VR6 Forum FAQ's

[24v]

Ok guys/girls, here is the deal. This thread will be for the FAQ section. If you didn't notice, this thread is locked. If you have a FAQ you want added, send it to my e-mail. I will read through it to insure it is factual, then I will post it here. If you have any questions or comments, you can also e-mail, or IM, me.

[24v]

Will a 24 valve head fit on my 12 valve block?
No, it will not fit. The 12v, and 24v use different mounting holes.

Link for parts list for headgasket replacement, timing chains, and a few other things.

[Modified by Boost Inside, 5:36 PM 3-4-2003]

[need_a_VR6]

The following is a copy of the original VR6 tech manual, with notes where applicable.

Service Training
Self-Study Program 402

Volkswagen of America, Inc.
Sevice Training
Printed in U.S.A.
Printed 12/91
Part # WSP 521-402-00

All rights reserved. All information contained
in this manual is based on the latest product
information available at the time of printing.
The right is reserved to make changes at any
time without notice.

Always check Technical Bulletins and the mirofiche
system for information that may supersede any
information included in this manual.

*** Introduction ***

Volkswagen has developed a new six-cylinder engine called the VR-6.
This 2.8-liter engine is unique in that the V-angle between cylinder
banks is 15° rather than the 60° or 90° found in most conventional
V-6 engine designs.

The engine features a cast-iron crankcase, one light alloy crossflow
cylinder head with two valves per cylinder operated by chain-driven
overhead camshafts.

All fuel and ignition requirements of the VR-6 engine are controlled
by the Bosch Motronic M2.9 Engine Management System.

This Engine Management System features an air mass sensor, dual knock
sensors for cylinder-selective ignition knock regulation, and Lambda
regulation.

Exhaust gases are channeled through a 3-way catalytic converter.

*** Engine Specifications ***

Engine code: AAA
Design: Four-stroke, internal combustion engine in "Vee"/in-line
Displacement: 2.8 liter
Bore diameter: 81.0 mm
Stroke: 90.0 mm
**note this is listed as 90.3mm elsewhere
"Vee" angle: 15°
Compression ratio: 10:1
Fuel and ignition systems: Bosch Motronic M2.9
Emission control: Lambda control with catalytic converter

The name, VR-6 come from a combination of Vee and the German word
Reihenmotor. The combination of the two can be roughly translated
as "in-line Vee."

Volkswagen has designed the 15° VR-6 to take advantage of
conventional in-line six-cylinder engine features (single cylinder
head, narrow width and excellent balancing) with the advantages
of a V-6 engine design (short overall length and compactness).

*** VR-6 ***

The VR-6 was specifically designed for transverse installation
in front-wheel-drive vehicles. By using the narrow 15° VR-6 engine,
it was possible to install a six-cylinder engine in existing
Volkswagen models.

*** V-6 Conventional Design ***

A wider V-6 engine of conventional design would have required
lengthening existing vehicles to provide enough crumple zone
between the front of the vehicle and the engine, and between
the engine and the passenger cell.

Using the narrow VR-6 engine will help Volkswagen meet current
and future front-end crash standards.

*** Overview ***

The drop-forged steel, six-throw crankshaft runs in seven main
bearings. The connecting rod journals are offset 22° to one
another.

Overhead camshafts (one for each bank of cylinders) operate the
hydraulic valve lifters which, in turn, open and close the 39.0-mm
intake valves and 34.3-mm exhaust valves.

Because of the special VR-6 cylinder arrangement with two rows
of combustion chambers in the same cylinder head, the intake
runners between the two cylinder banks are of varying lengths.

The difference in intake length is compensated in the overhead
intake manifold. Each runner is 420 mm long.

Exhaust gases are channeled from two 3-branch cat-iron exhaust
manifolds into a sheathed Y-pipe. From there, they are channeled
into a single flow before passing over the heated Oxygen Sensor
and then to the catalytic converter.

The oil pump driveshaft is driven by the intermediate shaft.

Fuel injectors of the Bosch M2.9 Engine Management System are
mounted behind the bend of the intake manifolds. Besides being
the optimum location for fuel injection, this location also helps
shield the injectors during a frontal impact.

The water pump housing is cast integral with the engine crankcase.
In addition to the belt-driven water pump, VR-6 engine will use
an auxiliary electric pump to circulate water while the engine is
running and during the cooling fan after-run cycle.

In the interest of environmental friendliness, a replaceable oil
filter cartridge is used on the VR-6 engine.

The sump-mounted oil pump is driven via the intermediate shaft.
An oil pressure control valve is integrated in the pump.

*** Crankcase ***

The crankcase is made from Perlitic gray cast iron with micro-alloy.
Two banks of three cylinders are arranged at a 15° axial angle from
the crankshaft.

The cylinder bores are 81 mm in diameter with a spacing of 65 mm
between cylinders. They are staggered along the length of the
engine block to allow the engine to be shorter and more compact
than conventional V-6 engines.

The centerline of the cylinders are also offset from the centerline
of the crankshaft by 12.5 mm.

To accommodate the offset cylinder placement and narrow "Vee"
design, the connecting rod journals are offset 22° to each other.
This also allows the use of a 120° firing interval between cylinders.
The firing order is: 1, 5, 3, 6, 2, 4

*** Cylinder Head ***

The aluminum crossflow cylinder head is manufactured in a permanent
mold casting. The combustion-chamber side of the head is hardened
through a separate chill casting

Twenty stretch bolts are used to retain the cylinder head to the block.
These bolts are accessible even with the camshafts installed.
However, it is necessary to retorque the bolts after installation.
Holes for bolts, numbers 12 and 20 are sleeved to make cylinder head
installation easier.

To help optimize flow through the cylinder head, the area above the
valve seats has been machined. Valve shaft diameter has been reduced
to 7.0 mm during development.

Cylinders 1, 3, and 5 have short intake runners and long exhaust
runners while cylinders 2, 4, and 6 have long intake runners and
short exhaust runners.

A crossflow cylinder head has allowed the use of a single cylinder
exhaust manifold rather than a manifold for each bank.

