Testing the 2011 Mazda 2 and 2010 Honda Fit B-Spec Racecars

Flirting with the rev limiter at the top of 4th gear, a faint brush of brakes is required as we hurtle into the left-hand kink at the end of the long front straightaway. The optimum turn-in point isn't entirely clear because our view of the exit curbing is blocked by the pavement itself as it rises and falls slightly between here and there.

And that's just Turn One. Four or five other corners here at Thunderhill Raceway are similarly obscured by the track designer's strategic exploitation of the gently rolling terrain found here in the foothills west of Willows, California.

A good lap around this place requires enough practice to "just know" the line despite the topography. After that it's a flowing circuit that favors a nimble car that can preserve momentum even as the surface below tries to shrug it off into the weeds. Luckily, that's just what we've got under us in the form of a pair of B-Spec racecars from Mazda and Honda.

Race-prepped versions of the 2011 Mazda 2 and 2010 Honda Fit are here at Thunderhill for NASA's (National Auto Sport Association) annual 25-hour enduro, and we've been invited by Mazdaspeed and Honda Performance Development to sample and compare the two on the open test day that precedes the event.

B Student
Small cars that we call subcompacts are termed B-segment cars within the auto industry. The Honda Fit and Mazda 2 occupy this space along with the Chevrolet Sonic, Ford Fiesta, Hyundai Accent, Kia Rio and others. Bigger cars like the Focus and Civic belong to the C-segment and the alphabet marches on from there.

But why make racecars out of the diminutive Mazda 2 and Honda Fit? For one, they're inexpensive to buy and maintain. Also, their small size makes them inherently lightweight and nimble.

From the automakers' perspective, these cars represent a growing segment in our market as manufacturers strive to meet tightening CAFE standards and consumers seek refuge from steeply rising gas prices. It's a far easier sell if people see subcompacts as something other than a P.O.S., a penalty box or a consolation prize. They want it known that small, economical cars can be spry and fun, too.

We totally get it. There's a certain perverse pleasure that comes from hustling a small car through twisty corners and then cruising innocently down the straights in classic "who, me?" fashion. Many such cars are just a set of tires and a couple of easy suspension mods away from embarrassing sleds that cost thousands more.

And that's exactly what the B-segment racers are all about. Representatives from Mazdaspeed and Honda Performance Development put their heads together to create a rules framework for a "B-Spec" race series in which the Mazda 2, Honda Fit and their competitors can do battle. Other manufacturers have been invited to join in and are watching how these two proof-of-concept machines perform on the track.

Race-Prep Recipe
Safety mods make up the bulk of the prep time and cost, as the innards of these racers have been gutted to make room for a substantial roll cage that's welded to the unibody at eight strategic points. Substantial steel side members extend into the doors, which have been cut open and stripped of their window mechanisms to make room.

Cars they beat include the Corvette Z06, Porsche 911 GT3 and any number of Nissan GT-Rs we've tested.

The lone seat in each car is a Sparco racing bucket mounted on the stock seat track so it can be repositioned to suit a variety of drivers. The dash and gauges are the only recognizable interior remnants.

Performance modifications are few and tightly constrained in order to keep costs down and real-world relevance high. That's why the internals of the engine and transmission can't be altered. There are no supercharger kits, no headers, no wild cams. Bottom line: The underhood area remains more or less showroom stock.

Underneath, both B-Spec racers ride on a Bilstein B14 PSS performance suspension kit that consists of monotube front struts and rear shocks with non-adjustable damping and matching springs that are height-adjustable. The original stabilizer bars and suspension bushings are retained, and no changes can be made to the brake system except for aftermarket brake pads and braided stainless brake hoses.

Finally, there's a common "spec" wheel and tire package, namely P205/50ZR15 BFGoodrich g-Force R1 Comp semi-slick race tires mounted on 15-by-7-inch alloy rims. They provide tons of stick, but don't even dream of street use because they've got almost no tread and their wear rating is 40. No, that's not a typo.

Over Thunderhill and Dale
In the open test session, the Fit and the Mazda 2 lap the 3.0-mile circuit within the same second, and with traffic it's hard to know if one has the upper hand.

In pure spec-sheet terms the Mazda 2 gives up 17 horsepower to the Fit, but the difference may be larger here because the Honda team removed their catalysts, while the Mazda folks went with a cat-back exhaust. Not only is the B-Spec Fit significantly louder, it's faster down the long front straight when we stand on the gas.

But the Mazda 2 has the advantage under braking, with a firmer pedal and more direct response. It carries a smidge more speed into corners, too, as the body rolls less, owing to a firmer setup despite similar suspension upgrades.

Physics is no doubt helping, as the Mazda 2's as-raced weight is 105 pounds less than the Fit's (2,237 vs. 2,342). It also stands 1.9 inches shorter (58.1 vs. 60) and measures a half-foot shorter in overall length (155.5 vs. 161.6 inches).

By contrast, the B-Spec Fit rolls a bit more in turns and its brakes and shifter feel somewhat more vague — the latter less of an issue because the Fit uses just 3rd and 4th gear while the Mazda 2 makes occasional forays into 2nd.

