Porsche 718 Downpipe Guide: Catted vs Catless, Sound, Power & What to Know
Everything Porsche 718 owners ask about downpipes — power gains, sound changes, spool, fitment, and the catted vs catless decision — answered in one place.
The downpipe is the single most impactful exhaust upgrade you can make on a Porsche 718 Cayman or Boxster. It's also one of the most misunderstood. Here's the straight answer to the questions we get every week.
What a Downpipe Actually Does
The downpipe is the section of exhaust directly after the turbocharger. On the factory 718, it includes a restrictive catalytic converter and tight bends that create significant backpressure. Backpressure on a turbo car is the enemy — it slows spool, reduces efficiency, and limits how much boost the turbo can build cleanly.
A high-flow aftermarket downpipe like the RaggDoll Stainless Downpipe replaces this restriction with a larger-diameter, smoother flow path.
Real-World Gains
On a tuned 718, a downpipe typically delivers: • 20–35 WHP gain when paired with a Stage 2 tune • Noticeably faster spool — boost arrives earlier and harder • Lower exhaust gas temperatures (EGTs) • Reduced timing pull under sustained load • A deeper, more aggressive exhaust note
Without a tune, you'll still feel the spool and sound difference, but power gains are modest. Always plan to retune.
Catted vs Catless: The Honest Breakdown
Catted (high-flow catalytic converter): • Street legal in most areas • Passes most visual inspections • Slight power penalty vs catless (usually 5–10 WHP) • Eliminates check engine lights with no tune work • Reduces rasp and drone • Our recommendation for street-driven cars
Catless: • Maximum flow, maximum power • Loudest option — significant rasp at certain RPM • Will throw codes without tune work to disable O2 monitoring • Not street legal in most US states • Best for dedicated track cars
The difference in power is real but smaller than the internet suggests. For 95% of 718 owners, a quality catted downpipe is the right answer.
Sound Changes
Expect a deeper, more present exhaust note across the rev range. Cold starts get noticeably louder. Cruising is similar to stock with most catted setups; catless will have noticeable cabin drone between 2,000–3,000 RPM.
Fitment & Install Notes
The RaggDoll Downpipe uses factory mounting points and OEM-style flanges. No cutting, no custom hangers. Plan for 3–5 hours on a lift; subframe access makes a real difference. Replace the turbo-side gasket and any rusted hardware while you're in there.
Pairing Recommendations
A downpipe punches well above its weight when paired with: • RaggDoll ELEV Exhaust Manifold (for velocity into the turbo) • RaggDoll High-Flow Turbo Inlet (so the turbo can actually move the air) • Stage 2+ tune • Eventually, an upgraded turbocharger
When NOT to Buy a Downpipe
If you're not planning to tune the car, you'll get sound and spool benefits but you're leaving most of the power on the table. Budget the tune in before the part.
Bottom line: a quality catted downpipe is one of the highest-ROI upgrades on the 718 platform. Just don't install it without a plan for the rest.
