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Audi S4 B9Stage 1 to Stage 4 tuning guide

The B9 S4 has the EA839 3.0 TFSI, a V6 with a single turbo inside the V, an 8-speed ZF automatic and quattro all-wheel drive. Audi quotes 354 PS and 500 Nm in Europe, and US cars are rated at 349 hp and 369 lb-ft (APR). From the 2019 facelift, European S4s switched to a 347 PS 3.0 TDI diesel (motor1), so this guide covers the petrol car, which other markets kept. The S5 and SQ5 with the same engine take the same tunes.

Years
2017–2024 (Europe: petrol until 2019)
Engine
3.0 TFSI EA839 turbo V6
Gearbox
8-speed ZF automatic, quattro
Stock power
354 PS / 500 Nm (US 349 hp)

Updated

White Audi S4 B9 saloon with grey wheels, parked on a dealership lot with palm trees

Power by stage

Stock is Audi's European figure. Stage 1 to 4 are tuners' own claims, mostly on US 93 octane, which equals 98 RON, the best fuel sold in Israel. Ethanol and race-fuel figures are higher and marked as such.

Stock354 PS
Stage 1430–450 hp Stage 2445–470 hp Stage 3530–620 hp Stage 4630–740 hp

Names with an arrow go straight to that part's product page for this car. Names in a dashed outline are other brands that make the part; exact links for them are being added.

1

Stage 1: Software only

430–450 hp

A tune on a standard car claims 430–450 hp on pump fuel. APR's Stage 1 lists 431 hp on 91 octane, 441 hp on 93 and 450 hp on 100 (APR), and IE claims 446 hp and 548 lb-ft on 93 octane, the same as 98 RON (IE). The car has a Bosch MG1 computer that has to be unlocked before it can be tuned, and several versions of it exist, so a dealer checks yours first (PASMAG).

Typical cost: APR Stage 1 $1,299.99, or $2,299.99 as APR Plus with a limited powertrain warranty.List prices, Sept 2026, before shipping, import tax and fitting.

Stage 1 tunes compared

TuneFuelClaimed powerClaimed torqueNotes
APR Stage 191 octane (95 RON)431 hp467 lb-ftAPR Plus adds a limited powertrain warranty at this level
APR Stage 193 octane (98 RON)441 hp483 lb-ft$1,299.99; APR says no gearbox tune is needed for full torque
APR Stage 1E60–E85480 hp549 lb-ftEthanol blend
IE Stage 193 octane (98 RON)446 hp548 lb-ftStage 1 gearbox tune included
IE Stage 1E85up to 505 hp585 lb-ft91, 93 and E85 maps

Parts list

  • Engine tune required APR ECU upgradeIE performance tuneUnitronic034Motorsport

    Flashed through the OBD port once the computer is unlocked.

  • Gearbox (TCU) tune optional APRIE

    IE includes its Stage 1 gearbox tune because its files exceed the factory torque limits.

Before you buyEuropean S4s from the 2019 facelift have the 3.0 TDI diesel, which none of these petrol tunes fit. Ethanol blends aren't sold at Israeli filling stations, so read the 93-octane rows. Ask what a tune does to the factory warranty: APR sells APR Plus, its Stage 1 with a limited powertrain warranty, for $2,299.99 (PASMAG).
2

Stage 2: Intake, intercooler and downpipe

445–470 hp

Stage 2 adds the breathing parts, and the gain is smaller than on the four-cylinder cars. IE says the factory downpipe is large and efficient and doesn't hold back the stock turbo (IE), and its Stage 2 file claims the same 446 hp as Stage 1 on 93 octane. Unitronic's Stage 2, with its downpipe and the supporting intake, turbo inlet and intercooler, claims 467 hp and 547 lb-ft on 93 octane / 98 RON, 116 hp more than stock (Unitronic).

Typical cost: APR Power Pack (tune, Ultralink, intake with turbo inlet) $1,599.95; Unitronic downpipe $2,634.99 (Black Forest Industries).List prices, Sept 2026, before shipping, import tax and fitting.

