Veteran rally driver Tim O'Neil looks at me, drops the clutch and smiles as all hell brakes loose. The flat four's loping idle explodes into a steady roar barely audible over the rattle of gravel spraying the underside of the car. The Pirelli KM5s struggle to send 400 hp to the ground, but O'Neil never lifts.
The run through the slalom isn't bad, though the view of the road ahead is usually out the side window. There's plenty of room at the top of the hill as O'Neil hand-brakes around the loop, but I learn the true meaning of pucker factor as he accelerates down the hill, bores off to the right and up a road no wider than a double yellow line.
Pinned in the seat, I hold my breath as O'Neil turns in over the blind crest, grabs fourth--or is it fifth?-- and apexes a millimeter away from a tire-eating rock that would have surely sent us through the trees if he'd missed. For a second, it totally takes my mind off the trees flashing past inches from my window. If only I hadn't braced myself on the co-driver's windshield wiper foot switch.
It feels like the world has stopped turning when Tim finally hits the brakes for the second-gear left coming out of the woods. Finally resigned to whatever fate awaits me, the last dash over the downhill crest, accelerating all the way through the increasing-radius turn past the garage and the double apex right-hander through the trees is a gravel-spraying thrill I'll never forget. It's odd to look out the windshield and see Doug, Lance and the boys flash past as O'Neil looks out his side window and plays the pedals.
After watching Patrick Richard win the first four rallies of the season in his Group N Subaru, we knew a Group N vs. Open Class comparison test was in order. Word got around, Lance Smith volunteered one of his Burlington-based Vermont SportsCar's brand-new Group N WRX STi's and Doug Havir of CPD Racing said we could drive his yellow Prodrive-built Open Class car. Now, a few months later, the plan has come together. We're all at O'Neil's rally school in Franconia, N.H., and our test equipment is ready to go. Let the thrashing commence.
The Cars
Group N is a production-based class in which, unlike the Open Class, the engine cannot be relocated or the suspension geometry changed. Springs and dampers are free but must be the same design as stock and use the stock pickup points. Brakes are from the production car and every performance piece not on the production car, an aluminum lower control arm for example, has to be homologated by the FIA.
The engine runs a 32mm turbo restrictor and stand-alone management system. Our STi test car is equipped with a five-speed synchro transmission (approved nonsynchro dog gearsets and stronger six-speed cases are allowed), a 4.44 final drive, programmable center differential and three-way adjustable RS&SP suspension. After the body is reinforced and caged, you end up with the world's ultimate production STi. Well, almost. The FIA Group N rules homologate the 2.0-liter EJ20, not the 2.5-liter EJ25 in the U.S. STi.
Havir's Open Class Subaru, on the other hand, is built to somewhat looser rules. In a nutshell, the same company must produce the body and engine block, the firewall and floors must be steel and the car must resemble, at least in silhouette, the car it is based on. "They'll let you know if you go too far," says Smith.
Any resemblances to the Group N car are strictly superficial. Although it's the first Prodrive USA customer car, CPD recently reskinned this rig with 2004 sheet metal. The 2,340cc Crawford Performance engine sits 32mm further back and lower in the chassis behind a Prodrive WRC radiator/intercooler package. Built in anticipation of next year's 34mm restrictor, the flat-four still cranks out more than 400 hp and 400 lb-ft of torque breathing through the current spec 40mm restrictor (roughly 100 hp more than a WRC car).
There's no need to use the clutch downshifting with the Hewland five-speed dog gearset (in a six-speed STi case). Throws are short and precise and the solid clunk when shifting soon becomes a reassuring sound.
The Prodrive ECU varies how much and how often the programmable center differential locks up based on road speed, throttle, brake and hand brake inputs. The front and rear diffs are clutch type. Tubular front and rear cross members lower the roll center while Prodrive control arms work with a three-way adjustable Oehlins damper/spring package and adjustable anti-roll bars to provide a surprisingly supple ride over O'Neil's rough roads. The power steering will go lock-to-lock in 1.7 turns.
Left-foot braking was the first crude anti-lag system. The giant turbos used during the heyday of Group B had lag to match their prodigious power output and drivers soon figured out that if they never lifted, there was never any lag
Both of our test cars were equipped with the latest ECU-controlled anti-lag systems. Lift for any reason and the computer fires the appropriate injector a second time, dumping raw fuel out with the exhaust gases. The gunshot-like backfires you hear are the fuel exploding as it hits the red-hot turbine wheel. It's tough on equipment but there's never any waiting for boost. Havir's car had both soft and hard settings.
Testing
To Smith's obvious relief, we enlist Tim O'Neil to drive the acceleration and handling tests. Unable to find 1,320 feet of gravel road not crawling with civilian traffic, we settle for a 1,000 feet of gravel in Team O'Neil's front yard. Conditions are nearly perfect, cool and overcast with just enough moisture in the gravel for great grip. Lest something unforeseen happen, the pro goes first, starting with measured acceleration runs followed by the handling loop.
