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Evolution of the Buick Turbo V6
The Buick Turbo V6 was introduced in 1978. Each year, engineers made improvements to the design. Due to these changes, many parts are not interchangeable and it is important to know the engine's production year. The following lists the upgrades made each year. Also, please check the Turbo Regal Website's "History of the Buick V6". If you have questions about anything listed, please use the MESSAGE BOARD. Information sources listed at bottom. Note: While I believe the following is accurate, please confirm them before making decisions regarding your car. Also, the literature sources used are NOT always 100% correct!
Casting Numbers have been moved to here.
HORSEPOWER: 4-bbl 165 @ 4000 rpm, 2-bbl 150 @ 3800.
TORQUE: 4-bbl 285 lbs.-ft @ 2800 rpm, 2-bbl 245 @ 2400.
All 3.8 V6 engines now even-firing (mid 1977 production change).
Turbocharging introduced, 2-barrel and 4-barrel versions available. 4-barrel much more common.
Electronic Spark Control (ESC) used to retard timing when detonation (knocking) is detected. This is what allows the Turbo V6 to work without a water/alcohol injection system like most other systems. The controller (a.k.a. Turbo Control Center) is located on fan shroud and the knock sensor is located on intake manifold. Same controller is used for all '78 Turbo V6's, GM part # 16005964. Please see the KNOCK, KNOCK page.
Three-speed automatic transmission standard. The Turbo V6 was never offered (in any year) with a manual transmission.
HORSEPOWER: Regal/LeSabre 170 @ 4000 rpm, Century 175
@ 4000, Riviera 185 @ 4200.
TORQUE: Regal/LeSabre 265 lbs.-ft @ 2800 rpm, Century 275 @ 2600, Riviera 280 @ 2400.
"Free breathing" cylinder heads. Requires different intake and exhaust manifolds than 1978.
Quadrajet now standard. 2-barrel version dropped.
Hotter spark plugs with narrow gaps to minimize fouling. Plugs changed from R44TSSX with 0.060-inch gap to R44TS gapped to 0.040-inch.
ESC controller same as 1978 for Regal, LeSabre and Century models (# 16005964). Riviera uses GM part # 16006614. Please see the KNOCK, KNOCK page.
Differences in HP/torque ratings between models due to exhaust systems.
HORSEPOWER: Regal/LeSabre/Monte Carlo 170 @ 4000 rpm,
Century 175 @ 4000, Riviera 185 @ 4200.
TORQUE: Regal/LeSabre/Monte Carlo 265 lbs.-ft @ 2800 rpm, Century 275 @ 2600, Riviera 280 @ 2400.
Electronic Spark Control (ESC) or "Turbo Control Center" moved from the fan shroud under the hood to the inside of the passenger compartment under the dash.
Aluminum intake manifold.
Knock sensor relocated from intake manifold to top, rear of block (behind and below the EGR valve). Moved because new aluminum intake would affect sensor operation. Please see the KNOCK, KNOCK page.
Thermal vacuum valve to the choke.
Dual bed catalytic converter.
California Models have Computer Command Control (CCC) to comply with emissions laws. Easily identified by presence of ECM, Oxygen sensor and electronic carburetor. May be identical to the 1981 system, or a hybrid of the two years.
HORSEPOWER: Regal/Monte Carlo 170 @ 4000 rpm, (Riviera
TORQUE: Regal/Monte Carlo 275 lbs.-ft @ 2400 rpm, (Riviera 270).
Computer Command Control (CCC) used to monitor and control engine systems. Easily identified by presence of ECM, Oxygen sensor and electronic carburetor. ALDL connector under dash uses five terminals. Models for Canada and Export do not use CCC.
Electric Early Fuel Evaporative (EFE) system added. The system uses a ceramic heater grid located underneath the primary bores of the carburetor as part of the carb-plenum gasket.
Normally open waste gate. Uses only one port connector (vacuum).
High-pressure oil pump.
Signal Noise Enhancement Filter to make detonation detection more precise (ESC system).
Torque Converter Clutch added to eliminate high speed slipping.
Performance package, RPO Y47, offered mid-year on Regal. Consisted of dual exhaust, high stall speed torque converter and 3.08 rear axle. Added 5 horsepower.
Export models have not have Computer Command Control (CCC). Easily identified by lack of ECM, Oxygen sensor and electronic carburetor. May be identical to the 1980 system, or a hybrid of the two years.
HORSEPOWER: Regal 175 @ 4000 rpm, Riviera 180 @ 4000.
TORQUE: Regal 275 lbs.-ft @ 2600 rpm, Riviera 270 @ 2400.
Note: Regal's HP from various magazine articles. Also reported as 170 @ 3800 rpm, but 1981 RPO Y47's components are now standard - HP must be 175 @ 4000 rpm.
The turbocharger is equipped with a smaller turbine wheel and housing (from 0.82 to 0.63 A/R ratio) to improve performance (compressor is A/R 0.42). The change greatly improves throttle response - less lag. Normally closed waste gate returns. Provides better control of boost at slower engine speeds. Original turbos do not have finned housings. The 1982 GM service (replacement) turbocharger has the finned housing (for better cooling) and is the same as the 1983 service turbocharger.
Turbo downpipe increased from 2.0 to 2.25 inches internal diameter.
New camshaft, valve springs and dampers to permit higher rpm.
Oil pan capacity increased to 5-quarts by use of internal baffles. This along with a new "squirt hole" in the turbo's center section and higher pump pressures, increases oil change intervals extended to 7,500 miles.
Exhaust heated plenum. To improve cold derivability, the new exhaust heated plenum replaces the previous years coolant heated plenum. The new design provides heat quicker on cold starts and results in a cooler operating intake manifold which allows for a denser air/fuel mixture.
More advanced form of Computer Command Control (CCC) used to monitor and control engine system. ALDL connector under dash now uses 12 terminals.
Higher stall speed torque converter, and torque converter clutch (TCC) computer controlled. The ECM PROM (code MR) was programmed to engage clutch at WOT as well as high speed cruising. A revised, mid-year PROM (ARW) was introduced to correct a "surge" problem associated this. (Not clear if WOT TCC engagement was modified or removed.)
Dual exhaust and 3.08 rear axle ratio standard on Regal.
Early Fuel Evaporation now electronically controlled.
HORSEPOWER: 180 @ 4000 rpm.
TORQUE: 280 lbs.-ft @ 2400 rpm (Riviera 290).
Note: Regal's HP incorrectly reported as 190 in Facts and Figures Books by Steven L. Dove and copied by Turbo Regal Website. All Buick literature states 180 HP.
Stainless Steel exhaust manifolds and a lower restriction exhaust crossover.
Knock sensor changed from accelerometer to piezo element. Generates better signal to ESC system. Same sensor and controller is used on the SFI Turbo V6 and other engines. Please see the KNOCK, KNOCK page.
Finned turbocharger housing. Helps keeps bearing cooler.
Regal T Type receives 3.42 axle ratio and overdrive THM 200-R4 (4-speed auto).
Riviera's plenum and EFE grid revised for more through fuel vaporization during warm-up.
Power Brake unit switched from vacuum to Hydroboost system. Uses power steering pump to provide power assist.
HP and Torque figures (Unless noted): Standard Catalog of Buick 1903-1990; Krause Publications.
All Other: Buick Sales Literature and Advertising.
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