*** Combustion Chamber ***

The surface of the combustion side of the cylinder head is flat.
The combustion chamber is formed by the shape of the piston head.

Ten different piston designs were tested during development of the
VR-6 engine.

The result of these tests was the selection of a slanted piston
head within eccentric trough. The trough is offset from the center
of the piston by 4.0 mm.

Compression gap height (at TDC) is 1.5 mm. the compression ratio is
10:1.

*** Chain tensioners ***

Operated by oil pressure and spring tension.

The camshafts are driven by a two-stage chain-drive system located
on the flywheel side of the engine.

Chains were selected to drive the valve train in consideration of
a Diesel version of the VR-6 engine.

A single chain (lower) is driven by the crankshaft which, in turn,
drives an intermediate sprocket and shaft at a ratio of 3:4.

The intermediate shaft sprocket drives the camshafts via a double
roller chain (upper) at a ratio of 2:3. A double roller chain is
used to drive the camshaft sprockets because it must transfer more
torque than the lower chain.

The specific gear ratio selection was chosen in order to keep the
camshaft sprocket size small. This helps keep the overall engine
height to a minimum.

Chain tension is maintained by two chain tensioners. The upper
chain tensioner is hydraulically operated by engine oil pressure
and spring tension.

The lower chain tensioner (with mechanical lock) is operated by
spring tension and lubricated with engine oil.

Chain flutter is prevented by guide rails on the slack side of
both chains.

*** Engine Cooling System ***

The VR-6 Engine uses an impeller-type water pump driven by the
poly-ribbed belt.

The pump housing itself is cast into the engine block adjacent
to cylinder number 2.

In addition, an Auxiliary Electric Coolant Pump also circulates
engine coolant anytime the ignition is switched on.

The Auxiliary Electric Coolant Pump also runs when the engine
is switched off and the coolant temperature goes over 107° C (220° F).
It runs in conjunction with the Radiator Cooling After-run System.

Circulating the coolant during this time helps cool the engine
block and prevent the possibility of air pockets forming in the
cylinder head.

The thermostat housing of the cooling system also houses the
temperature senders G2, and F87 for the Radiator Cooling After-run
System, and temperature sender G62 for the Motronic Engine Management
System.

*** Intake Manifold ***

Volumetric efficiency must be uniform to attain smooth engine
running and optimal power output under all operating conditions.
This, in turn, requires identical flow conditions in the intake
ports of all cylinders.

Since the lengths of the intake runners in the VR-6 cylinder head
are not equal, it was necessary to compensate with the internal
design of the intake manifold.

All air intake passages are 420 mm long.

*** Auxiliary Drives ***

A double-sided poly-ribbed belt drives all the auxiliary components
of the VR-6 engine.

A spring-operated tensioning roller keeps the poly-ribbed belt at
the proper tension. The belt tension is released by threading a
long 8 mm bolt into a threaded hole on the tensioner.

*** System Overview ***

The VR-6 engine will use the Motronic Engine Management System
version M2.9.

All Corrados will have EGR while only California-version Passats
will have EGR.

*** Fuel Delivery System ***

A two stage fuel pump supplies fuel through the filter to the fuel
manifold and the four hole injectors. The pump is located in the
fuel tank.

The fuel manifold is located on the intake manifold. A fuel pressure
regulator is attached to the fuel manifold on the fuel return side.

The fuel pressure regulator is a diaphragm-type regulator. Fuel
pressure is regulated depending on intake manifold pressure.

As intake manifold pressure changes, the pressure regulator will
increase or decrease the system fuel pressure. This maintains
constant pressure differences between the intake manifold pressure
and fuel pressure.

*** Two-Stage Fuel Pump ***

The two-stage pump has one motor that drives two separate pumps.

* Stage One *

Fuel is drawn in through a screen at the bottom of the housing
by a vane-type pump. The vane-type pump acts as a transfer pump.
It's designed to supply fuel to the fuel accumulator which is
within the pump housing.

Fuel vapors and air bubbles from fuel returning from the engine,
as well as excessive fuel, is forced out of the accumulator through
a fuel vent.

* Stage Two *

The gear-type pump draws fuel in from the bottom of the accumulator
and through a screen. The fuel is then forced through the pump
housing by the gear pump and out the top.

*** Fuel Injectors ***

The injectors are supplied 12 volts by the Power Supply Relay and
are grounded through the Motronic ECU. They are opened sequentially
in the cylinder firing order.

Injection quantity is determined by the injector opening time.

*** Fuel Tank Ventilation ***

The following inputs are used to control the fuel tank ventilation:

.Engine speed
.Engine load
.Engine coolant temperature
.Signal from throttle valve Potentiometer (G69)

Fuel vapors from the fuel tank are vented to the carbon canister.
When the engine is warm and above idle speed, the vapors will be
drawn into the intake manifold via the carbon canister.

Depending on engine load and oxygen sensor signal, a frequency valve
will regulate the quantity of vapors entering the intake manifold from
the carbon canister

* Carbon Canister Frequency Valve (N80) *

The ECU determines the duty cycle of the frequency valve to regulate
the flow of fuel vapors from the carbon canister to the engine.

When no current is supplied to the valve, it remains in the open
position.
The valve is closed (duty cycle 100%) when the cold engine is started.

* Triggering: *

The Carbon Canister Frequency Valve (N80) begins to operate after
oxygen sensor operation has begun.

Valve operation is load- and speed-dependent during driving operation.
The valve is completely open at full throttle and completely closed
during deceleration fuel shut-off.

* Substitute function: *

If power to the valve is interrupted, the valve remains completely open.
This could lead to rough running at idle speed and during partial load
acceleration.

* Self-diagnosis: *

The ECU recognizes open circuits and short circuits in the component.

*** Air Mass Sensor (G70) ***

A hot-wire air mass sensor is used to measure the airflow into the
engine. The air mass sensor is attached to the air filter housing.
The sensor housing includes a baffle grid which reduces air turbulence
and pulses. The sensor has no moving parts.

