I worked with Tom Hand and owned Waldron's Exhaust when we re-introduced the VOE mufflers.
There IS a performance improvement when switching from quiet mode to open mode, but even in open mode the VOE mufflers do not flow as well as current "straight-through" performance mufflers. (e.g. Goerlich XLerator, Dynomax UltraFlo, Magnaflow Universal Performance, etc).
In our dyno tests, "open" mode test results showed approximately 10% higher peak torque readings and 5% to 7% higher peak HP readings than "quiet" mode. With the best "straight-through" performance mufflers, we realized an addition 5% increase (above "open" mode levels) in both torque and HP output.
In open mode, the VOE mufflers performed about the same as a typical "turbo" muffler design. Quiet mode test results were equal to the results achieved with a typical OEM muffler.
The mufflers and the internal valves are constructed of stainless steel and I am not aware of any units that have stopped working due to soot or heat. The vacuum actuator that controls the valve function is a serviceable part that can be quickly and easily replaced if it fails. If the vacuum actuator does fail, the muffler defaults to "quiet" mode.
I ran a personal durability test with a VOE muffler on my full-size GMC pick-up, including Michigan winters with typical salt exposure. I had no issues with the muffler functions. I probably had about 35k miles on that muffler when I sold the truck.
1968 Pontiac GTO
1983 Pontiac Bonneville (G) wagon
2008 Pontiac G8 base
Last edited by jmt455; 03-26-2012 at 11:09 AM.