As any gearhead surely knows, an exhaust system is more than just a means of directing air out of an engine — instead, it plays a key role in the combustion process and ultimately in creating (or losing) horsepower and torque. For an engine builder, the ability to put this to the test is vital, and for racers, the option to make adjustments to overcome the conditions they face is likewise important. For that reason, Burns Stainless developed their adjustable collector setup more than a decade ago, and while it hasn’t been talked about a lot (until now), that hasn’t made this offering any less useful over the years for those who desire and need it.

According to Roman, an adjustable collector would be highly useful for two things: one is for dyno testing, allowing you to swap out different sized venturi inserts, or “chokes”, to see how it effects engine performance and be able to quantify it right there on a computer graph. Secondly, if you’re a racer, you can adjust the collector diameter when moving to different altitudes or environs to alter the characteristics of the engine to maintain optimum horsepower and torque.

The B-TEC, as Burns calls this system (the system geared toward the dyno is referred to as the DynoSys), became popular in the early 2000s with NHRA Pro Stock teams, who were impressed by their dyno results and likewise in the added ability to make fine-tuning adjustments to their engine performance for any given scenario at the track.

With the B-TEC, you simply replace the venturi, which slides in and is cleanly sandwiched in between the B-TEC collector and a slip-on megaphone and held in place by bolts or springs just as you traditionally would on an un-welded header.

“As you choke this thing down, you can actually build more torque in the motor. You can imagine if it gets too small, though, I’m going to hurt horsepower, so the secret is getting that compromise between a broad powerband and not sacrificing power. Using our design programs, we can actually calculate some of these things. For the dyno guy who might be making some camshaft and cam timing changes, he can actually play with this on the dyno and adjust the power as he sees fit.”

These B-TEC headers are available in 2, 3, 4, and 5 into 1 configurations, and only add about 8 to 10 ounces of extra weight to each collector. A minimum setup includes a merge collector with an adapter neck, one venturi insert, and a special slip megaphone with reverse cone.

Pro Stock teams found early on that they could wring as much as 150 horsepower out of their 500-inch engines when the weather and atmospheric conditions would vary drastically.