LFX 3.6 Liter DI-VVT V6 -- Official Details

[dwightlooi]

For release: April 13, 2011, 9 a.m. EDT

2012 Chevrolet Camaro Engine: More Power, Efficiency

New 3.6L V-6 LFX produces 323 horsepower and 30 mpg on the highway

DETROIT – A new, more powerful and more efficient version of the 3.6L direct-injected V-6 will be standard in the 2012 Chevrolet Camaro. It delivers an SAE-certified 323 horsepower (241 kW) at 6,800 rpm – 11 horsepower (8 kW) more than 2011 models. It is also 20.5 pounds (9.3 kg) lighter than the current engine, which enhances efficiency and driving dynamics.

The changes to the 3.6L V-6 – known by its new “LFX” engine code – represent greater refinements to an already well-balanced package, including the use of new, lighter-weight components and enhancements designed to improve performance, efficiency and durability. And while more powerful than the current 3.6L, the 2012 Camaro 2LS model will deliver an estimated 30 mpg on the highway with the LFX engine.

“This is a great engine architecture and our engineers have never stopped working to make it even better,” said Ameer Haider, assistant chief engineer for V-6 engines. “The enhancements for 2012 will deliver reduced engine weight and lower emissions – along with the greater power that Camaro drivers will certainly appreciate.”

The 3.6L is a 60-degree design, with the cylinder block and cylinder heads cast in aluminum for low weight. A forged steel crankshaft provides optimal strength in the bottom end, while the cylinder heads include four valves per cylinder, with a dual overhead camshaft design incorporating infinitely variable cam phasing. Compared to the 3.6L V-6 in 2011 models, the new LFX engine features:

• New cylinder head design with integrated exhaust manifold

• Improved intake port design and larger intake valves within the cylinder heads

• Longer-duration intake camshafts

• Composite intake manifold

• New fuel pump and isolated fuel rail

• New, optimized-flow fuel injectors

• Structural front cover and cylinder block enhancements

• Stronger and lighter-weight connecting rods

• Camshaft cap and throttle body design enhancements

The LFX engine is significantly lighter than the current 3.6L V-6. The integrated cylinder head/exhaust manifold design saves approximately 13 pounds (6 kg) per engine over the cylinder heads and manifolds of the current engine, while the new composite intake manifold saves approximately 5.5 pounds (2.5 kg) over the current aluminum intake. Additionally, a lighter-weight structural front cover and lighter-weight, high-strength connecting rods bring the total weight savings to 20.5 pounds (9.3 kg), which helps the vehicle’s fuel efficiency and enhances its feeling of driving balance.

“It isn’t often we get the opportunity to take more than 20 pounds off an engine. We met some aggressive targets while retaining great strength and reliability,” said Haider. “The engine is as durable as ever but now with improved performance and efficiency.”

Additionally, the optimized-flow fuel injectors and integrated exhaust manifolds/cylinder heads promote lower emissions. And along with its weight savings, the composite intake manifold has a smaller radiated surface area to help it maintain noise and vibration characteristics comparable to the previous aluminum manifold.

Greater airflow brings more power – and efficiency

The new cylinder heads also bring a revised intake port design that enhances airflow to the combustion chambers. Larger-diameter intake valves (38.3 mm vs. 36.96 mm) are used in the heads and work in conjunction with new, longer-duration intake camshafts to provide the engine’s boost in horsepower.

The valves let air in and exhaust escape from the combustion chambers. The duration of the camshaft determines how long the valves are open. By using larger valves and holding them open longer, more of the air is pulled into the combustion chamber, for a more powerful combustion. Often, the tradeoff for greater power is greater fuel consumption, but the LFX engineers adapted new fuel injectors that are optimized for the engine’s performance parameters. The result is more power without sacrificing fuel economy. The more-efficient combustion also means reduced emissions.

Of course, the LFX engine retains direct fuel injection. It optimizes fuel delivery to the combustion chamber by introducing fuel closer to the combustion chamber. The result is better efficiency in the combustion process leading to increased fuel efficiency at part and full throttle.

The LFX uses a new fuel pump for the direct injection system, along with a new, isolated fuel rail. The new fuel pump is quieter, while the isolated fuel rail further reduces fuel system noise.

