Audi S4 2.7 V6 Biturbo

Everything for your 2001 S4 on one page: specs, diagrams, the 6-speed 01E gearbox, calculators, a service tracker, symptom finder, known weak points and one-click access to your whole factory manual library.

Output

250 hp @ 5,800

Torque

258 lb-ft @ 1,800

Displacement

2,671 cc

Gearbox

6 -speed 01E

Final drive

4.11 : 1 ≈

Firing order

1-4-3-6-2-5

⏱ What's due next?⚙ 01E gearbox 🩺 Symptom finder 🛢 Oil & fluids ⚠ Common faults 🌀 Boost system 🔌 Fault codes 📂 Open a manual

My car — enter your VIN and the whole guide adapts (saved in this browser only)

VIN (17 characters) Nickname Odometer (miles) Engine Transmission Model year

Decode checks the VIN offline (year, plant, check digit) and, only if you agree, also asks the free NHTSA vPIC database for model/engine details. Engine and transmission can always be set by hand; the guide, specs and manual library filter to your selection.

How to use this page: press / to search everything (specs, problems, and the PDF manual library). Figures marked ≈ are typical values from experience/industry sources — always confirm torque specs and critical clearances in the factory PDFs linked in each section.

1 Quick specs

Your factory manual (APB, 09.1999→) and the common European variants side by side.

Engine · US-spec APB (from factory manual 00-1)
Engine code	APB (build from 09.1999)
Capacity	2,671 cc (2.7 L)
Power	250 hp @ 5,800 rpm
Torque	258 lb-ft @ 1,800–4,500 rpm
Bore × stroke	81.0 × 86.4 mm
Compression	9.3 : 1
Fuel	98 RON min. (95 RON usable, power loss) · US: premium 91+ AKI
Firing order	1-4-3-6-2-5
Engine management	Motronic, closed-loop lambda, on-board diagnostic
Cam timing control	Yes (intake variable) · Secondary air: no · EGR: no
Turbocharging	Yes – twin turbo · catalytic converters: yes

Valve timing (1 mm lift, 0 mm clearance, VVT inactive)
Inlet opens	10° after TDC
Inlet closes	20° after BDC
Exhaust opens	38° before BDC
Exhaust closes	8° before TDC

European variants ≈
AGB (1997–2000)	265 PS / 195 kW @ 5,800 · 400 Nm @ 1,850–3,600
ARY (2000–2002)	265 PS · same output, updated ECU/emissions
Block / heads	Cast-iron block · aluminium 5-valve DOHC heads

Car ≈
Chassis	Audi A4 / S4 Typ 8D (B5), sedan & Avant
Drivetrain	Longitudinal V6, quattro (Torsen centre diff)
Gearbox	6-speed manual 01E (see gearbox section) · Tiptronic 01V was the auto option
Kerb weight	≈ 1,550–1,650 kg (sedan / Avant)
0–60 mph	≈ 5.4–5.8 s
Wheels	5 × 112 · centre bore 57.1 mm · bolts M14 × 1.5 (≈120 Nm / 89 lb-ft)
Front brakes	≈ 312 mm vented discs (S4)

Jump to the source documents

Technical data pages, straight from your library:

2 Engine layout & firing order

90° V6 viewed from above. Cylinders 1-2-3 sit on the right bank, 4-5-6 on the left bank (numbering from the front/belt end). The engine number is stamped on the block at the front of the right bank.

Schematic cylinder layout (top view). Firing order from factory data 00-2.

Firing sequence

143625

Coil-on-plug: 6 individual coils with integrated output stages. Misfire on one cylinder = check that coil + plug first (swap coils between cylinders to confirm).

Where's the engine code?

Machined surface on the block, front of the right cylinder bank (code + serial, e.g. APB 000 405). Also on the vehicle data sticker (spare-wheel well / service book).

Engine manual pages (APB)

3 Timing drive

A toothed belt drives the exhaust camshafts (and water pump); short chains link each exhaust cam to its intake cam, which carries the variable-timing adjuster.

