The new Camaro is so close, we can almost taste it! GMHTP went through the basics of Chevy's gorgeous new muscle machine last issue ("Camaro Rides Again," January 2009), but left readers to drool in anticipation over perhaps the most important part: the gritty particulars on its trio of engines.
You'll find just about everything you're looking for here, save for finalized SAE-certified horsepower/torque and EPA fuel economy numbers (final testing and certification was still pending as of press time). They should be released as this issue is hitting newsstands, so point your browser to www.gmhightechperformance.com and we'll let you know as soon as the news breaks!
LS3 6.2L V-8
TR6060 six-speed manualHorsepower/Torque:
422/408 (preliminary, estimated)Features:
Big-cube pushrod power, tried-and-true in the Corvette
The Camaro-bound LS3 in cutaway view. Dig the "CHEVROLET" script on its engine cover! --->
Buyers of row-your-own SS models will be blessed with an engine that's been plastering smiles on the faces of automotive enthusiasts since its release in the MY 2008 Corvette. If you haven't had the pleasure of time behind the wheel in an LS3-equipped Y-car, rest assured: this mill is a torque monster that's not only built to thrill, but to take any and all abuse thrown at it in stride.
Taking a page from Corvette, both the Camaro-spec LS3 and L99 get rectangular-port cylinder heads featuring offset-rocker technology and big 'ol valves: two per cylinder, of course. As we know, this head has been revolutionizing the LS scene since debuting on the L92 a few years back. --->
For details on what changes the LS3 will take on in this new application, we spoke with John Rydzewski, Assistant Chief Engineer for Car Small Block Engines. Fortunately, Rydzewski had little to say, as this is one of those cases where no news is good news. The Camaro's LS3 will be, for all intents and purposes, identical to the mill we introduced in the November 2007 issue ("Sick Six Point Two"). As a recap, here are the essentials: based on the Gen IV small-block architecture, a 4.065-in. bore meets a 3.622-in. stroke to yield 376 cubes, and cast aluminum pistons put a 10.7:1 squeeze on the air/fuel mix. Rectangular intake ports provide flow never before possible in an as-cast factory LS head, and an aggressive hydraulic roller camshaft with .551-inch lift on the intake side takes advantage of their spectacular capabilities. A dependable nodular iron crank and forged powder metal connecting rods make for a durable bottom end. All of that stays for the Camaro, though the LS3 will make a handful less horsepower than in the Corvette simply because of slightly more restrictive intake and exhaust systems (and, we'll bet, the same corporate politics that have kept Vettes atop the GM horsepower pecking order for decades). Other differences include a unique oil pan to fit in the Camaro's chassis, along with rudimentary changes to items like the starter, dipstick, PCV, and accessory drive system.
The LS3 and L99 share the same engine block, and it's virtually identical to the one shown here from the 638hp supercharged LS9 (have a look at "LS9 Lives!," April 2008, for an exposition on that engine). The few details differentiating Camaro blocks from those in the Corvette ZR1 include lack of the LS9 block's piston cooling oil jets, larger head bolt holes, and deck plate hone, all left out mainly for cost savings. The "risers" in the lifter valley will also be drilled for use of AFM on the L99 (they'll be vestigial on the LS3). --->
But the story isn't quite over, because the Camaro's LS3 benefits from the same updates all 6.2L engines receive for MY 2009; namely, an even stronger aluminum block. "We went through a round of casting and machining improvements to the 6.2L block when the LS3 was introduced," explains Rydzewski. "Then, when the ZR1 went into production, we improved the safety factor further by working the window area in the bulkheads again, so we would be capable of meeting our durability schedules with the LS9's power levels." Just think: the LS3 block has been proven to factory robustness standards in a supercharged 638-horse engine that blistered a record run at Nrburgring Nordschleife! Even accounting for some detail differences like non-doweled, powder metal main caps (versus the LS9's forged steel units), this block has a great safety factor for added ponies-one we're certain many GMHTP readers are waiting in the wings to take full advantage of!
Of final note is that this LS3's ECM will be the same E38 controller found in the Corvette. The Camaro also takes advantage of GM's new generation of vehicle electrical architecture: known as Global A, it's basically a more efficient communications protocol for onboard systems. And while not needed for LS3, the E38 is capable of supporting VVT and AFM features found in the LS3's close relative and Camaro stablemate, the L99.
