B9.5 Audi S5 Sportback 3.0T Maintenance & Upgrade Log

The original hood was one of the major exterior panels damaged in the S5's front-end collision. In fact, the damage was severe enough that once the bumper was attached, the hood would no longer close properly and had to be hammered out just to get everything to align. With the rest of the front end now coming together, it was finally time to replace it.

Rather than going back to another factory hood, we installed a CAP Carbon Fiber Vented Front Hood.

The exposed carbon ties directly into the dry carbon fenders, mirror covers and other carbon pieces already installed throughout the build, while the vented design gives the front end a much more aggressive look.

At this point, one of the largest remaining pieces of visible collision damage was finally gone and the rebuilt front end was getting much closer to its finished look.

With the major collision repairs mostly behind us, we continued working around the exterior to bring the different areas of the build together.

CAP GLOSS BLACK FRONT LIP

The RS5 style front bumper was already a major change from the damaged factory S5 bumper, but the lower section of the front end was still missing a finishing piece.

We installed a CAP Gloss Black Front Lip, adding more definition to the bottom of the RS5 style bumper and giving the front end a lower, more aggressive appearance.

CAP CARBON FIBER SIDE SKIRTS

Next, we added CAP Carbon Fiber Side Skirts.

With exposed carbon already on the fenders, mirrors and spoiler, the side skirts helped carry the carbon theme across the full side profile instead of concentrating it only around the front and rear of the car.

CAP CARBON FIBER DIFFUSER V1

The factory rear diffuser was then replaced with the CAP Carbon Fiber Diffuser V1.

Adding carbon to the lower rear end helped tie the diffuser into the V3 spoiler and the rest of the exterior carbon, while giving the back of the S5 a more aggressive finish.

With the front lip, side skirts and diffuser installed, the exterior was finally starting to look consistent from front to back.

With the cooling system and charge pipes already upgraded, we continued preparing the S5 for the additional power planned later in the build.

CAP 8" INTAKE V2

We started by replacing the factory intake with the largest intake in the market the CAP 8" Intake V2.

Aside from opening up the intake side of the 3.0T, one of the biggest changes was the sound. The larger intake setup brings out significantly more of the turbo spool and induction noise that is muted by the factory system.

With future tuning already planned for the S5, upgrading the intake also gave us a better foundation for the airflow demands that will come with making more power.

CAP TITANIUM TURBO INLET V2

Next, we installed the CAP Titanium Turbo Inlet V2.

With the intake upgraded, it made sense to continue improving the airflow path into the turbo rather than leaving the factory inlet in place. The titanium inlet also adds another functional upgrade to the engine bay while pairing with the rest of the CAP intake setup.

CAP POST THROTTLE VALVE TITANIUM CHARGE PIPE KIT

We finished the airflow upgrades with the CAP Post Throttle Valve Titanium Charge Pipe Kit.

This continued the upgraded charge-air system beyond the throttle valve and added another titanium component to the setup, complementing the CAP intercooler and charge pipes installed earlier in the build.

Together, the intake, turbo inlet and post-throttle charge pipe moved the S5 another step closer to being ready for tuning.

With the major collision repairs almost complete and the S5 finally getting back on the road, it was time to take care of one of the most important baseline maintenance items — its first oil change since joining the CAP fleet.

ENGINE OIL & FILTER CHANGE

Instead of draining the oil from underneath the car, we used an oil extractor to remove the old oil through the engine bay. This makes the service much cleaner and allows the oil to be changed without lifting the car or removing the underbody panels.

With the old oil extracted, we replaced the oil filter and refilled the 3.0T EA839 V6 with approximately 7.3 litres of Liqui Moly Top Tec 6200 SAE 0W-20.

Starting the build with a fresh oil and filter change gives us a known maintenance baseline as the S5 moves into more performance upgrades and eventually increased power.

SERVICE SUMMARY

Service Reset: Audi MMI
Oil Used: Liqui Moly Top Tec 6200 SAE 0W-20
Oil Capacity: Approximately 7.3 L
Drain Method: Oil extractor
Oil Filter: Hengst Filter
Engine: 3.0T EA839 V6

The S5 was purchased without its front fender liners, another piece left missing after the collision.

With the dry carbon fenders, replacement impact bar and RS5 style bumper now installed, we could finally go back and finish the front wheel wells by installing the missing fender liners.

It wasn't one of the flashy upgrades of the build, but it was an important part of properly putting the car back together. The liners close off the wheel wells and restore the protection that had been missing since we purchased the car.

This checked off another remaining piece of the original collision repair and brought the S5 closer to being completely rebuilt.

With most of the major front-end work completed, attention started shifting toward the overall appearance of the S5.

CAP V3 DRY CARBON FIBER SPOILER

For the next exterior upgrade, we let the people following the build make the choice. We asked followers to decide between the CAP V1, V2 and V3 Dry Carbon Fiber Spoilers, and the V3 came out on top.

