Putting the accomplishments of Group A Autosports and its all-motor Skunk2 Racing Integra into perspective takes some work; it is difficult to put into words the enormity of running 10s in a front-drive vehicle that displaces a mere 122 cubic inches and flexes no power adders whatsoever. I remember a test-n-tune session before a race in Sacramento about three years ago.
In one lane there was an impressive Plymouth Barracuda with bright purple paint, meaty slicks out back and a "rumpity rumpity" cam'd V8 pulsating under the hood. The car was loud and filled the air with smoke while in the burnout box. Its foe was a beaten-down '92-and-up Civic with a big cooler up front and a missing headlamp for ducting. The race was an utter annihilation, but it was the V8 guy who drove down the return lane and kept going all the way home. The 'Cuda ran a 12 and change while the turbo Honda blasted an 11.0. I remember thinking, "I bet that guy now believes there is a replacement for displacement" referring to turbos.
What would the 'Cuda pilot's excuse be for getting broken off by a naturally aspirated Honda with about one-third of the displacement? He'd likely be digging deep for one. Additionally, the Skunk2 Integra recently strung together four 10-second passes in competition. Of course, there is a gaggle of 12-second, all-motor Hondas who could bring Mr. 'Cuda to tears as well. Place it in context you say? Put it this way, at the November '99 IDRC race the 11th qualifier in the Turbo Magazine Quick 16 ran a 10.91 so at the same event where Skunk2 ran its 10.9, the all-motor car would have qualified to run with the turbocharged cars. That's impressive.
There are four keys to building a quick all-motor Honda-weight, power, traction and weight. Yes, weight is important to any drag racer, but the all-motor racer has fewer ponies to use so he must maximize the pulling power. Some 700-horse turbo racers will light up the tires off the line and make up for the loss at the top end, a luxury the all-motor man doesn't have.
Since he is making less torque, less violently it is possible for the all-motor racer to nail some impressive 60-foot times but turbo cars have kept pace with bigger slicks and the advent of wheelie bars. No matter how you slice it, running consistent 1.55s will get it done and that's the kind of 60-foot times Tony Shagday is coaxing from the Integra.
Weight savings was an overriding aspect of Group A's development of the 1995 Integra RS. The body was picked clean and lightened to feather-like proportions with carbon fiber panels and a one-piece nose from MB Products of Bakersfield, Calif. The uni-body was seam welded to enhance rigidity and the car's eight-point roll cage was constructed of super-light chrome-moly tubing.
Beyond that, weight was a consideration for most every component on the car. The result is a car that tips the scales at 1,750 lbs with driver. Despite being light, a stout suspension is still needed to maximize traction. The Group A crew employs leading edge Koni 3012 aluminum race shocks and its own Skunk2 racing springs to claw at the track. The suspension works in tandem with 22x9-inch M&H slicks, 13x8 Bogart Racing Pro-4 wheels, an Advanced Clutch Technology (ACT) clutch and Pro Drive spool to jump the car off the line.
Thrust is the ultimate weapon in defeating the quarter mile. Group A has squeezed impressive power from its B18C GSR powerplant. The key to making all-motor power is airflow. Since there is no turbo blowing air through the intake, an all-motor engine must get as much air inside it as possible using only atmospheric pressure-the more air, the more potential for power. Group A has addressed both air volume and air velocity with extensive cylinder head development and by testing a myriad of cam profiles in search of the perfect package. Group A ported the head using techniques gleaned from hundreds of runs down the 1320. The head was then fitted with Skunk2 race-spec cams specially ground for all-motor mania, Skunk2 valve springs designed to rev to stratospheric engine speeds and heavy-duty retainers. Adjustable Skunk2 cam gears were also added so the Group A crew could precisely dial-in the power curve.
The foundation of the Skunk2 powerplant is a BRE moly block that is reinforced with chrome-moly sleeves. Inside, the B18C was stroked to 2.0 liters via a modified stock crankshaft. To stroke an engine the rod journal is moved outward from the center axis of the crankshaft, thereby increasing the diameter of the circle the rod journal makes as it spins inside the crankcase. This in turn increases the distance that the rod/piston combination has to travel. The lengthened stroke affects two aspects of the engine's operation. First, displacement is increased.
Displacement can be measured by pouring liquid in the cylinder and measuring how much liquid is needed to fill the cylinder. This is done with the piston at BDC (the lowest point in the cylinder). Its volume is measured in cubic centimeters, liters or cubic inches. A modified crank will position the piston lower at BDC thus increasing displacement. The second area has to do with controlling clearances within the cylinder. Since the piston also travels farther up in the cylinder, it can swing up and out of the cylinder or up enough to contact the valves (depending on head design). There are three ways to correct this. Run a shorter rod, move the piston pin location or add to the deck height of the block. The Group A used both the rod and modified piston pin methods to ensure its B18C maintained proper clearances.
The reconfigured crank spins custom Skunk2 forged rods and Skunk2 pistons, both of which are constructed to Group A specs. Compression has been bumped to 13:1. To further enhance airflow, induction is handled by an individual throttle body set-up featuring TWM components. When the ultimate goal is moving mega amounts of air into the engine, evacuating spent gases becomes an important issue as well.
After trying several custom headers, Group A decided to take matters into its own hands and developed a one-off racing header. All R&D and fabrication efforts were conducted in-house and the result was a header that provided dramatic power increases over previous designs. It's difficult to argue with 10-second timeslips.
Engine operating parameters are under the control of a Skunk2-spec Racing ECU while the VTEC effect is custom tailored by a Fields SFC-VTEC Controller. Fuel is provided by 440cc RC Engineering injectors and lit off by an MSD ignition. Dyno tuning prior to the February 2000 Battle netted impressive horsepower from the 2.0-liter but Group A was unwilling to release the power figures. Unfortunately, Battle was rained out for the first time in its 10-year history.
Group A is considering creating a crate race engine program where competitors lease a Group A-prepped powerplant and hit the strip. The company is also working on Project Alpha, a Pro-Street Civic that is slated to have its debut in mid-2000. In the meantime, the Skunk2 Integra is primed to continue its 10-second charge on a nationwide basis in 2000. Look for this purple all-motor monster at a drag strip near you.
|POWER TECHNIK |
|VEHICLE ||1995 Acura Integra RS |
|BEST E.T. ||10.91 @ 123 mph |
|ENGINE ||B18C |
|DISPLACEMENT ||2.0 liters |
|COMPRESSION RATIO ||13.0:1 |
|FORCED INDUCTION ||None |
|INTERCOOLER ||None |
|NITROUS OXIDE ||n/a |
|FUEL SYSTEM ||High-flow pump,regulator, |
|440cc RC injectors |
|IGNITION SYSTEM ||MSD |
|AIR INTAKE ||n/a |
|EXHAUST ||Skunk2 header |
|BOOST CONTROL ||n/a |
|ENGINE MANAGEMENT ||Skunk2 ECU, |
|Fields SFC-VTEC Controller |