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Discussion Starter #1 (Edited)
I originally posted on Solstice forum, but seeing as it's the same engine its worth repeating here.

Details from High Performance Pontiac article on this engine:

It is a high-tech wonder and really shows just how far engine development has evolved in the last several years.

IMPROVING AN ALREADY STURDY DESIGN
A lot of development work went into this new version of the Ecotec; it wasn't simply a matter of plunking a turbo on the engine. Indeed, every major casting was redesigned to provide a heightened level of reliability, though the engine was originally designed for use in forced-induction applications.

As with the new supercharged Northstar engine in the new Cadillac XLR, the displacement of the Solstice GXP's is slightly smaller than the normally aspirated version. Both feature a reduced bore size to increase cylinder-wall thickness. The Ecotec Turbo's stroke is also reduced and features a beefy, forged-steel crankshaft for additional durability. Bore and stroke are 86x86 mm (3.38x3.38 inches) for a total displacement of 1,998 cc's or 122 ci.

The Ecotec 2.0-liter Turbo uses a stronger "Gen II" Ecotec engine block, which was developed with input from racing experience to support increased horsepower and torque. Cylinder-block bulkheads -- the areas where the main bearing caps are attached -- and the cylinder walls are enlarged for strength. Other areas of the engine were enhanced to reinforce the structure, and the water jacket is deeper for added cooling capacity and improved cylinder-bore roundness. This architecture is shared with the 2.4-liter Ecotec engine that debuted in the Pontiac Solstice roadster.

Its bottom end is also upgraded to handle the additional boost. In addition to the forged-steel crankshaft, the Ecotec Turbo also employs forged connecting rods and cast pistons. The pistons feature a dish shape that deflects injected fuel toward the spark plugs. They are cooled with a jet-spray of oil on their undersides that directs the oil into a cast-in channel inside the piston, further resisting detonation.

Additionally, the Ecotec 2.0-liter Turbo four benefits from variable valve timing and an intercooled, twin-scroll turbocharger system to provide boost. A dual-scroll design is used on the exhaust turbine and speeds up velocity and response, much in the same way a two-plane intake manifold performs the identical function. The result is a nearly lag-free system, one that gives the 2.0-liter four the feel of a much larger engine. Dual cam phasing complements the turbocharging by optimizing valve timing at lower rpm for best turbo response and quick engine build-up time. "There is virtually no lag with this system," says Ed Groff, assistant chief engineer, Ecotec 2.0-liter Turbo engine. "Throttle response is immediate. The engine acts like it has a larger displacement engine."

Its turbocharger provides up to approximately 20 pounds of boost. It is matched to the engine's displacement and performance objectives, and is supported by the air-to-air intercooling system, which reduces inlet temperature pf the turbo-compressed air by approximately 212 degrees (100 degrees C), enhancing performance because cooler air is denser.

DIRECT INJECTION
Perhaps the most innovative feature of the new turbocharged Solstice powerplant is the direct injection system. Essentially, the system locates the injector in the combustion chamber rather than in the intake manifold runner or intake port. This arrangement is similar in layout to a diesel powerplant, exposing the injector to the heat and pressure of the combustion event. Unlike a diesel, the Eccotec uses a conventional spark plug and otherwise operates as a normal four-cycle spark-ignition engine. The system is referred to as Spark Ignition Direct Injection (SIDI).

With fuel delivered directly to the combustion chamber to create a more complete burn of the air/fuel mixture, less fuel is required to produce the equivalent horsepower compared to a conventional port-injection system, particularly at normal cruising speeds. "Direct-injection technology works well with turbocharging and helps deliver a great balance of power and economy," says Groff. "The Ecotec 2.0-liter Turbo produces the power expected of a V-6, but in a smaller, more efficient pacckage -- and the driving response is simply terrific."

To accomodate the direct-injection system, the Ecotec 2.0-liter Turbo has a unique cylinder head and intake manifold. The cylinder head incorporates mounting locations for the fuel injectors -- which are typically mounted in the intake ports or intake manifold on port injection engines. A high-pressure fuel pump delivers fuel to a variable-pressure fuel rail. Fuel enters the combustion chamber through multihole fuel injectors. The fuel pump, fuel-rail pressure, fuel injection timing, and injection duration are controlled by the engine control module. In this way, fuel is metered and delivered in a finely atomized spray, which, during the intake stroke, is introduced into the chamber near the intake valves, in direct line of the spark plug. SIDI also permits a slightly higher compression ratio than if the fuel were delivered with conventional fuel injection and allows the mixture to be leaner at full power.

