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.
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.
As for emissions, as long as you use a certified catalytic convertor, run both O2 sensors in the stock locations, and a silencer that silences enough, you will meet all emissions and sound level laws. Like I said, I have a 3″ downpipe back system, and I have yet to throw a light.
As for quality brands, I like Random Tech for their cats, but they are probably the most expensive. I’ve tried Vibrant Performance before and both in performance, and appearance both internal and external, without the Random Tech logo, you can’t tell the difference between the two, and the Vibrant Performance cat is WAY cheaper. As for piping, it’s basically all the same, but you may want to compare the piping used between shops. I found that the shop I used had slightly thicker piping, so I was pleased with that.
Exhausts and Rust Concerns
If you are really concerned with “I will less likely have a pile of rusted and burned out pipes under my car after a couple of years that once was called a performance exhaust system” then get T-304 stainless steel. It’s that simply, it’s either dry enough (no road salt usage) that you don’t have to worry about rust, or you don’t. BTW, short drives whether in cool or hot temperatures are even larger reasons for exhausts rusting out. Other things to consider are the quality/purity of the gasoline available to you.
In Canada, gas has a MUCH higher sulphur content than it does in the US. So just because you don’t get a lot of moisture or road salt or sea salt, doesn’t mean your exhaust won’t rust. The sulphur in the gasoline enters the exhaust stream in particulate form, and when dissolved in the condensed water that has condensed on the insides of the piping, becomes sulphuric acid, and acids rapidly accelerate rusting. That’s why exhausts rust from the inside out.
Put it this way, if you go with a T-304 exhaust, you will never ever have to replace your exhaust. It will DEFINITELY outlive your car. If a full T-304 exhaust goes for $1500 Canadian, then a full aluminized steel exhaust at the cheapest, will cost $1000 Canadian. Yes, that’s 1/3 cheaper, but I think it’s worth it. But then again, it depends on your driving habits, your climate, and how long you plan on keeping your car.
This Volvo Performance Exhaust writeup by “Sin”, circa 2001