Is this a trick question?
Yes, kind of.
The answer depends on the specific type of dual exhaust system to which you are referring.
Dual-Exit Exhaust Systems vs. True Dual Exhaust Systems
Dual-exit exhaust systems are basically a twist on the common single exhaust.
These systems utilize the same configuration as a single exhaust system—one headpipe, converter, and muffler—but have two exhaust tips exiting from the muffler.
There is no real performance advantage to this design, but some hot rodders prefer the added styling of the dual tips.
What is a True Dual Exhaust?
In the world of high performance, true dual exhaust systems are probably the most popular configuration. In this setup, two separate exhaust pipes run all the way back to the exhaust tips. In addition, there are two converters and two mufflers.
A true dual exhaust system does typically yield more horsepower and torque because it’s able to expel gasses more efficiently, which leads to better airflow and combustion. Dual exhausts typically work well with other aftermarket mods like cold air intakes, performance tunes, and headers.
Many people prefer this design because of its sporty look, the distinctive growl of the dual mufflers, and the high-flow capabilities of two separate exhaust passages for each bank of engine cylinders.
But wait, there’s more!
Why a Dual Crossover Exhaust System Might be Best
There’s also the dual crossover system, which is where the performance gains are really made.
These dual exhaust systems add in a crossover pipe (AKA, an H-Pipe or X-Pipe) that mitigates the uneven pressure that can occur between the two sides of the exhaust system. The crossover pipe allows exhaust gases to flow freely between the two sets of pipes, balancing out the exhaust flow and eliminating excess backpressure on one side.
That’s why the dual crossover exhaust is generally regarded as the highest performing exhaust system among automotive enthusiasts.
No matter which configuration you choose, there are other factors that will play a role in how your engine power increases, including engine size and other performance modifications.
Didn’t really answer the question