Cadillac surprised us all on Wednesday when it announced the 2019 Cadillac CT6 V-Sport. And the new 2019 CT6 isn’t just for show, with the brand bringing a lot of go by introducing the long-awaited Cadillac 4.2L twin-turbo V8 engine. Assigned RPO code LTA, Cadillac says the engine will be exclusive to its own vehicles, though we have reason to believe that may change in the future.
In developing the new engine, engineers started from a blank slate and focused on performance and small packaging. The result is an engine that pushes out an estimated 550 horsepower at 5,700 rpm and 637 pound-feet of torque between 3,200 and 4,000 rpm in the 2019 Cadillac CT6 V-Sport, along with 500 horsepower and a yet-to-be-determined amount of torque in the non-V-Sport CT6. The new Cadillac V-8 is decidedly different from any GM eight-cylinder engine used over the past eight years for two primary reasons: first, it’s a Dual Overhead Cam (DOHC) design and second, it features a “hot V” configuration, which delivers a tidy and small packaging and astounding performance.
DOHC Design
The Cadillac 4.2L Twin-Turbo V-8 is the first Dual Overhead Cam (DOHC) eight-cylinder engine from General Motors and Cadillac since the duo discontinued the Northstar V8 in 2010. Since then, all Cadillac and GM eight-cylinder engines were of the Overhead Valve (OHV) configuration otherwise known as “push-rod”.
The DOHC design lends itself to smoother operation compared to an OHV engine. Also, Dual Overhead Cam engines are typically more powerful than overhead valve engines from a displacement standpoint, though exceptions to the rule do exist. For instance, a 4.2L DOHC motor will likely be more powerful than a 4.2L OHV motor. But despite their more efficient use of displacement, DOHCs are typically larger in physical size compared to OHV engines, since the DOHC configuration is taller as a result of two cams residing above the valves.
“Hot V” Configuration
The new Cadillac V-8 LTA engine features what is now referred to as a “Hot V” configuration. To understand the Hot V design, it’s worth exploring how a traditional turbocharged engine works first.
In a typical turbo-charged engine, cylinder heads receive air through ports at the top of the engine, while exhaust exits lower through ports outside the manifolds, which connect to the turbos.
In a “hot V” setup, by comparison, intake-charged air enters through the lower outside of the heads and exits through the top inside – where the turbochargers are integrated with the exhaust manifolds. This results in a quick spool-up, translating into more immediate power delivery. The design also enables closer mounting of the catalytic converters, for efficient packaging.
Notably, modern V-8 engines from Porsche, Audi and Mercedes-Benz use the same “hot V” layout.
Twin-Scroll Turbochargers
The turbos feature a twin-scroll design broadens their performance capability, offering quicker response and greater efficiency. Instead of a single spiral chamber (scroll) feeding exhaust gas from the exhaust manifold to drive the turbine on each turbocharger, the engine’s twin-scroll design has a divided housing with two exhaust gas inlets and two nozzles to drive the turbine. Generally, one of the nozzles contributes to quicker response and boost production, while the other contributes to overall peak performance.
Each of the engine’s integrated exhaust manifolds/turbocharger housings splits the exhaust channels from the cylinder head so the exhaust flows through separate scrolls based on the engine’s exhaust pulses. When matched with precise valve timing, that separation leverages exhaust-scavenging techniques to optimize gas flow, improves turbine efficiency and reduces turbo lag.
The electronically controlled wastegates – one per turbocharger – are used for more precise management of the engine’s boost pressure and subsequent torque response for smoother, more consistent performance. They are independently controlled on each cylinder bank to balance the turbo compressors’ output, for greater boost pressure response.
Water-To-Air Charge Cooling
An efficient water-to-air charge-cooling system contributes to the engine’s performance, enhancing the turbochargers’ effectiveness. Similar in concept to an engine’s radiator, the system’s intercoolers cool the boosted air charge before it enters the cylinders. Cooler air is denser, which means there is more oxygen in a given volume, resulting in optimal combustion and resulting more power.
The system on Cadillac’s 4.2L Twin-Turbo V-8 LTA engine features a pair of heat exchangers located above the valley-mounted exhaust manifold/turbocharger housings. The turbos pump pressurized air directly through the heat exchangers and into the cylinder heads. The heat exchangers are cooled by their own coolant circuit.
The intercoolers lower the air charge temperature by more than 130 degrees F (74 C), packing the combustion chambers with cooler, denser air. Also, the system achieves more than 80 percent cooling efficiency with only about 1 psi (7 kPa) flow restriction at peak power, which contributes to fast torque production.
Dual Throttle Bodies
Before entering the combustion chambers, the cooled air charge flows through a pair of throttle bodies, one for each engine bank. Each electronically-controlled throttle body has a 59mm diameter opening.
10-Speed Automatic Transmission Pairing
The new 4.2L TT V-8 engine will be paired to the new GM 10-speed automatic transmission (the 10L9) in the 2019 CT6.
Production
The 4.2-liter LTA twin-turbo V8 LTA will be hand-built at General Motors’ Performance Build Center in Bowling Green, Kentucky.
