Vance & Hines 4 1/2″ Hi-Output Slip-On Mufflers For Harley Touring (2017–2026)
Aggressive Stepped Design Engineered for High-Horsepower Milwaukee-Eight Builds
Unleash maximum performance and a deep, thunderous exhaust note with the Vance & Hines 4 1/2″ Hi-Output Slip-On Mufflers. Designed specifically for 2017 through 2026 Harley-Davidson Touring models, the Hi-Output series is engineered for riders pushing high-horsepower Milwaukee-Eight (M8) builds, aggressive camshaft upgrades, or big-bore motor modifications. If standard slip-ons choke your engine’s top-end flow, these massive stepped mufflers deliver the expanded internal volume needed to maximize high-RPM horsepower.
Featuring a distinctive stepped body that expands into a massive 4.5-inch diameter, the Hi-Output series provides a deep bass rumble without harsh raspiness. Precision-crafted in the USA, these mufflers feature laser-cut badges and CNC-machined billet end caps, giving your bagger a dominant, muscle-bike presence under factory or extended saddlebags.
Technical Specifications & Product Features
| Feature / Metric | Product Specification | Rider Benefit |
|---|---|---|
| Brand / Manufacturer | Vance & Hines (Made in USA) | Proven race engineering, heavy-gauge construction, and exact OEM fitment |
| Muffler Body Profile | Stepped 4.0-inch to 4.5-inch Diameter Body | Increases exhaust velocity while providing maximum high-RPM flow capacity |
| Engine Platform | Harley-Davidson Milwaukee-Eight (107ci, 114ci, 117ci, & 121ci) | Engineered to prevent top-end restriction on stock or modified M8 engines |
| Model Compatibility | 2017, 2018, 2019, 2020, 2021, 2022, 2023, 2024, 2025, 2026 Harley Touring | Direct bolt-on fitment for stock dual crossover header pipes |
| Internal Core Baffle | High-Flow Fiberglass Wrapped Baffles | Delivers a deep, low-frequency V-Twin roar while managing exhaust backpressure |
| Finish Options | Show-Quality Chrome or High-Temp Matte Black Ceramic | Thermal-resistant finish built to withstand extreme exhaust gas temperatures |
| End Cap Style | CNC-Machined Billet Aluminum End Caps | Aggressive end treatment designed to fill saddlebag cutouts cleanly |
High-Flow Performance Engineering for Modified M8 Engines
Eliminating Top-End Flow Restriction
As Milwaukee-Eight engines scale in displacement or receive performance camshafts and headwork, standard diameter mufflers become a major airflow bottleneck at higher RPMs. The Vance & Hines 4.5″ Hi-Output slip-on utilizes a stepped canister design that maintains velocity at the inlet before opening into a large expansion chamber. This expansion allows exhaust gases to cool and scavenge efficiently, releasing hidden horsepower in the upper rev range without sacrificing rideability.
Dyno-Tested Power Output
Tested on dyno facilities across 107ci, 114ci, and 117ci Milwaukee-Eight engines, the 4.5″ Hi-Output mufflers deliver impressive performance gains:
- Horsepower Increase: +6.5 to +8.5 peak HP gains over factory mufflers on modified engines.
- Torque Improvements: Smooth, linear torque curve expansion right through the high RPM powerband.
- Stage 1 & Stage 2 Synergy: Essential companion for engines equipped with high-flow air intakes, performance camshafts, or Vance & Hines Power Duals headers.
Complete Vehicle Compatibility Guide
The 4.5″ Hi-Output mufflers feature 2017+ M8-specific asymmetric inlet sizes (right-side pipe inlet is larger than left-side pipe inlet). Fits all baggers listed below:
Harley-Davidson Touring Family (2017–2026)
- Street Glide: FLHX, FLHXS, FLHXST, CVO FLHXSE (2017–2026)
- Road Glide: FLTRX, FLTRXS, FLTRXST, FLTRU, FLTRK, CVO FLTRXSE (2017–2026)
- Electra Glide & Ultra Classic: FLHT, FLHTC, FLHTCU, FLHTK, FLHTKL (2017–2026)
- Road King: FLHR, FLHRC, FLHRXS Road King Special (2017–2026)
- CVO Bagger Models: All M8 CVO Street Glide, Road Glide, and Limited models (2017–2026)
Step-by-Step DIY Installation Guide
Installing Vance & Hines Hi-Output mufflers on your Touring model is a straightforward process taking approximately 45 minutes.