A thin, electrically-heated , platinum hot-wire in the sensor is kept
180°C (356°F) above the air temperature measured by the thin-layer
platinum temperature sensor.

As airflow increases, the wires are cooled and the resistance of the
sensors changes. Current to the platinum hot-wire changes to maintain
the constant temperature difference.

The resulting current change is converted to a voltage signal and is
used by the Motronic ECU to calculate the volume of air taken in.

Dirt or other contamination on the platinum wire can cause inaccurate
output signals. Because of this, the platinum wire is heated to 1000° C
(1832° F) for a period of one second each time the engine is switched
off to burn off this dirt or contamination.

If a fault develops with the signal from the air mass sensor, the signal
from the throttle potentiometer is used as a substitute in order for
the car to remain derivable.

[Modified by Boost Inside, 6:48 AM 3-4-2003]


[Modified by Boost Inside, 6:50 AM 3-4-2003]

[need_a_VR6]

Now for part 2

*** Throttle Valve Potentiometer (G69) ***

The throttle valve potentiometer is connected to the throttle valve
shaft. It informs the ECU about the power requested by the driver.

Idle and full load switched are not incorporated in the Throttle Valve
Potentiometer. Idle speed and full throttle applications are recognized
by the ECU from the voltage output of the potentiometer.

* Signal application: *

Throttle Valve Potentiometer signals are used for determination of idle
speed stabilization, idle air volume control, fuel after-run shut-off
and fuel load enrichment.

* Substitute function: *

The ECU uses the Air Mass Sensor signal and engine speed signal as a
replacement variables if the Throttle Valve Potentiometer fails.

* Self-diagnosis: *

Self-diagnosis recognizes:

Short circuits to positive
Short circuits to ground

Note: On vehicles with automatic transmission, this potentiometer is
combined in a housing with the potentiometer for the transmission
control.

*** Engine Speed / Reference Sensor (G28) ***

Engine speed and crankshaft position are registered by a single sensor
located on the engine block.

The sensor reads a toothed wheel mounted on the crankshaft to read
engine speed.

The toothed wheel has a two-tooth gap which is used as the measuring
point for the crankshaft position.

* Signal application: *

The signal is used for registration of engine speed and, in conjunction
with the signal from the Hall Sender, for recognition of ignition TDC
in cylinder Number 1.

* Substitute function: *

There is no substitute functions for Speed Reference Sensor G28.

* Self-diagnosis: *

The ECU recognizes a missing signal from the Speed/Reference Sensor
after cranking the engine for five seconds. An impaulsing signal
is recognizes by self-diagnosis when the reference mark signal and
Hall sender signal do not correspond.

* Hall Sender (G40) *

The Hall sender is mounted in the ignition distributor. It is an
electric control switch based on the Hall effect.

The hall sender consists of a magnetic enclosure and integrated
semiconductor circuit (the Hall IC). the IC is made of plastic to
protect it from dampness, soiling and mechanical damage.

A voltage signal is generated when the trigger wheel interrupts the
magnetic field created by the Hall IC. The trigger wheel turns at
camshaft speed. This means that the Hall sender generates one voltage
signal for every two crankshaft revolutions.

* Signal usage: *

The Hall Sender (G40) signal and the Engine Speed/Reference Sensor
(G28) signals are used to identify cylinder Number 1 for sequential
fuel injection and knock regulation.

* Substitute function: *

There is no substitute function for the Hall Sender signal. The
vehicle will start and run without this signal but the ignition
timing will be retarded and there will be no sequential fuel injection.

* Self-diagnosis: *

The ECU will recognize a break in wiring or a continuously applied
signal
voltage (during start attempts as well).

*** Knock Sensor I (G61) And Knock Sensor II (G66) ***

Two knock sensors are used. A knock sensor works like a microphone to
"listen" for spark knock or detonation.

When knocking occurs, the ignition timing is retarded until the knocking
is eliminated. Since the knock limit differs from cylinder to cylinder
and changes within the operating range, knock regulation is done
cylinder
selectively.

* Signal usage: *

Knock regulation does not occur until the engine coolant temperature of
40° C (104° F) is reached. Knock sensor I (G61) monitors cylinders 1,
2,
and 3. Knock sensor II (G66) monitors cylinder s 4, 5 and 6.

With the aid of the Hall sender signal, the ECU can determine which
cylinder is knocking. The ignition angle of the knocking cylinder is
retarded in steps until the knocking stops up to a maximum of 12°.

If spark knock is still detected, the ECU will retard the ignition
timing 11° for all cylinders and record a fault.

* Substitute function: *

If a knock sensor fails, the ignition timing angle of its assigned
cylinders is retarded.

* Self-diagnosis: *

The ECU recognized an open circuit if no signal from knock sensor I
(G61)
or knock sensor II (G66) is received by the ECU at an engine coolant
temperature above 40° C (104° F).

*** Oxygen Sensor (G39) ***

The oxygen sensor (G39) is made of a ceramic material called zirconium
dioxide. The inner and outer surfaces of the ceramic material are
coated with platinum. The outer platinum surface is exposed to the
exhaust gas, while the inner surface is exposed to the outside air.

The difference in the amount of oxygen contacting the inner and outer
surfaces of the oxygen sensor creates a pressure differential which
results in a small voltage signal in the range of 100 to 1000 mV.
The amount of voltage that is produced is determined by the fuel
mixture.

The oxygen sensor (G39) is heated electrically to keep it at constant
operating temperature. The heater also ensures that the sensor comes
to operating temperature quickly.

The sensor has four wires. Two are for the heating element (ground and
power). One wire is a signal wire for the sensor and one for the
ground.

* Signal usage: *

The base injection time is corrected according to the voltage signal
from the oxygen sensor to maintain a fuel/air ratio of approximately
14.7:1.
This allows the three-way catalytic converter to operate at its maximum
efficiency.

If the fuel mixture is lean (excess oxygen), the oxygen sensor will send
a low voltage signal (about 100mV) to the ECU.

If the fuel mixture is rich (lack of oxygen), the oxygen sensor will
send
a voltage signal (about 900 mV) to the ECU.

