As the Red Dog Silverado presses on, it sometimes presses backward. We are all familiar with the substantial power gains found in a simple intake and exhaust change. Right! On an otherwise stock engine, the word would be minimal. But the more that's done to the motor to let it breathe deeper and longer, the more important these basic areas become. Since it's dumb to drive a street-driven piece without some sort of filtration system (to keep the big chunks out, at least), there's not much to be done to the business-end of the unrestrictive air intake, other than keeping as far away from underhood heat as possible.The popular "cold air" systems still place the intake end under the hood, though it is somewhat isolated from the heat. The hot setup is to move the filter end physically outside the engine bay so it can access the cool air stream, making sure that the ducting leading to the throttle body is non-metallic and therefore less susceptible to heat sink. By its very nature, the Silverado's exhaust system holds more potential for increasing torque and manufacturing horsepower. For the ready-to-wear market, the portfolio includes tubular (somewhat tuned) exhaust headers, high-flow catalytic converters, and a larger-diameter exhaust tract with a minimally restrictive muffler. Those with loftier goals, a bent for the truly custom creation and the proper equipment can venture even further.
This month, we revisit the Red Dog, with its hybrid branch of cast-iron exhaust manifolds, OE catalytic converters, and a Bassani Quiet Thunder 3-inch after-cat muffler and exhaust pipe. On Vinci Hi-Performance's rollers, these items plus the K&N FIPK intake produced an additional 10 hp and 13.3 lb-ft of torque. This time, Greg Warner at Vinci Hi-Performance fastens a Magnaflow stainless steel high-flow catalytic-converter system between the cast-iron and the Bassani.
In a hostile environment, the Y's smooth, ample pipes, and less restrictive catalytic converters were good enough for 10 hp and 11 lb-ft at the ground. These numbers, as well as the seat-of-yer-Levis return, are equally impressive. Throttle tip-in and slow-speed response are markedly improved. Pat the pedal and you get a crisp peel-off that just wasn't there before. The OE cats had 44,000 miles on them, not what you'd call trash-worthy. Could be they were beginning to get stuffed up, though. We wouldn't say that Magnaflow high-flow cats cry out as a double-throwdown, go-out-and-get-it-now piece, but when your hellcat is ready for an exhaust tract rearrangement, what could be more sensible?