Audi B9 S4 / S5 3.0T Tuning Guide: Stages 1 to 3 (2026)

The B9 S4 and S5 share a 3.0L single-turbo TFSI V6 (the EA839 generation that replaced the supercharged 3.0T in 2018 for North America). Stock it makes 354 HP. With a Stage 1 flash you are at 420-450 wheel HP, and a full bolt-on Stage 2 setup pushes the car past 500 wheel HP. The B9 platform is one of the easiest cars in our catalog to take from stock to 500+ HP. This guide walks the Stage 1 to Stage 3 roadmap with the brands we install at KORE SPEED.

What is the Audi B9 3.0T?

The B9 S4 and S5 launched in 2017 (EU) and 2018 (NA). North American 2018+ B9 cars use the EA839 single-turbo 3.0L V6 making 354 HP from the factory. European 2017+ S5 used a 3.0L V6 turbo with slightly different tuning. The 8-speed ZF automatic (called Tiptronic in Audi-speak) is the only transmission offered in NA. EU cars got a 6-speed manual on early B9 S5 production.

Cars that use this engine

• B9 S4 sedan (2018+ NA, 2017+ EU)
• B9 S5 coupe and Sportback (2018+ NA)
• B9 SQ5 (2018+, slightly detuned variant)
• C7.5 and C8 A6 / A7 (variants of the EA839 family)

The RS4 / RS5 use a different engine entirely — a 2.9L twin-turbo V6 (EA839 variant) with substantially different tuning paths. We'll cover that in the dedicated B9 RS5 catalog.

Stage 1: Tune Only (420-450 HP)

Stage 1 on the B9 3.0T is software-only. On 93 octane (or 91 octane with E15-E30 pump mix), expect 420-440 wheel HP and a huge torque jump from 369 lb-ft stock to 470+ lb-ft. The tune is the highest gain-per-dollar mod you will ever do on this platform.

Best tuner for B9 3.0T in 2026

Three real choices:

• APR Stage 1: The community standard. Largest map library, most refined drivability, dealer-network installs. Stage 1 file is a one-time purchase.
• 034 Motorsport Dynamic+: Excellent map quality, more aggressive on E30+ mixes. Smaller dealer network than APR.
• Unitronic Stage 1: Solid third option. Stronger emphasis on cold-weather drivability.

All three flash via the OBD2 port and reflash back to stock for warranty visits (with the trace still in the DME).

Stage 2: Bolt-Ons (470-520 HP)

Stage 2 = downpipe, intake, intercooler, plus updated tune. Build in this order:

1. Downpipe: The B9 3.0T downpipe is the single biggest bolt-on. Catless or 200-cell catted. CTS Turbo, ARM Motorsports, 034 Motorsport, and AWE Tuning all make direct-fit B9 downpipes. Browse the downpipe catalog. We typically recommend catted for street cars to avoid CEL battles.
2. Midpipe / Test pipe: The B9 has a pre-cat that sits between the downpipe and the catback. Replacing it (or running a midpipe delete) drops backpressure further. ARM Motorsports and 034 Motorsport offer direct-fit B9 midpipes.
3. Intake / airbox: ARM Motorsports, 034 Motorsport, and CTS Turbo make B9 intake upgrades. Real-world Stage 2 gain is 8-15 wheel HP. See the intake catalog.
4. Intercooler: Stock B9 intercooler heat-soaks fast above 450 HP. APR, CSF, and Wagner Tuning make direct-fit B9 intercoolers. Mandatory for sustained Stage 2+ driving.

With Stage 2 hardware and a fresh tune, expect 480-510 wheel HP on pump gas and 510-540 wheel HP on E30 mix.

Stage 2+: Fueling (520-580 HP)

The B9 3.0T factory direct injection runs out of fuel above 520 wheel HP on E30. To safely run E40-E60 you need supporting fueling:

• High-pressure fuel pump (HPFP): Auxiliary upgrade from 034 Motorsport or APR. Bolt-on, plug-and-play.
• Auxiliary low-pressure fuel pump: Required at the 580+ wheel HP target. APR and 034 both sell B9-specific kits.
• E40-E60 ethanol mix: Where ethanol is available at the pump (or use a flex-fuel sensor and blend). E60 changes the safe peak HP target significantly.

