Like the LS9, the LSA also uses a forged 3.62-inch-stroke crankshaft with a proprietary flange. Instead of the traditional six-bolt flange, the LSA uses eight bolts to connect to the flywheel and flexplate (the LS9 uses nine bolts). The connecting rods are a forged powder metal that is both light and strong. The oil pump capacity was increased to 33.8 gallons per minute.
In addition to the bottom end, the LSA boasts many other improvements over the LS3. The cylinder heads, for example, are nearly identical aside from the actual casting process itself. Just like the LS9, premium A356-T6 alloy is rotocast; the mold is rotated as the molten alloy cools to eliminate porosity. The camshaft is relatively mild (.480/.480-inch lift, 198/216 duration at .050, 122 lobe separation angle) for the purposes of being more quiet and smooth than its naturally aspirated counterparts. The Eaton Gen VI supercharger and its twin four-lobe rotors belting out 9 psi of boost afford this luxury. The new rotor design was a 20-percent improvement in airflow over the previous generation.
Although the Camaro ZL1’s LSA is nearly identical to the 2009 Cadillac CTS-V in which the engine was originally designed, several improvements were made to the air-to-liquid intercooler as well as the lid. Hence its different appearance. It also uses cast stainless steel exhaust manifolds, which help account for the bump in power. However, like the CTS-V’s, the ZL1’s LSA uses a center-feed fuel system with a dual fuel pump that is pulse-width modulated (changes pressure according to throttle input) and an additional pickup. Other common features include: an 87-mm throttle body, direct-mount LS7 ignition coils, dedicated eight-rib supercharger drive system, and E67 computer.
The legendary 7.0L LS7, originally developed for the 2006 Corvette Z06, was adapted for use in the 2014–2015 Camaro Z/28 with a new accessory drive system, engine covers, Tri-Y headers, and open-element cold-air intake. No expense was spared to make the ultimate small-block with titanium rods and intake valves, high-port heads based on the C5R design, billet main caps, dry sump oiling, and the best OEM Gen III/IV intake manifold ever made.
Like the LS3, the 7.0L LS7 was first implemented on the Corvette before finding a home in the 2014–2015 Camaro Z28. The LS7 is the first engine to use dry-sump oiling on the Camaro.
As it was for the 2005–2013 Corvette, the LS7 is an engine built for the track, which made it the perfect choice for the purpose-built Z28. At 427 ci, the LS7 pushes the limit of cylinder wall thickness, since it is still bound to the 4.4-inch bore spacing, as are all LS engines. Being a small-block, though, it is still a fairly high-revving engine, maxing out at 7,100 rpm. A 4140 forged steel crankshaft, secured by forged steel main caps, provides 4.0 inches of stroke to forged titanium connecting rods and hypereutectic pistons. Titanium 2.20 intake and sodium-filled 1.61-inch exhaust valves in the C5R-derived cylinder heads complement these lightweight materials.
The LS7’s smaller CNC-ported runners are the highest flowing factory cylinder head in the LS lineup (and possibly ever made by General Motors). Raised intake runners and a 12-degree valve angle required matching intake manifold and 1.8-ratio rocker arms. As you’d expect, the camshaft is the biggest yet at .591/.591-inch lift and 211/230 duration at .050, cut on a 121 lobe separation angle.
In the 2014–2015 Camaro Z28, the LS7 appears more like something built from the Chevrolet Performance catalogue rather than an actual production car. Instead of the typical OEM air box, the Z28 uses an open element K&N air filter with a straight intake tube that clamps to the 90-mm throttle body. Even the ZL1’s stainless steel exhaust manifolds pale in comparison to the high-flowing Tri-Y headers used on the Z28, to say nothing of the dual-mode 2.75-inch exhaust with which it connects.
Further adding to the custom feel of the Z28’s powertrain, all LS7s are hand-built in the Performance Build Center in Wixom, Michigan. And to protect these high-dollar 427s from oil and fuel starvation, they were given a specially designed oil tank and fuel pump to account for the incredible g-forces in which the Z is capable.