A high-pressure, returnless fuel system is employed for this application. It features a high-strength stainless steel fuel line that feeds a variable-pressure fuel rail. Direct injection requires higher fuel pressure than conventional fuel injected engines, and an engine-driven high-pressure fuel pump is used to supply up to 2,250 psi of pressure. This system regulates lower fuel pressure at idle -- approximately 752 psi and higher pressure at wide-open throttle. The cam-driven, high-pressure pump works in conjunction with a conventional fuel tank-mounted supply pump.

Apart from the mounting position of the fuel injectors, the cylinder head has conventional port and combustion designs, although both are optimized for direct injection and high boost pressures. Sodium-filled exhaust valves and stainless steel exhaust manifold are durable components designed to stand up to the high-performance capability of the engine.

A unique cylinder head, fuel system, pistons, intake manifold, and the dual-scroll turbocharger are the olny major ccomponents that differentiate the 2.0-liter Turbo from other members of the Ecotec engine family. Mobil 1 synthetic engine oil is added at the factory. Synthetic oil was selected for its friction-reducing capabilities and high-temperature performance.

DUAL CAM PHASING
The camshafts of the Ecotec 2.0-liter Turbo engine have phasers that support the continuously variable intake and exhaust valve timing. They also have cam position sensors, so that the engine control module can accurately control valve timing. The crankshaft and camshaft position sensors are digital. A new engine controller, specific to this powerplant, is used to sense and dictate its performance parameters.

Variable intake and exhaust timing works synergistically with both the gasoline direct injection and turbocharging systems. The variable engine timing enabled by cam phasing allows the combustion process to be optimized. Also, valve "overlap" at low rpm can be adjusted by the controller to increase the response of the turbocharger, providing a more immediate feeling of power.

ECOTEC ENGINE FAMILY
The Ecotec 2.0-liter Turbo is built on a global platform that was designed at the outset for a range of performance and combustion capabilities. Gen II blocks support the high-performance demands of the engines, but are merely a strengthened version of the original Ecotec architecture. The oil pump, for example, is the same as used in all other Ecotec engines. It was originally designed to support high-performance applications of future engines.

"This 2.0-liter Turbo is the pinnacle of Ecotec performance to date, with additional growth planned," says Groff. The groundwork for its capabilities was laid on the drawing table at the beginning of the Ecotec's development. Prior work and a far-thinking engine design continue to help GM respond to market demands around the globe more quickly and with greater accuracy."

This new Ecotec family member also features:
  • Dual overhead camshafts (DOHC) and four valves per cylinder
  • Twin counter-rotating balance shafts for operational smoothness
  • "Drive by Wire" electronic throttle control
  • Low friction, roller-finger follower valvetrain with hydraulic lash adjusters
  • Low-maintenance chain-drive for the camshafts
  • 58X camshaft positioning
  • Direct-mount accessories, which reduce or eliminate traditional sources of noise and vibration
  • Full-circle transmission to reduce noise and vibration
  • GM Oil Life System, which can reduce the frequency for oil changes
  • Innovative cast-in oil filter housing, which eliminates the need to crawl under the vehicle to perform oil changes and eliminates throwaway oil filter cans that retain used oil.
  • As with other engines in the Ecotec family, the 2.0-liter Turbo engine also has premium features designed to ensure smooth and quiet operation, including a polymer coating and skirt design for the pistons that reduce noise during cold starts. An automatic hydraulic tensioner also is used to maintain optimal tension on the timing chain, which reduces noise and vibration.

The Solstice GXP is expected to debut in the summer of 2006. If it does come with an MSRP in the $25,000 range, it will be a serious "bang for the buck" value, and we expect that once the hurdles of figuring out the electronics are overcome, the aftermarket will quickly gear up with a host of performance upgrades. We see no reason to think this engine would have any problem supporting over 500 streetable horsepower, which would make for an insanely fast machine that would also get great mileage -- if, of course, you could keep your foot out of it.

