Inspecting Replacement Panels Before Fitting the Mid-Engine Coupe
When unboxing the stationary side glass for the Audi R8 Coupe, I first confirm the glass tint and NAGS references against the build sheet. These rear quarter windows are single-pane tempered units tinted with Audi’s factory green solar-control hue, cataloged under NAGS part number FQ28685 (or FQ28685GTY) for the driver side and FQ28684 (FQ28684GTY) for the passenger side. Because this glass is completely devoid of embedded defroster lines, radio antennae, or driver assistance sensors, the pre-installation check centers entirely on perimeter edge integrity and glass curvature.
I verify the black ceramic frit border on the inner perimeter to ensure it is continuous and free of pinholes or scratching. The glass must sit absolutely flush against the Audi Space Frame B-pillar jamb. Any warpage or unevenness in an aftermarket unit will cause wind turbulence directly behind the frameless door glass or disrupt the narrow reveal along the exterior roof frame. On the right side, the glass also terminates right next to the fuel filler flap assembly, meaning the outer edge radius must match the body contour exactly to prevent an uneven shadow gap against the aluminum body panel.
Exterior Clearance and Adjacent Component Alignment Checks
Once the side quarter glass is seated, the perimeter margins require meticulous evaluation. The R8’s distinct split-side aerodynamic design means this glass sits fractions of an inch ahead of the upper exterior side-blade intake scoops, whether finished in gloss Mythos Black or exposed carbon fiber. When I mount the glass, I back my workmanship with a lifetime guarantee, accompanied by a full year of defect coverage on the panel itself, ensuring the seal stays watertight against aggressive mid-engine airflow.
- B-Pillar Transition: The glass sits directly behind the frameless front window structure. With the door closed, I check that the leading edge of the quarter window sits on an even parallel plane with the drop glass seal to eliminate high-speed buffeting.
- Side-Blade Gap Consistency: The rear vertical edge of the quarter panel must maintain a uniform gap along the forward flank of the engine cooling scoop without pinching the surrounding clear-bra or paintwork.
- Interior Partition Seal: Behind the headrests, the cockpit is separated from the V10 engine bay by a heavy transverse glass partition (OE 4S8845151). I check internally that the quarter window's black band hides the adjoining edge of this rear partition glass and sits uniformly against the interior cabin B-pillar liners.
- Roofline Channel Depth: The top encapsulated moulding must sit dead flat into the upper roof rail recess so that rainwater channeling off the roof does not catch an exposed lip.
Post-Installation Water Ingress and Cabin Resonance Checks
Because the Type 4S R8 cabin is compact and positioned directly forward of the dry-sump V10, acoustic flaws behind the driver's ears are immediately noticeable. After the panel is bonded, I perform a closed-cabin airflow and localized water test around the entire quarter window perimeter. The passenger side demands particular scrutiny around the lower quarter fender edge near the motorized fuel door hinge housing, where trapped moisture could otherwise seep past inner liners.
I also inspect the cabin side trims to verify that the interior quarter panels and B-pillar interior covers clip back into position without putting mechanical pressure against the inner surface of the new glass. If an aftermarket panel is even slightly too thick or curved incorrectly, the interior plastics will creak over chassis flex or leave an unsightly gap against the rear firewall divider.
Does the Audi R8 Spyder use the same quarter glass?
No. The Spyder convertible features a completely different rear deck lid, buttress assembly, and folding soft-top mechanism that does not utilize side quarter windows. These fixed triangular quarter panels exist exclusively on the two-door Type 4S Coupe.
Can early Type 4S quarter glass interchange across later model years?
Audi revised the quarter glass part numbers on December 12, 2016, moving from 4S8845299 and 4S8845300 to the updated 4S8845299A / 4S8845299ANVB (left) and 4S8845300A / 4S8845300ANVB (right). While the outer glass shape remained uniform for the coupe body through 2024, the updated part codes correlate to internal moulding and encapsulation revisions matched to NAGS FQ28685 and FQ28684.
Does this glass house any hidden antennas or defrost grids?
No. The quarter windows on the R8 are dedicated structural panels of tempered safety glass. They contain no defroster heating wires, radio receiver elements, GPS antennas, or electronic brackets, which are instead integrated into the rear engine hatch glass and vehicle roof structure.
