Corvette Crossfire Engine
In 1982, Corvette buyers had no drivetrain options, it was the 350ci Crossfire Injection engine (RPO L83) backed by GM's new 700R transmission. The same engine was used in 1984 Corvettes (there was no 1983 Corvette produced).
Late-1982 and 1983 Z28 Camaros were also offered with the Crossfire Injection system, but only on the 305ci (5.0L) motor. The Camaro Crossfire engine gained 20 horsepower over the carbureted engine. Just 3,223 Z28's came with this option.
GM Fuel Injection History
Chevy's first fuel injection set-up was introduced in 1957. Called the RamJet, the system used inducted engine-air across a plunger that moved in proportion to the air volume. The plunger connected to the fuel metering system which mechanically dispensed fuel to the cylinders through individual distribution tubes. The Ramjet option provided extra horsepower, but was complicated to work on. The last year of of the RamJet option on Corvettes was 1965.
GM's next fuel injection setup appeared on the 1976 Cadillac Seville. Comprised of a single throttle-body, several sensors, and an analog computer, the system was simple but not much more powerful than a carbureted engine.
By the late 1970s, Corvette engines were being equipped with emissions and engine function controls, neither of which carburetors were ever designed to handle. Since emission standards were going to be even stricter in the 1980s, GM engineers began working on an electronic fuel injection system to replace the over-burdened carburetor.
Computer Command Control
In 1980, GM's first digitally-controlled system was introduced by Cadillac. The DFI (digital fuel injection) system was run by a "Computer Command Control" system. The CCC system monitored up to 15 engine/vehicle operations and controlled up to nine engine and emissions-control systems. In addition to regulating the air/fuel ratio, the CCC controlled spark timing, A.I.R. management for optimum catalytic converter efficiency, and torque-converter lockup. The CCC was updated in 1982 to make up to 80 adjustments per second.
Corvette 350 Crossfire Engine
The Crossfire system uses dual 48mm Rochester throttle-body injection units (PN# 17083055). Combined total flow is 750-cfm. Two cross-mounted throttle-bodies feed the engine, one for each bank (left and right) of cylinders. The right-side throttle body feeds the left bank of cylinders and the left-side feeds the right bank.
Crossfire Intake Manifold
The cross-ram intake manifold (PN 14057016) is made of aluminum, and designed to quicken the velocity of the air/fuel mixture ratio. The design dates back to 1968, when Mark Donahue dominated the SCCA Trans-Am series with his Penske-owned Z/28 Camaro, powered by a 302ci small-block V8 with dual Holley 4-bbl carburetors.
Crossfire Fuel Injectors
Two fuel injectors are used on the Crossfire motor, each opening every time there is a primary ignition pulse. Since two are used, each injector opens every other time a spark plug fires. They are wired to a switched 12 volt ignition and are grounded by the ECM to open them. Required fuel pressure is 9 to 12 psi.
With the help of the Crossfire injection system, engine output for the 1982 Corvette was 200 horsepower at 4,200 rpm and peak torque of 283 lb/ft. at 2,800 rpm. This was the highest engine output of any small-block Chevy since 1973.
The reason for peak torque happening at only 2,800 rpm was due to the ports on the intake manifold - they were about two-thirds the size of the port on the cylinder head. These small ports severely limited performance above 4,000 rpm. GM engineers claimed this was done to have more usable street torque on the bottom end, but Corvette enthusiasts have always debated the validity of this. For those looking for more power, proper porting will yield a solid increase.
Aftermarket Upgrades for Crossfire Engines
Several companies have offered performance upgrades, particularly manifolds, which have bigger ports than stock and really "wake up" the motor. However, checking on Corvette forums and Ebay, it seems these manifolds are not easily gotten.
Corvette Crossfire Misconceptions
When the Crossfire engine came out, there was virtually no-one who knew about it, save for a handful of trained factory techs. Due to both complexity of the electronic controls and special tools needed, Crossfire engine problems were often misdiagnosed and mishandled. Boy racers started playing with it like it was a carburetor - which is wasn't. Because of this, the Crossfire Injection system picked up an undeserved bad reputation.
Using good quality fuel is one of the best ways to ensure long service life from your Crossfire engine. This will eliminate the need for cleaners and also helps prevent moisture from contaminating the fuel system.
The Chevy 350 Crossfire engine is historically significant because it bridged the gap between yesterdays carburetors and today's modern fuel injection systems. Crossfire-equipped cars are unique because of their limited production, and over the years have slowly gained acceptance with Corvette enthusiasts.
External Links
Crossfire Fuel System Diagnosis
1982 Corvette History
1984 Corvette History
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