In the past several months I have seen a number of “HOT ROD” 911s all complaining of various abnormal noises. These noises have been described as anything from cam chain noise, to 5th gear noise, to ring and pinion noise. Are all these cars just getting noisier? Are gear surfaces failing? Or are these owners just becoming less tolerant of an inherently noisy car? Well no, most likely not. All of these cars have shared one common factor. They all had solid engine and/or transmission mounts recently installed.
In many of the cases, one pair was installed a month or so prior to the second pair, causing the gear noise to “become progressively worse”. In reality, the gear noise did not change at all. It was the insulation between driver and drive train that changed.
You might ask yourself why someone would intentionally install a device into his or her car that would make it so unbearable to drive? The answer is quite simple. Solid drive train mounting has many advantages; increased chassis rigidity, increased throttle linkage feel, more positive shift feel, indefinite mount life (no rubber to deteriorate), and low price (about $25.00 per mount).
The one sizable disadvantage, however, is the incredible increase in drive train noise and vibration. Such an increase for a dedicated racecar is not a real problem. For a car that serves a dual role as both street and track car, it can be a large one.
Fortunately there is a compromise between the soft stock mounts and the completely rigid, solid mounts. The compromise is a factory mount known as the Carrera “CLUB SPORT” mount. It was designed for the Carrera “CLUB SPORT” option (M637). This car was essentially a lighter, high performance, stripped version of the standard ’87-’88 Carrera. The premise was to build a car that was set up for club racing right out of the box. This is the car where our compromise component comes from. The (M637) engine mounts are considerably stiffer than the stock mounts, yet still offer some dampening not available from solid mounts.
So you’re thinking, ” A limited production racing part, it’s got to cost a fortune.” Well, sit down because you’re not going to believe this. The stock cushy motor mount part #911.375.043.00 lists for $83.45. The (M637) “CLUB SPORT” mount part 911.375.043.07 lists for $41.70. Yes, that’s right, twice the part, half the price! A true Porsche rarity!
So if you have just got to have the ultimate in rigidity, go out and buy yourself a set of solid mounts. If you want more rigidity but don’t want to feel as if you’ve been placed inside the drive train, try some club sport mounts. After all, life is just a series of compromises, isn’t it ?
P.S. If you have a convertible you don’t need to upgrade to these mounts because the factory did it for you!