AFM Support Rod for Aftermarket Air Cleaners

[dkirk]

During the winter when my 911 was hibernating, I performed the following modifications to the AFM (Air Flow Meter):

3.2 Carrera Air Flow Meter Modification

My stock inlet air filter box has been replaced by the AireTEK filter duct and low restriction element, as sold by our sponsor. The stock filter box provides support for the AFM in that it attaches via a rubber mount to the right side intake manifold. This support is lost when the aftermarket system is installed, allowing the AFM to drop to the point that it actually touches (and potentially rattles against) the intake manifold. Additionally, the now-unused intake manifold boss interferes with the conically-shaped air filter.

My friend and fellow '88 Carrera owner Brian Kearns came up with an elegant solution. It comprises a support rod, made of .124 diameter stainless welding rod that attaches as shown in the following picture:



The left side of the rod (difficult to see in photo) attaches to the rubber mount that supports the constant idle motor. This maintains full rubber support of the AFM. The rod, sized to be in tension, exerts the proper force to keep the AFM level and away from the intake manifold:



I replaced the conical air filter element that came with the AireTEK assembly with a K&N RU-2520 element (another Brian Kearns discovery), slightly shorter than the original. This reduces filter area slightly, but calculation shows there’s still about 15% more area than the stock filter. The close proximity of the element to the intake manifold boss was still disconcerting, so I fabricated a small bracket to provide support, and make that boss a purposeful feature again:



The modification only adds a few grams of weight and is almost invisible to the casual observer:



It’s great to have my 911 underway again. Started right up and ran perfectly after removing from storage. And, not a single drop of oil stained the clean concrete under the engine for the entire 4 months of non-use!