Pontiac 301 Turbo
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|Predecessor||301.6 cu in (4.9 L) Pontiac 301|
The Pontiac 301 Turbo was an engine that Pontiac produced for the 1980 and 1981 Trans Ams and Formula Firebirds. It was a V8 engine that produced a mild 210 hp (160 kW) and 345 ft·lb (468 N·m) of torque in 1980 and 205 hp (153 kW) and 336 ft·lb (456 N·m) of torque in 1981, more than any Pontiac engine since the 455 in 1975. The Turbo Trans Am replaced the 400 cu in (6.6 L) Pontiac and 403 cu in (6.6 L) Oldsmobile engines as the performance option for the Firebird model. The engine changes were partly motivated by the oil crisis of 1979, as GM pursued smaller, more efficient engines (both smaller displacement and forced induction).
Based on the standard Pontiac 301, the 301 Turbo was unique in that it had a beefier block than the 77-81 naturally aspirated, lower compression pistons, a relatively mild camshaft, a high pressure oil pump (60 psi) to ensure adequate oil to the oil-cooled Garrett TBO-305 Turbocharger, a rolled fillet crankshaft with 2 instead of 5 counterbalances, a fully baffled oil pan, and a high pressure fuel pump (10 psi), a unique single plane intake, side and turbo-specific exhaust manifolds, and an Electronic Spark Controller(ESC) using a knock sensor to retard timing when detonation is detected. The Turbo 301 used the same bearings, rings, lifters, and most external accessories used on the N/A 301s.
The M4ME (E4ME for 1981) 800 cfm Rochester Quadrajet, unique to the 301 Turbo, had super rich "DX" secondary metering rods and a remote vacuum source for the primary metering rod enrichment circuit; the "PEVR" or Power Enrichment Valve Regulator. Boost was wastegate limited to 9 psi (+/- 1 psi) although factory settings ranged from 7 on low to 10 psi on high.
The 301 Turbo package (RPO code LU8) mandated air conditioning (C51) due to the turbo-specific heater core box, and automatic transmission (TH350 (non-lockup) for 1980, and THM350C (lock-up) for 1981) and 3.08 positraction rear axle ratio (G80).
The main causes of engine failure and distrust was the public's lack of experience and knowledge of care and maintenance of the new turbo engines. Often, the turbo cool-down procedure was never followed or even known to exist to some owners allowing the turbo to burn or "coke" oil onto the turbo's bearings causing early (sub 50,000 mile) failure prompting service or even complete engine replacement. Combined with the mechanic's lack of knowledge ultimately caused GM to cease production after April 1981.
Even though the 301 was made on the same tooling as other Pontiac V-8's there is a limited interchange of parts and somewhat less popularity compared to traditional Pontiac engines. There is limited aftermarket parts, but replacement parts for the 301 Turbo engine can be sourced through the design's devoted followers.