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Installing New Mufflers And Exhaust Pipes - Stuff It

New Mufflers And Exhaust Pipes Make For Sound Performance

Eddie Paul Apr 1, 2004
Corp_0404_01_z Installing_new_mufflers_exhaust_pipes Fixing_muller_exhaust 2/11

When my editor called and asked me to install a set of Flowmaster mufflers in an '86 Corvette project car, I almost told him, "I would love to but I have to do something more pleasant, like have a root canal." Unfortunately, I couldn't come up with a believable excuse so I reluctantly agreed. My initial hesitation wasn't because I was busy (or liked dental work), it was that I have never found a muffler or tailpipe installation to be "just a half-hour job," as my editor promised. But I am big enough to admit when I'm wrong, as was the case with this install. It was a snap.

Corp_0404_02_z Installing_new_mufflers_exhaust_pipes Decibel_meter 3/11

Our Radio Shack decibel meter set us back around $50.

I rounded up the best guys in the shop, John Forseth and Bruce Busick, and told them we'd be busy for a few hours because I thought the mufflers wouldn't fit and I had to photograph each step. We were prepared for a few hours of knuckle-busting fun.

We hoisted the car on our trusty Bend Pack lift and started by unboxing the new parts for inspection. The kit included a set of Flowmaster mufflers, a Y-pipe, and two 211/42-inch muffler clamps. We tested the old bolts at the rear of the mufflers and prepared to use penetrating lubricant if need be, but found the bolts were easily removed without the use of chemicals. We used a tall jackstand at the rear of the muffler to hold it up, and released the front bolts. With seemingly little effort, the old muffler was free to be discarded.

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An impact gun is used after the bolts are loosened with a breaker bar.

At that point, I had photographed each step of the process from every conceivable angle and, after checking my watch, I found that only 15 minutes had elapsed since we put the car on the rack. Reversing the above process, we finished the job in a record-breaking 30 minutes. Everything went right into place as indicated in Flowmaster's instructions.

Corp_0404_04_z Installing_new_mufflers_exhaust_pipes Extension 5/11

An extension is needed to reach and remove the muffler bolts.

Sound intensity is measured in units called "decibels." The decibel scale is logarithmic and climbs steeply; an increase of around 3 decibels is a doubling of sound volume. In the wilderness, a typical sound level would be 35 decibels. Speech runs 65 to 70 decibels; heavy traffic generates 90 decibels. By 140 decibels, sound becomes painful to the human ear.

Our project car produced 80 decibels at idle with the original dead mufflers and 90 decibels at 3,000 rpm as measured from 10 feet behind the car. With the Flowmasters, the decibels at idle were 85, and 95 at 3,000 rpm, an increase in the overall sound. More sound generally indicates more horsepower by less restriction of the exhaust, which usually means better fuel mileage is on the way.

The new sound is certainly more performance-oriented, and interior noise is not objectionable. Frankly, we like it, and the new, nonrusty exhaust tips are clearly a major improvement.



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