* Substitute function: *

There is no substitute function for oxygen sensor (G39). If signal
fails,
no oxygen sensor regulation takes place.

* Self-diagnosis: *

The ECU recognizes a fault if no reasonable signal voltage range is
attained within five minutes after engine start with an engine coolant
temperature over 40° C (104° F).

The ECU also recognizes a open circuit in the wiring or a short circuit
to ground andshort circuit to positive (sensor heating).

*** Coolant Temperature Sensor (G62) ***

Coolant Temperature Sensor (G62) is an NTC resistor. It's located in
the
thermostat housing. AS engine coolant temperature rises, the resistance
of the sensor goes down.

* Signal application: *

Coolant temperature sensor signals are required as a correction factor
for determination of ignition timing, injection timing and idle speed
stabilization.

In addition, these systems are activated depending on engine coolant
temperature:

.Knock control
.Adaptation of idle speed volume control
.Oxygen sensor operation
.Fuel tank venting

* Substitute function: *

A fixed value of 80° C (176° F) is stored in the memory of the ECU and
used in case of a faulty coolant temperature signal.

* Self-diagnosis: *

Self-diagnosis recognizes:

Short circuits to positive
Short circuits to ground

*** Intake Air Temperature Sensor (G42) ***

An intake air temperature sensor is located in the intake manifold on
the
left side.

* Signal application: *

The signal is used for idle stabilization and as a correction factor for
ignition timing.

* Substitute function: *

If a failure of the Intake Air Temperature Sensor (G42) occurs, the
Motronic Electronic Control Unit assumes a temperature of 20° C (68° F).
If this happens, cold start problems could occur at temperatures under
0° C (32° F).

* Self-diagnosis: *

The Motronic ECU recognizes open and short circuits to this component.

*** EGR System ***

All Corrados will come equipped with EGR (Exhaust Gas Recirculation).
Passats sold in California will be equipped with EGR. The EGR system is
used to reduce nitrous oxide emissions (Nox). The system recirculates a
small portion of exhaust gas into the intake mixture.

This exhaust gas is noncombustible and takes up a small space in the
intake charge. The results is lower combustion temperatures and reduced
Nox emissions.

The EGR system does not operate at idle because Nox emissions are low
during this time.

* EGR Frequency Valve (N18) *

The EGR Frequency Valve (N18) is mounted on the back of the intake
manifold. A control pressure (vacuum) is formed in the frequency valve
from the intake manifold pressure and atmospheric pressure (from the
intake air elbow). This pressure is applied to the EGR valve via the
EGR frequency valve (N18).

The frequency valve controls the amount of vacuum supplied to the EGR
valve by switching between the connection to the EGR valve and the
intake air boot.

Thus, the actual amount of recirculated exhaust gas can be determined
by the ECU, depending on engine speed and load conditions. A membrane
valve limits the vacuum supplied to the frequency valve at 200 mbar.

* Self-diagnosis: *

The ECU will recognize an open circuit or short circuit in the EGR
frequency valve. If the EGR valve remains continuously open or closed
because of mechanical failure, the EGR temperature sensor (G98) will
signal this to the control unit.

* Triggering: *

The frequency valve (N18) ground circuit is controlled by the ECU
depending on engine load and speed.

* Substitute function: *

There is no substitute function. If current to the frequency valve
(N18) is interrupted, the EGR valve will remain closed.

* EGR Temperature Sensor (G98) *

The EGR temperature sensor (G98) is located in the EGR valve exhaust
gas channel. It measures the temperature of the exhaust gas.

The sensor is an NTC resistor. The electrical resistance of the
sensor decreases as the temperature of the exhaust gas increases.

* Signal usage: *

The signal from the EGR temperature sensor (G98) is used only for
the diagnosis of the EGR system and has no influence on the control.

* Substitute function: *

There is no substitute function.

* Self-diagnosis: *

The EGR system is switched on when the engine coolant temperature
reaches 50° C (122° F).

*** Crankcase Ventilation ***

Crankcase vapors are vented from the cam cover to the intake air boot.

A heating element is used to prevent icing during cold weather.

PIN 1 = Positive (+)

PIN 2 - To engine ground

*** Idle Stabilizer Valve (N71) ***

* Triggering: *

The idle stabilizer valve (N71) is actuated on the ground side by the
ECU.

* Substitute function: *

When a defect in the circuit is recognized, both output stages are shut
off and the valve rotates to a fixed opening cross-section. This allows
the engine to idle at a warm engine idle speed.

* Self-diagnosis: *

The ECU recognizes open and short circuits in the component.

* Ignition System *

Input Signals for Regulation of Ignition System

.Engine speed
.Engine load
.Signal from knock sensors
.Signal from throttle valve potentiometer
.Coolant temperature
.Signal from Hall sender

Functions of Ignition System:

.Ignition timing correction
.Dwell angle regulation
.Idling speed stabilization
.Selective cylinder knock regulation

The control unit uses the engine load and engine speed signals as well
as
the signal from the throttle valve potentiometer to calculate the
ignition
timing.

If signals from the knock sensors indicate knocking combustion, the
control
unit retards the ignition timing of the knocking cylinder by 3° to max.
12°
until the knocking tendency of the concerned cylinder is reduced.

When the knocking tendency no longer exists, the ignition timing is
returned
to the nominal value in steps of 0.5°.

When knocking occurs, the ignition timing can be different for all
cylinders
because of the selective cylinder knock regulation.

Fluctuations in the idling speed range are compensated by changing the
ignition timing with the help of idling speed stabilization.

The control unit receives the idling speed signal from the throttle
valve
potentiometer.

Dwell angle regulation guarantees the necessary charging time of the
ignition coil and, therefore, ignition voltage, regardless of speed and
load conditions.

Coolant temperature signals are required to correct the ignition timing
of a cold engine and activate knock regulation.

*** Power Supply Components ***

Power for the Motronic Engine Management systems is supplied via Fuse
(S18) and three relays:

Fuel Pump Relay (J17)
(Position 12)

Power Supply Relay (J271)
(Position 3)

Oxygen Sensor Heater Power Supply Relay (J278)
(above main Central Electric Panel)

There is no internal power stage relay in the Motronic ECU.