Complete Details
See complete details about and specifications on the Cadillac Twin-Turbo V-8 engine the LTA.
Comments
So beautiful and about time. Honestly I would love to see the new camaro SS get a 5.0l Dohc and give the new z/28 a 5.7l Dohc option pushing out 485hp and 550hp respectively. I think with that, the 10 speed auto, tri-y exhaust manifolds, dual injection fuel systems, active exhaust systems tuned to sound more like the old school camaros or the early 90s zr1coevette, magnetic ride, same big Brembo brakes recaro seats, improved stereo, heads up display, e-diff, and a few minor changes in styling, the camaro will moreso walk away from the mustang as the best pony Car on the market. I think the zl1 should move to a 6.2l Dohc supercharged v8 and make 800hp and stomp the new GT500 into the dirt.
As long as they do not cut corners with this they should have a real winner and the exact ticket in this segment needed to compete.
The Chevy engine is a very good engine but when paying more for a Cadillac people expect more than just the same engine in their Tahoe.
This engine in the Escalade should give people more reason to move up from a Yukon.
The HP here is only the ground floor. This will hold more in the future.
It will end up in the Corvette too in the higher end models. I expect some major changed in Liter size and power though.
An engine like this can do much more HP with some small changes.
This engine holds similar tech as the Ecotec. Similar compression to my SS engine and Boost with the upgrade from GMP.
For those who remember when there were 5 GM divisions, each made there own engines and most were exclusive to there own cars; exception a few smaller engines were shared. When GM started putting Chevy 8 cylinders in full size olds sedan owners were not happy when they found this out. Hopefully, Cadillac will have exclusive engines to there cars.
Or Olds engines into Pontiac Firebirds and Cadillacs. Iron Dukes into Chevys. Izuzu’z into Chevys and GMC’s Buick V6’s into everything and the list goes on.
Pontiac V8 could not pass California emissions test. So they used oldsmobile Engines. Oldsmobile could not produce enough engines for them and Pontiac so they ended up using Chevy engines. And some people started whining about that on the air cleaner it said rocket V-8. GM got sued for that. After that everything was labeled as a GM engine.
There was more brand loyalty then and the fact people were also being charged more for the Olds but not told they were getting a Chevy engine.
It was an ugly time.
They could make the Pontiac pass but it was just the cost to do so that lead GM to move to the corperate engines. Later to all the engines.
We even were given 305 Corvettes and Trans Ams.
GM needs to offer a 500+ HP truck and make that statement before Ram or Ford does. I give it a few years before someone has one, my money is on Dodge doing a Ram Hellcat
Actually on second thought. I would like to see the zl1 get an 800hp twin turbo setup like the new ct6 but with 6.2l displacement. Right along with the new corvette.
Can Cadillac afford to pay for this engine on its own or will it have to be shared throughout the GM lineup?
The engine will pay for itself over time since it will go in higher trim CT6s and future higher trim Cadillacs. The engine will mostly, not entirely, be Cadillac exclusive.
I think this Engine will start out exclusive Cadillac including the Escalade. The next vehicle to get it will be the mid Engne Vett. I don’t see a problem with it eventually spreading across other GM vehicles. The idea of a Cadillac worthy Engine spreading across GM is a good thing,where as a Chevrolet worthy Engine in a Cadillac was no t a good thing. Even the next generation 4 and 6 cylinder Engines should be brought up to Cadillac standards. That would save on cost,rather than having to develope engines for separate divisions. Besides it would benefit the other divisions having the finest engines in the industry.
The basic of this engine will be shared but sizes and other parts will be changed much like the platforms.
The Corvette is the primary other model to get it.
Keep in mind this is an hand assembled engine and not a cheap production model.
We at some point will see a DOHC in the trucks but it will be a cheaper and differently trimmed engine. The Emissions alone will force this at some point in the future.
I expect GM will share some but change other parts in the end to make it more brand specific.
All LS7 and grand sport LS3’s were hand assembled, I don’t imagine for this to be approach the volume of those.
scott3
That sounds reasonable. I wasn’t advocating putting the hand built one be in vehicles like the pickups. I was thinking to help spread the cost some form of this engine need to be offered in more than just the Cadillacs. I would also like to see some form of this engine available in all of the CT6’s, not just the v Sports and high trim level ones. Even a non turbocharged version would be nice. Speaking of Cadillac I think they all should come with all the avalable safety features. Lane departure, blind spot alert.360 cameras, collision avoidance, full leather interior, heated steering wheel, heated and cooled seats front and back and ect. I know there needs to be some separations between the trim levels but there should be no bare bones Cadillac with cheaped out interior and equipment.
Expect the engine to be more like the Alpha platform. It will be the foundation but it will differ in execution.
Much like the Camaro vs the CTS. Same base but much different takes.
I think they still need a vase model but restrict it here. Markets overseas are much more open to base models and versions we care less for here.
We need to think globally with Cadillsc now.
