The first LT-1 was created for 1970 Corvettes and Camaros.
When the Regular Production Option (RPO) code LT1 is mentioned, it’s important to note that this RPO has been used on three completely different versions of the small-block Chevy. With the major points covered, let’s dive into the Gen V’s internals. The LT4 uses a smaller, 1.7L supercharger while the big daddy LT5 spins a massive 2.65L high helix, four-lobe blower making 755 horsepower. It’s also important to note that GM has stuffed superchargers on two of its Gen V variants – labeled the LT4 and LT5 engines. Knowing that Corvettes would be subjected to higher lateral g-forces, those engines are fitted with a modified dry sump oiling system while the Camaro-bound engines retain the more traditional wet sump lubrication system. The reason for the different code is that the LB9 engines employ an electric-assist powertrain combining an electric motor that initially accelerates the vehicle away from a dead stop and then the gasoline engine takes over.įinally, there are two variations on the LT1 GDI engine. There’s also an RPO LB9 5.3L that is spec’d with a different RPO code but it is essentially the same as the L86. The truck engine employs a longer-runner intake manifold and deeper oil pan, but beneath the skin, the two engines are identical. The 6.2L L86 is very similar to the passenger car LT1 with the only real changes to the intake and exhaust. Note that the Gen V did not offer a 4.8L version as with previous generations. There’s even a 4.3L 90-degree GDI V6 base truck engine. The truck engines are offered in two V8 versions – the L83/L84 5.3L and the 6.2L L86/L87. GM also used this new injected technology across the V8 car and truck lineup by spec’ing this same engine package for trucks and other larger vehicles. You’d be Tuner of the Decade to achieve that with a 370 horse 1970 carbureted LT1. A 2016 6.2L LT1 Corvette makes 460 horsepower and with an automatic transmission earns an EPA highway fuel economy rating of 29 mpg.
The last time a small-block came anywhere near that number was in 1970 with the first generation LT-1, but that engine is crude in comparison. The new LT1 bumped the compression ratio to a GM unprecedented 11.5:1. The best way to make a gallon of gasoline go farther is by squeezing it harder with more static compression. The whole point of GDI is to improve combustion efficiency. This required a mechanically-driven high pressure pump that is driven off the rear of the camshaft. The 6.2L LT1 and its followers all employ a high pressure fuel system operating at over 2,100 psi to shoot the fuel directly into the combustion chamber. The whole reason for the Gen V was to introduce gasoline direct injection (GDI) to meet increased emissions standards. Because the intake ports are symmetrical, note that the intake manifold is oriented toward the rear of the engine.
The large plastic cover on the driver side front is the integrated dry sump tank, placing it on the engine to minimize external plumbing. Note the factory header and the relocated ignition coils. The most recent addition to the Gen V engine lineup is the 2020 C8 Corvette LT2 engine.