L99 6.2L V-8
Hydra-Matic 6L80 six-speed automaticHorsepower/Torque:
400/395 (preliminary, estimated)Features:
AFM and VVT for a more "refined" package versus the LS3
It may appear a whole heck of a lot like an LS3 at first glance, and your eyes are not deceiving you: the similarities are more than substantial. But look closely and you'll catch the traits that set the L99 apart. Visible are the exhaust valve reliefs, cam phaser system, and AFM components. --->
Camaro SS buyers who wish not shift their own tranny will get the only truly new engine in the Camaro lineup: the L99. This mill's similarities with the other Camaro V-8 are extensive: for example, its block, cylinder heads, crankshaft, and connecting rods-along with the intake manifold and throttle body-are all shared with the LS3. That said, there are some exciting additions that make the L99 best thought of as a "higher-tech" LS3; namely, Active Fuel Management and Variable Valve Timing.
Most readers are probably familiar with the functioning of AFM (formerly known as DOD, or Displacement On Demand). A quick refresher: under light-load conditions, the lifters on four of the cylinders deactivate and cease transmitting the cam lobe profiles to their valves, meaning the valves on those cylinders stay closed, reducing pumping losses (obviously, fuel is also cut to those cylinders). They do this upon receiving an oil pressure signal from the so-called Lifter Oil Manifold Assembly seen here, used in lieu of a valley cover. This is actually a unit from a truck engine, but the L99's will be very similar. --->
"For the L99, we tried to put in some technology to maximize as much fuel economy as we could out of the vehicle," John Rydzewski told GMHTP. "This is really a nice package to do that because we didn't really have anything like an LS3 [in terms of power] that was AFM-equipped. AFM works great when you have a lot of power in a lighter-weight vehicle. In a truck, it has only so much effectiveness." Up to this point, the only LS-equipped car featuring AFM has been the Pontiac G8 GT: how effective AFM proves in the Camaro remains to be seen in the EPA rating, but regardless of how the cards fall, keep in mind that G8 tuners have been able to tweak additional mpg out of those cars by altering AFM-related parameters in the ECM!
Active Fuel Management is a welcome addition for the Camaro, but this begs the question: Why only the automatic? Couldn't engineers incorporate this technology into manual-equipped cars as well? "When switching from 8- to 4-cylinder mode (or vice versa), there are some transitions that you have to deal with," explains Rydzewski. "Typically, a good way to do this is by using a torque converter. The ability to control the slip of the torque converter [via the torque converter clutch] is a big enabler in getting good transitions. The whole thought behind having AFM is, you don't want to have interruptions; you want it as seamless as possible." In other words, GM doesn't want to repeat the mistakes made with the 1981 V-8-6-4 Cadillacs, which often exhibited noticeable hesitations when switching cylinder modes (hence the technology only being offered for one model year). Nevertheless, we were told AFM could be implemented on a manual, and that GM actually is looking into it. But because a manual transmission's clutch is a straight coupling (and one that is hydraulically actuated only by the driver), it is not as adept at damping the slight drivetrain vibrations that occur during AFM activation/deactivation. That said, we know this: all things being equal, the efficiency of a manual transmission is always better than an automatic, so it will be interesting to see whether the L99 or LS3 achieves higher EPA numbers (one also needs to factor in the automatic car's 3.27 rear and 0.67 sixth-gear ratio versus the manual car's 3.45 rear and 0.57 sixth).
These special lifters (again, the one here is from a truck engine) deactivate on command and are found on cylinders 1, 4, 6, and 7 of the L99 and any other AFM-equipped LS-series engine. When commanded by the LOMA, they mechanically switch so that while the roller continues to follow the cam lobe profile, no motion is transmitted to the pushrod. --->
Interestingly, the use of AFM probably accounts for at least part of the L99's slightly reduced projected power output compared to the LS3, as the system (at least in its current form) creates issues from a valvetrain design perspective. "With AFM, there are design considerations you have to put into the lifters, the camshaft, the other components. You don't want to get into problems with valves deactivating at the wrong time or losing control of the valvetrain," says Rydzewski. "So there are things we do on such an engine for the sake of controlling the AFM." As a result, the L99's fuel cutoff is not as high-around 6200 rpm, versus 6600 for the LS3-and the camshaft specs out with a bit less lift (and reduced overlap) versus the bumpstick in its 6.2L brother.
This brings us to the L99's other feature that sets it apart from the LS3: Variable Valve Timing (or more appropriately, "dual-equal cam phasing"-intake and exhaust valve timing cannot be altered independently). Though it's been in use for a few years on Gen IV truck engines, the L99 represents the first appearance of VVT in a car application. Consider this: if you've ever "degreed" a cam in a small-block-LS or otherwise-you know that in general, advancing cam timing improves output at low rpm, while retarding cam timing improves high rpm performance. The VVT system is able to continuously vary how the cam is phased in relation to the crankshaft while the engine is running, acting within a fraction of a second. The system therefore allows a best-of-both-worlds approach to output by eliminating the compromise between low-end torque and top-end horsepower inherent in fixed cam timing. This is true regardless of whether you're talking about part- or full-throttle operation. There are other benefits to VVT as well: for example, it allows a smoother idle (via fully advanced valve timing events), and in addition to its own role in increasing fuel economy, it also allows the AFM system to function over a broader operating range.
