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http://www.saturnfans.com/Cars/Motorsports/saturnboostedecotec.shtmlBoosted Ecotec Engine Performs Under Pressure
SaturnFans.com · October 25, 2003
The Bonneville Salt Flats distills the science of speed to its basic elements: a contest between engine output and aerodynamic drag. The faithful who journey to Bonneville in pursuit of records know that horsepower rules on the salt.
The Saturn ION Red Line Bonneville racer has a formidable ally in its battle to overcome aero drag. Nestled beneath its sloped hood is a modified version of the production Ecotec engine. The production ION Red Line's supercharged and intercooled 2.0-liter Ecotec pumps out an estimated 200-plus horsepower. Equipped with an exhaust-driven turbocharger and burning methanol fuel, the modified ION Red Line Bonneville racer produces 700 horsepower. Should even this prodigious power prove insufficient for the task, a simple boost adjustment can summon up a veritable herd of horses to propel the ION Red Line racer through the thin air of Utah's high desert.
In production trim, the Ecotec inline four-cylinder engine delivers exceptional fuel economy, spirited performance and low exhaust emissions in a reliable, low-maintenance package. In racing trim, its mission is simply to deliver astounding power.
The turbocharged Ecotec engines that propel GM Racing's front-wheel drive Cavalier and Sunfire entries in the NHRA Summit Sport Compact drag racing series produce more than 1,100 horsepower from only 127 cubic inches of piston displacement - a staggering 8.6 horsepower per cubic inch.
While drag racing engines complete their quarter-mile sprints in less than nine seconds, engines at Bonneville must run flat-out for miles. Operating continuously at wide-open throttle subjects internal engine components to punishing loads and withering heat. GM Racing engine specialist Russ O'Blenes adapted his proven recipe for drag racing Ecotec engines to the harsh demands of the Salt Flats.
"We calculated the horsepower required to run 225 mph based on the Saturn ION's frontal area and coefficient of drag," O'Blenes explained. "Our target was 670 horsepower at 8,500 rpm. That's well within the Ecotec's capabilities, since the drag racing version produces more than 1,100 horsepower and revs to 10,500 rpm. We conducted a series of dynamometer durability tests to validate the turbocharged Ecotec engine combination for the record attempt."
The ION's race-prepared Ecotec engine inherited many of its fundamental strengths from its production counterpart. The Ecotec block's rigid bottom end resembles a classic racing engine, with a one-piece casting that incorporates the five main bearing caps (each retained by four fasteners) and mounts a structural cast-aluminum oil pan. The four-valve aluminum cylinder head's generously sized intake and exhaust ports provide excellent airflow (250 cfm at .400-inch intake valve lift), while a single centrally located spark plug in each pent-roof combustion chamber provides fast, efficient combustion. The two overhead camshafts actuate the inlet and exhaust valves via roller finger follower rocker arms - another design feature found in many high-rpm racing engines.
"The majority of the engine components are production parts," O'Blenes noted. "We're using a production block, production main bearing girdle, production cylinder heads, and a production drive chain. It's simply amazing what can be done with this basic Ecotec engine package."
The race-prepared engine builds on the strengths of these production components. The block was modified with stainless steel O-rings and copper head gaskets to withstand the extreme cylinder pressure produced by turbocharging. The cylinder heads were ported and outfitted with dual-coil valve springs and titanium retainers; reground production camshafts actuate the valves through stock finger followers. The camshaft drive uses a stock timing chain, guides and hydraulic tensioner. The original camshaft drive gears were slotted to allow adjustments in camshaft phasing.
Heavy-duty components replaced the production crankshaft assembly. A billet steel crankshaft, steel H-beam connecting rods with high-strength bolts, forged aluminum pistons and thick-wall piston pins were manufactured by aftermarket specialists to GM Racing's specifications. The crankshaft rotates in production thick-wall main bearing inserts.
The key to the race modified Ecotec's extraordinary performance is a turbocharger that produces up to 30 psi boost. A naturally aspirated engine depends on atmospheric pressure - the force produced by the weight of the earth's atmosphere - to fill its cylinders with fuel and air. At sea level, standard atmospheric pressure is 14.7 pounds per square inch (psi), but at the Bonneville Salt Flats, which are 4,214 feet above sea level, the pressure is only about 12.5 psi. This lower air density reduces the output of a naturally aspirated engine by approximately 13 percent from sea level. In contrast, the pressurized Ecotec that powers the Saturn ION on the Salt Flats is virtually immune to the effects of altitude. A driver-adjustable electronic boost controller operates a wastegate that regulates the flow of exhaust gases to the turbocharger's turbine. This controller allows higher boost levels to be selected, with corresponding increases in power. A water-to-air intercooler reduces the temperature of the intake charge after it is compressed by the turbocharger.
An electronic fuel injection system precisely meters methanol fuel into the Ecotec's fabricated induction system. Unlike petroleum-based gasoline, methanol can be produced from natural gas, wood, coal, agricultural waste, and even urban trash. Methanol is considered a renewable resource, and GM Racing's Ecotec engine program provides a laboratory for real-world experiments with this promising alternative fuel.
Methanol's octane rating is typically 10 points higher than pump gasoline, which means it is less prone to detonation, the destructive self-ignition of fuel in the cylinders. Methanol will tolerate a higher compression ratio than pump gasoline, thereby improving engine efficiency. Just as the alcohol in aftershave cools the skin when it evaporates, methanol cools the Ecotec's intake tract when it vaporizes. This cooling effect helps to increase air density and further enhances power on a record run.
Many of the heavy-duty Ecotec components developed by GM Racing are now available to enthusiasts through GM Performance Parts. These include complete race-prepared blocks, ported cylinder heads, steel billet crankshafts, connecting rods, pistons, copper head gaskets, aluminum intake manifolds, racing camshafts, neutral-balanced countershafts and intake and exhaust manifold flanges. GM Racing has published an Ecotec Engine Handbook (PN 88958646) with detailed information on preparing and assembling Ecotec engines for competition. GM Performance Parts will also offer a complete, over-the-counter Ecotec crate engine based on the ION Red Line's supercharged 2.0-liter/200-horsepower engine in mid-2004.
Just as the legendary Chevrolet small-block V-8 became the cornerstone of the hot rod and speed equipment industry in the 20th century, the Ecotec is GM's four-cylinder engine of the future.Ecotec Engine Specifications Production ION Red Line Bonneville ION Red Line
Type 2.0L supercharged/intercooled inline 4-cylinder engine 2.0L turbocharged/intercooled inline 4-cylinder engine
Displacement (cu in/cc) 122 / 1998 122 / 1998
Bore & Stroke (in / mm) 3.39 x 3.39 / 86 x 86 3.40 x 3.35 / 86 x 85
Horsepower 205 (estimated) 700+ @ 8700 rpm
Torque (lb-ft @ rpm) 200 (estimated) 575 @ 6000 rpm
Block Material Cast aluminum with cast iron cylinder liners Cast aluminum with cast iron cylinder liners
Valvetrain Steel Titanium
Fuel Delivery Sequential fuel injection Sequential fuel injection
Compression Ratio 9.5:1 10.4:1
Fuel 91 Octane Unleaded Gasoline Methanol
Maximum Engine Speed (RPM) 6450 fuel cutoff 10,500
Emission Controls 3-way catalyst None
Click here for photos of Saturn's Bonneville ION Red Line.
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