A bit of information for 1984-85 C4s
1984
- The 1984 Corvette was a complete redesign in almost every aspect. Handling considerations dominated, and the result was praised by the motoring press and the world's best cornering automobile.
- ·The 1984 Corvette was introduced in March 1983. Because it met all 1984 federal requirements, Chevrolet decided to skip the 1983 model designation. The result was a very long production run and the second-highest model year volume in the Corvette's history. 1983 Corvettes were built, serial numbered, and tested by both Chevrolet and the motoring press at the "long lead" preview at Riverside Raceway in December 1982. But 1983 Corvettes were not released for public sale.
- ·Design criteria specified that the 1984 Corvette have more ground clearance and more interior room, but less overall height. In order to achieve it, engineers routed the exhaust system through the center tunnel.
- ·A 4+3 4-speed manual transmission, built by Doug Nash, had overdrives in the top three gears for improved fuel economy. Not available early.
- ·All 1984 Corvettes were designed with one-piece, lift-off roof panels and rear hatch windows. At the time, the rear window glass was the largest compound glass ever installed in an American automobile. The front windshield was raked at the greatest angle, 64%.
- ·Brakes remained disc at all four wheels, but components were new and included aluminum calipers supplied by Girlock of Australia.
- ·Electronic instrumentation was standard and included digital readouts for engine monitoring and liquid crystal graphic displays for speed and engine revolutions. Analog instrumentation was not available.
- ·The 1984 Corvette was designed with a pad protruding from the passenger side of the dash. This was part of a passive restraint system conceived when it was assumed the federal regulation would require such restraints. The Reagan Administration dropped the restraint proposals, but the Corvette's pad remained.
- ·The 1984 Corvette was designed without fiberglass seams on exposed panels to eliminate factory finishing. The exterior seams were under the rub strip, extending around the entire body.
- ·The radiator was a new design using aluminum for the cooling fins and plastic for the reservoirs. A thermostatically controlled electric fan operates only when needed and only under 35mph.
- ·Chevrolet built specially modified 1984 Corvettes for the export markets of European, Middle East, Japanese, and Latin American countries. Changes included different license plate provisions, leaded fuel capability, and electrical, glass, lighting and mirror modifications.
- Single transverse plastic leaf springs were used front and rear.
1985
- ·The 1982 and 1984 Corvette engines had "Cross Fire Injection", but genuine fuel injection returned to the Corvette in 1985 for the first time in two decades. The 1985 tuned-port injection, built by Bosch, was standard equipment and featured a mass airflow sensor. Aluminum-tube tuned intake runners, a mold-cast plenum, and an air cleaner mounted forward of the radiator support. This new L98 engine delivered a horsepower increase from 2OShp to 230hp, a torque increase from 290 lb.-ft to 330, and a real-world fuel economy increase of about 11%.
- ·The overdrive selection switch for 4-speed manual transmissions was moved during 1985 production from the console to the gear shift knob.
- ·Suspension rates were lowered in 1985, a result of harsh ride criticism. Springs for the base suspension were softer by 26% in the front, 25% in the rear. Springs for RPO Z51 were 16% softer in the front and 25% softer in the rear. To compensate for the spring change, larger-diameter stabilizer bars were included with Z51 equipped models.
- ·In its January 1985 "ten best" issue, Car and Driver magazine pronounced the Corvette to be America's fastest production car at an even 150mph top speed. Corvette also took top honors in top-gear acceleration and tied for best (with Porsch) in road holding as measured by 0-force skidpad adhesion.
- ·The bore of the brake master cylinder was increased in 1985, and the booster itself was plastic, the first such application in an American Car. The new plastic booster was 30% lighter and less subject to corrosion.
- ·Manual transmission 1985s came with a new, heavy-duty 8.5-inch ring differential. Rear axle gearing for manuals was 3.07:1, Standard gearing for automatic transmission was 2.73:1, but the 3.07:1 could be ordered as RPO 092. Wheel balance weights changed in 1985 from the outside-rim, clip-on style, to an inner-surface adhesive type. The changer was mainly for aesthetics, but Chevrolet also believed a better balance resulted because of the adhesive weight's proximity to the wheel's depth center.
- ·A full length oil pan gasket reinforcement was added to the 1985 Corvette engine to improve gasket compression seal.
- ·Electronic instrumentation continued much as the previous year, but displays were revised and improved with cleaner graphics, less color on the speedometer and tachometer, and larger digits for the center-cluster liquid crystal displays.
- ·A map strap was added to the 1985's drive-side sun visor.
Being the crossfire engine was only used for the C4 for a couple of years could mean harder to get parts for it
You should check to see if the ECM (engine controller) is reporting any error codes to point to any engine running conditions
You might luck out as possible the reason to running too rich is to check to see if the aircleaner and the MAF are clean
Use only MAF spray cleaner
Also use some good fuel injector cleaner put into a tank of gas
If you find there are engine error codes, report here to see what they mean
