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7-5 Inch Semi-Truck Exhaust Stacks
Frequently Asked Questions About 7-5 Inch Semi-Truck Exhaust Stacks
What's the difference between straight cut and curved/mitered exhaust stacks, and which should I choose?
Straight cut stacks provide maximum exhaust flow and a classic look, while curved or mitered stacks direct exhaust away from your trailer and reduce soot buildup on cargo. If you frequently haul refrigerated units or flatbeds with tarps, curved stacks are recommended. For dump trucks or applications where exhaust direction isn't critical, straight stacks work well and typically cost less.
Will 7-inch or 5-inch stacks fit my truck, and what adapters might I need?
Most semi-trucks come with 5-inch exhaust systems from the factory, so 5-inch stacks typically bolt right on. For 7-inch stacks, you'll need a 5-to-7 inch adapter or expander. Check your current exhaust outlet diameter first - measure the outside diameter of your existing pipe. Common truck models like Peterbilt 379/389, Kenworth W900, and Freightliner Classic XL all use standard 5-inch systems that work with our stacks.
How difficult is the installation, and what tools do I need?
Installation typically takes 1-2 hours per stack with basic hand tools. You'll need a socket set, band clamps (usually 5-inch or 7-inch depending on your stack size), and potentially a sawzall if you're cutting existing pipes. Most installations don't require welding - our stacks use clamp-on designs. The hardest part is usually reaching the upper clamps, so having a helper or truck-height work platform makes the job easier.
What's the difference between chrome, stainless steel, and powder-coated finishes in terms of maintenance?
Chrome provides the brightest mirror finish but requires regular polishing (every 2-4 weeks) to prevent pitting and rust. Stainless steel offers good corrosion resistance with less maintenance - just occasional cleaning with stainless polish. Powder-coated black stacks need the least maintenance and hide soot well, but the coating can chip if hit by debris. For trucks in harsh winter climates with road salt, stainless steel typically holds up best long-term.
Do taller exhaust stacks affect engine performance or fuel economy?
Adding 36-48 inch stacks versus factory-height stacks has minimal impact on performance - typically less than 1% change in fuel economy. The slight increase in back pressure is negligible on modern diesel engines. However, extremely tall stacks (60+ inches) or stacks with built-in mufflers can create enough restriction to trigger check engine lights on newer emissions-controlled trucks. Straight-through designs without baffles provide the best flow.