Do Exhaust Tips Improve Sound?
Whether exhaust tips alone can change the sound of a car depends largely on the components used. Going from a 1.5-inch diameter tip to a 4-inch tip can make the exhaust note deeper but far less so than simply buying a new muffler. There are a number of factors to take into consideration, such as intended effects, budget and additional modifications.
Buying Factors
Though the main part of the exhaust note is determined by the mufflers, resonators, catalytic converter and pipe diameter, there are a few factors that affect sound at the tip. Tip size actually has very little to do with sound, unless you go to a much larger or smaller diameter. Smaller diameter pipe will restrict the engine, slowing the exhaust stream and decreasing engine noise, and a larger diameter tip will make the engine louder only if the original tip was a restriction.
Down-turned tips, particularly those that dump underneath the car, can deepen the exhaust note by bouncing sound off the ground and using the undercarriage as a resonator. The ground will absorb much of the annoying high-frequency sound from smaller displacement engines.
The only way to significantly affect exhaust register is with a tunable tip, such as those manufactured by SuperTrapp. These tips (originally designed for ATVs and dirt bikes) use conical or disc-shaped inserts to both alter the wavelength characteristics of the escaping exhaust and suppress the flames emitted by very short exhaust systems. These tips allow the user to tune the exhaust note slightly by inserting or removing disc spacers that act as a secondary muffler. This is the most effective option for exhaust note tuning, but considering the fact that they cost 10 times what the average tip does, it may be cheaper to just purchase a new muffler.
Length
On applications where it is possible to do so, like motorcycles and ATVs, lengthening the pipe by as little as 6 inches can drastically affect exhaust note. Doing so gives high frequency waves more opportunity to cancel out, allowing the long, low frequency waves to escape.
Installation
When installing tips with any kind of kick-out, try experimenting with the position before you settle on one. Tips designed for round tubing can easily be rotated by loosening the retaining screws and turning them. As stated, many engines sound better with down-turned tips, but try rotating the tips so they face outward, upward, and even inward to see what it sounds like.
After each adjustment, walk around the car while a friend revs the engine.
Turned-out tips will be much louder from the sides, and inward turned tips will move the sound dispersion further back so that it's only really loud when one is standing next to the rear bumper. If you desire an increase or decrease in sound, try rotating the tips so that they're at a 45-degree angle to the ground.
