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The MACH Force-Xp Axle-Back Exhaust System Built for Sound and Flow
The aFe MACH Force-Xp axle-back exhaust system 49-42079 is a precision-engineered replacement for your vehicle's restrictive factory exhaust, built from 409 stainless steel for reduced backpressure and genuine performance gains. Connects at the rear axle and replaces only the muffler and tip section. The 49-42079 is fully mandrel-bent for consistent interior diameter throughout every curve, preserving exhaust gas velocity from the collector to the tailpipe. The result is improved power delivery across the RPM range, a more aggressive exhaust note, and a polished stainless tip that improves the look of the rear fascia.
Key Features
- Material: 409 stainless steel, TIG-welded joints
- Mandrel-bent tubing for consistent interior diameter
- Tip finish: polished stainless
- Direct bolt-on using factory mounting points and hangers
- Reduces backpressure for measurable power and torque gains
- Aggressive exhaust note without excessive drone at highway speed
- All hardware and gaskets included for straightforward installation
Fitment
| Year Range | Make | Model | Trim |
|---|---|---|---|
| 2015 | Dodge | Challenger | Scat Pack |
| 2015-2018 | Dodge | Challenger | SRT 392 |
| 2015-2018 | Dodge | Charger | R/T Scat Pack |
| 2015-2018 | Dodge | Charger | SRT 392 |
| 2016 | Dodge | Challenger | 392 Hemi Scat Pack Shaker |
| 2016-2021 | Dodge | Challenger | R/T Scat Pack |
| 2017-2018 | Dodge | Challenger | R/T 392 |
| 2017-2018 | Dodge | Challenger | T/A |
| 2017-2018 | Dodge | Challenger | T/A 392 |
| 2017-2018 | Dodge | Charger | Daytona 392 |
| 2017-2018 | Dodge | Charger | R/T 392 |
| 2017-2021 | Dodge | Challenger | R/T |
| 2019-2021 | Dodge | Charger | Scat Pack |
Specifications
| Detail | Value |
|---|---|
| Part Number | 49-42079 |
| Brand | aFe Power |
| Product Line | aFe MACH Force-Xp |
| Material | 409 Stainless Steel |
| Tip Finish | Polished Stainless |
| Mounting | Factory hangers and OEM bolt positions |
| UPC | 802959603628 |
What's Included
- aFe MACH Force-Xp axle-back exhaust system (49-42079)
- All required clamps, gaskets, and hardware
- Installation instructions
Frequently Asked Questions
Will this exhaust require a tune after installation?In most applications, a bolt-on cat-back or axle-back exhaust does not require a tune. If you are also running a downpipe or header, a tune is strongly recommended to fully realize the power gains and prevent any lean conditions. Always consult your tuner when building a full exhaust setup.
Is this exhaust too loud for daily driving?The aFe MACH Force-Xp is designed to produce an enhanced exhaust note without excessive interior drone at highway speed. At idle and during spirited acceleration, the sound is noticeably more aggressive than stock. Sound level varies by vehicle platform and individual preference.
Does this exhaust maintain OEM ground clearance?Yes. The 49-42079 is designed around OEM ground clearance specifications. If your vehicle is lowered, inspect clearance at the lowest point during test-fit before final installation to confirm no contact with body or suspension components.
Are all clamps, gaskets, and hangers included?Yes. The 49-42079 ships complete with all clamps, gaskets, and hardware needed for the installation. No separate hardware purchases are required for a standard bolt-on installation.
How much power gain can I expect from this exhaust?Gains vary by vehicle, engine, and supporting modifications. A cat-back exhaust alone typically contributes 5 to 15 hp on naturally aspirated engines. On turbocharged or supercharged applications, a full exhaust system combined with a tune can yield significantly larger gains.
Will this exhaust void my warranty?Under the Magnuson-Moss Warranty Act, an exhaust upgrade alone cannot be used to void your powertrain warranty unless the dealer can prove it directly caused a specific failure. For any drivetrain or emissions-related service, discuss this with your service advisor before work begins.
Is this exhaust compatible with my OEM tips if I want to keep them?The 49-42079 comes with its own polished stainless tip. If you prefer different tips, the pipe outlet dimensions are listed in the product specs and compatible aftermarket tips from vendors like Borla or Magnaflow can be substituted. Contact us to confirm outlet sizing for your specific application.
What is the maintenance requirement on a stainless steel exhaust?Stainless steel exhaust systems require minimal maintenance. Periodic cleaning with a stainless steel polish keeps the tips and visible pipe sections looking their best. Inspect the mounting hardware once a season in regions that use road salt in winter months.
Installation Overview
- Safely lift and support the vehicle to gain access to the full exhaust system
- Allow the OEM exhaust to cool completely before beginning
- Apply penetrating oil to all exhaust flange bolts and hangers at least 15 minutes prior to removal
- Remove the OEM exhaust section by section, starting from the rearmost component
- Compare the new 49-42079 sections against the removed OEM pieces to confirm lengths and clocking
- Hang the new exhaust onto the factory hangers, starting from the front connection point
- Install all flange bolts and clamps without fully tightening to allow for alignment adjustment
- Adjust all sections for clearance from body panels, fuel lines, and brake lines
- Torque all hardware to specification and verify tip alignment before lowering
- Start the engine and check for exhaust leaks at all joints before the first drive
WARNING: This product can expose you to chemicals including lead and phthalates, which are known to the State of California to cause cancer and reproductive harm. For more information go to www.P65Warnings.ca.gov.
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