Dirt is cool. We have no problem with dirt.Stroll through the underground parking garage beneath the SCC offices and most times you'll find at least one SCC project car caked in the stuff. In most cases, it's applied in a thin layer spread evenly across the car as if it were applied by God's own paint gun. Dirt keeps us sane. It eases our nerves.
For Southern California's George Scott, dirt is more than a relaxant. It's crack, and he's addicted. This in itself isn't shocking.
Then Scott launched his car three feet in the air and landed it in the middle of our photo shoot, spraying editors and expensive digital camera gear alike with sand and gravel. We wiped the grime off our faces and our camera lenses and asked him to do it again. And again. And again.
We fully expected struts shafts through the hood, but every time the WRX came back unscathed. Impressive stuff, we thought. Almost like he had done this before.
Scott is a founding member of the Gravel Crew rally team, a grassroots organization of rally and dirt enthusiasts. The car was built as a flagship prototype for the group's core contingent, Subaru vehicles built to run on pavement or in dirt, and handle both with aplomb.
Gravel Crew named the WRX convert-to-dirt concept Playcar, as sort of a prerunner for rallycross courses. It's three-quarters production-based racecar, but retains enough creature comforts to remain worthy of pavement.
At the WRX's soul lies an adjustable suspension system from Drummond Motor Sport using 50mm Gravel Spec coil-overs front and rear. These coil-overs, according to Scott, are the determining factor that really makes the car what it is. And they are the life support system that allows it to thrive on this kind of abuse.
The system uses proprietary springs and inverted 50mm strut bodies incorporating some of the largest pistons on the market. In theory, those huge pistons provide superior control and more precise adjustment due to their larger displacement and pressure areas and the inverted design increases rigidity allowing the struts the strength to handle the side loads created sliding sideways on both paved and gravel roads.
From its lowest to highest settings, the 50mm coil-overs cover a range of about 3.5 inches, though in most cases, Scott leaves them set high when driving on the street. He said the ride is not as comfortable as it might be if he lowered the car a bit, but this way he doesn't need to adjust it for instant off-road excursions or jumping exercises.
DMS also offers 40mm coil-overs for street applications and 60mm Super Struts for full race applications, though you may need to refinance your house to afford the latter.
The stock anti-roll bars were not replaced, and usually Scott prefers to run without the front, especially when competing. The DMS system includes quick-change camber/caster plates for easy alignment tweaks. "We run about 2 degrees negative camber in the front and about 1.2 degrees negative in the rear with a toe setting of zero," Scott says. "Sometimes toe is set positive in the rear for turn-in on tight courses."
Extensive chassis prep went into the car to allow Scott to push the monster DMS coil-overs to their full potential. The centerpiece is a full custom roll cage hand-built by Scott and the Gravel Crew. The template is a basic four-point design the Gravel Crew can install on any member's vehicle-or anyone else willing to pay them for their services. It can then be customized as needed.
In this case, the basic four points have been enhanced with numerous cross braces and extensions that were grafted directly into critical points along the unibody. Gravel Crew welded steel plates around the tops and across the fronts and backs of the front strut towers to handle the loads the DMS struts send through the chassis on one of Scott's "superman" excursions.
The crew then ran extensions from the A-pillar tubes through the firewall and welded them to the strut towers. Next, tubes were welded between the front of the strut towers and the plates connecting the front suspension crossmember to the unibody, in effect creating a pair of tubular strut towers. Racecar principles applied to the street.
The rear towers were reinforced similarly, with a ridiculous number of additional braces extending between the B-pillar horseshoe as well as between the towers themselves. All told, this cage has tubes or dimple plates fixed to the body shell in no fewer than 28 places. The last step was painting it blue to match the exterior.
Two wheel-and-tire setups are used; one for pavement, one for dirt. For the latter, 15x7-inch Team Dynamics Pro Race 1 alloys with a 40mm offset front and rear are used with 215/60-15 Falken Azenis Rally tires. For tarmac or shows, Scott bolts up a larger set of 17x7-inch Pro Race 1 dishes with a 49mm offset and Falken Azenis Sport street tires in a 225/45-17 format.
Power upgrades are fairly benign. In fact, engine mods were dead last on the crew's to-do list; these encompass basic bolt-on treatments to open airflow into and away from the boxer's combustion chambers. There's a K&N drop-in filter and PDE exhaust components comprising new up- and downpipes and a full turbo-back exhaust system.
Probably the most significant performance gains were achieved by reflashing the ECU, a task that was contracted to GT Motorsports in Rancho Cucamonga, Calif., where the engine was dyno tuned to optimize low-end and midrange power. Ignition, fuel and boost curves were mapped for the low-end and midrange rpm levels.
The result of the mild bolt-ons and electronic tuning is a peak of around 210 hp at the wheels. Not much, but remember this car has been tuned primarily for torque to increase corner exit speeds for low-speed rallycross
The transmission internals were revised to take advantage of the low-range engine tuning. Scott used a sport ratio gear set from Gimme Gears & Composites (GG&C) that incorporates a taller first and shorter second through fifth gears. The revised gearbox interfaces with a DPG performance clutch and a lightweight 11-pound DPG flywheel. Lubrication is provided by Neo Synthetic oil to help prevent premature wear under Scott's hard driving. He says the fluid has made a huge difference in mechanical performance and reliability.
"After 30,000 miles, I can still go into first gear at 30 mph without any problems," Scott says. "Anyone with a Subaru can understand what that means."