1984 Corvette C4: Handling Updates, Chassis Engineering Drawings

One common technique for improving handling is to specify very stiff springs and/or shock absorbers. This was done on the standard Corvette and the optional Performance Handling Package (RPO Z51; $600.20) was equipped with even stiffer springs and German made Bilstein shock absorbers. As is often the case, there can be too much of a good thing and the 1984 Corvette is an excellent example. The Corvette had outstanding handling but a steep price was paid in the form of reduced ride quality. Terms such as "teeth rattling" "bone jarring" and "brain scrambling" were often used by passengers and drivers alike, many of which were not used to performance suspensions.

1984 Corvette body, chassis outline, rear view

1984 Corvette body, chassis outline, front view

1984 Corvette Body and Uniframe General Arrangement drawing from GM. Most people, although they know that the Corvette body was made of Glass Reinforced Plastic (Fiberglass), are not aware of the considerable amount of steel (and aluminum) that made up the Corvette chassis, which is illustrated here in red.

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1984 Corvette Rattle and Squeak resolution manual

Besides tormenting its occupants, the very stiff suspension also tortured the new Corvette body. Squeaks and rattles throughout the structure became common and so did complaints to the quality people at Chevrolet.

Right: The problem was severe enough that GM issued a 133 page "Squeak and Rattle Identification and Resolution Manual" to aid troubleshooting. Owners at the time reported that while there were many teething issues with the first C4 Corvettes, GM went to great lengths to resolve the problems.

One of the problems was with the Z51 suspension and the fact that many who ordered it did not know what they were getting in to. Despite its high price, nearly half of the 1984 production was Z51 equipped. Although it was a good idea for racetracks (which are typically billiard-table smooth) it had no place in the real world of potholes and speed bumps.

One of the ways handling is measured is known as "g force". "G" in this case is short for gravity. It is measured by driving the car around a 100 or 200 foot diameter circle (called a skidpad) and measuring the maximum lateral force it can generate without going out of control. Most standard issue passenger cars will measure about .70g. In 1984, the best handling performance cars would generate approximately .85g. When tested by the magazines, the C4 (with the Z51 performance suspension) generated around .90g, a very respectable figure. Using special suspension settings not advisable for everyday use, Corvette engineers were able to get an amazing (for 1984) 1.01g!