The 2010–2011 Camaro LS and LT featured the highest horsepower naturally aspirated V-6 General Motors has ever built. The 3.6L direct-injection LLT is part of the High Feature V-6 engine family, which is a far cry from the 3800 V-6s of yesteryear. Although the 3800 is a 90-degree pushrod engine with two valves per cylinder, such as any small-block V-8, the High Feature engines use a 60-degree “V” with 24 valves and dual overhead cams.
The Cadillac CTS was among the first U.S. applications for the High Feature V-6, and ultimately received the LLT two years prior to the Camaro’s initial release. The LLT is an incredibly efficient engine, capable of running on 87-octane with an 11.3:1 compression ratio thanks to direct injection (DI). By placing the fuel injectors into the combustion chambers, a more complete burn with a leaner mixture occurs at the same power level. The impetus for the system is a high-pressure mechanical fuel pump.
Other key features of the LLT V-6 include VVT, silent (inverted tooth) cam drive, and oil-spray cooled and coated pistons. As with the LSA, pressure-activated jets spray the underside of the cast aluminum pistons with oil to reduce the temperature for increased longevity. A polymer coating on the piston skirts, floating wrist pins, sinter forged connecting rods, and a forged steel crankshaft make up the rotating assembly. A319 aluminum alloy is used to cast the cylinder heads and block, which has six-bolt mains, cast-in iron cylinder liners, and bay-to-bay breather vents such as on an LS block.
The 2012–2015 Camaro LS and LT received a slight upgrade with the LFX V-6. The new design swapped the aluminum intake manifold for composite, used longer duration camshafts, and revised the cylinder head design. Improved intake runners were matched with larger valves, and on the exhaust side things got even more radical: casting the exhaust manifolds directly into the heads. This dropped 20 pounds and gained more than 10 hp. Other revisions made at that time included a new fuel pump and injectors, isolated fuel rail, stronger and lighter connecting rods, and improvements to the camshaft cap and throttle body design. The engine is even stronger externally, with improved structural front cover and block.
CAFE standards being what they are, it is no surprise that every fifth-gen Camaro came with a 6-speed transmission. With the V-6 LS and LT, it gave Chevrolet the opportunity to use some fairly aggressive gearing to keep the peaky engine in its powerband. The Aisin AY6 manual seems to use gears you’d usually see in a truck transmission, using an extremely steep 4.48:1 first gear. The 6L50E automatic mirrors the SS’s 6L80E fairly closely, which uses the close ratios down low for optimum acceleration and two overdrive gears, along with a 3.27:1 rear gear for better highway mileage. In fact, most Camaro models used 3.27 rear-end gears, with the exception being the manual-trans SS and 2LS, as well as the ZL1 and Z/28.
The 6L80E and 6L90E automatic transmissions represent a real departure in design for General Motors. Both are extremely strong, which is denoted by the second number (80 or 90). You can guess what the first number signifies. Both transmissions replace the 4L80E truck transmission (and the Turbo 400 before it), adding two gears. A compound planetary that functions as three planetary sets in one is the modus operandi (larger gears in the 6L90E’s output carrier give it increased holding power). Internally it is more than just a few extra gears that separate the two transmissions.
The 6L80E and 6L90E are increasingly reliant on electronics for operation, rather than hard parts that can wear out or be overwhelmed by engine torque. As a result, it uses no bands, just clutches, which must engage at the exact time another disengages. This requires precision transmission calibration. The 6L80E was first used in the 2006 Corvette before finding a home in various Cadillacs, trucks, and the Camaro. The 6L90E was introduced in the 2009 Cadillac CTS-V, which shares the ZL1’s LSA powerplant. In addition to the output carrier, its holding power is increased by way of a strengthened output shaft, strengthened input gear set, additional clutch plate, and two additional pinion gears.
The Camaro features many variations on the Tremec TR6060 manual transmission. Contrary to popular belief,