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Popular Hot Roding June Issue by Steven Rupp.

"You may be reading this and wondering why PHR is doing a story on a four banger. The answer is simple: this new turbocharged Ecotec makes V-8 power, while retaining four-cylinder fuel mileage. To illustrate the point, let's turn the clock back to 1985, when GM introduced its then fire-breathing 250 HP, L98 tuned port small block in the new C4 corvette. At the time, the Corvette was the fastest car you could buy in America; it was the pinnacle of power and performance, and now it's to be upstaged by a four cylinder. My, how far we've come.

Many of the technical innovations in the turbo Ecotec, like variable valve timing and intercooling, have been around for a while, yet it's the unique way these systems are combined with new cutting edge, technology that allows this small displacement engine to chum out a very impressive 260 HP and an equal amount of torque. It may not sound like much compared to GM's 505-HP LS7, but at only two liters, it's the highest specific output engine ever built by GM. WHAT'S NOT TO LOVE ABOUT 2.1 hp PER CUBIC INCH? We're not suggesting you rip out your 383 stroker motor and toss an Ecotec, but we invite you to learn about the technology that may eventually find its way into V8s that we love. After all, at 2.1 HP per cubic inch, GM's LS7 would be putting out over 896 HP, and that's a number worth shooting for."

DIRECT INJECTION

One key factor in the Ecotec’s ability to make power is the use of direct injection. This system differs from the fuel delivery process of a conventional engine by spraying fuel directly in the combustion chamber, where it is mixed with air drawn into the chamber through the intake. In a conventional fuel injected engine, air and fuel are mixed in the intake port or intake manifold prior to going into the combustion chamber. Direct injection is an evolution of this process and offers improved control of the fuel by introducing it closer to the point of combustion.

According to Ecotec’s chief Engineer Dean Guard, “Direct injection (spark Ignited Direct Injection – SIDI as GM calls it) is one of those rare technologies where we get a synergistic benefits from a single technology. Direct injection offers the opportunity to increase the compression ratio due to the charge-cooling effects of the in-cylinder fuel vaporization, and therefore helps both improve fuel economy, around 2%, and performance with roughly a 5% power increase.” The way that direct injection precisely delivers the fuel enables a more complete combustion, particularly on cold starts when emissions are higher. Better combustion means fewer emissions and a greater fuel economy benefit from the higher compression. It’s a win-win in an industry constantly trying to meet tougher government standards.

DUAL-SCROLL TURBO

Another technology unique to this motor is the use of a dual-scroll turbocharger. Dual exhaust passages from the engine to the turbine move the exhaust gas to the turbo more efficiently. This in turn reduces the time needed for the turbo to spool up and cuts the lag time commonly associated with turbocharging at low rpm. Guard told PHR: “The engine feels more like a naturally aspirated engine since there is virtually no lag. Throttle response is immediate.” Max boost for the intercooler system is about 20 psi and the motor is in boost as low as 1,700 rpm with peak boost at around 2,500 rpm. This turbo is well tested in currently used in boosted Saabs.” According to Ed Groff, assistant chief engineer of the Ecotec turbo: “Direct injection technology works well with turbocharging and helps deliver a great balance of power and economy. The Ecotec 2.0 liter turbo produces the power expected of a V6, but in a smaller, more efficient package – and the driving response is simply terrific.” We asked Guard why GM chose a turbo over a supercharger and he had this to say: “This engine from day one was designed as a global engine. Turbos are well-received in Europe, but the same cannot be said for supercharging. The turbo also suffers less from parasitic losses typically of supercharging. Also, the dual scroll turbo coupled with SIDI results in virtually no turbo lag, so a supercharger was even less necessary.” Being able to effectively market the engine overseas means that the overall cost for the powertrain development can be spread over the international market.”
 

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Opel Speedster



The only GM product with a factory Ecotec Turbo
 

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wt2ga said:
The only GM product with a factory Ecotec Turbo
wt2ga,

that's not correct: the first was Opel Calibra 1992 with 2.0 Turbo 204 hp, 207 lbft @ 2400. This engine was designed by Professor Fritz Indra, Opel Chief Engine Developer at the time.
Later cars where Opel Vectra, Astra and others with power range between 170 and 240 hp OEM.

The first years Speedsters from 2000 where equipped with the 2.2 natural aspirated 147 hp engine, later the 2.0 Turbo as above was added to raise up sales, but it didn't really help. Last years only Turbo produced. Stop of production mid 2005, ~ 7,000 cars produced in total.

Here is an old article of long run test (100,000km - 62,500 mls).
View attachment 3273 View attachment 3274 View attachment 3275 View attachment 3276 View attachment 3277
Bad scanner quality and in german language but I think the picture are understandable.
If you have a look at page three there is the exhaust integrated low pressure turbo (12 psi only) shown.

This car in light silver I'm driving since 1992, engine also shown in my avatar.
 

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And all the SAAB motors too..
 
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