Rennlist - Porsche Discussion Forums

Porsche 993: Exhaust Modifications

There are plenty of ways to boost your Porsche's sound without spending a fortune. Even the most novice DIY-er can tackle these exhaust modifications.

By William Henderson - March 20, 2015

This article applies to the Porsche 993 (1993-1998).

Modifying your exhaust is an easy way to increase your power, reduce your car's weight, and give your car that classic Porsche sound. You can try something as simple as disconnecting the vacuum line from the flap plug, or go for a more involved mod and replace your stock muffler and exhaust altogether. These aren't tricky or even difficult mods, even for the novice car owner, and not all of them will cause your neighbors to run for the hills every time they see you coming.

Figure 1. Porsche 993.

Exhaust Modifications

Secondary Catbypass Pipes

DIY Cost – $750-$900 for parts

Professional Cost – Between 1.5 and 4 hours plus parts

Skill Level – Moderate; you must remove your stock catalytic converters

Replacing stock catalytic converters with the less-restrictive straight-through pipes improves flow and performance. This modification can add up to 10-wheel horsepower and increase throttle response. It creates an exotic and aggressive exhaust note. Some secondary catbypass pipes directly bolt on and are lighter than the stock catalytic converters.

Muffler Bypass Pipes

DIY Cost – Between $450 and $650 for parts

Professional Cost – Likely around two hours of labor plus parts

Skill Level – Moderate; you must remove your muffler and then install the bypass pipes

Replace the factory mufflers for improved flow, and create a louder sports car sound without significantly increasing your power. Increases horsepower by 20 whp. Some Porsche owners who made this mod say installing muffler bypass pipes creates a flat-six exhaust note with “plenty of growl.” Muffler bypass pipes are lighter than your muffler, and removing it reduces car weight by approximately 30 pounds.

Have Sport Mode Sound Without Selecting Sport Mode

DIY Cost – $0

Professional Cost – Likely just labor, but your mechanic may charge you a flat fee for work that takes less than an hour to complete

Skill Level – Easy; you don't need tools or experience modifying your car

By selecting sport mode, your engine management system responds more aggressively when you press the brake or gas pedal. It also changes how your car sounds when you drive. A simple mod lets you sound like you’re in sport mode without actually being in it. Remove the vacuum line to the flap valve. This controls the second set of pipes. Plug the vacuum line with a golf tee, and then ziptie it out of the way.

Exhaust Tips

DIY Cost – Between $300 and $550

Professional Cost – Upward of two hours of labor plus parts

Skill Level – Moderate; you may need to weld them on

Installing exhaust tips won’t improve your ride’s performance or even affect how your car sounds, but installing them can improve your car’s overall sporty appearance, as long as you keep them shiny. Some aftermarket exhaust tips clamp on, which minimizes how much time installing them takes, but you may need to weld them on. The type you choose depends on how savvy you are with DIY projects. There’s really no difference in the final outcome.

Related Discussions