What’s the Best Exhaust to Gain Extra Horsepower?

The hooligans of Mighty Car Mods believe the answer might lie in your kitchen pantry.

OK, sure, the vehicle in the latest clip from the online series Mighty Car Mods isn’t exactly a Toyota pickup or SUV, but it is an old Corolla, and engines all make power in more or less the same way. Exhaust systems only really exist to evacuate the exhaust gasses safely out the back of the car. Sure, there are ancillary functions, like muffling the engine’s exhaust noise and providing some level of backpressure for fluid dynamics — science-related reasons that nobody really understands. So, if you were to do a completely scientific test to determine whether an aftermarket exhaust system was capable of making more power, will it?

In the case of the car here, the MCM hosts first test the car with a stock exhaust system to set a baseline number, which is 49.9 Kilowatts (about 67 horsepower). Removing the stock muffler and installing one of those nineties-tastic ‘cannon’-style mufflers, they re-ran the car to test it out, making 51.4 Kilowatts (about 69 horsepower).

The third test involves again removing the muffler and replacing it with a straight piece of pipe that deletes the muffler altogether. While much louder, the straight pipe did not make much more power, just 51.6 Kilowatts. Because the straight pipe does not provide any back pressure to the exhaust system, they decided to test “spherical back pressure oscillation” by installing an almost spherical potato in the very center of the exhaust pipe’s outlet. The potato pressure run on the dyno actually pumped out 54 Kilowatts, making that the most significant power increase. The little Toyota started the day with 67 horse power and ended with that pumped up to about 72.5 horses, nearly a 10% gain.

Sure, skeptics will say that the car’s ECU was simply adjusting fuel delivery after repeated wide open throttle runs, or perhaps the combustion chambers of the geriatric engine were simply burning off some soot with the high RPM jumps. Who knows, maybe they make horsepower backward down under. What do you think about potato power? Weigh in here on the forums.