Behind the Scenes
For most Corvette owners, spending time behind the wheel of America's most timeless sports car is food for thought while we grind through our 9-to-5. The moment the clock hits 5:01, we're out the door and aching to pound the pavement and feel the rush of 16 valves coming to life as we hit the onramp.
We know it sounds dramatic, but hey, that's why one invests all those clams in Chevrolet's fifth iteration of the Corvette, and if there's one thing we know about Duntov's followers, it's that they can never have enough of two things: horsepower and torque.
In search of both of the aforementioned underhood goals, we took a trip to Southern California-based BBK Performance Inc. for a little schooling on LS1 intake improvements. BBK has made a serious name for itself as a premier supplier of aftermarket throttle bodies to America's injection-wielding gearheads. According to BBK, it has dozens of applications for trucks, domestic autos and sport-compact vehicles. Over time, its product line has increased to include fuel system components, cold-air intake systems, exhaust products, intake manifolds, suspension components and various other performance engine bolt-ons. You may remember Andrew Sivori's 1999 C5 from our AFR 205 install (December 2005 GMHTP). Back then, Andrew's Vette made 356 horses at the wheels with the AFRs, a cold air intake, mufflers, and a custom SP Motorsports tune. This test, which would be done on a different dyno, included the above mods minus the cold air intake, as the stocker was put back on so we could accurately test the BBK unit.
As most of us know, combustion engines run on three basic elements: air, fuel and spark--the trick is knowing how much of each we can introduce, and in what proportions. To better improve our LS1's power and torque we installed BBK's new LS1 SSI Series aluminum intake manifold, larger 80mm Power-Plus throttle body and Cold Air Induction System. If everything goes as planned, the combination of all three components will provide a great show on BBK's in-house dynamometer.
How It All Works
As magazine editors, we always have to ask why: what made BBK's products produce an improvement over the stock components? To answer this, we turned to BBK President/CEO Brian Murphy. Cast from aircraft quality 356 T6 aluminum that is powder-coated, then CNC-machined to final specs, BBK's new intake manifold offers LS1 owners increased runner velocity, improved flow characteristics, physically larger port openings, and a 15 percent improvement in flow over Chevrolet's stock LS6 intake manifold. Other unique features include a weight-saving removable bottom cover plate that allows direct access to the runners for easy porting or nozzle routing (for the stroker/blower/NOS crowd) and an O-ringed EGR block-off plate for Corvette models, said Murphy. In addition, BBK's SSI manifold comes standard with an 85mm throttle body opening that accommodates BBK's available 80mm (street applications), or 85mm throttle body (for race or forced-induction applications). Since Andrew's C5 is still a naturally aspirated street driver, BBK recommended its 80mm unit to kick up the mid range and top end power without sacrificing the all important low end grunt. According to Murphy, the last element of the BBK intake package is its Cold-Air Induction System, which frees up the intake on the other side of the mass air meter. "In this chain of induction components, all play a major role in allowing the LS1 to breathe heavily. Especially with a combo like Andrew's where the cylinder heads ingest much more than the stock components are capable of feeding."
After installing BBK's line of C5 components we came to the conclusion that fit and finish were excellent, and that the components were well packaged and included a comprehensive set of instructions. Only one question was left, and the answer could be told by our right foot and the Dynojet dyno.
On The Dyno
Before starting the installation, we brought our donor six-speed C5 onto the rollers of BBK's in-house Dynojet dynamometer for a lil' truth or dare. The results were a baseline of 327 horsepower and 335 lb-ft of torque. After about one-and-a-half hours under the wrench, we brought in expert tuner Robert Barth from Strictly Performance Motorsports to keep an eye on things in the fuel department during the dyno pulls. According to BBK, the stock fuel system will adjust for all three modifications, but additional horsepower can be yielded with custom tuning. As we expected, the installation of the intake, throttle body and cold-air-intake produced an additional 21 horsepower and 13 ft-lbs of torque across the chart.