Exhaust for dummies

[kamaqazi86]

So I've been thinking about an exhaust system for my car but I don't really know much about it. I've been searching around but havn't really found a good source of information about the basics.

I'd like to know how things work and what everything is doing before I jump into getting something. I also wanted to get a sense of what the effect of changing different parts of the exhaust system has and the different options out there on what can be done.

[Bomis]

You will find millions of threads about this specific subject....

[ase93]

Look at fabspeed.

[tom @ eas]

Originally Posted by kamaqazi86

So I've been thinking about an exhaust system for my car but I don't really know much about it. I've been searching around but havn't really found a good source of information about the basics.

I'd like to know how things work and what everything is doing before I jump into getting something. I also wanted to get a sense of what the effect of changing different parts of the exhaust system has and the different options out there on what can be done.

Here is a good place to start.

E90/E92 M3 Exhaust Systems Overview
http://www.m3post.com/forums/showthread.php?t=165145

This will cover most exhausts available for the S65, feel free to email me directly if you should have any questions.

[kamaqazi86]

Originally Posted by Bomis

You will find millions of threads about this specific subject....

Yea...like I said, I've searched around. I haven't found a much. Theres good stuff on what aftermarket exhausts are out there but I was hoping for a more technical understanding.

[Mahmood07]

Originally Posted by kamaqazi86

So I've been thinking about an exhaust system for my car but I don't really know much about it. I've been searching around but havn't really found a good source of information about the basics.

I'd like to know how things work and what everything is doing before I jump into getting something. I also wanted to get a sense of what the effect of changing different parts of the exhaust system has and the different options out there on what can be done.

Basically, changing parts of your exhaust system makes the exhaust gas leaving the engine more free-flowing. This, in turn, gives your car more horsepower. This is because the leaving gas isn't restricted as much when leaving from the engine through the tailpipes. The Middle part of our stock exhausts have 'cats' (catalytic convertors) which are used to remove toxicity from the exiting gas (environmental reasons). These cats also restrict the flow of gas, therefore resulting in less power. In our stock exhausts there are also 'resonators' which the gas passes through that makes the exhaust quieter and less raspy. This also restricts the flow of the exhaust gas, and restricts power.

If you are looking for just sound and a little bit more power, you can change the muffler. The muffler is the end part of the exhaust which is stuck to your tailpipes. If you want the most power possible, you can change the muffler and Mid-pipes to ones that is free flowing and have the least backpressure. If you remove your cats and resonators, you risk not passing emission tests and you will get a bad smell from your exhaust. Also, your exhaust will be very loud.

Also, the exhaust is a heavy part of the car, so it's an opportunity to save weight by getting light exhaust systems. The ones made from titanium and very light and save lots of weight.

[DOUT]

Headers - The pipes from the engine that lead down to the exhaust. Only the most hard core enthusiasts mess with headers one the E92 M3 - They barely gain power when naturally aspirated however the power gains can be significant with forced induction. (Supercharger).
Currently, the only headers on the market that I know of are RD Sport (Racing Dynamics) and Gintani.

Section 1+2 (MidPipes) - The easiest/cheapest way to add some power on the M3 is to get catless/high flow catted mid pipes. Many variations are currently available be it catless/catted/resonated/non resonated/titanium/SS
Akrapovic, Gintani, Active Autowerke, Supersprint, Challenge, many more...

Section 3 (Muffler) - What most people think of when the term "Exhausts" comes in to play. You can make some power by changing the muffler but not much. You can easily lose some weight back there too. This section will effect the sound your car makes most significantly.
Akrapovic, Gintani, Eisenmann, Meisterschaft, Active Autowerke, Supersprint, many more...