With top-end power held back by the 32mm restrictor, O'Neil finds launching at 4000 rpm and short-shifting the Group N car produces the best times. Topping out in fourth or fifth shows no appreciable gains. He launches the Open car, without using the launch control, at 4500-5500 rpm and is still pulling strongly in fifth gear when he runs out of room. Watching the yellow car rocket away, dirt flying on every shift, leads to an instant reassessment of my skills and an unnerving feeling in my bowels.
Not surprisingly, the Open Class car is quicker. At 500 feet the margin is .6 seconds (8.36 vs. 7.76 seconds). There's only so much traction available to the Pirelli gravel tires. By the 1,000-foot mark the Open Class car has nearly doubled that gap to 1.17 seconds (12.88 vs. 11.71 seconds). With a 4.44 final drive, the Group N car ran from zero-to-60 mph in 6.72 seconds while the more powerful Open car ran zero to 60 in just 5.25 seconds. On gravel!"Whiskers" Evans, the former Prodrive WRC wrench now heading up CPD's shop, estimates his car would run zero to 60 close to 4 seconds flat if running a shorter 4.44 final drive instead of the tall 3.9 in the car.
The handling loop we've chosen incorporates a huge diversity of turns and road shapes into an .85-mile dirt loop around Team O'Neil's 600-acre training ground. Included in its design are several square junctions, a tricky left-right-over-crest combination and a quick increasing-radius turn leading into an even faster double-apex right-hander we think will further expose the handling and power differences in the cars. And it does, to a degree. The Group N car is only 1.16 seconds slower around the loop.
Surprised, we decide to measure each car's peak speed at the fastest section of the loop, the short uphill run exiting the slalom. Illustrating the power difference between the cars, the Open car is 7.7 mph faster here, topping out at 77.5 mph, but never has the room to capitalize on its speed advantage through the rest of the tight course.
"The Production car technique is to be very careful with the shifter and even with the brakes," says O'Neil. "The Group N car doesn't turn in as well either. Even with STi bushings there are a lot of parts in the system that are flexing, which makes the Group N car a little more forgiving. With the Open Class car, these problems have been designed out. With no rubber bushings in the suspension, you turn and it turns. You brake (four-pot Prodrive by Alcon all around) and the thing stops. You have to be right on it all the time and 100 percent committed when you drive the Open car. Try and drive it carefully and the car won't even move. To drive the Open car you need a more aggressive, caveman approach."
"There is a real fine line between being extraordinarily quick and ending up in the ditch," says Havir, speaking from experience. "This car will do exactly what you ask it to do exactly when you ask it to do it. You just need to be sure to ask it to do the right thing at the right time."
I'll wager Havir could use a Tums as he watches me pull away in his pride and joy. He needn't worry. Uncertain of exactly what to ask when, I drive the great yellow beast like a total wimp. Even Havir chides me for not thrashing his car. Back out again, a generous stab of the throttle pins me in the seat. Cat-quick responses and heavy but awesome brakes make O'Neil's 80-foot-wide slalom area seem the size of a compact car parking space.
Things happen in a hurry in this car. Even as I'm making a conscious effort to go carefully, the digital dash shows 70 mph after left-foot braking around the last cone and heading up the hill in third gear. This is more car than I have any business driving.
Without a doubt, Smith needs a Tums. I'm immediately more comfortable in the slower Group N car and more willing to push. The car's slightly slower reactions and more forgiving nature make it a pleasure to drive. I'm even quick enough for Smith to comment, "You've got to have a lot of faith in your gear. If something breaks [sliding through the trees], you can't do anything about it." Oddly, O'Neil catches more air in the Group N rig than in the faster Open car.
Still, the anti-lag betrays me, sounding off when I lift running down the narrow road through the trees and rocks in third gear. It turns out anti-lag likes full throttle. Coming out of the woods into the tight left-right combo and back through the increasing-radius turn, the car rotates willingly and is easy to balance with throttle and a dab of brake. It hooks up instantly as the wheel straightens. Smith is visibly relieved when I safely park his baby.Through our handling loop, the Group N car gives up about 1.4 seconds per mile to the Open car. On a 10-mile stage, that's 14 seconds. On the other hand, it's less than a 2-percent difference. Any Open Class driver who backs off even a little--at least in a tighter, more technical rally like our test loop--runs a real chance of coming in second to a Group N car driven to its full potential. Just ask Richard.
I would like to send a big, heartfelt thanks to Tim, Doug and Lance for granting us the extraordinary opportunity to drive these cars. As O'Neil pointed out, "Not many people on the planet get to drive anything like that yellow rig."
For the updated Race Report, pick up the March 2005 issue of Sport Compact Car.