There is a version of this engine that is going to be used in non “V” CT6 models. “What’s under the V-Sport’s probing hood is just as interesting as the redesign and the sporting thrust: A clean-sheet design of a 4.2-liter DOHC twin-turbo V8. In the V-Sport, the engine produces 550 horsepower and a Bentley-esque 627 pound-feet of torque. As an optional engine elsewhere in the CT6 range, the same engine produces 500 hp and 553 lb-ft. The displacement, specs, plus the fact that “each engine will be hand-built at the Performance Build Center in Bowling Green, Kentucky”-Autoblog.com
Got to admit a quick Google search was needed to learn about ‘Hot’ V as the twin turbochargers are nested in the V of the engine to save space as this is something Mercedes had done; a quick question is whether we’ll see a 3.0-3.5L V6 or even a new 2.0-2.2L 4-cyl from this engine design or if it’s a one off.
Back in 2008 Or 2009 The LMK engine 4.5 L Duramax That never went into production Was a Hot V.
And then Ford did it on their 6.7 litre diesel engine and Ford folks think that Ford came up with the technology.
Ford had HOT V FLATHEAD V8s,and a four cam 4.2 turbo win indy with MARIO ANDRETTI in 1969 !
After being depressed as a car guy with all this talk of self driving cars, ride sharing, and an all electric future and now the tragic death of a civilian at the hands of a self driven Uber it is so refreshing to see a honest to goodness new DOHC V8 engine design. Lets hope it doesn’t disappoint on the mileage figures.
The woman’s tragic death could easily have been avoided by looking both ways before crossing the street at night, something (most of us) were taught as children. It isn’t like the self-driving car was operating without headlights, changing lanes, or speeding.
This is a simple case of Darwinism at work.
It will be interesting to see how the insurance companies sort these inevitable situations out.
This is only the CT6 V-Sport I would like to see about the CT6-V. Like Scott said it’s only the beginning I know they could so much more especially with the top corvette coming in a few years
there will be no CT6 V.
No but there will be a CT5V
Ilke that but for the Corvette I’d like to see something like a 3.5 liter Dohc 5 valve percylinder flat plane crank twin turbo V8 that was partnered with ilmor enginerring for the mid engine layout. that would be awesome
Actually GM has hinted they would like to do a flat crank but they want to eliminate the vibration. That tells me they may be working on one.
I do not see a 5 valve or smaller engine. If anything it may be a little larger and 4 valves.
I’m shore they haven’t cut any corner’s scott 3 on this, JDN/Cadillac mean’s good attention to move forward. And this is just these stated. Corvette version will be 5.5 liters or smaller (4.4-liters) and these turbo’s will be on side, etc.
Scott 3, will Corvette Racing/ Chevrolet corvette c8 race with a TT V8 engine, and what size will it be?
This engine architecture will no doubt filter down into the C8 mid engined Corvette; hopefully in a 5.5L version (800+HP) as rumors have suggested.
Great way to roadtest and fine tune the tech before the C8 ZR1 TT hits the road.
Back to its V8 roots.
The late(1936-48) Cad-Lasalle flathead V8 had ‘Hot – V’ exhaust in combination with the intake.
The first Cad V8 was built in 1914 and was also a hot -V.
Love those old Cadillac Flatheads and those beautiful porcelain covered exhaust manifolds!
Ct 5 v? It’s gonna get in there. Hope the price starts at 55k and fully optioned to 75 k.
Corvette C8 TT V8 engine will have it’s turbo’s mounted on these side and not in a V configuration, these engine will be different, the”Hot V” configuration that’s Cadillac only engine design. If corvette racing race this engine witch they will, that displacement has to be smaller, not 5.5-liters for a turbocharger engine, it would have to be (4.4, 4.5, or 4.7-liter’s).
There is a base version, of this engine/car package of these CT6- 500hp/553lb-ft torque.
I am hoping this is the first of more Cadillac based engines.
The V8 is a start, they need to keep the V6 3.0TT and update it based on the new engine.
Then they need to take the 4 make it more quiet and make the base a 300 HP Turbo.
All engines should be of a Cadillac tune with appropriate changes to make them special. No more just changing the plastic engine cover.
To be honest this would be of benefit to Cadillac and Chevy. It would help remove the corperate engine brand from them too. They then could move to call them Chevy engines again for the most part as Buick and GMC are low enough volume to not interfere.
HOT-V 4.2L CAN YOU GET THIS AS A CRATE ENGINE, ALSO WILL IT FIT IN A 2005 XLR ?
Looks like this engine now has a name: Blackwing.
I’ve been saying for some time that Cadillac needs exclusive powerplants that have an identity as the Northstar had in its day. I’d love to see the “Blackwing 4.2 TT V-8” and then something like a “Blackwing 3.2 TT V-6”, etc. Basically a family of Cadillac-exclusive engines that are developed specifically for the brand.
Many years after the fact, car fans still speak about engines with names like Rocket, Blue Flame, Hemi, Cobra-Jet, Super Duty, and, yes, the Northstar. I very much applaud Cadillac if they’re branding their new engine as ‘Blackwing’.
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