Greater refinement and durability

Additional changes incorporated in the LFX deliver greater refinement, quietness and durability, starting with revisions to the front cover. It was redesigned with additional support ribs on the backside and an additional fastener to reduce noise and vibration. The cylinder block is modified slightly to accommodate the front cover’s additional fastener.

Inside the engine, the powdered metal connecting rods use a higher ratio of copper, which makes them stronger and enables further mass savings. Also, the camshafts feature new saddle-type caps for improved durability. Finally, the throttle body is updated with a new, digital throttle position feature that eliminates a previous mechanical contact for more trouble-free operation.

About Chevrolet

Founded in Detroit in 1911, Chevrolet celebrates its centennial as a global automotive brand with annual sales of about 4.25 million vehicles in more than 140 countries. Chevrolet provides consumers with fuel-efficient, safe and reliable vehicles that deliver high quality, expressive design, spirited performance and value. The Chevrolet portfolio includes iconic performance cars such as Corvette and Camaro; dependable, long-lasting pickups and SUVs such as Silverado and Suburban; and award-winning passenger cars and crossovers such as Spark, Cruze, Malibu, Equinox and Traverse. Chevrolet also offers “gas-friendly to gas-free” solutions including Cruze Eco and Volt. Cruze Eco offers 42 mpg highway while Volt offers 35 miles of electric, gasoline-free driving and an additional 344 miles of extended range. Most new Chevrolet models offer OnStar safety, security and convenience technologies including OnStar Hands-Free Calling, Automatic Crash Response and Stolen Vehicle Slowdown. More information regarding Chevrolet models can be found at www.chevrolet.com

# # #

SPECIFICATIONS

LFX 3.6L V-6 DI VVT

Type: 3.6L V-6

Displacement (cu in / cc): 217 / 3564

Bore & stroke (in / mm): 3.70 x 3.37 / 94 x 85.6

Block material: Cast aluminum w/ cast-in-place iron bore liners

Cylinder head material: aluminum

Valvetrain: DOHC, four valves per cylinder, continuously variable valve timing

Ignition system: Electronic individual coil-on-plug; individual cylinder knock control and extended-life platinum-tipped spark plugs

Fuel delivery: Direct fuel injection

Compression ratio: 11.5:1

Horsepower (hp / kW @ rpm): 323 / 241 @ 6800 (SAE certified)

Torque (lb-ft / Nm @ rpm): 278 / 377@ 4800 (SAE certified)

Recommended fuel: Regular unleaded; 87 Octane

Maximum engine speed (rpm): 7200

Emissions controls: Evaporative emissions system, catalytic converter, equal-length exhaust, dual close coupled and dual under floor catalytic converters, positive crankcase ventilation, intake and exhaust cam phasers, electronic throttle control

Edited May 13, 2011 by dwightlooi

[dwightlooi]

Compared to the 3.0 LF1, the LFX offers:-

• Equal Specific Output (90.6 bhp/liter vs 90.1 bhp/liter)
  
• Superior Specific Torque (78 lb-ft/liter vs 74.4 lb-ft/liter)
  
• Lower Peak Torque RPM (4800 vs 5700 rpm)
  
• Higher Maximum Permissible Engine Speed (7200rpm vs 7000rpm)*
  
• No additional demands on Fuel Grade (87 Octane)
  

* Manual Cars only; 6L50 and 6T70 transmissions mandates a 7000 rpm maximum shift speed.

Edited May 13, 2011 by dwightlooi

[ZL-1]

So could a 3.0L version of this be in the works? As both an entry-level V6 and the basis for turbocharged variants of this same engine family?

[ehaase]

If it were up to me, the 3.6L should be used across the board, and the 3.0L should only be offered as a twin turbo in the LaCrosse, XTS, SRX, and maybe the Lambdas, ATS, and CTS.

[eldiablobanshee]

Wow, I am impressed with all of this on 87 .

[dwightlooi]

So could a 3.0L version of this be in the works? As both an entry-level V6 and the basis for turbocharged variants of this same engine family?

Let's put it this way... the current "LF1" 3.0 and the "LFX" 3.6 are both 2nd generation GM DI V6es. You can think of the "new" 3.6 as a version of the current 3.0. The original 3.6 DI V6 "LLT" is an older design which is more a DI rendition of the "LY7" 3.6 HF V6. The LF1 and LFX shares details like the integrated exhaust collector (the heads both have only one exhaust outlet per bank). Both are around 90hp/liter.

