OBI WAN
11-11-04, 07:45 PM
The 4.3 V6
These 4.3's are 90 degree even-fire engines, with a 1-6-5-4-3-2 firing order.
4.3L translates to 262 cubic inches, and 4293cc's.
Bore is 4.00" (101.6mm) and stroke is 3.48" (88.39mm) with a 5.7" connecting rod.
All have overhead valves, with two valves per cylinder.
Cylinders are: 1-3-5 (Driver's side front to back)
2-4-6 (Passenger side front to back)
Almost all 92+ engines have an internal balance shaft to help reduce vibration.
The VIN engine digit is the 8th in the code. RPO list is in your glovebox.
The heads and blocks of these 4.3's are cast iron.
TBI (Throttle Body Injection)
http://hooverae.com/upload/files/1TBI.jpg
TBI is very similar to a carburetor, but much easier to maintain and more versatile. It has two injectors in a pod above the throttle plates. Injectors are batch-fired. Late model TBIs may have CPI (L35) Vortec heads (usually identified by plastic 'Vortec' valve covers) raising horsepower to 165 and ft/lbs to 235.
1988-1992 4.3 (4300)
RPO: LB4 VIN: Z
Compression Ratio 9.3:1
160 H.P. @ 4000 RPM
230 FT-LBS @ 2800 RPM
1993-1995 4.3 (4300)
RPO: LB4 VIN: Z
Compression Ratio 9.3:1
165 H.P. @ 4000 RPM
235 FT-LBS @ 2400 RPM
Turbocharged MPFI (Multi-Port Fuel Injection)
http://hooverae.com/upload/files/sycloneeng.jpg
Turbo-MPFI is the most powerful 4.3 released by GM, but it was only available in the Syclone and Typhoon trucks. A Syclone runs the 1/4 mile in roughly 13 seconds at 100 mph. 0-60 time is about 4.8 seconds. The block and cylinder heads are the same as the LB4 TBI, with the exception of lower-compression pistons and nodular iron main caps. Boost is provided by a Mistubishi TD06-17G at 550 CFM. Fuel injectors and throttle body are borrowed from L98 Corvette/F-body V8's. The fuel injectors are fed through fuel rails and are batch-fired.
1991-1993 4.3 (4300)
RPO: LB4 VIN: Z
Compression Ratio 8.35:1
280 H.P. @ 4200 RPM
360 FT-LBS @ 3600 RPM
Boost: 14 psi
CPI (Central Multi-Port Fuel Injection)
http://hooverae.com/upload/files/CPI.jpg
CPI operates very similarly to TBI with a central injection assembly mounted in the intake manifold. It uses single batch-fired injector feeding six poppet valves located at the intake ports. It has a dual-plenum manifold (upper and lower) with variable tuning with a manifold tuning valve to equalize pressure.
1992-1995 4.3 (4300)
RPO: L35 VIN: W
Compression Ratio 9.05:1
195 H.P. @ 4500 RPM
260 FT-LBS @ 3600
CSFI (Central Sequential Fuel Injection) or just SFI
http://hooverae.com/upload/files/CSFI.jpg
The heads on the CSFI engines are the best-designed for the 4.3 to date. They flow much higher CFM than any other head, and have a better designed combustion chamber. CSFI uses six individual injectors and a fuel pressure regulator that pulses fuel through six orifices through flexible nylon tubes. These tubes run to poppet valves at the intake ports. LU3 is the RPO for the 4.3's equipped with the new Multec II injectors.
1996-1998 4.3 (4300)
RPO: LF6 VIN: X
Compression Ratio 9.2:1
2WD 175 H.P. @ 4400 RPM
4WD 180 H.P. @ 4400 RPM
2WD 240 FT-LBS @ 2800 RPM
Central Sequential Electronic Fuel Injection
1996-2004 4.3 (4300)
RPO: L35/ LU3 VIN: W
Compression Ratio 9.2:1
2WD 180 H.P. @ 4400 RPM
4WD 190 H.P. @ 4400 RPM
2WD 245 FT-LBS @ 2800 RPM
4WD 250 FT-LBS @ 2800 RPM
Central Sequential Electronic Fuel Injection
In 1996 GM went with the use of the OBD2.
In 2001 GM went with the use of the second generation OBD2, which is nicknamed the LS Style OBD unit which is a 2 connector unit versus the previous OBD unit that used a 4 connector.
In 2000 the 4.3 began using a roller fulcrumed rocker arms at 1.5:1 ratio. Prior to that it used normal casted rocker arms.
In 2002 the older styled poppet injectors were replaced with the Multec II units which no longer featured the trouble some poppet ends which had a problem with plugging up using MTBE gas and or no regular maintainance like using fuel injector cleaners! (GM is offering an upgrade kit through dealerships for 96+ engines with CSFI.)
