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						Cobra Bracing A16
Brace Yourself!

Strengthening an FFR Cobra with additional bracing

Story and Photos by Dan Reiter

While the original Cobra replica was based on the design of a 1950s British sports car, modern technology has been adapted and integrated into replicas offered by various manufacturers. It’s an amazing melding of old and new.

Even so, we still encounter some of the same characteristics and flaws of the original design, which are exacerbated with improvements in power, performance tires and brakes. One of the most basic is chassis flex because of some similarities to the original’s bendy ladder frame.

While racing versions sometimes have a roll cage added to the base chassis design, a benefit both from a safety and rigidity standpoint, it can be a contortionist’s nightmare to get in and out of. So rather than a full roll cage, something else was needed to improve the rigidity of an older Factory Five Cobra replica (MkII).

One FFR owner, Mike Noyes, who consistently auto-crosses his car, overcame some flex problems by linking the front and rear cockpit bulkhead braces together, creating a box, and greatly reducing the chassis flex.

It worked well in his car, and seemed to be an ideal compromise between a full cage and ease of access. His design was the basis for the car shown here, with the additions of extra braces for safety, strength and appearance.

While not the full side roll cage of FFR’s Spec Racer, it offers the much-needed sides of the box in terms of design and strength. And the “X” design still allows access to the seats. The tubes are 2-inch steel, and are full thickness as specified by all racing organizations.

Once the X-tubes were installed on the car, a test drive revealed an immediate difference in character — much stiffer, bumpier and more responsive.

The next step was to upgrade the springs in the coilover shocks to address body roll. Once all work was finished, the car was brought to the shop of Mark Dougherty, FFR builder extraordinaire, to have the car balanced, corner-weighed and racing-spec aligned. Immediately, another plus was discovered: The chassis work allowed the car to be quickly set up, and very responsive to the coilover shock adjustments.

The new springs flattened the car out, the chassis mods ended any flexing, and the handling was now in the territory of a true race car. Quick, precise, lightning-quick reflexes and driver inputs now resulted in immediate response from the car.

Interestingly enough, a flaw in the brakes was now realized with the new chassis, as they were now working even harder. Very quickly, lap speeds increased, and the next step was deemed to be a brake upgrade. It is important to note that this design was never intended to be legal for full competition. A full roll cage is required and recommended for any racing use.

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Chassis Cobra Fabrication