26 Aug 2016

Before starting on the ducting there’s something that’s been a bit of a nuisance, but first some back story:

Honda FWD drivetrains use four engine mounts. The left and right mounts near the front pulley and rear of the transaxle support the drivetrain weight and are designed to filter out vibration during steady-state driving. The front and rear mounts on the other hand handle  engine torque. After one mount broke, aftermarket mounts were swapped in even though I’d heard they introduced more vibration, and boy did they, bad enough that OEM units were swapped back in for the weight-baring units, leaving aftermarket units to handle the torque.

Because the car was designed around OEM mounts, the front aftermarket mount didn’t fit and had to be redesigned, while the rear mount was pretty much forgotten about. When the engine was last removed, the rear engine mount was badly distorted, but when the engine went back it, it looked fine and was left as-is. Well all that turbo torque again severely distorted it. When the engine drives the car forward, it tries to rotate backwards, trying to lift the front mount and compress the rear mount. I thought the front mount could handle it but the engine was still rotating, trying to compress the left and right mounts and compressing the rear mount even more, so it had to change.

The correct material is probably stiffer polyurethane but I had a chunk of Delrin, probably not the best choice but it was on-hand. The hole is offset because that’s where the drivetrain wanted to sit with no torque on it. Haven’t driven the car yet and there will probably be more vibration under hard acceleration but so be it.

In other new, this weekend my brother is in Virginia City, Nevada, for their annual hill-climb. He’s got a good chance to place really well since his car is pretty much perfect for something like this. Sure, some of the other hardware is faster, but it’s likely the owners aren’t willing to push them due to a combination of inexperience and fear of bending their very expensive toys.