Simplified schematic — not to scale and not a timing-marks reference. Use manual 15-1 / 13-1 before touching timing.

Timing belt service ≈

Change belt ≈ every 60k miles or 6 yrs (an Audi interval of ~105k mi is often quoted but unconfirmed — see Owner knowledge).
Always replace tensioner, idler(s), water pump and thermostat at the same time.
Inspect cam chains/guides while the covers are off; rattle on cold start = look at chain tensioners.
Interference engine — a snapped belt usually bends valves.

Variable cam timing

Hydraulic adjusters on the intake cams, controlled by solenoids (N205/N208). Clean oil matters: dirty oil = sticky solenoids and rough idle or cam-timing DTCs.

4 Air & boost path

One combined air filter and hot-film air mass meter feeds a plastic air distributor that splits the air to two turbochargers (one per bank). The compressed air passes two charge-air coolers, the streams converge upstream of the single drive-by-wire throttle body, and diverter (air-recirculation) valves protect the compressors when you lift.

Flow overview (per factory Self-Study 198). One air mass meter, then an air distributor to the two turbos; each bank has its own charge-air cooler; the paths merge upstream of the throttle body. A boost leak anywhere on the blue side = low boost, lean codes or limp mode.

Charge pressure (factory spec)

Manual 21-1 test (tester V.A.G 1397/A): accelerate from 2000 rpm at full throttle in 4th gear and read the tester at 3000 rpm — specification 1.55 – 1.65 bar. The tester reads absolute pressure, so that is roughly 0.55–0.65 bar (≈ 8–9.5 psi) above atmospheric.

Read the manual page ↗

Fast leak hunt

Smoke-test the charge system (best).
Check intercooler end-tanks & hose clamps.
Inspect all vacuum lines at the manifold & diverters.

Manuals

5 Power & torque

A wide, flat torque plateau (1,800–4,500 rpm) is the characteristic of the twin-small-turbo setup — light spool, plenty of midrange.

Illustrative shape built from the published peak figures (not a measured dyno run).

6 Quattro drivetrain

Longitudinal engine → 6-speed manual (01E) or 5-speed Tiptronic (01V) → Torsen centre differential → front and rear final drives.

Torsen centre diff splits torque ≈ 50/50 by default and shifts it automatically to the axle with grip.

Transmission manuals in your library

Your folder covers the 5-speed 01A/01V family (related quattro final-drive and Torsen procedures). For your 6-speed 01E, start with the 01E section below.

Clutch & flywheel notes ≈

Dual-mass flywheel: rattle at idle/shutdown = wear.
Hydraulic clutch: bleed with DOT 4 (shares brake fluid).
Stock clutch is the first thing to slip on a tuned car.

7 Gearbox — 01E 6-speed manual

The S4's 6-speed (VW/Audi code family 01E, the same unit family as the RS4 but with different 3rd/4th ratios) bolts straight to the engine and feeds the Torsen centre diff. Ratios below are community-sourced ≈ — confirm with the code stamped on your own gearbox.

Gear	Ratio ≈	Overall (× 4.11)

Top speed available in each gear at the rpm you choose in the calculator below (updates live).

Identification

Family: 01E (6-speed, longitudinal, quattro).
Community lists the S4 box as ID DSY (RS4 = FDP) ≈ — your 2001 US-spec code may differ.
Final drive: 4.111 (37:9) ≈.
Code is stamped on the case near the bell-housing; also on the build sticker.

Gear oil

Synthetic 75W-90 to VW spec G 052 911 A2 (or equivalent, e.g. Castrol Syntrans/ Pentosin).
Fill ≈ 3.4–3.5 L (includes ~0.3 L for oil cooler & lines) — fill to the filler hole.
Front diff and rear diff have their own oil — change all three.
The S4 gearbox oil is circulated by an oil pump through an oil cooler (Self-Study 198, p.70).