Stage 3: Turbo Upgrade (600+ HP)

Stock B9 3.0T single turbo tops out around 540-560 wheel HP. For 600+ HP, upgraded turbos are mandatory. Options in 2026:

• APR Stage 3 turbo kit: Pure single-turbo upgrade with full APR tune integration. Supports 600-680 wheel HP.
• 034 Motorsport hybrid turbos: Drop-in fitment, retain factory aesthetic.
• Custom hybrid (FrankenTurbo, Pure): For built-engine cars chasing 700+ HP.

At Stage 3 you also need: forged rods or pistons (factory rods bend around 650 HP at sustained pulls), upgraded HPFP, ethanol fueling, and serious cooling.

Supporting Mods That Save Your Engine

DSG / Tiptronic transmission cooler

The B9 ZF8 transmission heat-soaks above 480 wheel HP under hard driving. Aftermarket coolers from 034 Motorsport and APR drop fluid temps by 30-50 degrees. Mandatory past Stage 2.

Oil catch can

B9 PCV system passes oil into the intake. A catch can keeps your intercooler, charge pipes, and intake valves clean. Recommended after 450 wheel HP.

Charge pipe and turbo outlet

The factory turbo outlet on the B9 has a known restriction. ARM Motorsports and 034 Motorsport make direct-fit upgrades that are a measurable 8-12 wheel HP gain at Stage 2+. See the ARM Motorsports B9 intake.

Differential and driveline

The B9 quattro driveline can take 550-600 wheel HP without issues. Beyond that, upgraded differential mounts (034 Motorsport street density bushings) tighten the rear-diff to subframe interface and improve traction.

B9 3.0T known issues to watch

• Carbon buildup on intake valves: Direct-injection-only design (no port injection) means carbon buildup on intake valves over time. Walnut blast every 60-80k miles.
• Wastegate rattle: Some early B9 cars exhibit wastegate flapper rattle. Aftermarket downpipes mask it but the underlying issue is mechanical.
• Oil consumption (early production): 2018-2019 cars consumed measurable oil. Levels off after break-in; if yours is excessive, BMW — sorry, Audi — has a TSB.
• PCV valve failures: The factory PCV valve fails around 50-70k miles. Replace proactively to avoid lean codes.

What chassis are you working with?

• Audi B9 S4 (2017-2023)
• Audi B9 S5 (2017-2023)
• Audi B9 RS5 (2018-2023) — different engine, see RS5 guide
• Audi B8 A4 / S4 (2013-2016) — prior generation

FAQ

What is the safe Stage 1 HP for the Audi B9 3.0T?

On 93 octane premium, 420-440 wheel HP is safely sustainable from a stock B9 S4 / S5. The factory rotating assembly handles Stage 1 indefinitely with no rod bend concerns under normal driving.

Will an aftermarket downpipe throw a CEL?

Catless downpipes will throw a CEL unless paired with a tune that disables the catalyst monitor. Catted high-flow downpipes (200 or 300 cell) usually pass the OEM O2 reading on B9 cars without a tune. We recommend pairing every B9 downpipe install with a Stage 2 tune to dial in fueling and avoid CELs.

Do I need a tune for catted downpipes?

Mechanically you can run catted high-flow downpipes unflashed without immediate issues, but you will not realize the bolt-on's full HP potential. We recommend Stage 2 tune any time you install a downpipe.

How much HP can the stock B9 turbo make?

The factory B9 single turbo tops out around 540-560 wheel HP on pump fuel with full bolt-ons. Past that point you need an upgraded turbo.

Is the B9 RS5 engine the same as the S4 / S5?

No. The B9 RS5 uses the 2.9L twin-turbo V6 (EA839 variant), which is a fundamentally different engine from the 3.0L single-turbo in the S4 / S5. Tuning paths, parts, and HP targets are different. See our B9 RS5 catalog for RS5-specific parts.

Where do I buy B9 parts in Canada?

KORE SPEED is Vancouver's Audi performance specialist. We stock APR, 034 Motorsport, CTS Turbo, AWE Tuning, ARM Motorsports, Akrapovic, and more in-stock for same business day shipping across Canada. Most products ship duty-free to the US under USMCA. Browse all tuning options or see the B9 S4 catalog.