There is a bi-turbo 3.0 on the way... the RPO is LF3.

Edited May 15, 2011 by dwightlooi

[ZL-1]

Let's put it this way... the current "LF1" 3.0 and the "LFX" 3.6 are both 2nd generation GM DI V6es. You can think of the "new" 3.6 as a version of the current 3.0. The original 3.6 DI V6 "LLT" is an older design which is more a DI rendition of the "LY7" 3.6 HF V6. The LF1 and LFX shares details like the integrated exhaust collector (the heads both have only one exhaust outlet per bank). Both are around 90hp/liter.

There is a bi-turbo 3.0 on the way... the RPO is LF3.

Ah, OK; I thought the 3.0L was a version of the pre-LFX 3.6L.

[Potluck]

With the lighter weight connecting rods, will it be more willing to spin now?

[dwightlooi]

With the lighter weight connecting rods, will it be more willing to spin now?

Hopefully

[dwightlooi]

Ah, OK; I thought the 3.0L was a version of the pre-LFX 3.6L.

LFX 3.6 DI-VVT V6 (Note: Integrated Exhaust Collector and single exhaust port per bank)

LF1 3.0 DI-VVT V6 (Note: Integrated Exhaust Collector and single exhaust port per bank)

LY7 VVT V6 (Note: Separate Exhaust Ports; three exhaust outlets per bank)

[Drew Dowdell]

What benefit does the integrated exhaust collector provide?

[riviera74]

If it were up to me, the 3.6L should be used across the board, and the 3.0L should only be offered as a twin turbo in the LaCrosse, XTS, SRX, and maybe the Lambdas, ATS, and CTS.

If it was up to me, that new LFX 3.6L v6 would be standard everywhere there is no 4cyl engine (i.e. all Buicks and Cadillacs, and the Impala and optional on the Malibu). The LFX could possibly be the answer to that Ford EcoBoost engine made for Chevy/GMC trucks.

[Potluck]

it's interesting after the impala update today, that it will get 300+ horsepower even in front drive versions

[loki]

What benefit does the integrated exhaust collector provide?

the collector is aluminum instead of cast iron?

O2 sensor is in exhaust, and closer to heads, decreasing warmup time: lowering emissions?

[dwightlooi]

What benefit does the integrated exhaust collector provide?

the collector is aluminum instead of cast iron?

O2 sensor is in exhaust, and closer to heads, decreasing warmup time: lowering emissions?

The collector is part of the cylinder heads and is made of Aluminum like the rest of the head. Proximity to the cylinder heads' water jackets ensures that they never get hot enough to be problematic.

Advantages are:-

• Eliminates the exhaust manifold -- saving weight, space and cost
  
• Makes it easier to turbocharge -- there is only one outlet
  
• Makes it possible to locate the Catalytic Converter closer to the exhaust valves -- faster light-off, lower emissions
  
• This also happens to be the shortest 3-to-1 header -- great for high RPM expiration
  

[loki]

The collector is part of the cylinder heads and is made of Aluminum like the rest of the head. Proximity to the cylinder heads' water jackets ensures that they never get hot enough to be problematic.

Advantages are:-

• Eliminates the exhaust manifold -- saving weight, space and cost
  
• Makes it easier to turbocharge -- there is only one outlet
  
• Makes it possible to locate the Catalytic Converter closer to the exhaust valves -- faster light-off, lower emissions
  
• This also happens to be the shortest 3-to-1 header -- great for high RPM expiration
  

nice. i was on the right track with my ideas. lol

[dwightlooi]

The collector is part of the cylinder heads and is made of Aluminum like the rest of the head. Proximity to the cylinder heads' water jackets ensures that they never get hot enough to be problematic.

