Porsche 991.1 / 991.2 GT3 / GT3 RS / 911R SOUL Valved Side Muffler Bypass Pipes

$2,095.00

Product Description

The SOUL Valved Side Muffler Bypass Pipes are designed for Porsche 991.1 and 991.2 GT3 / GT3 RS models and the 911R, replacing the heavy factory side mufflers with large-diameter 3-inch valved bypass pipes while retaining the factory center muffler and factory exhaust-valve functionality.

This configuration removes a substantial amount of weight and heat from the rear of the vehicle without giving up the factory car's ability to reduce exhaust volume when desired.

SOUL's system weighs approximately 9.5 lbs, compared with approximately 44.9 lbs for the factory side-muffler components, resulting in an impressive 35.4-lb / 16-kg weight reduction.

With the valves closed, exhaust is directed through the more restrictive upper route into the factory center muffler, maintaining a relatively comfortable and refined exhaust note. As the valves open, the system provides a much freer 3-inch flow path, producing a smoother, more exotic, race-inspired flat-six sound.

FITMENT:

• Fits 2014–2016 Porsche 991.1 911 GT3

• Fits 2016 Porsche 991.1 911 GT3 RS

• Fits 2016 Porsche 911R

• Fits 2018–2019 Porsche 991.2 911 GT3

• Fits 2018–2019 Porsche 991.2 911 GT3 with Touring Package

• Fits 2019 Porsche 991.2 911 GT3 RS

• SOUL specifies fitment for all 991.1 / 991.2 GT3 and GT3 RS models including the 911R from 2014–2019

• Retains the factory center muffler

• Retains factory exhaust-valve functionality

• Compatible with the factory headers and catalysts

• Compatible with applicable aftermarket headers

• Direct bolt-on installation

DETAILS:

• Replaces both factory side mufflers

• Retains the factory center muffler

• Retains factory exhaust valves

• Retains factory Sport / exhaust-valve control functionality

• 3-inch primary exhaust piping

• Constructed from mandrel-bent T304L stainless steel

• .065-inch wall thickness

• High-quality flex bellows incorporated into the system

• Flex bellows improve installation tolerance

• Flex bellows help reduce stress during aggressive track use

• High-quality exhaust valves designed to operate like the factory system

• Enlarged secondary-path opening helps equalize pressure in the factory center muffler

• Pressure balancing helps promote center-muffler longevity

• Deletes the heavy factory side mufflers

• Helps reduce heat soak in the engine bay

• Helps reduce heat transferred toward the rear tires

• SOUL system weighs approximately 9.5 lbs / 4.3 kg

• Factory side-muffler components weigh approximately 44.9 lbs / 20.4 kg

• Saves approximately 35.4 lbs / 16 kg

• No cutting required

• No welding required

• No permanent modification required

• Each system is fixture-tested prior to shipment

• Foam-packed following final inspection

• Optional O2 sensor bungs can be added for aftermarket-header applications that relocate oxygen sensors to the side-muffler section

• O2 bungs are not included by default

• Designed and manufactured in-house by SOUL Performance Products in Willow Grove, Pennsylvania

• Exhaust valves and piping are covered by SOUL's Lifetime Warranty for street and track use

WHY DELETE THE SIDE MUFFLERS?

The factory GT3 exhaust incorporates:

• Headers

• Side mufflers

• Center muffler

The side mufflers contribute significant weight and retain considerable heat near the rear of the vehicle.

SOUL removes these large factory side-muffler assemblies and replaces them with compact, freer-flowing stainless-steel bypass pipes.

The result is a dramatic reduction in:

• Exhaust-system weight

• Exhaust heat retention

• Engine-bay heat soak

• Heat exposure around the rear of the vehicle

while retaining the factory center muffler to provide meaningful sound control.

35.4-LB WEIGHT REDUCTION:

The weight savings are one of the most significant advantages of this system.