The existing spoiler was removed and the mounting surface was thoroughly cleaned and prepared before installing the V3 Dry Carbon Fiber Spoiler using double-sided tape.

CAP uses 3D scanning during product development to closely match the factory mounting surface, allowing the spoiler to follow the shape of the trunk for an OEM-level fitment without drilling into the car.

CAP DRY CARBON FIBER MIRROR COVERS

To continue the carbon theme throughout the exterior, we also installed CAP Dry Carbon Fiber Mirror Covers in place of the factory covers.

The exposed carbon adds another detail to the side profile of the S5 while tying in with the dry carbon fenders and V3 spoiler.

SILVER FORGED WHEELS

The S5 also came with a set of black wheels that didn't fit the direction we wanted to take the build.

We removed them and installed a set of silver forged wheels, giving the car a cleaner look and adding more contrast against the white exterior and exposed carbon fiber.

The passenger-side headlight was another expensive casualty of the front-end collision. A complete replacement assembly can cost around $4,700 USD, largely because of the amount of electronics and lighting hardware contained inside it.

Fortunately, the internal components survived. The main damage was to the outer lens and housing, so instead of replacing the entire headlight, we transferred the original internals into a replacement housing.

Since the headlight was already apart, we took the opportunity to customize it at the same time by blacking out the internals and installing demon eyes.

What started as an accident repair ended up becoming one of the most distinctive details of the rebuilt front end.

The front-end collision damaged several of the S5's exterior and structural components. Rather than simply returning everything to stock, we used the rebuild as an opportunity to start changing the appearance of the car.

CAP RS5 STYLE FRONT BUMPER

The original S5 front bumper was heavily damaged and needed to be replaced.

Instead of installing another factory S5 bumper, we upgraded the front end with a CAP RS5 Style Front Bumper, giving the car a much more aggressive appearance.

CAP DRY CARBON FIBER FENDERS

The passenger-side fender was also damaged in the collision. Rather than replacing only the damaged panel with another factory fender, we removed both original fenders and installed a set of CAP Dry Carbon Fiber Fenders.

This replaced the damaged panel while also becoming one of the first major exterior upgrades of the build.

IMPACT BAR REPLACEMENT

The original front impact bar had also been affected by the accident, with its supporting mounts broken off.

We sourced a replacement impact bar from a B9 Audi A4 part-out, painted it black and installed it in place of the damaged original so the front end could properly go back together.

The accident destroyed both the radiator and factory intercooler, making the cooling and charge-air systems one of the first major mechanical areas that needed attention.

CAP ALUMINUM CHARGE PIPES

With the CAP Intercooler already installed, we also replaced the factory plastic charge pipes with CAP Aluminum Charge Pipes.

The S5 remained on its stock tune at this stage, but with plans to increase power later in the build, upgrading the charge pipes now meant we wouldn't have to rely on the original plastic piping once boost levels increased.

ENGINE COOLANT FLUSH

When the replacement radiator was initially installed, the cooling system had to be refilled. We later found out that the coolant used for the initial fill wasn't something we trusted enough to leave in the car long-term.

We drained and flushed the cooling system before refilling it with OEM Audi G12EVO coolant, giving us a proper coolant baseline moving forward.

OEM RADIATOR & CAP INTERCOOLER

Both the radiator and intercooler were destroyed in the front-end collision.

The damaged radiator was replaced with an OEM replacement, but rather than installing another factory intercooler, we used the opportunity to upgrade to a CAP Intercooler.

The CAP unit features a bar-and-plate core, cast-aluminum end tanks and over 135% more volume than the OEM intercooler, helping reduce intake-air temperatures and pressure drop as power levels increase.

Since the factory intercooler already needed to be replaced and we plan on making more power later in the build, upgrading it now made much more sense than going back to stock.

On April 2, 2026, we purchased this 2021 B9.5 Audi S5 3.0T from auction with 118,675 km on the odometer.

The S5 had been involved in a front-end collision and had an estimated $26,585 in damage. Before any performance upgrades or product development could begin, the first step was documenting exactly what we were starting with and determining what would be required to bring the car back to proper condition.

S5 PURCHASE SUMMARY

Vehicle: 2021 B9.5 Audi S5 3.0T
Mileage: 118,675 km
Condition at Purchase: Front-end collision damage
Estimated Repair Cost: $26,585

COLLISION DAMAGE

The majority of the damage was concentrated around the front end of the vehicle.

• Front bumper damaged
• Hood damaged
• Passenger-side headlight damaged
• Passenger-side fender damaged
• Radiator damaged
• Intercooler damaged
• Front impact bar damaged
• Fender liners missing
• Lower splash guard missing
• Passenger-side ACC wiring cut
  

NEXT STEPS

With the initial damage documented, the first priority was restoring the S5 to proper mechanical condition and replacing the damaged or missing front-end components. Once the car was back together, we could begin moving into the upgrades and development work planned for the build.