g Masters - Lateral Acceleration Testing

Trophy truckers measure greatness by suspension travel. Muscle-car guys live a quarter-mile at a time. Show weenies are into... well, who cares what they're into?

Our car culture takes pride in owning the corners-on the street and track. Whether in a front-wheel-drive four-cylinder or an all-wheel-drive turbo six.

You see it in the data we collect and publish, though it is rarely the focus of the stories we do. Most often, it is a single line at the bottom of the spec box, or the small highlighted portion in some crazy graph we've generated. And it almost always takes a back seat to a lap time or horsepower figure. It's the measure of lateral acceleration, also known as cornering force, and is represented in a unit we have all understood since birth: gravity.

The 1982 Williams FW08C was the real deal. The thing was just a work of art, and one of the world's fastest cars in its day.

Though we have an inherent understanding of gs, how this force acts on a vehicle is more difficult to understand. Knowing that a car can pull 0.95g on a skidpad is like knowing a woman wears a size 34C bra. Each figure reveals one significant and specific characteristic, but doesn't say anything about the overall, uh, handling experience. In the case of the cars, what we found was that, with some heat in the tires and a lot of speed, some cars performed considerably better or worse than their skidpad numbers might suggest.

So when we came up with this idea of measuring the extremes of cornering force, we knew that simply recording skidpad gs was not enough. We'd have to wire up the cars with telemetry and hit the track as well.

At least that was the original plan: invite a few street cars out to Willow Springs for a few laps on the 'pad and track. At first, we biased our selection towards handling rather than outright performance, wanting to include as many combinations of layouts and drivetrains as possible. Front-, mid-, rear-engine? Check. Front-wheel-, rear-wheel-, all-wheel-drive? Check. We looked for popular cars with popular modifications, but threw in some high-performance stock cars for reference.

Our only rules were that street cars showed up on street tires, race and time attack cars showed up on the R-compounds that their respective series mandated, and the rest was a free-for-all. We wanted real-world g numbers, so each car was aligned for the track and not the skidpad. For those that have the luxury of adjustable aerodynamics, we went for full downforce over lap times. As the list grew longer, our aims grew bolder. Why stop at street cars? If we're looking to pull the highest g-force, don't we have to include some serious race cars?

So calls went out to our pals who have friends who know guys with money and fast cars. Industry connections got us the hook-up with the 2006 championship-winning Star Mazda team, World Speed Motorsports of Sonoma, California. The kicker, however, was when tech editor Chen casually dropped: "What if we could get an F1 car?" That explains how Keke Rosberg's 1983 Monaco Grand Prix-winning car ended up on the same track as Philip Phong's 2000 Honda Civic.

It was a surreal scene that morning at the edge of the Mojave Desert. In all, we invited 13 machines, from a go-kart to an F1 car. The paddock had the oddest mix of machinery ever seen. In the middle were your typical track-day guys, Phong's Civic and a couple of Nissans. Behind each car was the standard pit pile, consisting of a spare tire, floor mats, CDs and a duffel bag with a torque wrench on top.

Next to them were the club racer/time attack guys with pick-ups, trailers, and lots of spares. Out on the ends were giant transporters with crew members wrenching on open-wheel race cars. Somewhere in the middle was the kid with the kart. He looked bewildered, like he'd shown up at the wrong track or something. It was really cold with just a slight breeze, but the sun was shining on the track-the kind of weather that sees track records being broken.

The cars were all beautiful, but most were overshadowed by the formula cars. With their bodywork removed, showing off their brilliant engineering, they were like the hotties that show up at the Halloween party wearing just lingerie. The Pro Formula Mazda looked to be the perfect race car. It had all sorts of trickle-down technology from Formula One, but assembled with standardized parts for cost savings. It's like the Spec Miata of open-wheel racing.