Advantages are:-

• Eliminates the exhaust manifold -- saving weight, space and cost
  
• Makes it easier to turbocharge -- there is only one outlet
  
• Makes it possible to locate the Catalytic Converter closer to the exhaust valves -- faster light-off, lower emissions
  
• This also happens to be the shortest 3-to-1 header -- great for high RPM expiration
  

nice. i was on the right track with my ideas. lol

It's a good engine on paper. I'll reserve the "improved refinement" judgement until I actually drive one. I am kinda disappointed they didn't make a 91 Octane version for Cadillac though. The differences can simply be a set of higher compression pistons and slightly more aggressive camshafts. That'll take it to the 100hp/liter mark. 323 hp is nice and decent. But, 360hp out of 3.6 liters is actually something to brag about and most Caddy buyers probably won't mind the Premium Fuel requirement. A 12.5:1 or 13:1 engine will probably make 350~360hp @ 7000 rpm and about 280~290 lb-ft @ 5500~5800 rpm. It'll be peakier, but it should still have about the same torque output as the LFX below 5000 rpm.

[ZL-1]

It's a good engine on paper. I'll reserve the "improved refinement" judgement until I actually drive one. I am kinda disappointed they didn't make a 91 Octane version for Cadillac though. The differences can simply be a set of higher compression pistons and slightly more aggressive camshafts. That'll take it to the 100hp/liter mark. 323 hp is nice and decent. But, 360hp out of 3.6 liters is actually something to brag about and most Caddy buyers probably won't mind the Premium Fuel requirement. A 12.5:1 or 13:1 engine will probably make 350~360hp @ 7000 rpm and about 280~290 lb-ft @ 5500~5800 rpm. It'll be peakier, but it should still have about the same torque output as the LFX below 5000 rpm.

100% agreed. It would be a fairly simple way of making the Cadillac powerplant unique, as that idea of uniqueness is a driver of the sales price premium a brand such as Cadillac should command.

[dwightlooi]

For anyone who wants to see for themselves how that integrated 3-to-1 exhaust collector on the LFX looks like, here's a cutaway photo...

[riviera74]

I have to disagree. I am glad GM has largely moved away from requiring 91 octane on most (if not all) of their cars, including Cadillac. What benefit would using premium exists now (as opposed to 1999) given current engineering?

[Drew Dowdell]

As dwight said, better horsepower for Cadillac.

[dwightlooi]

I have to disagree. I am glad GM has largely moved away from requiring 91 octane on most (if not all) of their cars, including Cadillac. What benefit would using premium exists now (as opposed to 1999) given current engineering?

Well, going from 87 to 91 octane allows you to increase compression ratio by about 10%. This was true in 1999 and it is true now. In 1999 -- with port injection -- typical regular fuel engines run roughly 9.5~10:1 compression and engines specifying premium fuel run about 10.5~11:1. An LFX can go from 11.5:1 to somewhere between 12.5 and 13:1 . High compression ratios improve the combustion efficiency of the engine. And that 10% increase is generally worth an increase of between 5~6% in torque across practically the entire power band with no other changes. Hence, 278 lb-ft becomes 295 lb-ft. This is especially important if we want to tune the engine for more high RPM power with a set of camshafts with more valve overlap and base timing advance. Such cam grinds tend to shift the torque curve to the right increasing power output, but they also DECREASE the magnitude of the torque curve practically across the board. Higher compression helps mitigate that torque loss.

In short, going from 87 to 91 octane allows 1~1.5 points more compression. This is a key ingredient to increasing power from 323 hp to 360 hp, and do so in a manner that still at least maintain the status quo on torque and drivability from idle up to ~5000 rpm where the new cams would actually be DETRIMENTAL.

Another benefit incidental to the use of 91 octane fuel is better engine cleaniness over the VERY long run. Most brands of gasoline have a more generous detergent package with their premium gas than their regular. The downside for specifying premium is actually less pronounced today than in the early 90s when gas was $1.30 a gallon. The reason being that Premium is roughly $0.20 more than Regular regardless of the price of gas in general. Hence $1.50 vs 1.30 represents a greater percentage difference in price than $4.40 vs $4.20.

[ponchoman49]

Impressive. I do wonder why in the Impala that this engine is rated at only 252 torque. Perhaps it's downrated to try and keep so much power going to the front wheels. I'm curious if this will be the same HP and torque specs used in the Lax. Wish GM would use a detuned variant of the 3.6 LFX in the Nox/Terrain instead of the useless 22 MPG highway MPG 3.0 liter.

