How to Install an Akrapovic Exhaust on the 718 Cayman GT4

The Akrapovic Slip-On Race Line (Titanium) is a rear-section exhaust upgrade for the 2020+ Porsche 718 Cayman GT4 (982) that replaces the heavy stock muffler assembly with three titanium mufflers cast in Akrapovic's in-house foundry. On Akrapovic's own dyno it adds 6.4 hp at 3,000 rpm and 11.7 lb-ft at 2,900 rpm to the 414 hp 4.0L naturally aspirated flat-six – with no ECU tune required. Because it is a true slip-on, this is also one of the few upgrades on a GT4 you can realistically install yourself in an afternoon. This guide walks through every part you need, every tool, and every step, based on what we see in our Tampa, FL shop at NLP Performance.

What Does the Akrapovic Slip-On Race Line Do for the 718 Cayman GT4?

The Slip-On Race Line (part number S-PO/TI/18/1, the current “Option 2” version) replaces the entire stock rear muffler section of the 2020–2027 Porsche 718 Cayman GT4 with a three-muffler titanium assembly: two side mufflers plus one central muffler. The cast valve housings come out of Akrapovic's own titanium foundry, and the system reuses your factory exhaust-valve actuators, so the Sport Exhaust button on the console keeps working exactly as Porsche intended.

Akrapovic's published dyno data for the GT4 shows a gain of 4.8 kW (6.4 hp) at 3,000 rpm and 15.8 Nm (11.7 lb-ft) at 2,900 rpm over the stock system. Those are midrange numbers, not peak numbers – which is exactly where a naturally aspirated 4.0L that revs to 8,000 rpm spends most of its street life. The bigger transformation is acoustic: the stock GT4 exhaust routes through restrictive particulate-filter housings that noticeably mute the 9A2 Evo flat-six, and the Race Line opens that voice back up.

One production note our customers ask about: Porsche changed the muffler mounting brackets on cars built from roughly February 2020, which is why two versions of this system exist. The S-PO/TI/18/1 sold here is the later-bracket Option 2 version – verify your build date before ordering, and our Tampa team can cross-check fitment against your VIN if you are unsure.

Which Parts Do You Need Before Installing?

This is the single most common ordering mistake we see with this system at NLP Performance: the Slip-On Race Line ships without exhaust tips. The “Req Tips” in the product name means a separate Akrapovic tail pipe set is mandatory to complete the install. You have two finish choices, both dimensionally identical: natural titanium (part TP-T/S/27) or black-coated titanium (part TP-T/S/28). Both retail for $1,515.84 MSRP and sell for $1,310.64 at NLP Performance.

So a complete Akrapovic exhaust for your GT4 comes to $9,159.22 in parts – the $7,848.58 muffler section plus a $1,310.64 tail pipe set. Nothing else is required: no link pipes, no tune, no new actuators. Here is the full 718 exhaust parts picture, including the valve-control sound kit for GT4 RS owners and AWE's alternative for turbocharged 718 models:

What Tools Do You Need for a GT4 Slip-On Exhaust Install?

A slip-on install on the 718 Cayman GT4 needs no exotic tooling – this is a V-band-and-hanger job, not a fabrication project. Porsche shops quote 2.5–3 hours of labor for a comparable Akrapovic slip-on install (typically under $500), and a careful first-timer on jack stands should plan 3–4 hours. A lift is convenient but not mandatory. Here is the checklist we hand DIY customers in our Tampa shop:

• Jack and 4 jack stands (or a lift) – you need stable access to the full rear of the car
• Metric socket set with extensions – the diffuser fasteners, muffler bracket bolts, and bumper bolts are all standard metric sizes
• Torque wrench – for the V-band clamps and bracket hardware; torque all clamps to the values in Akrapovic's included instruction sheet
• Penetrating oil – the link-pipe V-band clamps and sleeve joints see extreme heat cycles
• Exhaust hanger removal pliers or silicone spray – for the rubber hangers
• A second set of hands – the stock assembly is bulky, and Rennlist DIYers consistently report the pipe-to-pipe fit is tight enough that an extra person to steady and “yank” parts into alignment saves real time

Let the exhaust cool completely before you start – titanium and stainless hold heat far longer than you expect after even a short drive.

How Do You Install the Akrapovic Slip-On Race Line? (Step-by-Step)

The install below follows the sequence Akrapovic's instructions and experienced 718 GT4 owners use. The headline for nervous first-timers: full rear bumper removal is not strictly required. Owners on Rennlist complete this swap by removing only the center diffuser and working through the opening, though loosening the bumper's lower bolts gives useful wiggle room if you are working alone.

Step 1: Raise the Car and Let the Exhaust Cool

Lift the rear of the car on a lift or secure jack stands at the factory jacking points. Removing the rear wheels one side at a time – a trick from Rennlist DIY threads – opens up access to the side muffler brackets without needing the car dangerously high.