The 1982 Williams FW08C was the real deal, though. The coffin was surrounded by polished aluminum. The suspension pick-up points, coolant and exhaust routing, engine mounts, everything was totally exposed. And it all made sense. With such straightforward engineering, the thing was just a work of art, and one of the world's fastest cars in its day. Even better, owner and driver Erich Joiner arrived at the track in his brand-new 997 Porsche turbo, and graciously allowed us to test it alongside the 13 other cars. It's always nice when the rich guy with the supercars turns out to be a cool dude.

Everything started out about as expected with the street cars all pulling numbers in the mid-0.9g range. Surprisingly, the exotics didn't do much better. In the paddock, the Noble M12 looked every bit an imported supercar. Out on the 'pad however, it acted more like an 80s station wagon. Owner Matt Bell wagged it back and forth from over- to understeer, while dealing with significant body roll. We expected more from the 2300-pound lightweight. The 997 Porsche Turbo seemed to negotiate much better, but its additional 1500 pounds gave it about the same performance as the GT-R, which we should have expected.

Our race car group, with their competition tires, stepped things up to just over 1g. It seemed like the amount of whining from the drivers was directly proportional to the amount of gs they pulled. The carbon fiber-bodied C-West S2000 didn't have a driver, so I drove it, along with the stock RX-8 we brought out for baseline numbers. The S2000 was a real handful. I couldn't get any heat in the tires and the back end would break loose, with the most un-progressive snap oversteer I've felt since testing Calvin Wan's FD drift car. I would have felt much more content at the time if I'd known the thing was pulling 1.15g.

The open-wheel guys had even more to moan about. According to Joiner, the Cosworth V8 in his F1 car comes up on its cams right at the top speed he was going in first gear. With just a 500rpm increase, the horsepower would ramp up from around 200 to 450. You could feel it too, as the rear end would step out while the motor roared up to its sweet spot. It was bad ass. Tom Hughes Jr. in the Mazda also complained he couldn't heat the tires up, but added words like slippery, bumpy, and dusty. Still both guys ripped off numbers like nothing we had seen before on hard compound tires-because that's what they were going to race on the following week.

Quiet Cory Fancy recorded the highest g reading of the skidpad with his Superkart. The 250cc two-stroke came to life with the fury of a 300-pound carpenter bee. According to Fancy, it may have been jetted a little rich for the cold weather, as the throttle response was like an on/off switch. The 80hp bursts shocking the tiny rear wheels of the suspension-less frame made for some really busy hands. The kart was catching air off the small dips and bumps and never looked like it was going straight. He pulled 1.39g and earned every bit of it.

For track testing, we focused on the lateral g readings in Turn Two of Big Willow. During this test, it became really obvious which cars and drivers had spent a lot of time on a race track and which hadn't. Rather than risk stuffing private vehicles, we left it up to the owners to attempt fast and sticky laps and only drove our RX-8 and the C-West S2000 for the test.

The GT-R, S13, and Civic were all set up for the street. Their suspensions were stiff at the front and aligned with toe-in up front as well. This makes for really good handling during panic stops on the street, but quickly overheats the front tires on the track. The GT-R and Civic ran their fastest segment times on their first lap of the test. Sean Holloway of A'PEXi, in the GT-R, actually pulled off a respectable average g reading, beating not only all the street cars, but every supercar except for the slick tire-shod 2200-pound Exige S. The Noble had a quicker time through the segment, but pulled fewer gs. This suggests the GT-R was already slipping off the faster inside line on its first lap.

The Noble was having its own issues, though. In a 2300-pound mid-engined car with almost 400hp, you really need to feel how much grip the front tires have. The power-assisted steering on the Noble gives little feedback at speed. Without being able to feel the front tires dig in, the first indication the thing is going to swap ends is when the back end comes flying around. Driving at the limit of adhesion is a guessing game as to how much traction is left, followed by frantic countersteering in the ensuing moments of terror. I drove a different Noble at the same track a few months earlier and it was anything but confidence-inspiring.