The Audi 4.0l V8 TFSI engine
from the EA825 series
eSelf Study Program 920493

Audi of America, LLC
Service Training
Created in the U.S.A.
Created 2/2020
Course Number 920493
©2020 Audi of America, LLC
All rights reserved. Information contained in this manual is based on the
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The eSelf-Study Program (eSSP) teaches a basic understanding of the design and mode of operation of new models, new
automotive components or new technologies.
It is not a repair manual! Figures are given for explanatory purposes only and refer to the data valid at the time of
preparation of the SSP.
For further information about maintenance and repair work, always refer to the current technical literature.

Release Date: February 2020
2

Introduction
Engine description and special features
Technical data

Engine mechanics
Cylinder block
Crankshaft
Cylinder head
Camshaft drive configuration
Crankcase ventilation system
Positive Crankcase Ventilation (PCV)
Fuel tank ventilation
Vacuum system

Oil supply
Oil circuit overview
Oil pump
Piston cooling
Sensors and actuators
Oil filter and oil-coolant heat exchanger
Oil filter module
Oil supply in the cylinder head cover

5
6
7

8
8
12
18
31
36
41
42
44

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46
48
50
51
53
54
55

Drive for ancillaries

56

Cooling system

58

System overview
Coolant circuit in cylinder block
Cooling concept for the cylinder head
Transmission coolant circuit

Air supply
Overview of air ducts
Intake manifolds
Throttle Valve Control Modules GX3 and GX4

Turbocharging
Twin scroll exhaust manifold
Twin scroll turbochargers
Turbocharger mounting
Turbocharger oil and coolant connections
Heat shield in inner V of engine

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60
62
67

69
69
71
72

73
73
74
76
77
78

Exhaust system

79

Fuel system

80

High-pressure injector

Engine management
System overview
Engine Control Module

Inspection and maintenance
Service information and operations
Special tools and workshop equipment

Knowledge assessment

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84

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85
86

87

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4

Introduction
The new Audi V8 engine from the EA825 series is a joint
development of Porsche and AUDI AG. The engine construction is based on the V6 engine from the EA839 series. This
has advantages not only for the manufacturing process; the
close relationship has benefits for after sales service as
well. For example, many of the special tools can be used for
both engines.
The new V8 engines were first introduced by two other
Group brands: Bentley and Porsche. At Audi, the new V8
will be installed first in the A8.
The engines are manufactured in the new Porsche engine
production facility in Zuffenhausen.

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Learning objectives of this eSelf-Study Program:
This eSelf-Study Program describes the function of the 4.0l
V8 TFSI engine of the EA825 engine series. Once you have
completed this eSelf-Study Program, you will be able to
answer the following:

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What are the technical characteristics of the engine?
How do the oil supply and engine cooling systems work?
What are the special features of the air supply system?
What effect does the improved injection system have?
What has changed for after-sales service and maintenance?

5

Engine description and special features
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Eight-cylinder V-engine with 90° bank angle
Aluminum cylinder block
Chain drive valve timing
Four valves per cylinder, double overhead camshafts (DOHC),
roller cam followers, variable valve timing
Turbochargers with charge air cooling (maximum charge
pressure: 31.9 psi [2.2 bar] absolute)
Emission control system with pre and main catalytic
converter system, Oxygen sensors
High-pressure and low-pressure fuel systems
(controlled according to demand)
Cylinder on Demand (CoD)
Indirect charge air cooling system
Fully electronic direct injection with electric throttle
Adaptive Oxygen sensor control
Mapped ignition with single ignition coils
Cylinder-selective adaptive knock control
Thermal management system

Advantages over the previous version V8 from the EA824 family:
› High torque at low rpm
› Improved responsiveness
› Significant increase in efficiency
› Increased power output and torque
› Better fuel economy
› Meets the relevant country-specific emission standards
› Thermal management system (new cooling module)
› Reduced engine friction
› Improved injection system

Highlights of the new V8 engine

Crankcase (optimized for weight) with
APS-coated cylinder running surface

Thermal management

Friction-optimized
valve gear

Fuel system with
central injector
configuration

Cylinder head design with
valve lift and Cylinder on
Demand

“Hot Side Inside” (HSI)
turbocharging system

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6

Technical data
Torque-power curve of 4.0l V8 FSI engine
(engine code CXYA)
486.79 lb ft
(660 Nm) at
1850 - 4500

453.26 hp
(338 kW)
at 5500

Diagram: engine at full load
  Power output in kW
  Torque in Nm

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Features

Specifications

Engine code

CXYA

Design

8-cylinder engine with 90° V angle

Capacity

243.85 cu in (3996 cm)3

Stroke

3.38 in (86.0 mm)

Bore

3.38 in (86.0 mm)

Cylinder spacing

3.22 in (82.0 mm)

