AUDI S5 V8 ENGINE FOR SALE

Audi S5 V8 Engine for Sale: Unmatched Performance and Reliability

The Audi S5 V8 engine with its perfect blend of power and refinement is another testimony to how good German automotive engineering can be. The V8 engine in the Audi S5 propels it from 0-60 mph in approximately 4.9 seconds, with a driving feel that few vehicles can match. The high-revving NA V8 sound is music to the ears of any enthusiast, and the way the car hauls itself from any speed is satisfying in itself.

The Audi S5 V8 engine for sale here is not just about power; it showcases reliability and longevity. It’s built with the precision and quality that Audi is known for. Whether you are cruising the highway or driving spirited backroads, this engine delivers.

Engine Overview: Audi 4.2 FSI V8

The Audi S5 V8 is the 4.2 FSI V8 engine (engine codes BNS and CAUA) that powered the B8 chassis Audi S5 Coupe and Cabriolet from 2008 to 2012. Specifications:

Critical Disambiguation: B8 S5 V8 vs Post-2012 Supercharged V6 S5

This is the most important purchasing distinction for the Audi S5. The Audi S5 model name covers TWO completely different engines across generations:

B8 S5 V8 (2008-2012) , THIS LISTING

Engine: 4.2 FSI V8 (BNS/CAUA)

HP: 354 HP

Aspiration: Naturally aspirated

Character: High-revving V8 sound, 7,200 RPM redline

Performance: 0-60 in ~4.9 seconds

B8.5 / B9 S5 V6 Supercharged (2013-Present)

Engine: 3.0 TFSI V6 supercharged (CGWC/CREC)

HP: 333-349 HP

Aspiration: Supercharged

Character: V6 with supercharger whine

Performance: 0-60 in ~4.7 seconds (slightly faster despite less HP due to torque)

For replacement applications: verify which engine your S5 has. The V8 and supercharged V6 are NOT interchangeable.

The VW-Audi Group 4.2 FSI V8 Architecture

The Audi S5 V8 is part of one of Audi’s most important performance V8 engine families. The same fundamental 4.2 FSI V8 architecture powers:

Audi S5 V8 (This Listing)

Application: B8 S5 Coupe and Cabriolet (2008-2012)

HP: 354 HP

Character: Refined sports coupe tuning

Audi RS4 B7 (2006-2008)

Application: RS4 B7 sedan and Avant (wagon)

HP: 420 HP (the more aggressively tuned variant)

Character: RS-tuned for maximum performance

Differences: Different ECU, intake, exhaust, and supporting components

Audi R8 V8 (2007-2015)

Application: R8 V8 supercar

HP: 420 HP (R8-specific tuning)

Character: Mid-engine supercar configuration

Differences: Different ECU, intake/exhaust, oil system for mid-mount, supporting components

The shared 4.2 FSI V8 architecture means all three engines use the same fundamental block, heads, FSI system, and basic V8 design , with Audi RS / R8-specific tuning for higher output. For replacement applications, the S5-specific variant should be matched (BNS or CAUA engine codes for the S5).

FSI Direct Injection Technology

The “FSI” in 4.2 FSI V8 stands for Fuel Stratified Injection, Audi’s direct injection technology:

What FSI Does

Fuel injected directly into combustion chambers (not into intake ports)

High pressure injection (200+ bar)

Multiple injection events per combustion cycle

Stratified charge operation at part-throttle for efficiency

Homogeneous charge operation at full-throttle for power

Benefits Over Port Injection

Higher compression possible (enables 12.5:1 in 4.2 FSI V8)

More power from same displacement

Better fuel economy at part-throttle

Lower emissions with optimized combustion

Trade-Off , Carbon Buildup

FSI direct injection doesn’t wash intake valves with fuel (port injection does)

Result: Carbon builds up on intake valves over time

Symptoms: Reduced low-RPM power, rough idle

Service: Walnut blasting at 60,000-100,000 miles

Cost: $1,500-3,000 for proper service

Vehicle Applications

Audi S5 Coupe B8 (2008-2012)

The original 4.2 FSI V8 S5 application:

Body style: 2-door sports coupe

Drivetrain: Audi quattro AWD standard

Transmissions: 6-speed manual, S Tronic 7-speed DCT, Tiptronic 6-speed automatic

Performance: 0-60 in ~4.9 seconds

Production: 2008-2012 US market

Audi S5 Cabriolet B8 (2010-2012)

The convertible variant of the V8 S5:

Body style: 2-door soft-top convertible

Drivetrain: Audi quattro AWD standard

Transmissions: S Tronic 7-speed DCT or Tiptronic 6-speed

Performance: 0-60 in ~5.1 seconds (slightly slower than coupe due to weight)

Production: 2010-2012 US market

Common 4.2 FSI V8 Service Items (Honest Disclosure)

The 4.2 FSI V8 has several significant documented service areas that buyers must understand:

Timing Chain Tensioner Failures (THE PRIMARY 4.2 FSI V8 CONCERN)

This is the most well-documented and concerning service area for the 4.2 FSI V8.

#### What Happens

Audi 4.2 FSI V8 uses timing chains at the rear of the engine (between engine and transmission)

The chain tensioners (multiple) can fail over time

Failed tensioners allow chain slap and eventual chain skip

In severe cases, complete engine destruction

#### Symptoms

Cold-start rattle from rear of engine

Persistent timing chain rattle

Check engine light with cam/crank correlation codes

In severe cases, engine no-start or running poorly

#### Why It’s Severe

Engine-out service required: The chains are at the REAR of the engine

Transmission must be removed to access the chains

Significant labor: 25-40+ hours typical

Service cost: $4,000-8,000+ when performed properly

#### Audi TSB and Updates

Audi issued multiple updated tensioner designs throughout production

Later production examples may have updated tensioners

Replacement engines should have current updated tensioner design ideally

#### Our Inspection Approach

Cold-start rattle assessment: Listening test for tensioner symptoms

Cam/crank correlation check: ECU scan for timing-related codes

Engine code documentation: BNS vs CAUA for service history context

Honest disclosure: We disclose any concerns identified

Carbon Buildup on Intake Valves

Typical FSI direct-injection issue:

Symptoms: Reduced low-RPM power, rough idle, misfire codes

When: 60,000-100,000 miles typical

Service: Walnut blasting service ($1,500-3,000)

High Oil Consumption

The 4.2 FSI V8 is known for oil consumption:

Common rate: 1 quart per 1,000-3,000 miles at high mileage

Causes: Piston ring wear, valve seal wear

Mitigation: Regular oil top-off, quality 5W-30 or 5W-40 synthetic

Severe cases: May indicate need for piston/ring service

Water Pump Failures

Service interval: 60,000-100,000 miles

Service: $500-1,000 typical

Cost includes: Coolant flush, thermostat often replaced together

Coil Pack Failures (8 Coils)

Symptoms: Misfire codes, rough running

Service: $80-150 per coil

Multiple failures: Common across engine lifetime

High-Pressure Fuel Pump (HPFP)

Service area for FSI engines: Documented HPFP failures

Service cost: $1,000-2,000 typical

FAQs

What is the Audi S5 V8?