We decided to see just how fast old racing cars actually are. Where do they get their speed compared with a modern supercar? Where on a track-and why-are they slower? How do different generations of racing cars compare with one another and with a supercar?
We assembled three great old racing cars and a Porsche 911 GT3 at England's Donington Park circuit. We chose cars that are the fastest of their breed today: an ERA (English Racing Automobile), to represent the prewar era; a Lotus 16, as the ultimate front-engined Formula 1 machine; and a Brabham BT11A from the early mid-engined period. We used our Racelogic VBox to analyze acceleration, braking, and cornering performance objectively, and we drove all four for subjective comparisons.
1935 ERA R4D
At the end of the 1930s, the fastest racing cars on the planet were German: the Mercedes-Benz W154 and the Auto Union D-type. Nowadays, however, for a number of reasons, they would struggle to keep up with Mac Hulbert's sinister black ERA, chassis R4D, around Donington. First, this particular ERA has been tweaked continually since the 1930s. Second, the Mercedes and the Auto Union use nineteen-inch tires that don't have as much grip as the ERA's sixteen-inch tires. Finally, the German cars were built for long straights and fast, open corners-a circuit type that has all but disappeared.
This ERA is thus the fastest prewar car in vintage racing. It uses a supercharged, 2.0-liter OHV in-line six-cylinder engine that makes about 300 horsepower, which is fed to the rear wheels via a four-speed Wilson planetary preselector gearbox. The car has a live axle with semielliptic leaf springs at the back and a Porsche-type trailing-arm independent front suspension with torsion-bar springing. Ready-to-run weight with the driver aboard is 1834 pounds.
Around Donington, the ERA lapped three seconds off the pace of the GT3, which is as good a track car as you can buy. A regular Porsche 911 Turbo or a Ferrari 360 Modena would be hard-pressed to better the ERA's time. The almost-instant gearshifts, which barely register on the data traces, and the 1.14-g cornering limit are amazing. Sure, the tires are tenacious, but the car generates all that grip despite a high center of gravity and relatively narrow rear tires on 5.5-inch-wide rims. It loses out to the Porsche in cornering speed-especially in the faster bends-and in braking, but it holds its own in acceleration once you have it pointing straight.
You feel the ERA's age when you step into it, however. You're perched high in what feels like an armchair, with a giant steering wheel ahead of you. The monstrous Godfrey supercharger lives between your legs, which is scary when you realize that the rotors will be spinning at about engine speed. There's a commanding view over the long hood and the front wheels, which makes the car easy to place in the corners, and you can see much of the track ahead of you at any given time. You tend to drive the ERA based on what the front wheels are doing: because you actually can see the understeer, you just add power to get the front wheels into a neutral attitude. When the front wheels are countersteering, you back out the throttle.
The preselector gearbox is as fast as and smoother than a modern sequential manual. To shift, you preselect the required gear on a quadrant down by your right leg and engage it by pressing the left-hand gearshift pedal. The ERA's handling balance relies on your right foot and your own bravery, because it will understeer off throttle, become neutral under power, then oversteer wildly if you use too much of the abundant torque. R4D has a reputation for being evil at the limit, but stiffer front torsion bars have made it friendly, even in the wet. The steering is deliciously accurate but is heavier than the Lotus's or the Brabham's.
The brakes are powerful (for drums) and produce 0.71 g under heavy retardation. The engine is a thing of some beauty, producing lots of power from 1500 rpm to Hulbert's 6500-rpm redline. It makes a wonderfully sharp exhaust bark overlaid by the whine of the supercharger, and it emits a heady stench of Castrol oil and burnt methanol. It also propels the ERA extremely quickly down the straightaways.
1959 LOTUS 16
By the time Lotus founder Colin Chapman built the first type 16 in 1958, the front-engined grand prix car was becoming an endangered species, with Jack Brabham and Cooper taking the first driver's championship for a mid-engined car in 1959. At that time, the 16 was fast and fragile, but since then, the car has come into its own, running sprint races on tighter tracks in vintage events. In owner Philip Walker's hands, chassis 368 even dukes it out with the Cooper that Brabham drove in 1959.
The 16 is a radical front-engined design, as you would expect from Chapman. It uses a spaceframe chassis with a Coventry Climax 2.5-liter twin-overhead-cam in-line four-cylinder engine canted over at seventeen degrees to reduce the frontal area. Instead of using a conventional transmission, the 16 has what was dubbed the "queerbox," featuring dog rings with a positive-stop motorcycle-type sequential operation. This was troublesome when the car was new, but it has been developed to the point where it is reasonably reliable. The 16 has control arms and coil springs at the front, with a Chapman strut and lower control arm at the back. Disc brakes are used all around.
The Lotus produced identical lap times to those of the Porsche at Donington and was very evenly matched in acceleration, cornering grip, and braking. It has pretty grippy tires, a low center of gravity, and a rearward weight bias, but the key to its speed is its 1327-pound weight-just 40 percent of the Porsche's.
Unlike in the ERA (and earlier F1 cars such as the Maserati 250F), you sit very low in the Lotus, with your left leg over the offset prop shaft, which is then angled to run alongside your hip. There is still lots of leg and elbow room and a large-diameter, thin-rimmed steering wheel, but you are enveloped by bodywork rather than perched above it. You can only just see the tops of the front tires, so you drive corner by corner and feel what the car is doing by the seat of your pants instead of relying on visual references.