Step 2: Remove the Center Rear Diffuser

Unbolt the center diffuser panel below the bumper. This exposes the stock muffler assembly, the link-pipe connections, and the hanger points. Keep the hardware organized – the diffuser goes back on last.

Step 3: Loosen the V-Band Clamps at the Link Pipes

Soak the V-band clamps where the muffler section meets the link pipes with penetrating oil, then loosen them. These joints seal metal-to-metal under heat cycling, so expect them to need a firm break loose on a car with miles on it.

Step 4: Disconnect the Valve Actuators and Unbolt the Stock Muffler

Unplug or unbolt the two factory exhaust-valve actuators from the stock valve housings – you are reusing them, so treat them gently. Support the stock assembly, unbolt its brackets, free the rubber hangers, and work it off the link pipes. This is the moment the second set of hands earns its keep.

Step 5: Transfer the Actuators to the Akrapovic Valve Housings

Bolt the factory actuators onto the Akrapovic cast titanium valve housings per the included instructions. Because the system reuses Porsche's own actuators, valve behavior stays fully integrated with the car's drive modes and Sport Exhaust button – no error codes, no resistors, no extra module needed.

Step 6: Hang the Akrapovic Mufflers and Seat the Connections

Lift the three-muffler assembly into place, seat it onto the link pipes, and hang it on the mounts. Leave every clamp finger-tight until the whole system is on the car – you will need the play for alignment.

Step 7: Fit the Tail Pipe Set and Align Everything

Slide the titanium (TP-T/S/27) or black-coated (TP-T/S/28) tail pipes into position and center them in the diffuser openings. Step back, sight the tips against the bodywork from several angles, then torque all V-band clamps and bracket bolts to Akrapovic's specified values in sequence.

Step 8: Refit the Diffuser, Start It Up, and Leak-Check

Reinstall the center diffuser, start the engine, and check every joint for exhaust leaks with the engine warm. Re-check clamp torque after the first full heat cycle and again after the first spirited drive – standard practice for any slip-fit exhaust.

How Does the Akrapovic Exhaust Sound Compared to Stock?

The character change comes from the architecture. The Race Line has no X-pipe: each bank of the 4.0L flat-six exhales independently, which produces a lower, rawer, more vintage air-cooled-adjacent tone rather than the smooth modern-Porsche wail. Owners who have compared systems back-to-back describe the Akrapovic as “lower with more volume” than crossover-style rivals.

Volume reports genuinely split, and it is worth being honest about that. Some GT4 owners report improved sound at every rpm with no highway drone whatsoever; at least one found it loud enough with the valves closed that in-car conversation took effort. Others consider the system restrained – even “sometimes quieter than stock” – when paired with the factory link pipes. Where you land depends on the rest of your exhaust path: on US cars, the factory particulate-filter housings contain an inert straight-through matrix rather than the coated filters EU cars run, but they still act as significant sound attenuators. Keeping them keeps the Akrapovic civil; deleting them is what turns the volume up.

That tunability is the point: valves closed, the GT4 stays neighborhood-friendly for a 6 a.m. exit. Valves open at 8,000 rpm, it finally sounds like the motorsport-derived flat-six Porsche built.

What Should You Check After Installation?

Three things separate a clean install from a comeback, and they take ten minutes total. First, re-torque every V-band clamp after the first full heat cycle – slip joints settle as they expand and contract, and a clamp that was perfect cold can loosen a quarter turn after one drive. Second, cycle the exhaust valves through the Sport Exhaust button and each drive mode with the engine running to confirm both actuators respond; a lazy valve usually means a connector left half-seated in Step 5. Third, inspect tip alignment in the diffuser openings after a week of driving – hangers relax slightly as new rubber takes a set.

At NLP Performance we also tell customers to keep the stock exhaust boxed and stored flat. A complete, uncut factory GT4 exhaust holds real value with these cars' collector trajectory, and returning to stock for resale or inspection takes the same 2.5–3 hours in reverse.

What Other Upgrades Pair Well With the Exhaust?

The GT4's chassis has more headroom than its 414 hp suggests, which is why exhaust-first owners usually go to suspension second. For track-focused builds, the KW Clubsport 3-way coilover kit – developed on the Nordschleife with independent high-speed and low-speed compression plus rebound adjustment – is the matching-caliber chassis upgrade for the 982 GT4. And if there is a GT4 RS in your garage next to the GT4, Akrapovic's Sound Kit adds driver-controlled valve override to the RS for $788.05.

Driving a turbocharged 718? The four-cylinder 2.0T and 2.5T Boxster and Cayman models take a different path: AWE's SwitchPath valved cat-back (for PSE-equipped 2017–2024 cars) delivers the same closed-quiet/open-loud dual character for $3,075.00. Note it is a non-CARB item and cannot ship to California addresses.