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Chrome Rush countdown – 14% off semi truck parts and chrome accessories at 4 State Trucks
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What is Dummy Exhaust on a Semi Truck?

2nd Oct 2026
What is Dummy Exhaust on a Semi Truck?

Dummy exhaust stacks restore the classic look vertical exhaust stacks for modern Aero-trucks.

Most modern Next-Gen semi trucks have sophosticated emissions systems that connect to horizontal exhaust outlets designed to route fumes toward the ground.

Older, pre-emissions trucks have vertical exhaust systems, displayed as single or dual chrome stack tops that glisten and shine.

Next-Gen truck owners who sorely miss the old-school big-rig aesthetic can find a solution: dummy stacks.

Peterbilt 589 dummy exhaust kit
Peterbilt 589

Lincoln Chrome 7" Dummy Exhaust Kit

Designed for horizontal-exhaust Peterbilt 589 trucks, with separate day-cab and sleeper configurations. Bracket requirements vary by setup.

View Peterbilt 589 Dummy Exhaust Kit ›
Kenworth T680 Next Gen dummy exhaust kit
Kenworth T680 Next Gen

BESTfit Dummy Exhaust Stack Kit

Built for 2022 and newer T680 models, with non-functional chrome stacks, mounting clamps, brackets, bushings, and multiple stack-style options.

View Kenworth T680 Dummy Exhaust Kit ›

Dummy Exhaust Stacks vs. Functional Exhaust Stacks

These artificial vertical chrome stacks are just for show.

Dummy exhaust stacks DO NOT affect: 

  • Exhaust sound profile 
  • Backpressure 
  • Horsepower rating

TIP: Adding larger chrome stack diameters won't change the sound on modern emissions-compliant semi trucks. The sound profile is ECM controlled. Stack sizes affect the sound of older, pre-emissions trucks. 

They mount along the sides or rear of the sleeper/cab but do not connect to the exhaust system. 

Types of Dummy Exhaust Stacks for Semi Trucks

Dummy exhaust stacks come in single or paired kits, with several chrome stack style choices available.

Complete exhaust kits don't always include every visible pipe or hardware piece. It varies by the manufacturer. Check the fitment specs before ordering artifical exhaust stacks. 

Dummy Exhaust Stack Configurations, Sizes, and Mounting Styles

Design Choice What It Changes What to Verify
Configuration Single vs. Paired Dummy Stacks Adds one or two cosmetic stacks and changes the truck's visual symmetry. Confirm which existing pipes are functional exhaust and which are decorative before ordering.
Mounting Style Cab-Mounted vs. Frame-Supported Determines where the stack is supported and how it moves with the truck. Match the correct brackets, rubber isolators, and sliding supports to the mounting system.
Build Type One-Piece vs. Sectional Affects visible seams, shipping size, and how easily damaged sections can be replaced. Check joint overlap, support-bracket locations, and overall shipping length.
Pipe Size 5", 6", 7", or 8" Changes visual scale, weight, cab clearance, and clamp requirements. Verify the diameter of stacks, spools, elbows, clamps, and other mating parts.
Tip Style Flat, Miter, Curved, or Bullhorn Changes the truck's upper profile, stack projection, and overall appearance. Measure total height, outward projection, and clearance around the cab and nearby structures.
Base Design Lower Elbow vs. Straight Section Changes the lower-stack appearance and routing around tanks, steps, and brackets. Check ground clearance, surrounding components, and compatibility with existing lower supports.
Package Type Hardware Kit vs. Complete Assembly Determines whether you receive mounting hardware only or stacks, supports, and related components. Review the parts list carefully and identify which original components must be reused.
Swipe horizontally on mobile to view the full dummy exhaust stack comparison.

The type of dummy exhaust you choose is entirely based on the style you want to show off: Bull Hauler, West Coast Curve, Flat Top, and more. 

Which Semi Trucks Use Dummy Exhaust Stack Kits?

Dummy stacks can be mounted on the side or rear sleeper cab of any Next-Gen Aero-truck model with horizontal exhaust systems: 

Dummy stacks do not work on older truck models, and are completely unecessary.

Mechanical, pre-emissions (DPF and SRC) truck models already have vertical towering chrome stack tops.

How to Install Dummy Exhaust Stacks

#1. Find the live exhaust.

Before taking anything apart, figure out which pipe is actually venting real exhaust so you don't accidentally disconnect your main system.

#2. Inspect the frame and mounts.

Look over the existing brackets and mounting spots for rust, cracks, or odd past modifications.

#3. Install the new hardware.

Put the kit’s brackets, rubber bushings, sleeves, and bolts in their proper locations.

#4. Leave things loose while you align.

Prop the pipes up and keep the hardware hand-tight at first. Adjust the height and position so both stacks match before doing a final tightening.

#5. Check for clearance.

Make sure the stacks won't rub or hit anything when the cab bounces, doors open, steps are used, or the trailer swings.

#6. Finish up with a final check.

Tighten all bolts to the right specs, make sure the joints fit together properly, and give everything one last once-over.

Common Dummy Exhaust Stack Problems and Fixes

Most issues come down to not properly mounting them in place so that they're not rattling and shaking while flying down the highway.

And if they're really not properly maintained, rust and elemental wear can weaken the structural integrity of the clamps that hold it in place. 

Problem What to Check How to Fix It
Stack Rattles Worn isolation bushings, loose hardware, or metal-to-metal contact. Tighten mounting hardware, replace worn rubber isolators, and restore proper clearance around the stack.
Stack Leans or Rotates Loose clamps, shallow slip-joint engagement, or bent supports. Support the stack, repair damaged brackets, fully seat the joints, realign the assembly, and retighten.
Repeated Bracket Cracks Excessive cab movement, tall stacks, insufficient support, or the wrong mounting design. Reevaluate cab-mounted versus frame-supported mounting and add the correct flex joints or heavier supports.
Water Collects Inside Blocked weep holes, debris buildup, or lower closures trapping moisture. Remove debris and restore the intended drainage path so rain and condensation can escape.
Rust Around Joints Trapped moisture, scratched chrome, damaged coatings, or dissimilar metals at clamps and joints. Clean and inspect the area. Repair minor coating damage or replace sections with significant corrosion.
Exhaust Fumes Enter Cab Leaks in the functional exhaust system or a live exhaust outlet positioned too close to cab air inlets. Inspect the active exhaust system immediately. Exhaust fumes point to a functional exhaust leak or routing problem, not the decorative dummy stack.
Swipe horizontally on mobile to view the full troubleshooting table.

How to Choose the Right Dummy Exhaust Stack Kit

Before You Buy Dummy Stacks

  1. Know your truck. Input the make, year, model, and possibly the cab or sleeper configuration.
  2. Check your exhaust. Take photos of the emissions equipment, exhaust outlet, stacks, and both cab sides.
  3. Choose your setup. Use one working stack with one dummy, or two dummy stacks with a separate exhaust outlet.
  4. Confirm fitment. Check brackets, mounting holes, stack lengths, and installation instructions.
  5. Measure clearance. Leave room for doors, steps, tanks, air lines, trailer turns, and overhead obstacles.
  6. Compare total costs. Include all pipes, mounting hardware, shipping, labor, and required exhaust changes.

Shop Dummy Exhaust & True Exhaust Stacks

Upgrade your semi truck exhaust system with new stainless-chrome exhaust kits and dummy exhaust mods at 4 State Trucks. 

2nd Oct 2026

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