The left-hand gearshift is simple to operate: forward to go up a gear, back to go down the five ratios. The higher the ratio, the longer the travel on the lever, which means it isn't the fastest gearshift ever. The Climax four-banger doesn't sound particularly memorable but has very usable power from around 3000 to 6500 rpm, and it ensures that the slippery Lotus goes very well down the straightaways.
In some ways, the Lotus feels the most modern of all the cars. The steering is light and superaccurate. It demands geometric precision rather than being flung into corners with your throttle foot sorting everything out. On turn-in, you get mild understeer, followed by neutral behavior with the application of power. The tail will come out, but the car doesn't like being driven that way and feels as if it would swap ends in an instant. The brakes, however, are superb, with great feel and feedback.
The 16 probably requires a better driver to get the most from it than does the ERA, which is actually quite friendly at the edge of its performance envelope. With the 16, the margins between going fast and falling off the black stuff are much narrower than with the ERA, but the limits are higher.
1964 BRABHAM BT11A
Brabham's 1964 grand prix contender was the BT11, fitted with the Coventry Climax 1.5-liter FWMV V-8 engine. The 11A was essentially the same, except that the larger 2.5- (or 2.7-) liter Coventry Climax FPF four-banger was slotted in for Tasman and Formule Libre races. This is convenient for vintage racers, because the four makes about 240 horsepower compared with the V-8's 200 horsepower, and most events for pre-1966 GP cars admit both types. Philip Walker's BT11A, chassis IC-1-64, was delivered new to Charles Vgele in Switzerland.
Typical for a racing car of this era, the Brabham has a multitube spaceframe chassis, with the engine behind the driver. This car's original Hewland HD5 transaxle has five forward speeds. The front suspension is by classical upper and lower control arms with coil-over dampers; there's a transverse top link, a lower control arm, two long radius arms, and coil-overs at the back. This car should have thirteen-inch-diameter wheels and tires, but it has to run fifteens at the back because the correct size of tire isn't available. Compared with the Lotus, the BT11A displays how wheel rims got wider at the back and tire profiles got lower. With fuel and a driver on board, the BT11A weighs just 1234 pounds.
The Brabham was the fastest of our four cars around Donington, outperforming the Porsche in acceleration, under braking, and through the fast corners. Although the Dunlop racing tires on the Brabham were two years old and felt rock-hard, the car still generated 1.22 g's through Donington's dauntingly fast Craner curves when Andy Wolfe was driving. Lower weight, a more sophisticated suspension, and the traction offered by a mid-engined layout help explain the performance improvement over the Lotus.
Of course, the Brabham feels the most like a modern racing car. You sit very low, in a semireclined driving position, grasping a small-diameter steering wheel, with the shift lever to your right. There's a lot less bodywork and a lot less room in the cockpit. Very little of the car ahead of you is visible, except for the tops of the wheels. You're aware that there is a lot more mass behind you, too, as you're much closer to the front wheels, and you need a good sense of spatial awareness to get the best from it.
The Brabham gets along very smartly out of the corners, thanks to an impressive weight-to-power ratio of 5.1 pounds per horsepower. The car dives noticeably under braking, but it's possible to get on the brakes really late. Whereas the older cars like to be rotated on the throttle, you can brake the Brabham up to the apex of a corner, taking advantage of its greater front-end bite. The steering is light and deft but loads up perfectly with g-force. Out of the corners, traction is better than that of the older cars, although the handling is still throttle-dependent. Brabhams are said to be user-friendly, which seems to be a synonym for "tail-happy." Another corollary of the engine's location is a lowered polar moment of inertia, which means that it rotates more willingly than the two front-engined cars, but it also gets back into line faster if you respond quickly.
PORSCHE 911 GT3 CLUBSPORT
The Clubsport version of the 911 GT3 features a competition seat and half roll cage but is otherwise identical to Porsche's street racer. At Donington, the car generated 1.14 g's of lateral grip from its 235/40 and 295/30ZR-18 Michelin tires, easily the widest and lowest-profile footwear of the four. With 375 horsepower, the GT3 gets down the straightaways smartly, while traction out of slow corners is pretty impressive, thanks to the rear engine location. The brakes are amazing-although the peak g figure reflects our driving style rather than their effectiveness-as is the engine, which produces usable power from 3000 to 8200 revs and an amazing wail that defeats the sound-deadening properties of a crash helmet.
The GT3 feels far too stiff on public roads and suffers from too much initial understeer, but it's transformed on a racetrack. As with the ERA, cornering attitude is dependent on throttle position, which means lots of sideways action. The steering weights up nicely with g's, and the understeer that's so pesky on the road can be dialed out easily with throttle. The car feels really sorted on smooth pavement, although you need maximum concentration to drive it swiftly on bumpy, curving roads. But then, you are accessing the same level of performance as in a 1959 grand prix car, and you can do it while listening to the stereo. It shows how far street cars have come, but it also makes the point that old cars-especially old racing cars-aren't slow. Not at all.
Thanks to Mac Hulbert and Philip Walker for providing the cars; Andy Wolfe for driving the Brabham so rapidly; Graham Millard and Steve Slyfield for the car preparation; and Donington Park for their helpfulness. The BT11A is for sale-contact Philip Walker via Automobile Magazine.