The IMSA 914 Options

[gms]

After the comment I was reading in the “914-6/904 project begins” thread I felt the need to inform some of the members of this board about the 914s in IMSA or the 914 GTU. I am currently involved in research to write a book about this very subject so I will share some of my findings.

Between 1971 and 1987 there were forty-two 914s built and entered in IMSA sanctioned events in North America. In 1971 and 1972 the cars sported the factory M491 option package or their equivalent built by the privateer. The extensive use of fiberglass in the hood, rear deck lid, bumpers and rocker panels lightened the car while the 911 engine upgrades gave the horsepower to make this car competitive against all racers.

Starting in 1973 the cars had started to evolve into homegrown and sometimes innovative thoroughbred built by Americans with that “can do” attitude. It was not that Porsche didn’t do a great job converting the 914 into a race car it was just that the development done in 1970 was becoming outdated.

Wheels and tires were getting wider and this would drastically affect its shape as the fenders became wider and body panels were constructed of fiberglass. The Porsche factory never constructed a tail or developed any aerodynamic aids for the rear of a 914.so this would become the area of most diversity.

The 914 competed in the IMSA GTU class which allowed a 911 engine starting at a two liter displacement and expanding all the way up to three liters by the end of its eligibility.
There were also some 914/4s that competed; they were allotted a chassis weigh savings for their lack of displacement and two cylinders.

As the handling, acceleration and speed of the 914 were enhanced by these advancements the chassis required more strength, this was accomplished by the extensive use of tube framing and suspension reinforcement. In some cases suspension components were borrowed from the 911 RSR and 935.

Once the cars became firm and fast they needed improvements in their braking capability. As has always been the case the 914 borrowed calipers and master cylinders from its Porsche siblings, a few examples even used aircraft brake calipers.