Hey guys

Im new to the whole loud exhaust club but I was wondering

Going from a stock exhaust to a 2.5 inch custom exhaust, the guy who fit it tried his best to create a system without any droning and a relatively quiet system, but my ****in god its loud.

How long does it take for carbon and whatever to build up and does this quieten the system and stop the droning slightly?

Going by how you explained the sound I doubt carbon build up will make it ok for you.
What muffler did you add? Straight through mufflers are very loud and will always be loud.
You can quieten it down and get rid of a lot of drone by adding additional resonators.
Is yours a 4 cylinder?

Nah its a v6

And its a straight through muffler, that might be why, he added what he called a baffle plate or whatever to reduce droning which is fine, but its just loud

The only way to reduce sound / drone is adding more mufflers. or larger mufflers, you should keep then all straight through for performance.

A quick lesson in exhausts:

Loudest exhaust is a straight through pipe with nothing added. Totally illegal for street use.

Add a straight through - which is basically a pipe drilled with many holes inside a chamber, the chamber being packed with some sort of sound dampening material. (Which packs down, or gets burnt up and blown out). A straight through can only get louder with age.

Adding a resonator - which is basically a straight through tuned to a dampen a certain frequency of exhaust impulses - will quieten the maximum noise down a bit, and may even reduce drone. Adding more resonators and straight through mufflers will reduce noise, but by the time you get it down a standard sound level, you have added a lot of weight and probably have the same back pressure as a standard resonator/muffler setup anyway.

A proper exhaust box has 3 pipes, drilled with many holes. The gases make a circuitous path through it, to go out the exhaust tip. The holes in the pipes allow some of the gas pulses to escape into a dampening material.

Basically, you want the exhaust gas pressure pulses to be converted to a steady stream by the time it gets to the exhaust tip, for the system to be really quiet. Only back pressure will do that, which reduces engine performance.

So you can have either a loud system, with resonance peaks (the drone) for good performance, or a quiet system with reduced engine output. There is no magic combination of quiet with performance, but I bet Mitsu have designed the original system with the best compromise possible.

Hrrmm I guess I'll be happy with my new exhaust then, it is pretty decent.

Lol, reading this made me smIle on my 91 TR 4Cyl, I have extractors witch split two cyls to each pipe then return to one at the back I have a 100 cell cat and no resinator but have a straight through muffler the more you rip the throttle the more you will melt the fiber glass thats in the mullfers causing it to get deeper aka louder, one way to totally make it not rear drony is to add a pod filter to a boxed area under the hood

There is no way on gods green earth that im putting one of those stupid pod filters in my car, I hate them with every fiber in my body, they make a car look like the whitest grain of rice you'll ever lay eyes on

Having said that though, im switching out the straight through shortly, found one that fits my requirements