More than likely there's very few of us gearheads who haven't made a circuit around the neighborhood (usually soon after the installation of a fresh engine) with our vehicle's exhaust uncorked. Neighborhood cats scattering in terror, little girls with fingers in their ears, and huge grins 'n' thumbs up from all the little "guys" were only a bonus in comparison to the satisfaction received from the throbbing rumble we enjoyed before headin' back to the garage to button up our exhaust systems. Too bad we don't have a volume knob on the dash so we'd have the opportunity to experience that feeling/sound whenever we cared to.
Well guys, your wish is Patriot Exhaust Products' command. The engineers over there are gearheads just like you and me, and the throb of an aggressive exhaust note is music to their ears too. That's why they've been working enthusiastically to bring to market a new muffler that'll tattoo a grin on all us truckers' faces! That's right, they've finally invented mufflers with a volume switch - the Varaflow.
Patriot's new Varaflow mufflers make use of new SFI technology - Sound Flow Inversion. Well, sound flow inversion is a bit too technical a term for me (invoking visions of listening to the stereo while upside down), so I cornered Don Lindfors, one of Patriot's sales managers, to help explain the term and here's what he had to say.
"As the name suggests, there's a valve within the muffler that changes the flow of the exhaust through it causing an increase or decrease in sound levels. As used in the new Varaflow, the driver, via the use of an electric switch, can open or close the valve to fine tune the sound - quieter when heading to his favorite cruise event and louder when he gets there and wants to show off a little.
"The DC servo motor mounted to the exterior of the all-stainless-steel muffler controls the valve and the change in sound takes about three to four seconds to occur. Sound testing was performed on a variety of cars with the following numbers generated by a mildly built 302 Ford in a '63 Falcon representative of all findings: At idle with the valve closed, 86 dB was recorded, while opening the valve increased the sound to 92 dB.
"At approximately 4,500 rpm in the closed position, the sound was 100 dB, and open it increased to 108 dB. For comparison, normal conversation is approximately 60-65 dB. A busy street corner is in the range of 70-75 dB. Cranking that iPod to max volume produces 100 dB, while the front row of a rock concert can be easily 110 dB (125 if it's The Who).
"The threshold of pain is 125 dB and instant perforation of the ear drum occurs around 160 dB. Normal human perception is a 10dB difference is twice as loud, while 20 dB is four times louder." For most applications you can expect to hear a 7-8dB difference between open and closed."
Well, it sounded good to us, but we wanted to check these things out for ourselves. So, with a shiny new pair of stainless Varaflows in hand we began the search for a likely candidate to do a muffler swap.
Well, as luck would have it, Publisher Tim Foss' '41 Ford had been scheduled for a new exhaust system within a week or so anyway, so we were good to go. We called over to our exhaust shop of choice (Josh Glendhill's - The Muffler Man, in Placentia, California) and asked him to pass on mufflers for the '41 and just run tubing front to rear instead. This way we could install a pair of Varaflows ourselves to check out. Well, a few days later the exhaust work was done and we in fact did install the Varaflows - and they worked just as well as advertised! Tim loves 'em, and so do we. So, let's take a look at the process - it was easy, the work great, and we love crankin' it up!
01 Patriot's Varaflow SFI mufflers come in a 21/2-inch diameter inlet and outlet configuration with an overall length of 24 inches. They're constructed completely from stainless steel and the sound absorption material is ceramic glass for long life. The included wiring harness assembly features pre-terminated connectors that plug into the motors on each muffler. The internally lighted switch is a simple two-wire hookup with one going to ground and the other to a 12-volt positive source.
02 The servo motors on the Varaflow are heavy duty and will easily withstand exhaust temperatures and the under-car environment, as well.
03 This less-than-perfect image shows a shot right down the barrel, so to speak. Here you can see the motor-actuated butterfly valve in its open position. The valve, as we said, is actuated by a dash-mounted rocker switch that allows the driver to basically turn up the volume with the touch of a finger. How cool is that?
04 After first hearing about the new Varaflow we decided that we wanted to give 'em a try and fortunately we came across a perfect test subject in the way of a SBC-powered '41 Ford. We brought the car over to our pal Josh at the Muffler Man in Placentia, California, and asked if he'd have time to run us a fresh new exhaust system - minus mufflers.
05 Once we explained to him the reason we were opting out of mufflers in this case he enthusiastically complied, as he was intrigued with the Varaflow concept as well.
06 As always, the Muffler Man wasted no time whipping up a fresh new custom 2 1/2-inch aluminized system for the '41...
07...leaving us with more than ample room for our subsequent Varaflow muffler installation.
08 We then buzzed the '41 over to the SIM Tech Center and the capable hands of our resident technician Jason (installation Jason) Scudellari and Patriot's own Don Lindfors to do the actual muffler install. After deciding exactly where in the system the mufflers would be located, Jason and Don held up the first Varaflow and marked the cut lines where they'd remove the sections of exhaust tubing.
09 Using a Sawzall, Jason and Don removed a section of tubing long enough to fit the mufflers.
10The pair made sure to leave enough tubing to fully seat in the muffler inlet and outlet without altering the length of the tailpipes - and so all the hangers and tailpipe exit positions were left unchanged, as well.
11 The guys started on the passenger side and then turned to the driver's and positioned the second Varaflow in an identical spot there as well. Positioning the mufflers an equal distance from the header collectors ensures the tone to be the same from bank to bank.
12 A quick deburring with a half-round file cleaned up the sharp edges left by the saw and ensured that the new Varaflows would slide on easily.
13 In order to get the mufflers onto the exhaust tubing the guys had to loosen the rear pipe hangers...
14...so the rear sections of the system could be moved rearward enough to slide the muffler outlets over them. It worked well, and the mufflers slid over the pipes without a snag.
15 With the Varaflows in place, the guys rotated them so that the servo motors faced the center of the car. This way the motors didn't hang below them and possibly snag on a road obstruction or bang against the floorboards if they were located further up.
16 As you can see, the servo motors are completely sealed from the environment and are high-quality units that'll withstand the vehicle's exhaust heat.
17 Each one comes with an integral wiring pigtail with a weather-tight plug for secure attachment to the switch harness.
18 Here's the switch and actuator harness. The harness is made with automotive-quality wire with a tough temperature-resistant insulating layer. The dual-connector harness terminates at a rocker switch and is of ample length to allow the owner/installer to position the switch within easy reach of the driver.
19 Wiring is a snap, both figuratively and literally. All one needs to do is snap the plugs into the pigtails of each servo motor and then pick an unobtrusive route to the vehicle's interior (securing the wiring prudently during its routing).
20 The final step is locating the momentary rocker switch. This is left up to the owner/installer to determine. The switch's small size and handy design allows for a multitude of installation location choices, and the harness' integral inline fuse protects the system (both the vehicle's and the Varaflow's) from any kind of overload. All in all, the install was a snap (especially since Jason and Don did all the work), and with the aid of a drive-on lift, it took all of about an hour to complete - though you could more than likely add another half hour or so doing the job on your back. But, we have to say, standing up or layin' down, the Varaflows sound great both open and closed, though we do have to admit we like 'em open more!
The Muffler Man
467 Industrial Lane
Patriot Exhaust Products