About the Audi S4 Engine

Know how it feels to perform with a used Audi S4 engine for sale. Famous for the powerful 4.2L V8, this engine provides splendid acceleration and the kind of roar that lovers of power will appreciate. This engine generates 340 horsepower and 302 lb-ft of torque which makes it respond well for a fun, fast and exciting drive. Ideal to go for when you may be looking forward to a replacement or integrating a quality used Audi S4 engine in your build, choosing this 4.2L V8 means choosing an engine that is reliable, capable, and perfectly suited to the high-performance characteristics expected from Audi's sport sedans. Get a closer look at this legendary engine and learn how it can help take your motoring to another level.

The Iconic 4.2L V8 Audi S4 Engine

The 4.2L V8 engine is a spectacular powerplant in the Audi S4 that promises powerful work and a bright, powerful sound in the framework of Audi's range. This particular engine is used in the B6 and B7 Audi S4 models and churns out 340 horsepower and 302 lb-ft of torque. The V8 engine configuration with 90 degrees of cylinder bank angle and dual overhead camshafts offers free-revving and responsive power. The engine contains a forged steel crankshaft and has an aluminum alloy body making it both strong and lightweight.

Looking specifically for a 2005 Audi S4 engine? The 2005 model year falls within the B6 generation production run (2003 to 2005), which used the BBK engine code variant of this 4.2L V8. The 2005 model year was the final year of B6 production, after which the B7 generation (with the BHF engine variant) took over for 2006 model year onwards.

Audi S4 Generation History: Why This Engine Matters

To understand the significance of this 4.2L V8, it helps to know the full Audi S4 generation lineage:

The B6 / B7 S4 (2003 to 2008) is widely regarded as the most charismatic S4 ever produced , the only V8-powered generation, with a high-revving 7,000 RPM redline and one of the best-sounding V8 exhaust notes in any production sport sedan. The combination of the 4.2L V8 with Audi's Quattro all-wheel drive and a 6-speed manual (or Tiptronic automatic) made this generation the enthusiast's choice.

BBK vs BHF: B6 vs B7 Variant Identification

The B6 and B7 S4 share essentially the same 4.2L V8 with minor refinements:

For most service and engine swap purposes, the BBK and BHF are essentially interchangeable with proper ECU programming. Engine code matching to the host vehicle is preferred for OEM electronic compatibility.

Audi S4 Body Styles

The B6 and B7 S4 were offered in three body styles, all using the same 4.2L V8:

• B6 / B7 S4 Sedan (4-door) , most common US variant
• B6 / B7 S4 Avant (wagon) , popular performance wagon
• B6 / B7 S4 Cabriolet (convertible) , B6 only (no B7 Cabriolet)

All three body styles use the same 4.2L V8 engine.

Performance Characteristics

The B6 / B7 S4 produces remarkable performance for its era:

• 0 to 60 MPH: 5.2 seconds (B6 manual) / 5.5 seconds (B6 Tiptronic)
• Top speed: 155 MPH (electronically limited, removable)
• EPA fuel economy: 14 city / 21 highway MPG (B6 manual)
• Transmission options: 6-speed manual, 6-speed Tiptronic automatic
• Drivetrain: Quattro all-wheel drive (standard)

The 4.2L V8 Audi V8 Family Heritage

The S4's 4.2L V8 is part of a broader Audi V8 family that includes:

• Audi A6 4.2 (C5 / C6 generations) , 300-335 HP
• Audi A8 4.2 (D2 / D3 generations) , 310-335 HP
• Audi RS4 B7 (BNS) , 4.2 FSI V8 with 420 HP (the FSI direct injection variant)
• Audi Q7 4.2 FSI (BAR) , 350 HP V8 with FSI direct injection

Many parts and architectural elements are shared across the Audi V8 family, though specific tunes, internals, and accessories differ.

Key Engineering Features

• 90-Degree V8 Configuration

Traditional V8 architecture producing the smooth power delivery and characteristic V8 exhaust note. Two cylinder banks set at 90 degrees to each other.

• DOHC, 5 Valves Per Cylinder (40 Valves Total)

One of the few production V8s ever produced with 5-valve heads (3 intake, 2 exhaust). The 5-valve arrangement delivers exceptional high-RPM breathing, enabling the 7,000 RPM redline.

• Forged Steel Crankshaft (as noted on the live page)

Heavy-duty forged crankshaft engineered for sustained high-RPM operation. Significantly more robust than typical cast crankshafts.