01E documents

External link — it isn't in your local folder. Save it into Transmission and I can add it to the library.

8 Gear & speed calculator

Pick tyre size, final drive and rpm to see road speed in every gear. Great for gearing up/down, tyre swaps and checking speedometer error.

Tyre width (mm) Aspect ratio Rim (in) Final drive Engine speed: 6000 rpm Units

Ignores clutch slip, tyre growth and speedometer error. Default tyre ≈ 235/40R17 (common S4 size).

9 01E care & weak points

What owners and rebuilders report on the 6-speed. Forum-sourced — treat as guidance, not factory data.

fix soon 1st/2nd gear synchros

Symptoms: crunch or resistance going into 1st/2nd, popping out of gear. Notes: the most-reported 01E fault; Audi later revised the synchro parts (coated/updated). Fix: rebuild with updated synchros — needs the box out. Rule out clutch drag and old gear oil first.

watch Clutch, flywheel & hydraulics

Slip under boost = tired clutch (common on tuned cars). Chatter/clunk at idle or shut-down = dual-mass flywheel wear. Soft pedal or hard-to-select gears can be the hydraulic system — bleed with DOT 4, replace slave/master if leaking. Replace clutch, flywheel and release bearing together.

watch Sloppy shifter / linkage bushings

Vague or notchy shifts are usually worn shifter and linkage bushings, not the box. A bushing refresh plus fresh gear oil often transforms the feel. Inspect before assuming internals are bad.

watch Whine, bearings & leaks

Whine in a gear or on overrun can be input/pinion bearings; oil seeping from flange seals or the oil cooler lines is common with age. Check oil level and condition (metal glitter = wear). Cooler lines (≈0.3 L circuit) can leak — inspect hoses/clips.

info Torque tolerance

Stock-to-moderate tunes are fine on a healthy box; the clutch gives up long before the gearbox. Rebuilders describe the 01E as strong but its syncros are marginal when abused and the pinion bearings are often worn — refresh both before big power. Far higher torque (≈650 lb-ft) is called "edge of safe" by builders of diesel swaps.

Fluid change recipe: warm car → level car on ramps → remove filler plug first (so you can refill) → drain → refit drain with new seal → pump in oil until it weeps from the filler hole → repeat on front and rear diffs. Use fresh sealing washers.

10 Interactive diagrams

Click any part for what it does, how it fails, the manual pages, step-by-step jobs, a parts-list shortcut and supplier links.

— labels

11 How the 2.7T works — from the factory Self-Study

Key facts from Audi Self-Study Programme 198 (“Design and Function — The 2.7-litre V6 Biturbo”), each with a button that opens the original page.

Bottom end

Crankshaft identical to the 2.8 V6; main bearing caps held by 4 bolts each, the middle two also bolted to the side of the crankcase. Pistons are forged; rod-side bearing shells are 2-material, caps 3-material.

Variable valve timing

Intake-cam adjustment of 22°, activated by load and speed through valves N205 / N208; gives roughly +10% torque at the bottom and top of the rev range and better emissions/economy.

Oil circuit

Duocentric oil pump; oil goes through the cooler and filter (with a parallel bypass filter) to the main gallery. The two turbos are fed from the main gallery via a distributor piece and drain straight to the sump. Piston spray jets and a revised cooler for the higher thermal load.

Air path

A combined air filter + air mass meter feeds a plastic air distributor that splits air to the two turbos; each side has a charge-air cooler; the streams converge upstream of the throttle valve control part.

Boost control

For safety the biturbo regulates charge pressure (not just air mass). Motronic ME 7.1 sets it with solenoid N75 (duty cycle) which modulates the control pressure that opens each wastegate; sender G31 measures it.

Where things are

Top-view map labelling N75, the divert air valve N249 and the two divert valves, G31, N205/N208, Hall sender G163, injectors and the fuel pressure regulator.

Air mass meter G70

Hot-film thermal meter that recognises reverse flow (intake pulsation). If it fails the Motronic calculates air mass from throttle angle and engine speed (substitute function).