The front-mounted vane-type camshaft phaser is the heart of the L99's VVT system. Operating off of a varying oil pressure signal, it turns the camshaft relative to the cam sprocket, thereby changing the cam's phase relative to the crankshaft. A so-called actuator solenoid valve is used in lieu of a cam bolt, and it gets its instructions from a corresponding computer-controlled unit mounted in the L99's special front engine cover. Oil-pressurized inside the hollow front portion of the cam thanks to a feed hole in the second journal from the front-acts upon the phaser's vanes. The more oil pressure the actuator solenoid valve permits the vanes to experience, the more the cam is turned. While this setup is from a truck engine, the system found on the L99 will be similar. --->
Finally, compared to the LS3, the L99's compression ratio is slightly lower (around 10.4:1), basically dictated by the design of the top of the piston: while the LS3 features flat-tops, the L99's pistons have a recess in the vicinity of the exhaust valve to accommodate valve movement sans contact. This might seem a bit odd considering the L99 cam's lower lift, but it just goes to show you how drastically the VVT system can alter cam phasing. It will be interesting indeed to see how well these technologies perform on the road with the L99-and how the Camaro will fare with its even more technologically advanced base engine, the LLT.
LLT 3.6L V-6
Camaro LS / LTTransmissions:
Hydra-Matic 6L50 six-speed automatic
Aisin Warner AY6 six-speed manualHorsepower/Torque:
300/273 (preliminary, estimated)Features:
SIDI, DOHC, VVT: a high-tech, high-output engine for the masses
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."
The combustion chamber in the LLT's 319 cast-aluminum heads. Peeking in at far right is the tip of the injector. Not visible are the so-called secondary throat cut inlet ports (which are in the valve seat area), said to improve the tumble of airflow into the combustion chamber. Interestingly, the intake ports are fed not by the weight-saving composite intake typical of many new engines, but rather one cast from aluminum. The reason is that being a denser material, aluminum is better able to suppress radiated noise. It's one of many NVH-friendly items befitting a Cadillac that trickle down to the Camaro. --->
But there's much more that makes this engine special, as high-strength and durability-enhancing features abound. For one thing, there's a forged steel crank. "This is one of the big enablers," says Lee. "It allows us to put quite a bit of force through the crankshaft and still maintain a lot of refinement, and tolerate pretty high output levels." There are also sinter forged steel connecting rods, an inverted tooth timing drive (for durability and noise improvement), and piston-cooling oil jets. It's noteworthy that this engine is used in some GM truck lines-like the award-winning Acadia/Enclave/Traverse/Outlook crossovers-and GM subjects all engines destined for truck duty to further durability testing above and beyond what is done on a car. "So the design is very, very robust because of that," notes Lee.
The V-6 engine block is sand-cast from 319 aluminum and features cast-in iron cylinder liners. High-strength features include sintered steel, copper-infiltrated main caps with a 6-bolt design (4 vertical and 2 side bolts, just like in an LS) for a very rigid bottom end. There's also a structural cast aluminum oil pan (not shown). A nice feature, and one the LS-series lacks, is a cartridge-style oil filter for less messy oil changes and reduced waste; you can see where its adapter bolts to the block near the front driver side corner. --->
Lee's enthusiasm about the LLT was clear during our conversation with him. "This engine is extremely efficient; its Brake Specific Fuel Consumption numbers are outstanding, both compared to anything internally that we have as well as to our competition. For the fact that we can put a base engine in the Camaro that not only gets good fuel economy, but also makes a lot of power, I think it gives us an edge on our competitors. Most people who drive a GM car with this engine are very shocked at how fast it is-for a base powertrain, they are thrilled that it has that much performance." Having track-flogged LLT-equipped CTS Cadillacs, we GMHTP editors can tell you that's the truth and nothing but! And just in case you think GM is blowing smoke about this being a durable performance engine, Tim Price chimed in to say the high-feature V-6, in addition to its being used in performance-oriented Holden vehicles, has been tested extensively for this application at various locations in Australia, and "it's performed extremely well for the Camaro. That included work at Holden's proving ground at Lang Lang, and calibration and development trips throughout Victoria and Australia."