Stage 2 packages compared

PackageFuelClaimed powerClaimed torqueRequired hardware
Unitronic Stage 293 octane (98 RON)467 hp547 lb-ftUnitronic downpipe and supporting bolt-ons
IE Stage 293 octane (98 RON)446 hp548 lb-ftAftermarket racing downpipe and catalyst

Parts list

  • Intake and turbo inlet recommended APR Power Pack (tune, intake and inlet)UnitronicIE034Motorsport

    APR sells its intake with turbo inlet in a pack with its tune and Ultralink cable for $1,599.95.

  • Intercooler recommended APRIEUnitronicWagner Tuning

    Keeps power steady on repeated pulls; APR measured its Stage 3 figures with its intercooler fitted.

  • Downpipe optional Unitronic downpipe with catalystIE

    Unitronic's has a 400-cell catalyst and needs its Stage 2 file; $2,634.99 at Black Forest Industries.

  • Gearbox (TCU) tune recommended APRIE

    IE's Stage 2 gearbox tune adds raised torque limits, faster shifts and launch control.

Before you buyUnitronic's downpipe is listed as a race-only part in the US (the listing), and in Israel exhaust changes need approval at inspection. On Israeli 98, use the 93-octane figures.
3

Stage 3: Bigger turbo in the factory position

530–620 hp

Stage 3 replaces the turbo inside the V with a bigger one that bolts into its place. APR's DTR8868 is a new turbo, not a modified factory one, so no core is needed, and its software claims 529–620 hp depending on fuel, up to 620 hp and 622 lb-ft, without fuel-system upgrades (APR). APR measured its figures with its intake, intercooler and gearbox tune. IE's Stage 3 files claim 534 hp on 91 octane, 557 hp on 93 and 601 hp on 104, and 613 hp with a TTE810 turbo and an upgraded fuel pump (IE).

Typical cost: APR DTR8868 turbo with Stage 3 software $3,099.95 (ORT Motorsport), £3,128.44 in the UK (AwesomeGTI).List prices, Sept 2026, before shipping, import tax and fitting.

Turbo upgrades compared

KitFuelClaimed powerPriceNotes
APR DTR8868 Stage 395 RON to E85529–620 hp$3,099.95New turbo with Stage 3 software included; files for 95, 98, 104 and 108 RON and E60–E85
IE Stage 393 octane (98 RON)557 hp—534 hp on 91; 601 hp on 104 race fuel
IE Stage 3, TTE810 and fuel pump93 octane (98 RON)613 hp—631 lb-ft

Parts list

  • Upgraded turbo required APR DTR8868APR DTR8868 (UK)TTEPure Turbos

    In the UK the DTR8868 is £3,128.44 at AwesomeGTI.

  • Intercooler required APRIEUnitronic

    APR's figures were measured with its intercooler and intake.

  • Gearbox (TCU) tune required APRIE

    IE says bigger turbos need a full recalibration of both the engine and gearbox computers.

  • Spark plugs required APRNGK

    APR specifies its plugs or NGK heat range 9 gapped to 0.6 mm, changed every 10,000–15,000 miles.

Before you buyA changed turbo isn't road-legal in Israel without approval. APR says its Stage 3 software keeps the emissions parts working, which helps abroad but doesn't replace Israeli approval. On 98 octane, read the 93-octane figures.
4

Stage 4: Hybrid turbo, fuel pump and ethanol

630–740 hp

The last step adds fuel. APR's Turbo Pack combines the DTR8868 with its high-pressure fuel pump, intake, intercooler, exhaust, coils and plugs, and claims up to 630 hp and 630 lb-ft (NGP Racing). IE's Pure750 hybrid turbo with its Stage 3 engine and gearbox tunes claims up to 739 hp and 710 lb-ft, and needs the Stage 2 parts plus IE's turbo inlet adapter (IE); 034Motorsport tunes the same turbo (034Motorsport).

