Chevrolet Camaro IROC-Z

Camaro IROC-Z at a glance

The IROC-Z belongs to the third generation of the Chevrolet Camaro and to the long line of the Camaro Z28. On 1CARS it is one of the muscle cars of the comeback era between the malaise years and the modern revival.

The third-generation Camaro and the IROC name

Production of the third-generation Camaro began on 12 October 1981 for the 1982 model year. Motor Trend named the 1982 Z28 its Car of the Year; about 173,000 Camaros were sold in the US that year.

For 1985 Chevrolet used the initials of the International Race of Champions for a new top Camaro. The IROC-Z began as an option package on the Z28. According to Eighties Cars, it cost extra on top of the Z28 and sold 21,177 times in its first year out of 68,199 Z28s, and by 1986 it accounted for 56 % of Z28 sales.

What the IROC-Z package added

Wikipedia lists the chassis changes:

• a lower ride height (Eighties Cars gives about half an inch) and specially valved Delco-Bilstein dampers;
• larger-diameter anti-roll bars and a steering and frame brace known as the "wonder bar";
• 16 × 8-inch five-spoke aluminium wheels with "Front" or "Rear" cast into them;
• Goodyear unidirectional tyres in size 245/50VR16, close to the Corvette's 255/50VR16;
• optional Tuned Port Injection, the fuel-injection system of the Corvette.

Eighties Cars adds louvred bonnet inserts and more aggressive ground effects and spoilers than on the Z28. Four-wheel disc brakes, T-tops and air conditioning were among the options.

IROC-Z engines by year

Eighties Cars also lists the carburettor 5.0 LG4 with 116 kW (155 bhp) as the standard engine of the 1985 Z28 range. Wikipedia gives 1986 for the 5.7 in its text and 1987 in its table; the table year is used here. Motor Trend timed a 1985 IROC-Z with the LB9 at 6.9 seconds from 0 to 60 mph, as Eighties Cars reports.

Fuel economy of the 1985 engines

Eighties Cars quotes the 1985 EPA ratings for the three 5.0 engines of the Z28 and IROC-Z range. The litre figures are our conversion from US miles per gallon.

The fuel tank held 16.1 US gallons, about 61 litres, which Eighties Cars puts at a range of 250 to 275 miles (400 to 440 km) with a 10 % reserve.

Convertible, 1LE and special runs

For 1987 the American Sunroof Corporation (ASC) converted T-top Camaros into convertibles. Wikipedia counts 1,007 of them across models but does not split out the IROC-Z share.

Some IROC-Zs received extra hardware. The G92 performance axle package without air conditioning triggered the 1LE equipment, built on 111 IROC-Z coupés in 1989 and 62 in 1990. In 1989, 1,426 coupés had the G92 package. Wikipedia also lists 2,497 IROC-Zs with the L69 and 205 with the LB9 and G92 axle in 1985.

Why the IROC-Z ended in 1990

Chevrolet decided not to renew its contract with the International Race of Champions, so 1990 was the last IROC-Z year. That year the Camaro also became the first F-body with a driver's airbag. For the 1991 facelift Chevrolet offered the RS and the Z28 again, but no IROC-Z.

Buying a Camaro IROC-Z

• Engine and gearbox: a 5.7 car should have an automatic; a manual car has a 5.0.
• Wheels: original 16-inch five-spoke wheels have "Front" or "Rear" cast into them.
• 1LE cars: check for the G92 axle and the absence of air conditioning on a claimed 1LE.
• Convertibles: 1987 and later, converted by ASC.
• 1988 on: the IROC-Z replaced the base Z28, so a 1988–1990 IROC-Z is the performance Camaro of those years.

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