Tech Corner

GM began producing a new 4-cylinder motor in 1977. It was a 2.5 liter, overhead valve engine that consisted of an iron block head, a short stroke and initially carbureted. It became known as the “Iron Duke”. In the 1980’s, the Iron Duke progressed to be one of GM’s electronically fuel-injected motors. GM then marketed and rebranded it as the Tech IV. The Pontiac Fiero was the only mid-engine vehicle that would have the Tech IV.

What is the SD4? If you have an Indy Fiero then you might know that the SD4 stands for the Super Duty 4 cylinder. It was the engine in the 1984 Indy Pace Car. It allowed the car to pace over 138 mph. Although the SD4 was not installed in the two thousand Indy Pace Car replica’s sold from GM, the Tech IV in the Indy Pace Car has an upgraded appearance.