Big-turbo builds compared

BuildFuelClaimed powerPriceNotes
APR Turbo Pack—630 hp$9,475.95DTR8868, fuel pump, intake, intercooler, exhaust, coils and plugs
IE Stage 3 with Pure75091 octane (95 RON)566–589 hp—IE's pump-fuel figures for this turbo
IE Pure750, top claim—739 hp—710 lb-ft, with IE engine and gearbox tunes

Parts list

  • High-pressure fuel pump required APRIE

    APR says its pump adds software headroom without overdriving the injection system.

  • Hybrid turbo required Pure750 (IE)Pure750 (034Motorsport)

    Built from a modified factory turbo housing, and it reuses the factory wastegate actuator.

  • Exhaust optional APRMilltekAWE

    Part of APR's Turbo Pack.

  • Flex-fuel kit optional IE TrueFlex

    Lets the engine computer read any ethanol blend.

Before you buyThe highest figures on this page are on race fuel or ethanol blends, which aren't sold at Israeli filling stations; on 98, IE's 93-octane figures are the ones to read. Buy the engine and gearbox tunes from the same tuner, since the ZF gearbox's torque limits set the ceiling.

Where to buy

OBDeleven's plug-in reader and app offer one-click customisations for Volkswagen-group, BMW, Toyota, Ford and Mercedes-Benz cars. ECS Tuning is a US parts shop that stocks several of the brands in this guide and takes international orders; import tax and duties are charged on delivery. It lists US-market fitments. Check the fit for your car and the shipping cost before you order. We earn a commission on orders through these links, at no extra cost to you (how the site makes money).

Quick answers

How much horsepower does a stock Audi S4 B9 have?
354 PS from the factory.
How much hp does a Stage 1 Audi S4 B9 make?
Tuners claim 430–450 hp at Stage 1, up from 354 PS stock (Stage 1 options).
How much hp does a Stage 2 Audi S4 B9 make?
Tuners claim 445–470 hp with a Stage 2 file and the parts it needs (parts list).
How much hp does a Stage 3 Audi S4 B9 make?
Tuners claim 530–620 hp at Stage 3: bigger turbo in the factory position (Stage 3 parts).
How much hp does a Stage 4 Audi S4 B9 make?
Stage 4 is the top of the ladder for this car: hybrid turbo, fuel pump and ethanol. The biggest builds claim 630–740 hp. Check which fuel each figure needs: Israel sells 95 and 98 octane only (Stage 4).
How much does a Stage 1 Audi S4 B9 cost?
List prices: APR Stage 1 $1,299.99, or $2,299.99 as APR Plus with a limited powertrain warranty.

Watch: real builds

From tuners', shops' and motoring journalists' own YouTube channels. Nothing loads from YouTube until you press play.

10:45
Stage 1Three Stage 1 tunes on 93 octane on the dyno: Boost Dynamic Tuning, 034Motorsport and IE (B9 S5)Boost Dynamic Tuning on YouTube
1:50
Stages 1–2034Motorsport on what Stage 2 adds over Stage 1 on the 3.0T034Motorsport Uncut on YouTube
23:54
Stage 3Fitting the APR DTR8868 turbo to a B9 S4, step by stepECS Tuning on YouTube
11:32
Build034Motorsport rebuilds a burnt-out B9 S4 in 24 hours034Motorsport on YouTube

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Questions to ask the shop

  1. Is my car the petrol 3.0 TFSI or the European 3.0 TDI, and which computer version does it have?
  2. Can you unlock the Bosch MG1 computer through the OBD port, or does it have to be removed and sent away?
  3. Is the file written for 98 octane, and what does it make on 95?
  4. Do I need a gearbox (TCU) tune at this power, and is it included?
  5. Does the tune keep the catalysts and emissions parts working, so the car passes inspection?
  6. What does it do to my warranty, and do you offer your own powertrain cover?

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