Number of valves per cylinder

4

Firing order

1-3-7-2-6-5-4-8

Compression ratio

11.0 : 1

Power output at rpm

453.26 hp (338 kW) at 5500

Torque at rpm

486.79 lb ft (660 Nm) at 1850 - 4500

Fuel

Premium unleaded

Turbocharging

“Hot Side Inside” (HSI) turbochargers with charge air cooling
(maximum charge pressure: 31.9 psi [2.2 bar] absolute)

Engine management

Bosch MG1CS008

Engine weight

509.2 lb (231 kg)

Emission control

Dual exhaust system with pre-catalytic converter and 3-way catalytic converter

Emission standard

ULEV125, (Pr. number:7MU)

Firing order during changeover to
4 cylinder operation (cyl. 2, 3, 5, 8
shut off)

1-7-6-4
7

Engine mechanics
Cylinder block
The aluminum (ALSi9Cu3) cylinder block is single sand cast unit. It is a “deep skirt” design. This means the individual cylinder walls reach down as far as the upper oil sump providing a very high degree of rigidity. The entire cylinder block including
the bearing covers and corresponding bolts weighs 86.2 lb (39.1 kg).

In addition to the oil and cooling passages, the following
components and assemblies are integrated with or
installed on the cylinder block:
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The engine number is engraved on a plate on the front of
the engine below cylinder bank 1. There is also a sticker
with the engine code and serial number attached to the
vacuum pump cover.

Oil spray jets
Water pump intermediate shaft
Oil pump
Oil cooler
Coolant pump
Engine mounting
Mounting points for ancillary components

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8

Atmospheric plasma spraying (APS)
To create a sufficiently robust iron running surface, the
cylinder walls are first roughened with a special milling tool
which cuts a dovetailed pattern into the cylinder. The
resulting undercuts ensure that the APS coating adheres
properly.
A rotating plasma torch is then inserted into the cylinder.
An arc discharge is used to create a plasma into which a
powdered coating material is blown using compressed air.
The powder melts and is sprayed onto the rough cylinder
wall. There it solidifies and fills the undercuts thus creating
a wear layer.
A layer of iron (roughly equivalent to 100Cr6 bearing steel)
is applied in several layers in approximately 30 seconds.
The final thickness is approximately 150 micrometers.
(One micrometer equals one millionth of a meter.)
Application of plasma coating

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Wear layer on cylinder wall

Cylinder block

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9

Crankshaft bearings
The upper crankshaft bearing bosses are integral with the
cylinder block. The grey cast iron bearing caps are retained
with longitudinal and transverse bolts.

Grey cast iron bearing cap

Crankshaft bearing shell (bottom)

Crankshaft bearing shell (top)

Hole for locking pin T40069
(with engine removed)

Transverse bolt for cross-bolting
the crankshaft bearing caps.

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Sump (top section)

Timing chain cover

The top section of the sump is made of an aluminum die
cast alloy. Dowel pins are used to ensure exact positioning
during assembly.

This die-cast component is made of an aluminum alloy; if it
needs to be removed, it can be pressed off the cylinder
block using auxiliary bolts. The engine speed sensor as well
as the crankshaft oil seal are located in the cover.

Sump (bottom section)

Sealing flange (pully end)

The bottom section of the sump is made of an aluminum
sheet metal. The oil drain plug and the oil level/oil temperature sensor are integrated with it.

This component is also made of an aluminum alloy. It
provides the attachment point for the dipstick tube and the
crankshaft oil seal.

Cylinder 1

Oil seal
Oil ring

Sealing flange
Pulley end

Timing chain
cover

Engine number
Oil baffle plate

Oil pan top section

Oil pan bottom section

Oil drain plug

Oil Level Thermal Sensor
G266

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Note

Housing cover and sumps are sealed by a liquid gasket (see ElsaPro for details).
11

Crankshaft
The forged steel crankshaft is supported by five main
bearings to ensure a smooth running engine.
The cylinder banks are positioned at a 90 degree angle to
one another with connecting rods of the cylinders opposite
of each other sharing the same bearing journal.

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12

Crankshaft bearings
The IROX bearings conform to the high demands of hybrid
drive and start/stop operation.
Three-layer bearing construction:
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The steel backbone provides the required stability.
The second layer is made of a soft metal carrier substrate to
which the third layer is fixed.
The third layer consists of a polymer base with a homogeneous
distribution of filler materials which ensure the best possible
running and wear characteristics.

Crankshaft bearing
shell (top)

Timing gear
(drive gear)
Crankshaft bearing 1
(pulley end)
Chain sprocket
(drive gear for oil
pump)

Crankshaft bearing
shell (bottom)

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Thrust washers
Four thrust washers (top and bottom) are installed on
crankshaft bearing four to control longitudinal movement
of the crankshaft. The oil grooves of the thrust washers
face towards the crankshaft.

Crankshaft bearing four
Thrust washer (bottom)

Thrust washer (top)
Crankshaft bearing shell
(top)