Factory Side-Muffler Components:
Approximately 44.9 lbs

SOUL Valved Side Muffler Bypass Pipes:
Approximately 9.5 lbs

Weight Savings:
Approximately 35.4 lbs / 16 kg

That represents nearly an 79% reduction in the weight of the components being replaced.

Because this mass is located at the extreme rear of the vehicle, the reduction is particularly attractive on a rear-engined 911.

HEAT MANAGEMENT:

The factory side mufflers retain considerable heat within the rear of the vehicle.

Removing them reduces the amount of hot exhaust hardware surrounding:

• The engine bay

• Rear suspension area

• Rear tires

SOUL specifically highlights improved heat management as one of the major benefits of the Side Muffler Bypass design.

This becomes particularly relevant during repeated track sessions where heat accumulation can become substantial.

3-INCH PRIMARY PIPING:

The Valved Side Muffler Bypass Pipes use large:

3-inch primary tubing

to increase available exhaust flow compared with the factory side-muffler architecture.

The system is built from:

T304L stainless steel

with:

.065-inch wall thickness

This provides a balance of durability, heat resistance, and relatively low weight.

RETAINS THE FACTORY CENTER MUFFLER:

Unlike SOUL's Center Muffler Bypass Exhaust, this system removes the side mufflers while retaining the original Porsche center muffler.

That difference fundamentally changes the sound character.

The retained factory center muffler continues to provide:

• Acoustic attenuation

• Reduced cabin resonance

• Meaningful valves-closed refinement

• A smoother overall sound transition

This makes the Valved Side Muffler Bypass a particularly appealing option for owners prioritizing weight reduction and heat management without turning the car into a permanently extreme exhaust setup.

VALVES CLOSED:

With the exhaust valves closed, gases are routed through the smaller secondary path and into the more restrictive portion of the factory center muffler.

SOUL enlarged the opening into this secondary path to help equalize internal pressure in the center muffler.

With the valves closed, expect:

• Moderate increase in exhaust volume compared with stock

• Comfortable cruising characteristics

• Relatively restrained cabin presence

• Retention of the factory center muffler's sound attenuation

• Smoother sound transition than a Center Muffler Bypass configuration

• Greater exhaust character without excessive volume

VALVES OPEN:

As the factory exhaust valves open, exhaust gains access to the freer-flowing 3-inch primary path.

Expect:

• Greater exhaust flow

• Increased overall volume

• Smoother and more exotic exhaust tone

• Greater naturally aspirated flat-six presence

• Stronger high-RPM character

• More aggressive downshifts

• More pronounced burbles

• Refined race-derived pitch rather than simply additional bass

SOUL specifically describes the valves-open sound as having a more exotic character appropriate for the GT3 engine.

SMOOTHER VALVE TRANSITION:

One of the most important sound differences between a Side Muffler Bypass and a Center Muffler Bypass is how dramatically the sound changes when the valves open.

With a Center Muffler Bypass, the difference between valves closed and open can be very pronounced.

With the Valved Side Muffler Bypass:

• The valves-closed configuration is somewhat louder than a Center Muffler Bypass setup

• The valves-open configuration is somewhat less aggressive than a Center Muffler Bypass

• The transition between the two modes is noticeably smoother

This produces a more progressive change in sound as the factory valves operate.

SIDE MUFFLER BYPASS VS. CENTER MUFFLER BYPASS:

Valved Side Muffler Bypass

• $2,095.00

• Removes factory side mufflers

• Retains factory center muffler

• Retains factory exhaust valves

• 3-inch primary piping

• Approximately 35.4 lbs lighter than factory side-muffler components

• Greater heat reduction

• Smoother, more exotic exhaust tone

• Smoother transition between valves closed and open

• Slightly louder with valves closed

• Slightly quieter with valves open compared with a Center Muffler Bypass

Center Muffler Bypass

• Removes factory center muffler

• Retains factory side mufflers

• Retains factory valves

• Approximately 11 lbs lighter than factory

• Deeper and more aggressive sound

• More dramatic valve-open transition

• Quieter valves-closed behavior

• Louder valves-open character

The Valved Side Muffler Bypass is the stronger choice when weight reduction and heat management are major priorities.

