RS4 maintenance

This page contains our videos on the various Audi B7 RS4 build and maintenance items with our Frooog race car but also our daily driver RS4.

Stud conversion

One of the most convenient and necessary modification for any RS4, a stud conversion kit will make changing wheels so much easier and not need to have different sets of bolts if you are using spacers.

We use the stud conversion kit from ECS with 62mm studs for our OZ Rally wheels: https://www.ecstuning.com/b-ecs-parts/ball-seat-stud-conversion-kit/001467ecs01kt1/

Suspension

DRC

If you have to take out your DRC suspension for repair or for installing coilovers, you first need to depressurize / discharge the system before disconnecting the lines. In this video we show how to depressurize and drain the DRC system with just a hose and a cotter pin. Here we have a DRC suspension in full working order and we are just removing it to install coilovers (another video will be coming up about it).

If you need to repressurize the DRC system, there is a handy DIY guide here: https://www.audizine.com/forum/showthread.php/995408-DRC-hydraulic-suspension-pressurization-DIY

Upper strut bracket threads repair

If you have serviced your suspension you probably have encountered at some point damaged threads in your upper strut bracket that prevented you to achieve the proper torque of 55 ft.lbs for the bolts securing the bracket to the chassis.

We show two option to attempt a repair, either by tapping to a larger 7/16 thread or using an upside down M10x1.5 bolt (min 40mm, max 55mm). We had little success with the tapping as it held up for only one more install/deinstall. The reverse bolt option seems to be the strongest and most reliable.

Bilstein B16 PSS9 coilovers installation

We are showing all the steps for the removal of a stock DRC suspension to the full installation and adjustment of Bilstein B16 PSS9 coilovers on a 2007 Audi RS4.

Links:

B16 coilovers: https://www.demon-tweeks.com/us/bilstein-b16-pss9-ride-height-and-damping-adjustable-kits-bls48-105958/
Vevor strut compressor: https://a.co/d/3gTYGS9
ECS coilover instllation kit (but you don't need the rear spring pads): https://www.ecstuning.com/b-assembled-by-ecs-parts/cup-kit-coilover-installation-kit/4f0513353dkt/

Clutch

The ACT clutch install video is an excellent reference with all the torque specs to do a clutch job. We made a companion video to address the parts that are not addressed in the ACT video. We also show the Sachs slave cylinder install with the USP motorsport kit but we were sent the wrong line so we had to use some of our own brake lines for it.

Windshield washer pump

The RS4 has 2 washer pumps, one for the windshield and another one for the headlights, one on each side of the washer tank. Thankfully the windshield washer pump is the most accessible one!

Brakes

It is worth upgrading the stock brake line with a stainless braided line kit. In the video below we show the installation video of the JHM Brake Line Kit-Stainless for the B7- RS4 (https://jhmotorsports.com/brake-line-kit-stainless-jhm-front-and-rear-lines-for-b7-rs4.html). We also show how to use the Pesko Manual Brake Fluid Bleeder Kit (https://a.co/d/6aeayuv) to bleed the air out between each hose installation.

Underbody protection

Whether you have a stock or aftermarket engine tray, upgrading the stock bolts for U-nuts will improve a lot the tightness and make the install/removal much less fussy.

Contact sales@octcomposites.com for a 15% discount when you use promo code FROGRACING! You can find OCT composite products at https://shop.octcomposites.com/car-parts/Audi/rs4-b7

U-nuts hardware: https://www.amazon.com/gp/product/B0BWM49ZPL
Replacement plastic clips: https://a.co/d/5m9n3CF

18" OZ Racing wheels

If you are looking at installing 18" wheels, OZ Rally Racing wheels 18x8 5x112 et35 with 10mm spacers in front and 15mm spacers in the rear are the way to go. Note that you will need 62mms studs to be able to run those wheels with the spacers.

Racing specific maintenance

Interior and rollcage

In this section you will find the videos related to the interior removal and rollcage construction.

Audi RS4 Froooog rollcage

Wheel scrapers

When fitting 18" wheels, the clearance between the wheel and the RS4 calipers, especially in the front becomes extremely small. Any dirt, silt or gravels to the inside of the rim can quickly damage the calipers. Wheel scrapers help prevent this issue by scraping the inside of the wheel before debris can reach the caliper. We build custom scrapers out of custom made aluminum brackets and a replaceable piece of UHMW-PE for scraping.

Cartek GT kill switch installation

If you want to learn more about kill switches, check out our Kill switch page.

If you retain the factory key so that the immobilizer and other security features remain enabled, you will have to use a relay to control the ECU fuse. You can use the Cartek GT ECU power lead to power the relay and the ignition lead from the fuse to control the relay. This way if you shut off the ignition or lose power from the Cartek, the car will shut off in both cases.

The diagram below shows how to wire a Cartek GT on the Audi RS4 by tapping fuse #43 (engine management/ECU) that is located on the side of the dash on the driver side. You can look at the accompanying video to see how we routed the wires through the car and installed the Cartek GT near the battery in the trunk.

List of parts:

Cartek GT: https://rally.build/products/cartek-gt-solid-state-battery-isolator-kit
Fuse tap: https://www.amazon.com/gp/product/B0CHF4LDGH
Relay: https://www.amazon.com/gp/product/B072QXDZRD

Ignition switch wiring on an Audi B7 RS4

As the steering column lock needs to be disabled, the ignition switch can be rewired to independent switches. We have traced all the wires coming to the ignition switch and show how to wire them in case you want push start buttons to start the car. Note that you can't completely get rid of the key as it is needed for communications with the immobilizer system. But the 2 wires for the key run under the ignition lock to the key side.

