleek, modern touch. Turn-out tips are ideal for preventing rain entry but may not suit every driver's aesthetic preference. Chrome tips require regular polishing, while powder-coated options offer lower maintenance.
How do aftermarket exhaust parts affect my engine warranty and emissions compliance?
Replacing exhaust stacks and tips typically won't affect your engine warranty as long as you maintain proper backpressure specifications. However, removing or modifying DPF/DEF components will void warranties and violate federal emissions laws. Our replacement parts maintain factory backpressure ratings when properly installed. For pre-2007 trucks without emissions equipment, you have more flexibility in exhaust modifications. Always check local state regulations as some areas have additional noise restrictions.
Kenworth W990 Chrome Stacks & Tops
Kenworth W990 Clamps, Brackets & Mounting
Kenworth W990 DPF & Mufflers
Kenworth W990 Elbows, Piping & Comp.
