We've all heard the old gearhead adage "Louder is power". And, for the most part, it holds true; rip the stock exhaust and airbox off an older car and chances are it will make more power on the dyno... and be a hell of a lot louder on the street. Increased airflow equals increased power, and increased noise is a by-product of that. But for certain mildly tuned street cars, can there come a point where excess noise is simply excess? Can a car make impressive power and still remain quiet enough to ward off unwanted attention?
Does "More Noise" Always Equal "More Power"?
Minding the largest contributor to vehicle "noise pollution", a car's exhaust, we took our project DC2 to the rollers of MD Automotive's Dynojet dynamometer to see how three different exhaust systems impacted power production. Blowing through three different exhausts for three runs each--an OEM-spec stock replacement system, our "two-ticket" (for obvious reasons) custom straight-through, three-inch cat-back system, and finally a low-key, low-decibel APEX'i Noir cat-back--here's what we found:
Staying Legal Or Staying Lethal Doesn't Have To Be A Choice
The Verdict:
As suspected, the OE-spec muffler system--the quietest of the three--weighed in with the lowest power numbers. And also as expected, our straight-through, one thousand-or-so decibel three-inch system posted the largest gains. But, surprisingly, A'PEXi's Noir managed to produce nearly the same peak power, and even more peak torque, while keeping noise levels nearly the same as the stock system. The secret lies in the design of the APEX'i unit; a baffled, canister-style muffler for increased sound absorption, but one that's far less restrictive than stock systems, coupled to larger-diameter piping for increased flow. Add to that A'PEXi's optional exhaust control valve (ECV) for race or high-power applications, and staying legal or staying lethal doesn't have to be a choice.