"From mechanical fuel injection to our modern day Chevy Corvette LS2, LS3, LS7 and LS9 EFI system" Corvette American Metal Muscle Carsfuel injection history before moving on to how the present day fuel delivery systems are being modified for greater performance. All induction modifications are going to be relative to the EFI on the modern Corvette.
The first actual production Corvette fuel injection was the Ram Jet mechanical fuel-injection. It had to be adjusted manually vs. the automatic electronic adjustments found on today's models (which also equaled an emissions nightmare when misadjusted). In the early 80's carburetors were on their way out of the street legal Corvettes.
GM Ram Jet modernized Crate Motor picsIt is claimed that Chevrolet Corvette fuel injection began around 1957 on the 283 c.i. V8, but this article is concerned with the EFI (Electronic Fuel Injection), so most things began with this around 1980. Nothing is written in stone, though, because there are always special model Corvettes that are there to break, or bend, the rules.
1965 Chevrolet Corvette FI (fuel injection) unit pictured - cranescorvette.com1980 California bound Corvettes got electronic carburetors on the 305 c.i. V8. These were mainly designed for emissions, but they also were one of the first main stepping stones on the way to EFI (electronic fuel injection).
GM had now gone one step beyond basic carburetors with the mechanical fuel-injection, and had experimented with the other half of the EFI equation with the electronically enhanced carburetors.
This new electronic system was known as the "Computer Command Control system" (CCC) and was actually an evolution from an existing system (at the time) known as the C-4. The C-4 was actually a Computer Controlled Catalytic Converter. The newer CCC system, also worked with the cat, but added timing, torque-converter lockup, and air/fuel ratio mixtures to the programming mix.
Emissions control regulations jump started the evolution of the automotive computer systems. The basic functions of these computers will always be to keep pollution to a minimum, and to balance fuel economy and power output as part of the equation.
Cross-Fire Fuel Injected Corvette picture - santiagosc.comIn 1982 they finally fully mated the fuel injection and electronics for the Corvette. It was called Cross-Fire Injection (CFI) (RPO L83) and evolved in the Vette until 1984.
1984 Cross-fire Fuel Injection Chevy Corvette pictures - howstuffworks.com
The Corvette evolved from the C3 (Shark) to the C4 while the Cross-Fire injection was used, so both body styles can be found with this fuel delivery system.
Tuned Port Injection (TPI) was the new thing in 1984. Maximum horsepower reached 205 with the previous CFI (Cross-Fire injection), but the new TPI came in with a bang at 230 horsepower.
In 1985 MAF sensors were used on the new Tuned Port Injected (TPI) motors for fuel regulation. The MAF's measure intake volume, and provided a much more accurate air flow reading (at the time) than could be attained from the previous versions reliance on the intake vacuum lines.
1985 L98 TPI (Tuned Port Injection) Chevrolet Engine picture
In 1990 though, an improved system was devised which went back to the intake vacuum for readings. This new "Manifold Absolute Pressure" (MAP) perimeter, was used by the computer, along with intake temperature, and a few other readings, to get a pretty good reading on the actual air mass being ingested through the system.
Of course during this evolution many different fuel injectors where used. Bosch, Lucas, and Multec were all tested out, and shipped from the factory, on various models.
Intake runner length was also adjusted in the quest for performance. The 1992 LT1 featured shortened intake runners, and was kicking out more than 300 horsepower.
1992 LT1 5.7 L 350 c.i. GM Chevrolet V8 engine pictures
In 1993 the LT1 went back to the MAF sensor (with a MAP sensor backup unit). Most MAF sensors use a heated wire to measure the air flow which passes by on the way into the motor.
1994 saw the introduction of Sequential Fuel Injection. SFI was a big step in refining the fuel control. This system allowed for an injector to specifically service, and be regulated, for one cylinder. Many earlier systems were designed to fire off a whole bank of injectors at once, and it was impossible to regulate any single injector.
1997 saw the implantation of the Throttle Actuator Control system (TAC) which basically included a motor which controlled the throttle body at idle. This allowed for a total drive-by-wire system with no throttle cables.
2003 LS1 5.7 L V8 Chevrolet Corvette Motor images
The LS1 then came along with an improved intake runner design that provided improved flow at lower the RPM which equaled more torque. This design was again improved on the 2001 LS6 Z06 engine.
2001 saw the MAF go from a 74mm to an 85mm bore, and a relocation of the MAF air temperature sensor.
2002 Z06 Corvettes saw some obstructions removed from the MAF (a screen).
LS9 ZR1 C6 Chevy Corvette Fuel Rail picture
Just so you know; the 2010 ZR1 LS9 motor uses an electronic 87-mm single-bore throttle body, and high-capacity 48-lb. /hr. fuel injectors with center-feed fuel lines.
Plus, the ZR1 LS9 Chevrolet Corvette supercharger helps things along
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Chevrolet Corvette Fuel injection YouTube Videos:
While we reminisce - the 1957 Fuel Injection Corvette Video
1957 Chevrolet Rochester Corvette fuel injection advertisement video
Visit the Corvette “American Metal Racing” modern muscle cars index for more information, images and videos.
[ref] corvettefever.com (Andy Bolig), wikipedia.org, howstuffworks.com
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