Wiring for the Motronic Engine Management system is routed to the engine
via a single multi-pin connector. This makes engine removal quicker and
provides a test point for trouble shooting procedures.

A central ground station is located on the engine block below the intake
manifold.

It provides a ground point for:
.ECUs
.Sensors for the Motronic Engine Management system (and their shielding)
.Output components (injectors, etc.)

[Modified by Boost Inside, 6:47 AM 3-4-2003]

[need_a_VR6]

The COMPREHENSIVE VR6 CAM LIST:

Coming soon!

Please email me if you have cut sheets of any of these cams with lift, duration, specs, etc. paul_VR6@hotmail.com

<color=red> Stock </color>

Duration @ 1mm: 220
Duration @.050" : 215
Lift: .400"
Lobe center: 115
Intake open @ .050": -7.6deg (7.6deg BTDC)

Schrick

248

Advertized Duration: 248/260 (In/Ex)
Duration @ 1mm: n/a
Duration @.050" : n/a
Lift: .4016"/.4409" (In/Ex)
Lobe center: n/a
Intake open @ ???": 14.25deg btdc (all in crank degrees)
Intake closes @ ???": 53.75deg abdc
Exhaust open @ ???": 66.25deg bbdc
Exhaust closes @ ???": 13.75deg atdc
Peak timing In: 109.75deg
Peak timing Ex: 116.25deg

260 (mech)

Advertized Duration: 260
Lift: .4488"
Peak timing In: 116deg
Peak timing Ex: 118deg

264/260 In/Ex

Advertized Duration: 264/260
Duration @ 1mm: n/a
Duration @.050" : n/a
Lift: .4488"/.4409"
Lobe center: 115
Intake open @ ???": 17deg btdc (all in crank degrees)
Intake closes @ ???": 67deg abdc
Exhaust open @ ???": 65deg bbdc
Exhuast closes @ ???": 15deg atdc

268

Advertized Duration: 268
Duration @ 1mm: n/a
Duration @.050" : n/a
Lift: .4488"
Lobe center: 115deg
Intake open @ ???": 18deg btdc (all in crank degrees)
Intake closes @ ???": 70deg abdc
Exhaust open @ ???": 68deg bbdc
Exhaust closes @ ???": 20deg atdc

276

Advertized duration: 276°
Lift: .4527"
Peak timing: 112°
Intake open @ ???": 26deg btdc (all in crank degrees)
Intake closes @ ???": 70deg abdc
Exhaust open @ ???": 70deg bbdc
Exhaust closes @ ???": 26deg atdc
overlap 2.20mm

Cat

268

Advertized Duration: 268
Duration @ .1mm: 266
Duration @.050" : 230
Lift: .452"
Lobe center: ??
Intake open @ .1mm: 13deg btdc (all in crank degrees)
Intake closes @ .1mm: 73deg abdc
Exhaust open @ .1mm: 63deg bbdc
Exhuast closes @ .1mm: 23deg atdc
Intake open @ .050": -5deg btdc (all in crank degrees)
Intake closes @ .050": 55deg abdc
Exhaust open @ .050": 45deg bbdc
Exhuast closes @ .050": 5deg atdc

272(4)

Advertized Duration: 272
Duration @ .1mm: 274
Duration @.050" : 234
Lift: .452"
Lobe center: ??
Intake open @ .1mm: 17deg btdc (all in crank degrees)
Intake closes @ .1mm: 77deg abdc
Exhaust open @ .1mm: 67deg bbdc
Exhuast closes @ .1mm: 27deg atdc
Intake open @ .050": -3deg btdc (all in crank degrees)
Intake closes @ .050": 57deg abdc
Exhaust open @ .050": 47deg bbdc
Exhuast closes @ .050": 7deg atdc

280 Mech

Advertized Duration: 280
Duration @ .1mm: 280
Duration @.050" : 242
Lift: .419" @ .010" check
Lobe center: ??
Intake open @ .1mm: 30deg btdc (all in crank degrees)
Intake closes @ .1mm: 70deg abdc
Exhaust open @ .1mm: 70deg bbdc
Exhuast closes @ .1mm: 30deg atdc
Intake open @ .050": 11deg btdc (all in crank degrees)
Intake closes @ .050": 51deg abdc
Exhaust open @ .050": 51deg bbdc
Exhuast closes @ .050": 11deg atdc

284 Mech

Advertized Duration: 284
Duration @ .1mm: 284
Duration @.050" : 242
Lift: .473" @ .015" check
Lobe center: ??
Intake open @ .1mm: 32deg btdc (all in crank degrees)
Intake closes @ .1mm: 72deg abdc
Exhaust open @ .1mm: 72deg bbdc
Exhuast closes @ .1mm: 32deg atdc
Intake open @ .050": 11deg btdc (all in crank degrees)
Intake closes @ .050": 51deg abdc
Exhaust open @ .050": 51deg bbdc
Exhuast closes @ .050": 11deg atdc

308 Mech

Advertized Duration: 308
Duration @ .1mm: 308
Duration @.050" : 266
Lift: .500" @ .009" check
Lobe center: ??
Intake open @ .1mm: 48deg btdc (all in crank degrees)
Intake closes @ .1mm: 80deg abdc
Exhaust open @ .1mm: 80deg bbdc
Exhuast closes @ .1mm: 48deg atdc
Intake open @ .050": 27deg btdc (all in crank degrees)
Intake closes @ .050": 59deg abdc
Exhaust open @ .050": 59deg bbdc
Exhuast closes @ .050": 27deg atdc

DSR

256

Advertized Duration: 256
Duration @.050" : 222
Lift: .4323"
Lobe center: 112in/116ex (NA), 118 (FI)
Intake open @ ?": 8deg btdc (all in crank degrees)
Intake closes @ ?": 68deg abdc
Exhaust open @ ?": 68deg bbdc
Exhuast closes @ ?": 8deg atdc