VALVED VS. NON-VALVED SIDE MUFFLER BYPASS:

SOUL also offers a non-valved Side Muffler Bypass.

Valved Side Muffler Bypass

• Retains factory valve functionality

• Approximately 9.5 lbs

• Saves approximately 35.4 lbs

• Allows quieter and louder operating modes

• Better suited to mixed street and track use

Non-Valved Side Muffler Bypass

• Permanently unrestricted

• Approximately 6.6 lbs

• Saves approximately 38.3 lbs

• Approximately 2.9 lbs lighter than the valved version

• No exhaust-volume control

• More track-focused configuration

The valved system sacrifices only about 3 lbs relative to the non-valved version while retaining factory sound control.

FLEX BELLOWS:

SOUL incorporates high-quality flex bellows into the bypass pipes.

The bellows provide additional compliance between exhaust components, helping compensate for:

• Manufacturing tolerances

• Thermal expansion

• Engine movement

• Chassis movement

• Repeated track-induced heat cycles

SOUL notes that this approach mirrors the durability philosophy used by OEM exhaust systems.

CENTER-MUFFLER PRESSURE MANAGEMENT:

SOUL enlarges the opening leading into the secondary center-muffler path.

The goal is to help:

• Equalize pressure within the center muffler

• Distribute exhaust flow more effectively

• Reduce localized stress

• Promote factory center-muffler longevity

This is particularly relevant because the side-muffler bypass substantially changes how exhaust gases enter the retained factory center muffler.

DIRECT BOLT-ON INSTALLATION:

The Valved Side Muffler Bypass Pipes are designed for straightforward installation.

There is:

• No cutting

• No welding

• No permanent exhaust modification

• No ECU programming required for the bypass pipes themselves

Each system is built and tested in a dedicated fixture before shipment to ensure consistent fitment.

OPTIONAL O2 SENSOR BUNGS:

SOUL does not install oxygen-sensor bungs in the Side Muffler Bypass Pipes by default.

This keeps the system as simple and lightweight as possible.

However, optional O2 bungs can be added for vehicles using aftermarket headers that relocate oxygen sensors into the side-muffler section.

Customers running such a header configuration should confirm their oxygen-sensor arrangement before ordering.

WITH FACTORY HEADERS:

With factory Porsche headers retained, the oxygen sensors remain in their original locations and the optional side-bypass O2 bungs are generally unnecessary.

This configuration provides:

• Major weight reduction

• Improved heat management

• Increased exhaust sound

• Retained factory catalysts

• Retained factory center muffler

• Retained valve functionality

WITH AFTERMARKET HEADERS:

The bypass pipes can also be paired with upgraded headers.

If those headers relocate the oxygen sensors downstream into the side-muffler section, SOUL can add the required O2 bungs to the bypass pipes.

This should be determined before the parts are manufactured and shipped.

PERFORMANCE:

The large 3-inch primary piping and removal of the restrictive side-muffler assemblies increase available exhaust flow.

However, SOUL does not publish a verified standalone horsepower or torque gain for the Valved Side Muffler Bypass Pipes.

The primary manufacturer-documented benefits are:

• 35.4-lb weight reduction

• Reduced heat soak

• Increased exhaust flow

• Increased sound

• Retained factory valve functionality

EXHAUST TIPS:

This product does not include or require a separate exhaust-tip option.

The Valved Side Muffler Bypass Pipes replace the side-muffler assemblies while retaining the factory center-muffler / center-exit architecture.

There are therefore no tip style or finish variants associated with this standalone product.

EMISSIONS NOTE:

The Side Muffler Bypass Pipes themselves do not remove the factory catalytic converters when used with the original Porsche headers.

If the system is paired with aftermarket headers that alter or remove factory catalyst components, emissions compliance will depend on the complete exhaust configuration.

Customers are responsible for determining compliance with applicable regulations for their vehicle.