We have been given ample evidence that GM and Pontiac-GMC have come a long way to understanding how to market an affordable two-seat performance car. It appears the bitter lessons learned by the demise of the Fiero have not been lost. With an attractively priced performance package that should deliver on all fronts, a realistic sales forecast, innovative marketing, and the potential for even more power, the Solstice GXP could end up being one of the best performance cars Pontiac has ever released. It had better be -- Pontiac and GM really cannot afford anything other than a grand slam.
 

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Thanks so much for the great article! It seemed to me GM came out of nowhere with an Ecotec that combines the best features of the Lancer Evo (twin scroll turbo, sodium filled valves, and variable valve timing) and Mazdaspeed 6 (direct injection) engines.

I'm even more impressed that GM planned and developed this block not from the 2.0 supercharged motor, but a beefed up and debored/destroked 2.4. It shows they finally have not only the engine, but the determination to beat the Japanese manufacturers at their own game.
 

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dual scroll turbo can also be found in the jap spec Subaru sti spec C.
Apart from this,the ecotec sidi turbo is producing 1.25 bar(20psi) of boost.

EDIT:...it's better to say the dual scroll turbo is producing this amount of boost!
 

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I really don't think you're going to hit 500HP without making changes to the internals. Yes this GEN II ECOTEC block is stronger then the previous ones, but the ECOTEC Buildup article shows a significant # of parts having to be replaced before the 2.2L ECOTEC would produce 500HP.

It's a very good read too.
 

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The interals of the new 2.0L engine can handle a 100 hp increase without internal modifications (my tech wizards are telling me). A re-tune ECM, higher output turbo, better intercooler, and new intake. Expect to see stage increase kits directly from GM in 2007, as well as aftermarket kits. Over 400 hp with nitrous kit is within the limits, but go easy on the button.
 

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why would you need nitrous to reach 400hp? if it's already at 260 with a relatively small turbo than it seems a Garrett GT28, 30, or 32 should put out around 350. with supporting mods, 400hp shouldnt be too difficult...
 

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Delnari said:
The interals of the new 2.0L engine can handle a 100 hp increase without internal modifications (my tech wizards are telling me). A re-tune ECM, higher output turbo, better intercooler, and new intake. Expect to see stage increase kits directly from GM in 2007, as well as aftermarket kits. Over 400 hp with nitrous kit is within the limits, but go easy on the button.
Sa-weet!!

I want GM warranted 360hp!
 

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Delnari said:
The interals of the new 2.0L engine can handle a 100 hp increase without internal modifications (my tech wizards are telling me). A re-tune ECM, higher output turbo, better intercooler, and new intake. Expect to see stage increase kits directly from GM in 2007, as well as aftermarket kits. Over 400 hp with nitrous kit is within the limits, but go easy on the button.
Thier test engine did not have a forged crank shaft and forged rods when they first started, and the LNF does. I can guarantee the only weak point on this motor is going to be the head gasket, head studs and maybe cast pistons (4-500hp range). Thier engine is also running a higher compression than the LNF will be running.
 

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capa said:
why would you need nitrous to reach 400hp? if it's already at 260 with a relatively small turbo than it seems a Garrett GT28, 30, or 32 should put out around 350. with supporting mods, 400hp shouldnt be too difficult...
You may not want to push this engine pass 28 lbs of boost. Better to use a more effecient turbo unit as you suggested, but keep the boost levels below 30 lbs. A 15-25 second nitrous burn will keep the engine from getting too hot too fast. I wonder how long before some of the Japanese tuners get their hands on tuning it. I would like to get it running 300 whp without having to go to crazy on the mods.
 

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what's stock boost set at? are there gonna be any fuel cuts? boost cuts? speed/rev limiters?
 

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holy sh*t! 20 psi! I wonder at what rpm it achieves full boost...?

another question... what's max boost for the turbo to be efficient? I know people are going to start hooking up boost controllers to these cars.
 

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No need for a MBC, you just reflash the car with HPT. Just cant go over 23psi for more than 4sec. limphome.
full boost rpm in 4th:
Stock 2250
Stock w BTF wheel 2700
Gt3076RSS 3400 .63AR
Gt3582RSS 4400 .63AR
 
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