LLT V6 Engine

LLT 3.6L V-6
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The LLT "high-feature" V-6 has about as much advanced technology as you can find in an engine these days: DOHC, VVT, and most significantly, SIDI. Note the intricate detail on the crowns of the pistons, with "bowls" the fuel injectors spray into. --->

Cost-conscious buyers who forego the Camaro's SS package (and its accompanying LS-series V-8) will receive a corporate GM V-6 known as the LLT. Available with either a six-speed manual or six-speed automatic tranny, it's the engine that will power the majority of Camaros on the road. But it's probably not the engine most GMHTP readers will be interested in-or is it?

Named one of Ward's Ten Best Engines for 2008 (one of the most prestigious honors in the industry) and known as the "high-feature V-6" to most within GM, the LLT is nothing less than GM's world-beating six-banger, first introduced in the 2008 Cadillac STS (and also optional in the CTS, where it's rated at 304 SAE-certified horsepower). It's important to mention that two versions of this 60-degree engine exist, and the one that we'll get in the Camaro is of the direct-injection variety. A lower-output, PFI version of this engine (which carries RPO LY7) is standard in the Cadillac CTS and also powers vehicles like the Chevrolet Malibu and base Pontiac G8. Therefore, it's critical to note that Camaro is getting the "cream of the crop" of GM V-6 engines-a showing of GM's commitment to this vehicle and to the high-performance character of all Camaros, SS or no.

The meat and potatoes of the LLT's direct injection system. How it works: a conventional in-tank electric pump sends fuel toward the fuel rails, at which point a mechanical pump-seen at right side of photo driven off one of the exhaust cams-is used to boost fuel pressure to 1,700+ psi (or "only" about 500 psi at idle). Fuel then travels through stainless steel fuel rails to highly specialized fuel injectors, which spray directly into each cylinder. --->

Here, the LLT is basically unaltered from its other applications, save that the accessory drive is changed, and the air intake and exhaust systems are tuned for different amounts of restriction and noise characteristics. The major feature of this engine is one we've already indicated: its Direct Injection (DI) system (also known as Spark Ignition Direct Injection, or SIDI, to differentiate it from systems used on diesels). It's a technology that made its North American debut for GM in the 2.0L turbocharged (RPO LNF) versions of the Saturn Sky and Pontiac Solstice, and its myriad advantages include enhanced engine output, improved fuel efficiency, and reduced emissions. For details on this and other aspects of the LLT, we spoke with Jordan Lee, Assistant Chief Engineer for Global V-6 Engines, and Tim Price, Resident Engineering Manager at GM Powertrain-an Australian on assignment here from Holden.

With traditional port fuel injection, fuel is mixed with air in the intake port and drawn past the intake valve. But with direct injection, fuel is sprayed directly into the cylinder at extremely high pressure. Says Lee, "As the fuel evaporates, it draws in a lot of heat, so it has a cooling effect on all the components in the chamber. As a result, higher compression ratios are possible on SIDI engines." That's 11.3:1 for the LLT, to be exact. Amazingly, the highly controlled nature of the combustion process also means that maximum performance is had on regular fuel! "This engine is rated using 87 octane-a lot of our competitors don't do this. Spark calibration strategies in the ECM are all done based on regular gasoline, so there is no advantage to running premium."