Quick release and racing steering wheel

The video below shows how to install an NRG SRK-180H short hub and an NRG 2.5 quick release system with a Sparco 383 racing steering wheel on the RS4:

RallySafe

The RallySafe permanent installation kit is required for stage rally competition as it is used for both safety and scoring.

Hood pins

If your factory latch is broken or you need to disable it for racing, hood pins can be the solution.

Mud flaps

Rally regulations require 4 mud flaps for 4wd cars. Thankfully it is pretty easy to use the existing fender liner bolts to secure the mud flaps. Watch our installation video below.

The mud flap kit we used can be found on Amazon at: https://www.amazon.com/gp/product/B09LCCGHYY

Spare tire tie-downs

We need to carry at least one full size spare tire in the car (and sometimes 2 if the conditions are rough) and we need to be able to get them out quickly while still being secured when not in use. We found a simple solution to add anchoring points to the rear of the trunk and use automatic ratcheting straps to secure the assembly in place.

Tow hook

Rally regulations require front and rear tow hooks, unfortunately the RS4 does not have any provision for a rear tow hook. So we came up with a minimally invasive solution hooked up to the rear bumper beam bar.

ABS and airbag modules

If you lose the communications with your airbag controller module, your ABS will stay in limp mode with a brake distribution of 50/50 instantly locking up the rear wheels on any significant braking. There is a thread here tracking down the progress on this issue: https://forums.ross-tech.com/index.php?threads/47221

It turns out that the ABS module won't start if it cannot communicate with the Airbag controller module (don't ask why). So we embarked on the task of reconnecting the Airbag controller module to the car wiring harness to offer minimal functionality to allow the ABS to work. Power and CAN bus wires are all that is needed as shown in this video:

VCDS tips/coding

VCDS is a diagnostic software produced by Ross-Tech, you can find the latest version here: https://www.ross-tech.com/vcds/download/current.php

On the hardware side we use the HEX-NET interface (https://www.ross-tech.com/vcds/hex-net.php) which allows us to either use a USB connection with the laptop or a Wifi connection directly on the phone.

Enabling/Disabling TPMS sensors

You can check the video below for a demo of the steps.

To Disable the TPMS, follow these steps in VCDS:

Select Control Module
25- Immobilizer
Adaptation
Select Channel 51 - CAN-Databus Comfort (Installation list)
Select Read
Remove 512 from the value you read (My value was 3843 so 3843-512=3331)
Put he value in the New Value field
Click Test
Click Save
Click Yes in 'Are you Sure'
The TPMS light will disappear from the dash

To Enable the TPMS, follow these steps in VCDS:

Select Control Module
25- Immobilizer
Adaptation
Select Channel 51 - CAN-Databus Comfort (Installation list)
Select Read
Add 512 to the value you read (My value was 3843 so 3331+512=3843)
Put he value in the New Value field
Click Test
Click Save
Click Yes in 'Are you Sure'
The TPMS light will appear on the dash

Headlight adjustment

This video shows you how to resolve a code 01539 - Headlights Not Adjusted issue on an Audi B7 RS4. This code can usually be triggered after a loss of power when changing a battery. We show you the simple steps to follow through VCDS to calibrate/code the headlights to resolve the issue.

Steering wheel angle sensor calibration/coding

After replacing the battery or changing the steering wheel angle sensor in your Audi B7 RS4, you are likely to get the following error: 01826 - Sensor for Steering Angle (G85); Supply Voltage Terminal 30.

This error can only be resolved by re-calibrating the steering wheel which is what we are showing in this video using VCDS.

The steps of the procedure are also described on the Ross Tech wiki at http://wiki.ross-tech.com/wiki/index.php/Audi_A4_(8E)_Brake_Electronics_(Bosch_8.0)#coding

Sensor for Steering Angle (G85)

[Select]
[03 - ABS Brakes]

[Fault Codes - 02]
[Done, Go Back]

Start Engine (session still running).

Turn steering wheel at least 30 ° left and back straight ahead.

[Meas. Blocks - 08]
Group 005 Field 1 (Steering Angle Sensor -G85-)
Specification: 0.0 °
Tolerance (when straight): ±5.0 °
[Done, Go Back]

[Security Access - 16]
Enter 40168
[Do It!]

[Basic Settings - 04]
Group 001
[Go!]
[Done, Go Back]

[Fault Codes - 02]
All fault codes should have disappeared.
[Done, Go Back]

[Close Controller, Go Back - 06]

The first video below shows you how to execute this procedure. The second video shows the symptoms of a non calibrated Steering Angle Sensor that reports bogus values in VCDS.

If at the end of the procedure you get a 01486 System Function Test Activated code, the procedure described here didn't work for us: http://wiki.ross-tech.com/wiki/index.php/ESP_System_Function_Test

Here is what we did instead:

[03-ABS]

Start [Basic Setting]

Choose 'System Test Activation Function' or Group '003' and Go

It will show 'Test Enabled'

Then go to Group '103' and Go

It will switch to 'System Test OFF'

Done, Go Back

The code will be gone.

Disabling airbags

It turns out that you cannot remove the airbag controller module out of the car without rendering the ABS module non-functional. If you want to retain the ABS and all its subsystems (ESP/EBD/HBA/EDL/ASR), you need to have minimum communications with the Airbag controller module as shown in this video:

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