You may have noticed many owners of the 92-95 Civic hatch’s drill holes in their rear bumpers. This is due to the rear bumper acting as a parachute catching air increasing drag. They are called ‘speed holes’ that release pressure from the high pressure area created by the open area in the bumper. On the passenger side of the civic, the stock exhaust muffler / canister fills up this space, but on the drive side it is completely open leading to this issue.
Honda did create a factory solution to this, but it was only on the VX model of the EG hatchback, due to this model being mainly focused as a super fuel economic model with the d15 Vtec-E Motor. The thought behind this was a diffuser that covered the space allowed air to pass more freely thus reducing drag and giving slightly better mpg.
If your like me and don’t want to drill ridiculous holes in your bumper, finding the OEM rear diffuser for this is the perfect solution. My primary reasoning for this is slightly better aero performance for use on track sessions. It’s also pretty cool that its a very rare part to come across these days as most people didn’t even know it existed except for the few people who owned VX models.
Luckily it fits all trims and I was able to find one on Ebay after months of searching, I will provide all the OEM part numbers for the diffuser and required hardware as well to make it work.
(x1) Rear Diffuser: 74663-SR3-H00
(x1) Screw, Tapping (6X16): 93903-46220
(x1) Grommet, Screw (6MM): 90666-SD9-000
(x3) Clip, FR. Spoiler: 60854-SB2-000
Diffuser and Hardware:
Diffuser with hardware mocked up in mounting locations:
White Plastic Gromit installed on frame rail
Diffuser installed with all clips in place.