266

Advertized Duration: 266
Duration @.050" : 224
Lift: .4409"
Lobe center: 112
Intake open @ ?": 13deg btdc (all in crank degrees)
Intake closes @ ?": 73deg abdc
Exhaust open @ ?": 73deg bbdc
Exhuast closes @ ?": 13deg atdc

TT

264/260 In/Ex
Duration @ 1mm: 240/238
Duration @.050" : 224/223
Lift: .447/.440"
Lobe center: 115
Intake open @ .050": -5.2 (5.2deg BTDC)

288

TT288s

Advertized duration; 288
Duration at .020": 261
Duration at 1mm: 249.5/248.5
Duration at .050": 245/244
Lift; .460"
Lobe center: 110
In open @ .050": 12btdc

#109 063:
Advertized duration: 288
Duration at .050": 245.2/247
Lift Intake .45528"
Lift Exhaust .45512"
Lobe center: 112.3deg
In open @ .050": 11btdc
Valve overlap 22deg crank

Kent

264

Advertized Duration: 264
Duration @ .1mm: n/a
Duration @.050" : n/a
Lift: .4307"
Lobe center: 100deg
Intake open @ ?: 22deg btdc (all in crank degrees)
Intake closes @ ?: 62deg abdc
Exhaust open @ ?: 62deg bbdc
Exhuast closes @ ?: 22deg atdc

Piper

264 "Fast Road"

Advertized Duration: 264
Advertized Powerband: 1800-6000
Duration @ .1mm: n/a
Duration @.050" : n/a
Lift: .428"
Lobe center: ??deg
Intake open @ ?: 22deg btdc (all in crank degrees)
Intake closes @ ?: 62deg abdc
Exhaust open @ ?: 62deg bbdc
Exhuast closes @ ?: 22deg atdc

276 "Road/Rally"

Advertized Duration: 276
Advertized Powerband: 2300-6500
Duration @ .1mm: n/a
Duration @.050" : n/a
Lift: .450"
Lobe center: ??deg
Intake open @ ?: 30deg btdc (all in crank degrees)
Intake closes @ ?: 66deg abdc
Exhaust open @ ?: 66deg bbdc
Exhuast closes @ ?: 30deg atdc

294 "Rally"

Advertized Duration: 294
Advertized Powerband: 2700-7000
Duration @ .1mm: n/a
Duration @.050" : n/a
Lift: .445"
Lobe center: ??deg
Intake open @ ?: 41deg btdc (all in crank degrees)
Intake closes @ ?: 73deg abdc
Exhaust open @ ?: 73deg bbdc
Exhuast closes @ ?: 41deg atdc

WEB Cams

244

Advertized Duration: 244
Duration @ .1mm: n/a
Duration @.050" : 230
Lift: .428"
Lobe center: ??deg

254

Advertized Duration: 254
Duration @ .1mm: n/a
Duration @.050" : 237
Lift: .432"
Lobe center: ??deg
Note: check all valve/piston clearances before installing

DRC

268

Duration @.050: 226
Valve lift: .450"
Lobe center: 115 deg

272

Duration @.050: 230
Valve lift: .442"
Lobe center: 116 deg

276

Duration @.050: 238
Valve lift: .442"
Lobe center: 116 deg

Many thanks to Jeremy@Matrix, Andy@Denon, Dick@DSR and HerrMuller&HerrWolf@Schrick for providing some great info!



Modified by VgRt6 at 9:58 AM 11-10-2008

[24v]

How do I change my serpentine belt? And, what if I have A/C? Also, can I remove the A/C?
The vr6 uses a double sided 1360mm 7 rib k-crosssection multirib style belt. The OE part number for cars with AC is 021145933H. To change the belt all that is needed is a m8x1.25 bolt that is atleast 40mm long to release the tension on the belt tensioner, (there's a threaded hole on tensioner, you'll see it). You can pull on the bolts that hold the tensioner on and use is to release the tension. Most people remove the airbox on corrado's and mkIII's for more room to work.

For AC removal the belt that is need is a 1285mm or 1290mm 7 rib k-crosssection multirib style belt. Single sided will work. Contitech's part number for this belt is 7pk1285. Part stores will also have this belt by different brands, all you have to do is convert 1285mm to inches. They may only carry 8-rib belts, so you might have to cut one rib off.

Taking out the AC removes 15 to 25 lbs from you car depending on how much you remove. The engine will also rev faster because a pulley is removed.

Search the keyword "removal" in archived topics for detailed write-ups of AC removal for your car. It involves removing the compressor and most people remove the condensor. This procedure is a little different for each vehicle. Also,If you remove your AC and you don't want the high speed fan to run when it's not supposed to you can unplug the brown sensor on the t-stat housing.

Online retailers that carry the contitech non-ac belt.
http://www.rpi-equipped.com
http://www.vwparts.com
submitted by furiousgeorge!!


[Modified by Boost Inside, 2:34 PM 3-4-2003]

[24v]

Can I bypass my throttle body coolant lines, and how do I do it?
First, remove water hoses from throttle body and connect them with a 1/4" brass hose connector (5/16" will also work, and will be a bit of a tighter fit)and tighten up the hose clamps. You can either leave the hoses long in case you want to reconnect or cut them short for a cleaner look, and you don't have to cap the hose nipples on the throttle body, its a "u" shaped water circuit, not a water injection port.
submitted by TrailOfDeadHondas

[Modified by Boost Inside, 5:34 PM 3-4-2003]


[Modified by Boost Inside, 12:48 PM 3-6-2003]

[24v]

How do I clean out my mass air flow sensor?
Take the large Ziploc bag and place the MAF sensor in it.
Pour enough Isopropyl alcohol into the bag to completely cover the MAF sensor. Gently shake the bag to allow the alcohol to pass through the sensor. Take the MAF sensor out and let the excess alcohol drip off. Set the MAF sensor down on a paper towel to drip/air dry. You may want to use the compressed air spray to blow dry parts such as the connector port. Allow the MAF sensor to dry completely before reinstalling it in the car. This will take between 1-12 hours. Reinstall.
submitted by TrailOfDeadHondas


[Modified by Boost Inside, 5:34 PM 3-4-2003]

[24v]

How do I clean my throttlebody?
Unscrew 4 bolts in back with allen wrench. Use carb cleaner, or air intake cleaner, and gently wipe all grime and build-up away. Reinstall.
submitted by TrailOfDeadHondas

[Modified by Boost Inside, 10:38 AM 3-5-2003]

[need_a_VR6]

EGR Delete

This first method was developed because some people have had trouble with the resistor trick. This is a bit simpler, but leaves the EGR control solenoid still wired and in the car. If you want that gone too, read below for the resistor trick.