Required Tools & Supplies
- 3/8″ Drive Ratchet with 1/2″ and 9/16″ sockets
- Torque wrench (ft-lbs)
- High-temperature copper anti-seize compound
- Rubbing alcohol and a clean microfiber towel
Step 1: Removal of Factory Stock Mufflers
Ensure your motorcycle is completely cool and safely secured. Remove saddlebags to expose the rear mounting brackets. Loosen the factory Torx exhaust clamps connecting the mufflers to the head pipe collector. Unbolt the two rear 5/16″ mounting bolts under each saddlebag bracket. Gently twist and slide the stock mufflers backward off the headers.
Step 2: Preparing New Hi-Output Mufflers
Apply a thin layer of copper high-temp anti-seize to the header pipe ends. Slide the included heavy-duty Torca exhaust clamps onto the front slip-on joints of your new Vance & Hines Hi-Output mufflers.
Step 3: Mounting & Alignment
Slide each Hi-Output muffler onto its respective head pipe (matching the larger inlet to the right-side header). Align the top mounting bracket channels with your frame’s rubber isolators. Thread in the stock mounting bolts loosely. Adjust alignment from the rear of the bike to ensure both 4.5-inch end caps are level with your saddlebag cutouts.
Step 4: Torque Specs & Degreasing Wipe-Down
Torque the rear rubber isolator bracket bolts to 18 ft-lbs. Tighten the front heavy-duty Torca barrel clamps to 38–42 ft-lbs.
CRITICAL WARNING: Clean all chrome or matte black surfaces thoroughly with rubbing alcohol prior to starting the engine. Oil or fingerprints left on the finish will permanently bake into the metal during the initial heat cycle!
Sound Profile & EFI Tuning Requirements
Acoustic Sound Profile
The Hi-Output 4.5″ muffler produces one of the deepest, most aggressive tones in the Vance & Hines lineup. Its stepped canister design lowers sound frequencies to create a rich bass rumble at idle and a deep, authoritative roar under heavy acceleration, while keeping high-pitched raspy tones out of your helmet.
EFI Tuning Recommendations
- Mufflers Only: On otherwise stock motorcycles, an ECU tuner is optional, as the factory ECM can manage mild flow adjustments.
- Stage 1 / Stage 2 Upgrades: When pairing these high-flow mufflers with an aftermarket air intake or upgraded camshafts, you must reflash the ECU using a tuner like the Vance & Hines Fuelpak FP4 to optimize fuel delivery and prevent lean engine running.
Frequently Asked Questions
Will these 4.5″ Hi-Output mufflers fit Harley Trike models?
No. Trike models (Tri Glide, Freewheeler, Road Glide 3) require Trike-specific slip-on part numbers designed to clear rear trunk bodywork and frame brackets.
Are quiet baffles available for the 4.5″ Hi-Output series?
Yes. Vance & Hines offers optional quiet baffle inserts (Part #21841) for riders who want to tone down overall decibel output while maintaining the deep bass sound signature.
Do these mufflers keep the factory catalytic converter intact?
Yes. On 2017–2026 Harley Touring models, the catalytic converter is located inside the head pipe collector, not in the mufflers. Installing these slip-on mufflers keeps factory emissions systems functioning normally.
Order Your Vance & Hines Hi-Output Mufflers Today
Give your 2017–2026 Harley-Davidson Touring motorcycle the ultimate combination of high-RPM horsepower, bold styling, and deep V-Twin sound. Order the Vance & Hines 4 1/2″ Hi-Output Slip-On Mufflers today with full manufacturer warranty protection and fast US shipping!