Clutch & gearbox

Dual-mass flywheel + self-adjusting (SAC) clutch that compensates lining wear; an 11 mm spacer ring sits between engine and gearbox on manuals. The S4 uses the 01E (C90) 6-speed quattro box, oil-cooled by a pump and cooler.

Charge-pressure test (manual)

Spec 1.55–1.65 bar at 3000 rpm (full throttle, 4th gear from 2000 rpm). No pressure plus a throbbing noise = faulty air-recirculation valve or leaking/disconnected vacuum line.

12 Step-by-step jobs

Guided procedures transcribed from your factory repair manual — every step shows the original page next to it, with tools, torque values and warnings, a progress checklist, and a one-tap parts list.

All jobs in your manuals

Every repair procedure in the factory manuals for your selected car, turned into a checklist with the original page beside each step.

For any other job, use the search box (e.g. “heater core”, “clutch”, “brake pads”) — each manual page opens as a readable image with torques and tools pulled out, and you can tick pages off as you go.

13 Maintenance schedule

Practical intervals for a ~25-year-old turbo V6 (≈ conservative, specialist-style). Check "Maintenance" PDFs in your library for the factory schedule.

Item	Interval ≈
Engine oil + filter	5,000 mi / 6 mo (turbos like fresh oil)
Spark plugs	every 30k mi (boost & coil wear)
Ignition coils	replace as a set when misfires start (~80–100k)
Timing belt kit + water pump	60–75k mi / 6 yrs
Air filter(s)	15–20k mi
Coolant (G12)	every 2–3 yrs
Brake fluid (DOT 4)	every 2 yrs
Manual gearbox / diffs oil	40–60k mi
Tiptronic ATF (01V)	40–60k mi (pan + strainer)
Power-steering fluid	every 3–4 yrs
Diverter valves, hoses, clamps	inspect yearly
Fuel filter	30–40k mi

Service timeline

Every oil changeOil + filter, look for leaks (turbo oil lines, valve covers), check coolant level.

Every 15–20kAir filters, brake inspection, tyre rotation, charge-pipe clamps.

Every 30kSpark plugs, fuel filter, brake fluid check, PCV/breather inspect.

Every 60kTiming belt & water pump kit, drive belt, tensioner, gearbox & diff oil.

~100k+Coil packs, engine mounts, turbo health check (shaft play, smoke), suspension bushings.

14 My service tracker

Set your odometer in My car, then enter when each job was last done. The tracker shows what's due — saved automatically in this browser.

15 Fluids & consumables

Typical spec — confirm with your VIN/year in the manuals or Audi parts lookup.

Item	Specification ≈
Engine oil	Fully synthetic 5W-40 to VW 502 00 / 505 00 · ≈ 4.5–5 qt (4.3–4.7 L) with filter — fill to the dipstick
Coolant	G12 / G12+ (pink/purple) mixed 50/50 with distilled water
Brake / clutch fluid	DOT 4, replace every 2 years
Power-steering fluid	Pentosin CHF 11S (VW G 004 000)
Tiptronic ATF	Dexron-III compatible / VW ATF G 052 025 A2 (check 37-133 PDF)
Manual gearbox & diffs	75W-90 synthetic gear oil (see transmission PDFs for exact fill)
Spark plugs	Audi-spec/NGK/Bosch cold-range plugs, gap ≈ 0.8 mm (check parts catalogue for your code)
Fuel	Premium: 91+ AKI (98 RON) — 95 RON works with less power

Tip: Don't mix coolant types and don't run straight distilled/straight coolant — the plastic coolant flanges and radiator are weak points already.

16 Symptom finder

Tap what the car is doing — get the likely causes in order of "check this first".