Remove your EGR can, just unplug the temp sensor and leave it hanging. The sensor does not have diagnostics so you can leave it unplugged with no problems. The open sensor has a default value, and you'll notice this on VAG logs.

You'll have to clean up the vac hoses running to and from the EGR control solenoid (it's small and brown, one electricl connector, thee vac fittings). Just remove and cap what's necessary, I shouldn't have to explain too much here.

If you leave the solenoid plugged in it'll just operate as it should, but with no effect on the running of the car. If you have issues, it's probably a vacuum leak from a spliced or capped line, check there first.

Nice to have no EGR and no CEL!

EGR Delete Resistor Trick

The EGR solenoid/switch has a resistance of 30 Ohm, & the temperature sensor has a value of 2M Ohm to 700k Ohm, which decreases with an increase in temperature. I used a value of 1M Ohm in its place, since that's a ~median value of a warm engine, & an easy-to-find resistor value.
Installing these two resistances in their respective places (mentioned
below), my car idles better than it ever has. Until now I've just used the
30 Ohm resistance in place of the EGR solenoid, & my idle would dip low
after stabbing the clutch, but not quite die (without the 30 Ohm, it would
die immediately with a warm engine). With both these resistances, the EGR
is entirely electrically simulated, & my idle is like new, dropping to ~1k
RPM & then slowly settling to 600-750 RPM.

Here's where to connect the two resistances, if you don't have a Bentley.
If you do, double check me! This "diagram" (*cough*) shows the wires coming from the EGR & its temp sensor plugs. If you still have the plugs in place, you can identify the plugs & their function by the wire color:

green/grey ------EGR solenoid (30 Ohm)--- red/black
brown/yellow ---EGR temp sensor(1M Ohm)--- violet

Other notes:

1M Ohm = 1 MegaOhm = 1,000,000 Ohms
30 Ohm = 30 Ohms

My EGR is physically removed from the engine... the connection points are
capped off. An oil drain plug can be used to cap off the connection point at the exhaust manifold...it fits perfectly. Also remember to cap off the vacuum line that runs to the intake.

Twist the wires together securely, use crimp/snap on connectors for the
resistors, & mummify it all in heat shrink tubing. Soldering around the
engine is dangerous, difficult, & solder tends to weaken & let go in
environments with a lot of vibration. Don't let any metal show, since
everything in the area(cylinder head, block, etc) is grounded.

Resistors don't have a polarity or direction, so you can't get them flipped
around. Just attach the two ends to the wires noted. If you still have the
plugs in place, try putting these in the plug... make sure the leads can't
touch each other, or Bad Things could happen!

I used three 10 Ohm resistors- with 1W dissipation capacity each- in series
for the 30 Ohm load. I wasn't sure how much power the EGR's switch used; I
wanted to be safe with 3W handling. The 1M Ohm load, being much higher
resistance & simply a sensor, received a "standard" 0.25W resistor. At
Radio Shack, the 1W variety are grey & slightly larger than the 1/4 W beige
ones.

I have no credit to give on this one b/c I've had it saved for so long! If you're the original author, pls shoot me an IM or email and credit will go right here.


Modified by need_a_VR6 at 11:54 AM 6-19-2003

[need_a_VR6]

OBD1 vs OBD2

Any more info on this is appreciated!!

e-mail here

OBD1

Model years 92-95, through the July 95 build date. Early ECU's used socketed EPROMS, later cars had soldered in EPROMS. ECU numbers are xxxxx through xxxxx.

Early OBD1 cars (Passats and Corrados) had the scan plug underneath the shifter console and don't use an OBD2 compatible plug. There is an adapter available that lets you use the VAG-COM software on these cars.

OBD1 uses a normal plate style throttle body, and uses an external idle air control valve to control the idle. The TPS is removable and replaceable. Idle adaptation (????)

OBD1 features only a primary oxygen sensor (O2) for closed loop fuel trim. The O2 loop is disregarded at WOT.

OBD1 uses exhaust gas recirculation (EGR) to lower emissions and the minimum octane rating. There is a control solenoid, as well as a vacuum operated valve in the EGR system.

Later cars use a smog pump to lower startup emissions.

OBD1 computers only have minimal diagnostic functions and do not have datalogging capability on board. There are many OBD2 blocks that are not accessable on these ECUs.

Intake manifold is drilled for the EGR, early Throttle Body, as well as the idle air control valve. Not interchangeable with OBD2 ones without major modification.

Early production 92 cars have no check engine light, all others are equipped with one.

OBD2

Model years 96-present, from the August 95 build date onward. ECU numbers are xxxxx through xxxxx.

OBD2 cars feature the scan port in the dashboard for diagnostics, as well as a check engine light in all models.

OBD2 uses a normal plate style throttle body, and uses an internal idle air control valve to control the idle. The TPS is not removable and replaceable. Idle adaptation can be done with the VAG-COM software(????)

OBD2 features dual oxygen sensors (O2). The precat O2 is for closed loop fuel trim. The post cat O2 is used for emissions. The O2 loop is disregarded at WOT.

OBD2 does not use exhaust gas recirculation (EGR).

All cars use a smog pump to lower startup emissions.

OBD2 computers only have full diagnostic functions and have datalogging capability on board. These codes can be scanned by a generic OBD2 reader, a VAG machine or the VAG-COM software package. There are many diagnostic blocks available.

Intake manifold not drilled for EGR, or the idle air control valve. Not interchangeable with OBD1 ones without major modification.