In sum, this mill has a lot going for it: it's a heck of a medium-displacement engine that promises additional fuel economy and reduced cost over the V-8s while still providing at least 300 horsepower. And while we haven't seen any forced-induced Saturn Outlooks prowling the streets, the LLT should be sturdy enough to tolerate abundant power-enhancing modifications. Fans of fourth-gen, 3800 V-6 Camaros, rejoice: the LLT is ushering in a new era of six-cylinder Camaro performance. We say, "bring it on!"
It should go without saying that GMHTP's editorial staff is chomping at the bit in anticipation of a full-fledged flogging of the new Camaro and its lineup of superb engines (all of which, by the way, will be built in St. Catharines, Ontario-not far from Camaro final assembly). As far as the V-6 cars go, GM has set the stage to absolutely smoke Challenger and Mustang, what with at least 50 and 90 more horsepower than those cars' base engines, respectively. And with the V-8s, Camaro will certainly eclipse the power of the Challenger R/T and should come very close to meeting the output of the heavy 6.1L SRT8. (Let's not even waste our breath on the Mustang GT-the LLT should just about take care of it.) As to the GT500 et al, we'll leave the upcoming Z28 to put the smackdown on those high-dollar Fords!
Check out this 1038 V forged steel crankshaft. "It's the basis for a very solid engine design," says Lee. It's one part of the LLT that allows it to achieve a 7,000-rpm fuel cutoff! The crank's 3.37-in. stroke combines with the block's 3.70-in. bore to yield 217 cubic inches. --->
It's clear that the 2010 Camaro offers an engine for just about any need, in the true spirit that is the ponycar. But this author doesn't think it's premature to ask: Where do we go from here? As you may have noticed, in my interviews with GM engineers, fuel economy was on par with horsepower in terms of hot discussion topics. We all know that CAFE standards aren't getting any lower (and despite the usual wintertime dip, long-term gas prices are only heading one direction). While all indications point to the Camaro's dynamite initial engine lineup easily offering class-leading fuel efficiency, like it or not, this car's long-term viability will likely depend on two interrelated things: (1) GM's ability to innovate even more fuel economy into Camaro, and (2) Joe Q. Public's interest in purchasing said innovations, whatever they may be.
The LLT's pistons, cast from a high-strength aluminum alloy, receive cooling oil from pressure-actuated jets-something unique to the LS9, as far as GM pushrod V-8s go. Also of note are polymer-coated piston skirts, and (not shown) full-floating wristpins. Heavy-duty stuff, indeed. --->
Weight reduction is one thing, but the issue of engine choices simply cannot be avoided. Not so many years from now, will V-8s be limited to high-dollar Camaro versions like the future Z28? Let's hope not, and perhaps GM could broaden the powertrain lineup over the next couple of years and offer a smaller-displacement (4.8/5.3L) V-8 for enthusiasts who can't live without V-8 sound, but can get by with a bit less horsepower in exchange for a reduced sticker price and increased fuel efficiency. Beyond the LS engines we know and love, this author is also excited about the prospect of factory turbocharged 'Maros that could include the likes of the boosted 2.0L LSJ Ecotec GM has already hinted at (insiders have indicated to me personally that "a lot of margin for improvement" above the current 260hp rating has been engineered into that engine). Dare one dream of a turbo six offering (hey, sounds like Ford's putting one in the Mustang)? To turn up the wick on either of those would be sublime. And how about some FlexFuel capability to coincide with GM's circa-2011 rollout of high-volume, high-octane cellulosic ethanol?
The LLT also features a VVT system which, unlike the single-cam-phaser setup implemented on the L99, alters the phase of the intake and exhaust camshafts independently, resulting in Variable Valve Timing in an even truer sense (or as engineers like to call it on this application, "four-cam continuously variable cam phasing"). It's basically a more effective system, with the same results in mind: reduced emissions coupled with improved fuel economy and a broader powerband. --->
Alas, these are just the dreams of a journalist. But I do know this: we've festered seven long years in a Camaro-less existence. Enthusiasts will always want to buy these cars, but there are only so many of us-and low sales (resulting from different issues than those being discussed here) were the impetus for GM's pulling the plug the last time around. We want Camaro to be here to stay, and can take solace in the fact that GM has a century of industry-leading innovation under its belt to not just keep this car selling, but make it better and better in the face of increasingly stringent auto industry regulation. Here's to 1967 all over again-with any luck, technology will keep 2002 from biting us in the ass. With AFM, VVT, and SIDI already incorporated into the lineup, GM is off to a good start!
Special thanks to Tom Read at GM Powertrain, along with Jordan Lee, Tim Price, and John Rydzewski, for their assistance with this story.