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.