17 Common problems & fixes

Sorted roughly by how often they bite. Priority: fix soon watch minor

fix soon Failed diverter (recirculation) valves

Symptoms: hiss/flutter on lift-off, boost loss, hesitation. Why: original diaphragms tear with age. Fix: replace with updated metal-piston style valves (fit both). Cheap and common first upgrade.

fix soon Vacuum & boost leaks / brittle hoses

Symptoms: low boost, lean codes, rough idle, limp mode. Check: smoke test; rubber elbows/T-pieces in the "hot V", intercooler couplers, N75 vacuum lines, brake booster line. Fix: replace cracked hoses with silicone/OEM updated parts.

fix soon Overdue timing belt / tensioner

Risk: interference engine — failure destroys valves. Do: full kit every 60–75k mi (belt, tensioner, idlers, water pump, thermostat, seals). Also: check cam chain tensioners and guides.

watch Ignition coils & misfires

Symptoms: flashing CEL under boost, shuddering. Fix: swap coil to a different cylinder to see if misfire follows; replace plugs at the same time. Use quality coils (OEM/Bosch).

watch Coolant flanges & leaks

Plastic coolant flanges on the back of the engine, thermostat housing and hoses age and crack. Check for sweet smell, white crust, falling level. Replace with updated metal/aluminium flanges when accessible.

watch Turbo wear / oil supply

Symptoms: blue smoke, whine/siren noise, slow spool, oil in charge pipes. Cause: neglected oil changes, shutting off hot, clogged oil feed/return. Fix: check shaft play, rebuild/replace in pairs ideally, replace oil feed filters and lines.

minor MAF sensor (G70)

Dirty or failing sensors cause lean/rich codes and hesitation. Clean with MAF cleaner only; replace if readings are out of balance in the measuring blocks.

minor PCV / breather & oil leaks

Cracked breather hoses, valve-cover gaskets and cam-adjuster seals leak oil. Replace as a group; blocked PCV can push oil past seals.

minor Front suspension wear (B5 classic)

Four-link front axle: bushings, tie rods and wishbones wear. Clunk over bumps or vague steering = inspect control-arm bushes and track-rod ends. Manuals: Suspension, Wheel & Steering folder.

18 Diagnostics & codes

Quick reference for scan-tool work. Use a VAG-COM/OBDeleven-class tool for measuring blocks and adaptation.

Code	Meaning ≈ / first checks
P0299	Underboost — leaks, diverters, N75, wastegate
P0234	Overboost — N75/hoses, wastegate stuck, tune
P0243	N75 wastegate solenoid circuit
P0171 / P0174	Lean bank 1 / 2 — vacuum or boost leak, MAF, fuel pressure
P0101	MAF plausibility — sensor dirty/faulty, intake leak
P0300–P0306	Misfire (random / cyl 1–6) — plugs, coils, injectors
P0420 / P0430	Cat efficiency bank 1 / 2 — old cats, O2 sensors

Useful scan-tool functions

Address 01 Engine → read DTCs, measuring blocks (MAF, boost actual vs specified).
Check specified vs actual boost under load (a data-log pull in 3rd gear).
Fuel trims (long-term) tell you about vacuum leaks vs fuel delivery.
Confirm misfire counters per cylinder.

OBD manuals (APB)

19 Upgrades & sensible limits

What's popular on the 2.7T and where the weak links are.

Stage 1

ECU tune + metal diverters + test pipes/cat-back. Typical ≈ 300–340 hp on stock turbos. Needs healthy plugs/coils and fresh maintenance.

Stage 2 / K04

K04 turbo swap, bigger SMICs/FMIC, 440cc injectors, upgraded clutch & fueling. ≈ 350–420 hp. Boost control and cooling become critical.

Weak links

Clutch & dual-mass flywheel, 01E/Tiptronic torque tolerance, stock fuel pump, small SMICs, rubber vacuum parts. Plan drivetrain upgrades before power.

Reality check: every 20+ hp costs reliability. Fresh timing belt, healthy cooling, a wideband gauge and conservative boost are the best "mods" for longevity.

20 Parts list

Add parts as you read the manual, run a search or look up a problem — then export a shopping list. Every part can carry a part number, price, vendor, notes, and a link back to the exact manual page.

