Plan the replacement
The selected 2004 RX-8 listing specifies an aluminum intake and washable cotton-gauze RU-5123 filter, with a 60–90-minute installation estimate. Its California status fields conflict with the historical EO reference, so confirm current vehicle-specific status directly before purchasing. Keep that fitment/legal check separate from deciding whether the kit’s mechanical configuration matches the car.
Sources 2
Remove stock assembly
Save settings; ignition off, disconnect negative. Remove cover, disconnect MAF and vent lines, loosen intake clamps. Release airbox grommets and harness clip; remove box and intake hose. Remove lower support bolts. Transfer MAF and grommets.
Sources 1
Build replacement
Fit grommets to shield. Stack original screen/gasket on adapter, then shield/second gasket; attach tube and MAF. Fit throttle coupler. Place supplied rubber/fender washers on mounts, seat assembly, connect coupler and secure with original bolts.
Sources 1
Finish
Reconnect vent lines with supplied clamps; for two-line cars, cap/clamp unused port. Fit filter, reconnect MAF, cover and battery. Inspect clearance/fasteners. Start in Park with brake applied; correct leaks/noise before road test and investigate rattles.
Sources 1
Document the exact branch
Write “automatic branch, non-EU/UK procedure” in your installation notes together with the original vent-line count and kit number. That detail helps a future owner distinguish this arrangement from an RX-8 with the vacuum-switch hardware covered elsewhere in the instructions. Keep all original parts together; do not mix spare branch-specific components into the vehicle simply to empty the kit box.
Products in this guide
Sources / references 2
- K&N 69-6030-1TFK instructions ↗Reviewed Oct 9, 2026
- K&N 2004 RX-8 application ↗Reviewed Oct 9, 2026
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