• Aluminum Alloy Block and Heads (as noted on the live page)

Lightweight aluminum construction reduces front weight bias in the S4 chassis.

• Variable Valve Timing on Both Camshafts

Continuous variable timing on intake and exhaust camshafts for performance and efficiency optimization.

• Multi-Port Sequential Fuel Injection

Traditional MPI fuel system (NOT direct injection like later Audi V8s) , simpler to service, more affordable injectors, and known characteristics.

• Compression Ratio 11.0:1

High compression ratio takes advantage of premium fuel for maximum power output.

• Stainless Steel Exhaust Manifolds

Tubular stainless steel manifolds optimize exhaust flow and reduce weight.

Honest Disclosure: Known Service Items

We believe in honest disclosure of known service items for the 4.2L V8 BBK / BHF:

• Timing Chain Tensioners (THE famous service item)

The B6 / B7 S4 4.2L V8 uses timing chains with tensioners that are mounted at the rear of the engine (between the engine and transmission). At 100,000 to 150,000 plus miles, the tensioners can wear and the chains can stretch , service requires significant labor as the engine must come out of the car (typical service cost $4,000 to $7,000 at independent specialists; $8,000 to $12,000 at dealerships). This is the primary high-mileage service concern with this engine. A used BBK / BHF with documented recent timing chain service is significantly more valuable. Engines we sell are inspected for current timing chain condition.

• Carbon Buildup on Intake Valves

Like many high-compression engines, the 4.2L V8 can develop intake valve carbon buildup at 80,000 to 120,000 miles. Walnut blasting service ($400-700) addresses this.

• Coil Pack Failures

Individual coil packs can fail (one per cylinder, 8 total). Replacement is straightforward.

• Secondary Air Injection Pump Failures

The SAI system that helps cold-start emissions can fail, triggering a Check Engine Light. Common service item.

• Oil Consumption

Some BBK / BHF engines develop oil consumption at high mileage (200,000+ miles) due to valve seal or piston ring wear. Monitor oil level between changes.

These are typical European V8 service items , not catastrophic flaws. The 4.2L V8 in well-maintained service routinely exceeds 150,000-200,000 miles, with some examples seeing 250,000+ miles with proactive maintenance.

Why Choose a Used 4.2L V8 BBK / BHF?

A used 4.2L V8 offers compelling value:

• Cost savings vs reman ($3,299 used vs $6,500-$11,000 reman plus core)
• Direct OEM fit for B6 S4 (2003-2005) and B7 S4 (2005-2008) sedan / Avant / Cabriolet
• Iconic V8 exhaust note , one of the best-sounding sport sedan engines ever produced
• Audi V8 family heritage with shared parts across A6 / A8 4.2 applications
• Foundation for restoration , the B6 / B7 S4 is becoming a sought-after modern classic

Here at Vaz Auto Solutions, you'll find this Audi S4 engine for sale at the most reasonable price possible, with engine code verification (BBK or BHF), timing chain tensioner condition documentation, and clear B6 vs B7 generation identification.

Vehicle Compatibility

Direct Fit B6 Audi S4 (BBK Engine Code):

Direct Fit B7 Audi S4 (BHF Engine Code):

NOT Compatible (Different S4 Engines):

Condition and Inspection

• Engine code verified (BBK or BHF)
• Generation identified (B6 vs B7)
• Donor vehicle body style confirmed (sedan / Avant / Cabriolet)
• Donor vehicle confirmed and miles documented where available
• All 8 cylinders compression tested
• Oil pressure verified at idle and operating speed
• Timing chain tensioner condition documented (THE primary service item with this engine)
• Variable valve timing system function tested (intake and exhaust)
• Fuel injection system verified (multi-port sequential)
• Spark plug condition documented (8 plugs)
• Coil pack condition assessed (8 coils)
• Secondary air injection pump function checked
• Carbon buildup on intake valves noted where observable
• Oil consumption assessment based on observable indicators
• Cooling system function verified
• Engine code verified (BBK B6 vs BHF B7 distinction)
• Generation identified (B6 2003-2005 vs B7 2005-2008)
• Timing chain tensioner condition documented (critical for high-mileage 4.2L V8 valuation)
• All 8 cylinders compression tested
• Variable valve timing system verified
• Audi V8 specialist support team
• Free specialty freight delivery to all 50 states
• 15 day replacement warranty on internal defects
• Cross-reference assistance for B6 / B7 S4 sedan / Avant / Cabriolet applications