[Robert Hall]

I'd like to see what they could do w/ a V8 version of this engine, maybe around 5.0L..

[dwightlooi]

I'd like to see what they could do w/ a V8 version of this engine, maybe around 5.0L..

There is no V8 version in existence or under development. However, if there is, it will displace 4752 cc (4.8 liter), sport a compact 60 degree Vee angle and probably require a balance shaft to be refined. It'll also probably make about 420~430 hp and 365~375 lb-ft on regular 87, perhaps 20 more on 91 octane. Its use however will require that GM revamp its transmission lineup, because an LFX derivative V8 will make its maximum power at about 6800~7000 rpm. Currently, all GM automatic transmissions capable of handling over 300 lb-ft of torque have either 6500 rpm or 6200 rpm maximum shift speeds.

Edited June 27, 2011 by dwightlooi

[Robert Hall]

I'd like to see what they could do w/ a V8 version of this engine, maybe around 5.0L..

There is no V8 version in existence or under development. However, if there is, it will displace 4752 cc (4.8 liter), sport a compact 60 degree Vee angle and probably require a balance shaft to be refined. It'll also probably make about 420~430 hp and 365~375 lb-ft on regular 87, perhaps 20 more on 91 octane.

I know, I was speculating...GM is not ambitious enough to build a modern DOHC V8. And why would be 4752cc? How can you speculate such a precise number?

Edited June 27, 2011 by Cubical-aka-Moltar

[loki]

I'd like to see what they could do w/ a V8 version of this engine, maybe around 5.0L..

There is no V8 version in existence or under development. However, if there is, it will displace 4752 cc (4.8 liter), sport a compact 60 degree Vee angle and probably require a balance shaft to be refined. It'll also probably make about 420~430 hp and 365~375 lb-ft on regular 87, perhaps 20 more on 91 octane.

I know, I was speculating...GM is not ambitious enough to build a modern DOHC V8. And why would be 4752cc? How can you speculate such a precise number?

adding 2 cylinders to the 3.6L V6 easy peasy.

[riviera74]

While the LFX 3.6L DI-VVT V6 sounds fantastic, a V8 derivative should be simple to do. A better question is why GM should actually do that given their very good existing Vortec V8 line. In other words, does Cadillac need a spiritual successor to the Northstar V8, or is it merely to keep up with MB, BMW, Lexus et. al.?

[dwightlooi]

I know, I was speculating...GM is not ambitious enough to build a modern DOHC V8. And why would be 4752cc? How can you speculate such a precise number?

The very premise of an LFX derived V8 is that it uses the same exact valves, springs, lifters, bolts, rods, pistons, sprockets, chains, accessory drive, combustion chamber geometry, intake design and the whole nine yards. The difference being a new block casting for two more cylinders, a new crankshaft and accommodations somewhere for a balance shaft. Retaining the the 94 x 85.6 mm (bore x stroke) of the 3.6 V6 and adding two cylinders yield ((94/2)^2)*3.1416*85.6*8 = 4752 cc

[dwightlooi]

While the LFX 3.6L DI-VVT V6 sounds fantastic, a V8 derivative should be simple to do. A better question is why GM should actually do that given their very good existing Vortec V8 line. In other words, does Cadillac need a spiritual successor to the Northstar V8, or is it merely to keep up with MB, BMW, Lexus et. al.?

Well, we know what GM is currently doing. They are do a direct injected, variable timing equipped and cylinder deactivation capable version of the LS3. From a performance, packaging, weight or fuel economy standpoint such an engine gives no ground to a DOHC V8. A 60 deg DOHC V8 however will at least be similarly narrow as a pushrod 90 deg V8 and fit in the same approximate space. This engine will be economical to engineer and produce because it shares the majority of its component, design and assembly tooling as the high volume V6. It will also match the LS3's 420~432 hp with 23% less displacement, albeit with a torque deficit of 60~70 lb-ft. This does not necessarily translate into better fuel economy because of the higher parasitic frictional losses of a DOHC design and it does incur an MPG penalty. On the flipside, because the pistons are smaller and strokes are shorter the vibrational forces are also milder while rpm limits are higher. The reduced rotational inertial also makes for a faster revving engine.

