Introduction to Exhaust Systems
The cat back exhaust system is possibly the best place for a beginner to start. Thankfully, this type of modification
usually will not affect mileage, emission or drivability very much unlike many hp mods. It is the perfect mod to start
with, it looks and sounds cool, to you, the performance addict that you are.
The stock exhaust system that comes on your Celica was not designed for power or looks as a priority. It was designed to be
as cost effective and emission friendly as possible. Things most people want, but not you, the performance enthusiast.
The Muffler
To produce the most amount of power, an exhaust system should restrict exhaust flow as little as possible. The more restriction
means the more backpressure which causes the engine to have to work harder to pump the exhaust gas out of the engine. Your
stock muffler can create up to 18 psi of power-robbing backpressure. Whereas a well designed muffler typically has about 2-6
psi of backpressure. The Best type of muffler should have a straight-through perforated core design. Stay away from louvered
core mufflers. The louvers generate a lot of backpressure because they stick into the exhaust stream, creating turbulence.
These types of mufflers can actually create more backpressure than a stock baffled muffler!
When looking for a straight-through muffler, look for one with a perforated core if you are interested in producing more
power. A good sized perforated muffler, such as an Apexi, Borla, Tanabe, Magnaflow provide good low back pressure mufflers.
Exhaust Tips
Many people like to add big exhaust tips, but this does nothing when it comes to performance. If you are on a tight budget
add the big tip after you get a performance exhaust. You don't want to look like an amateur. Although some tips come with a
resonator that quiets the exhaust note. They are actually functional. So don't worry, no one will ridicule you when you show
up at the track.
Pipe Diameter
It is important to not use a pipe diameter that is too large for a variety of reasons. An exhaust pipe that is too large
can cause a loss in power, especially in low end torque. Because a big pipe has less exhaust stream velocity than a small
pipe, and exhaust stream velocity is essential in creating a vacuum behind the closed exhaust valve. That vacuum helps pull
out more burned exhaust fumes, which increases efficiency and power. The only exception to this rule is Turbocharged engines
and engines running NOS, because of pressure differentials.