The VAG-COM software site is HERE



[Modified by need_a_VR6, 10:37 AM 4-8-2003]

[tatge]

Cam installs w/o valve spring replacement.

Cam install on MKIII 12v

Cam install on a MKIV 12v


[Modified by tatge, 5:25 PM 3-26-2003]

[tatge]

Which chip for a MKIV 12v VR6?

[need_a_VR6]

Good link for VR6/8 W8,12,16 technical design info

http://autozine.kyul.net/technical_school/engine/tech_engine_packaging.htm

{submitted by ninja-vanish}


[Modified by need_a_VR6, 3:44 PM 4-11-2003]

[tatge]

Firing Order: 1-5-3-6-2-4

[need_a_VR6]

A note about oil temps

Quote, originally posted by Daemon42 »

Come on folks. Don't even *blink* until your oil temps hit 235+F.. the VR6 doesn't. It'll happily run 230's all day long and it's possible to see 250-260 if pushed hard on the highway, like A/C on, 104 degrees out, uphill. And if you run it on the track, it's good till about 280F, and then you should consider backing off a little. Mine's seen just a tick over 300F on the track and is none the worse for wear. When I see people worried about oil temps of 200-210.. I seriously gotta roll my eyes. The VR6's *optimum* temps are between 180F and 210F, and it's only mildly warm in the 210-235 range. There should be something in the VR6 FAQ here. The VR6 RUNS HOT and that's normal! ian Modified by Daemon42 at 9:14 PM 5-14-2003

[need_a_VR6]

A note about compression, preignition, detonation and fuel choice

Something I found that I thought was pretty neat.

http://naca.larc.nasa.gov/repo...2.pdf

A bit on the old side but it's still all very true.

Key points on compression vs fuel type, additives, alcohol/gas mixtures, altitude, etc.

[EPilot]

Fixing cracked VR6 coil pack with JB Weld Part1
Fixing cracked VR6 coil pack with JB Weld Part2

Just a little help

[need_a_VR6]

A little tip for removing wires from the coilpack...

Quote, originally posted by Ph00 »

A thin coating of lithium grease on the outside of the plastic posts on the VR6 coilpack where the wire plug on makes the wires slide on and off very smooth which reduces the chance of breaking the coilpack posts when removing the wires

[need_a_VR6]

Submitted by RadoBoi

A note about 2nd gear grind

Quote »

Ok first...This may not apply to everyone...but in my case it wasn't the syncro. So, every since I bought my car the 2nd gear liked to grind on occasion...I read around and learned it was my second gear syncro going out and I should try switching to redline tranny fluid...I did. When I put in the tranny fluid I noticed absolutly no difference...That seemed weird cause everyone else I read about said it was a night and day difference with redline fluid. So I was driving to get a slurpee one night and I did a 5 grand shift from 1st to 2nd... thats all it took....somehow 2nd gear wasn't working...I had to drive home with no 2nd gear...it would grind everytime I tried to put it in. I was able to start out in second but not when moving. I had my dad help me try and figure out what had happened...he had me shift around through the gears while he watched the shift cables. That was the problem...when shifting into second the cable would bow way out...we rolled up the rubber gaurd to take a look...it was broken. I checked out out my friends GTI VR6 and noticed his was rock solid so it was obviouse what was wrong now. My shifter had always felt stiffer than his and I guess I finally know why... I get the new cable tommarrow so I will let you know how it works out, I'm just hoping the cable didnt cause my syncro to wear out completly...but I doubt it. CHECK YOUR SHIFT CABLES, SAVE A SYNCRO

[EPilot]

DIY - Removing and cleaning a MKIV throttle body (throttle valve control module) http://forums.vwvortex.com/zerothread?id=1116399


Modified by EPilot at 2:41 AM 12-3-2003

[EPilot]

DIY - Replacing the main water pump on a MKIV 12v VR6
http://forums.vwvortex.com/zerothread?id=1154344

[SaabFan]

Very well written DIY - replacing the timing chains and related parts on a 12v VR6:

http://forums.vwvortex.com/zerothread?id=1264409

-Nate

[SLC4EVER]

Spark Plug Gap - Measuring and Adjusting

NGK - BKR5EKUP

Submitted by Steve Colen II.

The way most plugs work is that the spark will jump from the electrode to the point in a straight line, this is a simple gap and easy to measure. In the case of the VR6 plug, the spark will jump from the electrode, travel across the surface of the insulator, then jump the gap to the points. Therefore the gap isn’t the distance from the electrode to the point, but rather from the insulator to the points.

To gap this plug a wire gauge must be used since the point has an arc that maintains an even distance to the insulator and electrode. Use a .7 mm wire gauge and slide it in-between the point and the insulator, then adjust the point until the wire gauge fits between them without any slop at all. Most gapping tools will have a little notch in them that will allow you to grab the point. The key is very small increments, so don’t bend the point, just apply pressure on it and keep measuring even when you don’t think it moved.

http://forums.vwvortex.com/zerothread?id=1458763

Nice job Steve.

[David@vwvortex]

DIY Seamfoaming the Engine Submitted by ericthebikeman:

http://forums.vwvortex.com/zer...83762

[David@vwvortex]

Secondary Air Injection Incorrect Flow (P0411) fix posted by benny_mech:

http://forums.vwvortex.com/zerothread?id=1995162

[VgRt6]

Great DIY for replacing the t-stat housing and "crack pipe" on a 12v VR6. Also has a link for removing the front end and bringing the "lock carrier" to the service position on a MKIV car.

T-stat housing and "crack pipe" replacement DIY

[VgRt6]

DIY for replacing the alternator - http://forums.vwvortex.com/zerothread?id=2455185.

Gary

[staggered mk4]

DIY- Replacing the downpipe/cat on a 12v VR6 and using a 24v cat on a 12v DP by FaelinGL

12v cat and downpipe replacement


Modified by staggered mk4 at 10:08 PM 8-30-2006

[staggered mk4]

Another alternator replacement DIY with fuel line replacement added for the MkIV 12v VR6 by Slimjimmn.

http://forums.vwvortex.com/zerothread?id=3644162