In the end, the Fit's power advantage makes it easier to work through traffic because it can more readily recover from being balked — a likely advantage in the 25-hour contest to come.

Bees on Our Test Track
Let's cut to our own test track for a moment to see just how much the simple B-Spec mods improve performance over that of the 2011 Mazda 2 and Honda Fit sitting on your nearby dealer's lot.

There's little reason to expect much change in the quarter-mile, but stickier tires and exhaust mods apparently do count for something. The B-Spec Fit gets there in 16.2 seconds at 83.0 mph, about 0.4 second and 0.6 mph better than a normal Fit. At 16.6 seconds at 81.0 mph, the Mazda 2 racer is a bit slower, but it still bests a production version by 0.8 second and a full 2.5 mph.

Panic stops from 60 mph require 129 feet in a garden-variety Honda Fit, but the modified one is stationary in 111 feet. Similarly, our "before" 2011 Mazda 2 long-term test car stops in 133 feet, but the "after" B-Spec version gets it done in just 106 feet.

Reality starts to come unglued through the slalom. A standard Mazda 2 and Honda Fit make runs of 65.0 and 66.0 mph, respectively. But the B-Spec racers do it about 7 mph faster, with the prepped Fit knifing through at 72.9 mph and the Mazda 2 coming through at 72.0 mph. This is rarefied $100,000 car territory.

Both Bs putter around our skid pad with little apparent effort, drama (or obvious speed), but the two-way average of the B-Spec Fit nevertheless works out to 1.03g, 0.21g better than a stock Fit. The Mazda 2 responds by knocking the Fit off its short-lived podium, registering 1.04g on identical tires.

A partial list of cars they both just beat includes the Chevrolet Corvette Z06, the Porsche 911 Turbo (or GT3), the Dodge Viper SRT10 and any number of Nissan GT-Rs we've tested, including the 2012 Black Series.

Racing Through 25 Hours
Because they have little in the horsepower department, the B-Spec Mazda 2 and Honda Fit are classified in the E3 category, the slowest of the five classes sharing the track for the NASA 25-hour enduro. In all, 69 cars line up for the start, with the Honda Research West #15 Honda Fit starting 34th and the Robert Davis Racing #20 Mazda 2 starting 40th on the strength of their fastest laps in a traffic-filled qualifying session that we happily watched from the pits.

In the early going, the Fit's advantage in traffic allows it to edge away from the Mazda 2, leaving several cars in between as a buffer. Then the first pit stops allow both Bs to demonstrate their fuel economy advantage. NASA rules allow just 10 gallons to be added per stop, and the two B-Spec racers ride that for nearly 2 hours, oftentimes 30 minutes longer than those around them. The high-powered leaders are stopping every 45 minutes.

And then the rains come — or rather, the heavy drizzle. This benefits the Fit and its softer suspension much more that the stiffer Mazda 2, and at one point the Honda drives past the leading Porsche 911 GT3 and some other front-runners before everyone eventually decides rain tires are a good idea.

Wet or damp asphalt dominate the event for something like 20 hours as the two B-Spec cars march steadily up the charts. The track doesn't actually dry enough for really quick times until the final hour, at which point Honda plugs pro racer Simon Pagenaud into the Fit to lay down its fastest lap of the weekend, a 2:09.364. At that point the Mazda 2 is nursing worn-out brakes and can't respond with anything better than a 2:14.

In the end the Fit finishes 15th overall and the Mazda 2 comes across 19th — pretty damn impressive for lightly modified subcompact cars with unmodified 1.5-liter four-bangers.

It's a Hit
This dry run of the B-Spec racing concept has people smiling up and down the pit lane. Pagenaud is as enthusiastic as anyone, climbing out of the Honda Fit at the end with a huge grin, saying, "I love it. It's one of the best cars I ever drove." We're pretty sure he actually means it, too. The Mazda 2's drivers and crew are slightly less famous but no less enthusiastic.

In 25 hours, neither car had a serious problem or an on-track incident. Their crews poured gas in them, changed a few tires and rotated drivers in and out. The Honda team installed new front brake pads sometime during the night, totally expected in a 'round-the-clock enduro, while the Mazda 2 squad went the distance on the ones they started with — barely.

The proposed B-Spec series is envisioned as a sprint race series to keep costs in check, but this 25-hour test proved beyond a doubt the cars are durable and raceable. In addition to proving that the concept has merit, the Thunderhill experience gave the rule makers some real-world data to chew on.

Both sides think it's better to run functional catalysts with cat-back exhausts, and things like ballast and car-specific ECU reflashes are being tossed around as possible ways to equalize cars with different horsepower levels.

Let's hope the B-Spec concept takes root somewhere and that Ford, Chevy and others decide to play, too. From where we sat, inside both cars and in the pits, the B-Spec Mazda 2 and Honda Fit deserve a huge thumbs-up.

Beyond the actual racing, the Thunderhill weekend underscores what the manufacturers are trying to say with the B-Spec series: The current and future crop of small, hyper-efficient economy cars can also be fun. It makes us want to bolt a few strategic mods on our own 2011 Mazda 2 long-term car and see what a street version of the B-Spec formula is like.