How to add parts

In the manual viewer: press ＋ Add part (it links the part to that page), tap a part mentioned on the page, or add a ready-made job kit.
From search: searching “timing belt”, “clutch”, “heater core”… shows a Typical parts kit.
From problems: each fault card has a ＋ Parts button.
Floating 🧰 button (bottom-left) opens your list anywhere.

Supplier catalogs

Options show a saved snapshot of the ECS Tuning catalog filtered to Audi B5 S4 2.7T, plus live IND results in local mode. Every part you save carries a fit-verified status. Confirm fitment with your VIN before ordering.

21 Owner knowledge & sources

Extra information gathered from specialist shops and owner communities (forum-sourced — treat as guidance and confirm against the factory manual). Links open the original sources.

Timing belt interval — what sources say

Interference engine: a failed belt or tensioner can destroy the engine.
An Audi interval of about 105k miles is often quoted but not confirmed for the B5 S4; owners report belts failing in the 60–80k range.
Specialists (e.g. 034Motorsport) advise doing it before the manufacturer interval; a parts retailer lists 70,000 km for belt + water pump.
Practical: ≈ every 60k miles / 6 years, or immediately if history is unknown.

034Motorsport timing belt service · AUTODOC S4 kit listing · Audizine kit thread

More known weak points (owner-reported)

Coolant after-run pump — fails often enough that Audi offered a kit to relocate it.
Intercooler plastic end caps can leak (power loss).
Secondary-air pump & combi valve — reported problem on 2000+ cars.
MAF sensors — reported failures, especially MY2000.
Intake manifold rattle, cracked F/Y and other intake hoses.
Turbo oil feed/return lines can coke up; turbo replacement is reported to be a big (engine-out) job.
Airbag inflator recall — confirm it’s done (button below).

RS246: B5 S4 — what every owner should know · Audizine: common B5 issues · Known issues (2000 S4) · B5 S4/RS4 FAQ

Logging with VCDS / VAG-COM (forum-sourced)

Boost: log Group 115 (specified vs actual) — actual should track specified; a gap of several hundred mbar through the pull points to leaks, weak turbos or a restriction.
MAF: Group 002/003. A full-throttle 2nd-gear pull should peak around 80% of rated hp in g/s (≈ 200 g/s for 250 hp) — much lower suggests a failing MAF.
Fuel trims: Group 032. Read additive and multiplicative separately; log them before clearing codes (clearing resets them).
Sanity-check VCDS boost against a gauge; thresholds vary between sources — verify with your own label file.

VCDS logging guide · Diagnosing a VW/Audi MAF · 2.7T boost check

Basics ≈

Tyres: 225/45 R17 (205/55 R16 also listed) · 5 × 112.
Fuel tank ≈ 62 L (16.4 US gal).
Brakes: ventilated front, solid rear discs.
Quattro with Torsen centre diff; 6-speed manual standard.

Spec-site data — confirm on your own car.

Recalls

Look up open safety recalls for your model/year in the free NHTSA database (no VIN is sent).

Where to read more

22 Manual library — PDFs, one click

Every PDF in the Audi_A4-B5-chassis-Typ-8D-1994-2001 manual library, grouped by system. Start with the S4 (APB / quattro) tab; the other engine families are kept separate so they don't clutter your searches.

Find a procedure

Browse by system

23 ID, codes & notes

Where to find codes

VIN: base of windscreen (driver side) & B-pillar plate.
Data sticker: spare-wheel well + service book (engine, gearbox, paint, option codes).
Engine code: front of right bank on the block (e.g. APB).

Engine-code cheat sheet

Code	Market / year ≈	Output
AGB	EU, 1997–2000	265 PS
ARY	EU, 2000–2002	265 PS
APB	US, 2000–2002 (your manual)	250 hp

Your own notes: use the browser's Print → Save as PDF to take a snapshot, or add your VIN / service history below this line in the HTML file.