Credits- Jedi Master, Matt 4.3 TBI
These 4.3's are 90 degree even-fire engines, with a 1-6-5-4-3-2 firing order.
4.3L translates to 262 cubic inches, and 4293cc's.
Bore is 4.00" (101.6mm) and stroke is 3.48" (88.39mm) with a 5.7" connecting rod.
All have overhead valves, with two valves per cylinder.
Cylinders are: 1-3-5 (Driver's side front to back)
2-4-6 (Passenger side front to back)
Almost all 92+ engines have an internal balance shaft to help reduce vibration.
The VIN engine digit is the 8th in the code. RPO list is in your glovebox.
The heads and blocks of these 4.3's are cast iron.
TBI (Throttle Body Injection)
http://hooverae.com/upload/files/1TBI.jpg
TBI is very similar to a carburetor, but much easier to maintain and more versatile. It has two injectors in a pod above the throttle plates. Injectors are batch-fired. Late model TBIs may have CPI (L35) Vortec heads (usually identified by plastic 'Vortec' valve covers) raising horsepower to 165 and ft/lbs to 235.
1988-1992 4.3 (4300)
RPO: LB4 VIN: Z
Compression Ratio 9.3:1
160 H.P. @ 4000 RPM
230 FT-LBS @ 2800 RPM
1993-1995 4.3 (4300)
RPO: LB4 VIN: Z
Compression Ratio 9.3:1
165 H.P. @ 4000 RPM
235 FT-LBS @ 2400 RPM
Turbocharged MPFI (Multi-Port Fuel Injection)
http://hooverae.com/upload/files/sycloneeng.jpg
Turbo-MPFI is the most powerful 4.3 released by GM, but it was only available in the Syclone and Typhoon trucks. A Syclone runs the 1/4 mile in roughly 13 seconds at 100 mph. 0-60 time is about 4.8 seconds. The block and cylinder heads are the same as the LB4 TBI, with the exception of lower-compression pistons and nodular iron main caps. Boost is provided by a Mistubishi TD06-17G at 550 CFM. Fuel injectors and throttle body are borrowed from L98 Corvette/F-body V8's. The fuel injectors are fed through fuel rails and are batch-fired.
1991-1993 4.3 (4300)
RPO: LB4 VIN: Z
Compression Ratio 8.35:1
280 H.P. @ 4200 RPM
360 FT-LBS @ 3600 RPM
Boost: 14 psi
CPI (Central Multi-Port Fuel Injection)
http://hooverae.com/upload/files/CPI.jpg
CPI operates very similarly to TBI with a central injection assembly mounted in the intake manifold. It uses single batch-fired injector feeding six poppet valves located at the intake ports. It has a dual-plenum manifold (upper and lower) with variable tuning with a manifold tuning valve to equalize pressure.
1992-1995 4.3 (4300)
RPO: L35 VIN: W
Compression Ratio 9.05:1
195 H.P. @ 4500 RPM
260 FT-LBS @ 3600
CSFI (Central Sequential Fuel Injection) or just SFI
http://hooverae.com/upload/files/CSFI.jpg
The heads on the CSFI engines are the best-designed for the 4.3 to date. They flow much higher CFM than any other head, and have a better designed combustion chamber. CSFI uses six individual injectors and a fuel pressure regulator that pulses fuel through six orifices through flexible nylon tubes. These tubes run to poppet valves at the intake ports. LU3 is the RPO for the 4.3's equipped with the new Multec II injectors.
1996-1998 4.3 (4300)
RPO: LF6 VIN: X
Compression Ratio 9.2:1
2WD 175 H.P. @ 4400 RPM
4WD 180 H.P. @ 4400 RPM
2WD 240 FT-LBS @ 2800 RPM
Central Sequential Electronic Fuel Injection
1996-2004 4.3 (4300)
RPO: L35/ LU3 VIN: W
Compression Ratio 9.2:1
2WD 180 H.P. @ 4400 RPM
4WD 190 H.P. @ 4400 RPM
2WD 245 FT-LBS @ 2800 RPM
4WD 250 FT-LBS @ 2800 RPM
Central Sequential Electronic Fuel Injection
In 1996 GM went with the use of the OBD2.
In 2001 GM went with the use of the second generation OBD2, which is nicknamed the LS Style OBD unit which is a 2 connector unit versus the previous OBD unit that used a 4 connector.
In 2000 the 4.3 began using a roller fulcrumed rocker arms at 1.5:1 ratio. Prior to that it used normal casted rocker arms.
In 2002 the older styled poppet injectors were replaced with the Multec II units which no longer featured the trouble some poppet ends which had a problem with plugging up using MTBE gas and or no regular maintainance like using fuel injector cleaners! (GM is offering an upgrade kit through dealerships for 96+ engines with CSFI.)
Credits- Jedi Master, Matt 4.3 TBI