Is this a better engine for Cadillac in lieu of a advanced pushrod? That is debatable. It will however be more like what the Europeans, Japanese and Koreans are offering both in terms of displacement as well as specific output. Again, whether it is better to be like everybody else, is debatable. It will also have a tax advantage in Global Warming coolaid drinking countries with a displacement tax, however this is probably not a significant consideration for a V8, unlike more economy oriented V6 and I4 offerings.

[riviera74]

So is the LS3 engine being used right now? If so, which cars? If not, how soon will it be on the road in a GM car?

[dwightlooi]

So is the LS3 engine being used right now? If so, which cars? If not, how soon will it be on the road in a GM car?

The LS3 is the engine currently in the Corvette and Camaro SS. It is a 16v Pushrod V8 without variable timing or direct injection. It displaces 6.2 liters and makes 436hp @ 5900 rpm / 428 lb-ft @ 4600 rpm in the Corvette (426hp @ 5900 rpm / 420 lb-ft in the Camaro). It is physically smaller and lighter (183 kg) than the BMW 4.0 V8 in the M3 (202 kg). Fuel economy is exemplary for its power class, delivering 16 / 26 MPG in the Corvette and 16 / 24 MPG in the rather heavy Camaro SS (3860 lbs).

The LS3 is not the highest revving or most powerful of the current small blocks -- those honors will have to fall on the 7.0 liter LS7 (505hp) or and Supercharged LS9 (638hp). Rather, it represents the middle of the road, mainstream, version of the current generation of small block V8s.

The LS family is considered the Gen IV Small Block V8. GM is currently working on its successor family -- collectively known as the Gen V Small Block V8. The Gen V engines are expected to retain the 2-valve per cylinder layout, but add direct gasoline injection, variable valve timing and cylinder deactivation as standard features. The Gen V engines, by virtue of direct injection and resultant increase in compression ratio alone is expected to make between 6~10% more power (~470 hp). Fuel economy is also expected to be slightly better, probably on the order of 1 mpg.

[riviera74]

OK, thanks. When does the Gen V small block come out?

[dwightlooi]

OK, thanks. When does the Gen V small block come out?

The engine will probably launch on the C7 Corvette around 2013. Versions of it will probably replace the V8s in the Cadillac Vs, the Camaro SS, as well as GM's Light Trucks and full-size SUVs.

[Guest Rob-O]

Hi All,

Does anyone know where I can get a detailed diagram of the GM 3.6 LFX measurements?

Thanks!

[dwightlooi]

Hi All,

Does anyone know where I can get a detailed diagram of the GM 3.6 LFX measurements?

Thanks!

I don't think GM publishes a "drafting grade" drawing of the LFX. But you can get the majority of the official statistics here.

http://www.gmpowertrain.com/VehicleEngines/PowertrainProducts.aspx

[Guest tom]

question: doesen't the integrated 3-to-1 exhaust collector on the LFX rob HP? Now I can't put on headers.

[dwightlooi]

question: doesen't the integrated 3-to-1 exhaust collector on the LFX rob HP? Now I can't put on headers. 

 

question: doesen't the integrated 3-to-1 exhaust collector on the LFX rob HP? Now I can't put on headers. 

 

Yes, it does but not as much as you think. A properly designed, integrated collector will flow as well as ANY header placed on individual ports. No matter how fat or fancy the header, it is not going to flow any more exhaust than the size of the ports themselves dictate -- whish is why many engien builders feel a need to open up the ports by hand or through machining. The biggest thing isn't power, but the ability to tune the torque band. An integrated 3-to-1 collector is in effect the shortest possible 3-to-1 header. That is good for high RPM breathing actually but not so good for low RPM torque. Exhaust pulses travel at roughly the speed of sound. Exhaust pulses will travel from the valve to the collector where it opens up to the other two passages as well as the downpipe. This is when it is at the lowest pressure. At a particular RPM, this will happen the same amount of time it takes for the engine to open that valve again and this conincidence of a low pressure event in the exhaust and the opening of the valve(s) help with scavenging at that particular RPM. With short headers, this resonant scavenging happen at a high RPM, with long headers it happens at a lower RPM.

 

An integrated collector does not allow you to design, or put in as an aftermarket accessory, long headers for trucks and shorter ones for sports cars for instance.

Edited July 12, 2014 by dwightlooi