Give your K5 a louder exhaust sound and a real quad-tip setup with this stainless steel axle-back from Bull Boost Performance. The factory rear muffler is removed and replaced with a freer-flowing Y-pipe that splits into two polished tips on each side.
This system is built around the K5 GT with the 2.5L turbo engine. It can also be installed on 1.6L turbo models, but those cars require diffuser modification or a compatible replacement diffuser to make room for the quad exhaust tips.
Fitment Information
- 2021 Kia K5 GT DL3 2.5L Turbo
- 2022 Kia K5 GT DL3 2.5L Turbo
- 2023 Kia K5 GT DL3 2.5L Turbo
- 2024 Kia K5 GT DL3 2.5L Turbo
- 2021 Kia K5 DL3 1.6L Turbo with diffuser modification
- 2022 Kia K5 DL3 1.6L Turbo with diffuser modification
- 2023 Kia K5 DL3 1.6L Turbo with diffuser modification
- 2024 Kia K5 DL3 1.6L Turbo with diffuser modification
2025 Fitment Note: The 2025 K5 received a different rear bumper and diffuser, so 2025 fitment should be confirmed before ordering.
1.6T Fitment Note: The 1.6L turbo was offered in trims such as the LXS, EX and GT-Line. These cars do not use the same rear diffuser as the K5 GT, so diffuser cutting or replacement is required.
Does Installation Require Cutting or Welding?
Cutting is required, but welding is not. The factory exhaust pipe must be cut so the Bull Boost axle-back can slide over it. The new exhaust is then secured using the supplied clamp.
The installer should position the complete axle-back under the car before marking the factory pipe. This makes sure there is enough overlap for the slip-fit connection and allows the quad tips to be centered before the pipe is cut.
Welding the inlet connection is optional. The supplied exhaust clamp allows the system to be installed without welding and makes it possible to remove the axle-back later.
Specs & Features
- Three-piece axle-back exhaust system
- 2.5-inch stainless steel piping
- Quad polished exhaust tips
- Muffler-delete design
- TIG-welded construction
- Back-purged welds
- Slip-fit inlet connection
- Uses exhaust clamps rather than a bolted inlet flange
- Designed around the Kia K5 GT 2.5L turbo rear diffuser
- Bull Boost part number 720595373654
Included in the Box
- Center inlet and Y-pipe section
- Left-side quad-tip section
- Right-side quad-tip section
- Three exhaust clamps
- Three adjustable rubber exhaust hangers
How Does It Sound?
Removing the large factory rear muffler gives the K5 a louder and more noticeable exhaust note, especially during startup and acceleration. Since this is only an axle-back, the factory catalytic converter, front pipe and center section remain in place.
The 2.5T and 1.6T engines will not sound exactly the same. The K5 GT 2.5T has a deeper note, while the smaller 1.6T tends to sound sharper as the revs come up.
Installation Notes
- Mock up the complete axle-back before marking the factory exhaust pipe.
- Measure the required slip-joint overlap before cutting.
- Use an exhaust pipe cutter or reciprocating saw to make a straight cut.
- Deburr the factory pipe before installing the Bull Boost inlet.
- Leave the clamps loose until all four tips are centered in the diffuser.
- Tighten the clamps after checking bumper and suspension clearance.
- Recheck the clamps after the first few heat cycles.
Professional installation is recommended because the factory exhaust must be measured and cut. Incorrect placement of the cut can leave too little pipe for the clamp connection or position the tips incorrectly.
Pairs Well With
- SXTH Element CPLT Intake for Kia K5 GT 2.5T - Replaces the complete factory intake assembly and adds more turbo and induction sound to go along with the louder Bull Boost axle-back.
- HPS Performance Air Intake for Kia K5 1.6T - A vehicle-specific intake for 2021-2024 1.6L turbo models that adds more intake and turbo sound from the front of the car.
- Godspeed MonoSS Coilovers for Kia K5 DL3 - Lowers the K5 and gives you adjustable damping, helping the chassis sit better over the quad-tip exhaust setup.
Emissions and Sound Notice
This axle-back installs behind the factory emissions equipment and does not replace the catalytic converter. Check your local exhaust-noise regulations before ordering.
About Bull Boost Performance
Bull Boost Performance makes exhaust, engine, suspension and fabrication parts for modern turbo cars and older import platforms. Its lineup includes parts for Kia, Hyundai, Honda, Nissan, BMW and several other enthusiast platforms.
WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov.More in this category
Bull Boost Performance Exhaust
Kia K5 Parts
Brand: Bull Boost Performance
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