Performance Exhausts for Volvos: Theory and Practice
If you care about getting good performance, mandrel bending is important. Mandrel bending is bending the pipe such that the cross sectional area remains a perfect circle, as opposed to be distorted to an ellipse, which has a smaller cross sectional area, which also has poorer flow characteristics. Well, I have a feeling the “sound” is for those that are looking to change the sound of their exhaust.
For example, my Volvo 850 now sounds much deeper and more refined. A “dual conversion” will be for those that have a single pipe and want a dual exhaust outlet. The majority of the time, this occurs right at the very end of the exhaust stream, so it makes little to no performance difference. “Glaspac” is something used in mufflers for silencing. Imagine I took a 3? pipe and punched regularly spaced holes throughout the piping for about 14?.
I then put an 8? pipe around it. I then packed the glasspac (basically a form of fibreglass) between the inner 3? pipe and the outer 8? pipe, then sealed both ends. This is now a straight through silencer.
Performance Exhausts — Where to Go?
As for Meineke and Midas, these places don’t do custom performance exhaust work. They don’t mandrel bend their piping, use baffled silencers as opposed to straight through. I recommend going to a shop that specializes in high performance exhaust work. They use mandrel bent tubing, are experienced with dealing with clearance issues with using larger then stock piping, as well as performance friendly such that when you decide to do other mods which might conflict with the ones you already have, they are usually happy to help out.