What do these cars have in common The formidable 5.7 litre 350 CID 16-valve LT1 powered both What do these two automobiles have in common besides both of them being GM products? A Cadillac Fleetwood Brougham and a Chevrolet Impala SS are a highly unlikely pair. One is decadently luxurious and the other is built for high performance. The 1996 model year was the finale for the full-size “B-body” rear drive cars. They both shared the second generation 5.7 litre LT1 V8 engine introduced in 1992 by the Corvette. They both share the same “B-body” platform. Their high performance camaraderie changed the way one thought of American cars. The 1996 Fleetwood Brougham retained its classic Cadillac elegance and style. The dramatically aerodynamic and powerfully sporty 1996 Impala SS was a spacious and understated. This was a unique encore duet performance in the continuing saga of “As the Standard of the World Turns.” Two complete opposites at each end of the spectrum…luxury and performance were elements for each car. The heart of the camaraderie was the 5.7 litre LT1 V8 engine, yes, they were both powered by “the Heart-beat of America.” The formidable 5.7 litre 350 CID LT1 V8 engine combined efficiency, emissions compliance, durability, and performance. It was first introduced as the second generation of the 5.7 litre LT1 in the 1992 Corvette. The differences being both the Fleetwood and the Impala SS used cast iron cylinder heads, a camshaft designed for low-end torque rather than high-end hp, and 2-bolt main bearing caps. The Vette used aluminum cylinder heads and 4-bolt main bearing caps. The 5.7 litre LT1 V8 engine was a highly sophisticated not to mention adaptable powerplant. It used exhaust manifolds with tri-layered stainless-steel gaskets to reduce exhaust leaks and improve durability. Copper lead cam bearings replaced the cadmium bearings previously used. The LT1 featured platinum tipped spark plugs and low resistance ignition wires that improved idle quality and cold starts. The pistons were revised using a positive-twist top ring that improved the ‘piston-to-cylinder’ seal and reduced blow by emissions at high engine speeds. Sequential Fuel Injection (SFI) optimized combustion by using input from the PCM to precisely match fuel delivery to each cylinder’s intake stroke. SFI is designed to provide smooth idle, impressive overall operation, and precise emissions control. The Powertrain Control Module (PCM) monitored the emissions controls and its components to detect deterioration or malfunction. It also controlled individual fuel injectors, optical ignition system, and interacted with the electronic transmission. A mass airflow sensor provided accurate information regarding air entering the engine that the PCM used to determine the fuel requirement for maximum efficiency.A low-restriction intake and air filtration system allowed the engine to breathe freely for efficiency and met federal noise relations. Cylinder head ports and weight saving one-piece intake system improved air flow into combustion chambers for a clean-burn enhancing power and efficiency. The reverse flow cooling system circulates coolant thru dedicated cylinder heads BEFORE the engine and radiator providing a higher compression ratio for more power. A gear-driven coolant pump virtually eliminated side-load stress providing uninterrupted coolant flow even if a belt breaks. The 5.7 litre LT1 included an oil change monitor that calculated and displayed the condition of the engine oil. An oil level sensor alerted driver should engine oil drop one-two quarts, unlike the traditional systems that alert the driver AFTER the engine is cooked from friction due to low to no engine oil situations. A heavy-duty upgraded oil pan substituted the standard version. The second generation 5.7 litre 350 CID 16-valve LT1’s operating range extended hundreds of rpm beyond most OHV V8 engines giving the LT1 the low-speed thrust of a traditional push-rod engine and the high-speed performance of an OHC design. It was the best of both worlds. The 1996 Cadillac Fleetwood Brougham’s 5.7 litre produced 260 hp @ 5,000 rpm with 447 Nm of peak torque @ 3,200 rpm. Performance was rated as 0-60 mph in 8.2 seconds, 0-100 mph in 22.3 seconds with a top speed of 142 mph. It did the ¼ mile @ 88 mph in 16 seconds. The engine used Sequential Port Fuel Injection controlled by the Powertrain Control Module (PCM) with a paper element fuel filter and electric in-tank fuel pump. GM’s Turbo Hydra-Matic 4L60-E 4-speed automatic transmission was equipped with electronic shift control, torque converter clutch, and overdrive. Emission controls included (AIR) Air Injector Reactor with Computer Command Control (CCC), (EGR) Exhaust Gas Recirculation with controlled flow, 3-way warm-up catalytic converter, Evaporative Emission Control with charcoal canister, and (PVC) Positive Crankcase Ventilation. Image Image Image The Impala SS 5.7 litre 350 CID 16-valve LT1 produced 260 hp @ 5,000 rpm with 447 Nm of peak torque @ 2,400 rpm. Performance was rated as 0-60 mph in 7.4 seconds, 0-100 mph in 20.8 seconds with a top speed of 142 mph. It did the ¼ mile @ 88 mph in 15.4 seconds. It was mated to GM’s Turbo Hydra-Matic 4L60-E 4-speed automatic transmission. Most Impala SS owners usually rebuild the standard basic automatic transmission to the T-56 manual transmission used by the Camaro and Firebird. With all of the power/torque thrust available, the transmissions usually require service at 100,000 miles. There were also other hp versions of tune for the 5.7 litre LT1, one was tuned to produce 300 hp @ 5,200 rpm and one was tuned to produce 285 hp @ 5,200 rpm. The trusty 5.7 litre 350 CID V8 was an extremely popular GM powerplant. The chassis for this brute was upgraded with the 9C1 police interceptor package which included a tuned and lowered suspension, reinforced springs, high-capacity reverse-flow cooling system, large 12.1” disc brakes, transmission cooler, dual exhaust, and a high-output electrical system. Image Both Cadillac Fleetwood and Chevrolet Impala SS were large front engine rear drive vehicles built as body on frame construction built on a ladder-type frame. The Impala SS rode a 115.9” wheelbase, was 214.1” long and 77” wide. The Fleetwood Brougham rode a long 121.5” wheelbase, had the luxury length of 225.1” and was 78” wide. Image Image The Impala SS began as the brainchild of Jon moss, then Manager of Chevrolet Special Vehicles His task assigned was to boost the sagging sales of the full-size “B-body” Caprice. “Orca” was tanking fast after a complete redesign for the 1991 model year. The Caprice was nick-named after the killer whale it resembled because of its odd proportioned styling. The Impala SS 510 Concept was the vehicle that started it all. Moss created the concept powering it at first with an 8.2 litre 500 CID V8 engine. The 5.7 litre LT1 was installed to show the public what the production version would be like. An 8.4 litre 510 CID V8 engine was ultimately installed into the prototype’s engine bay.
Posted on: Thu, 16 Oct 2014 03:03:03 +0000
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