New 4.2L V8 from GM and Cadillac

[Quattro Pete]

Originally Posted By: edyvw
Originally Posted By: MrHorspwer
GM/Cadillac announced today a new 4.2L twin-turbo V8 for the CT6.

Clean-sheet design that shares nothing with any existing GM engines
Hot-V design, with the exhaust ports exiting into the valley of the engine, directly where the turbos are located
Cylinder deactivation
Hand-built and signed by the builder at the Bowling Green Corvette Plant

550 HP/627 lb. ft. for the CT6 V-Sport.

The non V-Sport version will also have the engine available, though with *only* 500 HP.

The V-Sport is also getting an insane 19" Brembo brake package.


That is going to be problem. Just ask BMW how that worked on N63 engine. Rock hard gaskets due to extreme temperatures that start leaking. Valve stems that harden because of that etc.
GM want to join elite, but does not learn from others and their mistakes.

VAG has been using similar "hot-V" design in their 4.0 V8 for a number of years now. I am not hearing of any issues related to this design.

 

[nthach]

Originally Posted By: edyvw
Just ask BMW how that worked on N63 engine. Rock hard gaskets due to extreme temperatures that start leaking. Valve stems that harden because of that etc.
GM want to join elite, but does not learn from others and their mistakes.

Ford has been doing hot-v on the 6.7L Power Stroke diesel for a while. And that's an engine that gets driven hard on the job in countless work trucks, ambulances, fire rigs, and in the military/police as AMRAPs. Probably harder than a BMW N63 will ever see.

 

[Quattro Pete]

Not to mention that BMW's gaskets become brittle and start leaking regardless if there is extreme heat or not. Why they keep using these inferior gasket materials is beyond me.

 

[OVERKILL]

Originally Posted By: Quattro Pete
Not to mention that BMW's gaskets become brittle and start leaking regardless if there is extreme heat or not. Why they keep using these inferior gasket materials is beyond me.


Amen to that one!

 

[oil_film_movies]

Originally Posted By: SubieRubyRoo
I'd take two of today's available turbos over any supercharger. You simply can't match the power and torque available from twin turbos with a streetable supercharger.
You would be right, Except the pushrod LT4 with supercharger makes 650hp & 650ft-lbs torque at low mass (due to no massive complex heads). Your statement doesn't hold water.

Again, this isn't about the cheapest, most elegantly optimized way to achieve some high performance. -----> This is about selling cars in the showroom to dentists and lawyers that don't care or even know that BMW, Audi, Mercedes, and now Cadillac throws in twin turbos in a "cool" multi-valve overly complicated set-up. They get to brag to friends about what its got & how much they spent. And it is technically interesting to gear-heads too, I've got to admit.

 

[john_pifer]

Originally Posted By: SubieRubyRoo
I'd take two of today's available turbos over any supercharger. You simply can't match the power and torque available from twin turbos with a streetable supercharger.

Just look at all the German cars... 4.0L TT making well over 600HP, 0-60 in the low 3s, and 25+ mpg on the highway. If I could sell some of my offspring, the M5 would be the next thing in my driveway.


Yeah, and all those German cars are entirely too complex and unreliable, and cost a fortune to maintain, too.

 

[Quattro Pete]

Originally Posted By: john_pifer
Yeah, and all those German cars are entirely too complex and unreliable, and cost a fortune to maintain, too.

Let's see how reliable these new complex American engines will be.

 

[oil_film_movies]

If Cadillac spends a lot on this new engine and they don't make money on it, at least they can get the taxpayers to bail them out .... again..... AND even zero out all their common stock and create a "New-New GM" ... again ... sca-rewing the stock holders yet again.
So where is the risk?

 

[SubieRubyRoo]

Originally Posted By: oil_film_movies
Originally Posted By: SubieRubyRoo
I'd take two of today's available turbos over any supercharger. You simply can't match the power and torque available from twin turbos with a streetable supercharger.
You would be right, Except the pushrod LT4 with supercharger makes 650hp & 650ft-lbs torque at low mass (due to no massive complex heads). Your statement doesn't hold water.[/i]



I stand by my statement. There have been several people on the GRRRR8 board with G8 GTs (just the 6.0, not even the GXP) that have gone twin 62mm or slightly larger turbos, and made WAY more than 650HP, some well over 800+ RWHP. The torque curve across the rev range with properly sized turbos just can't be matched by a supercharger, as evidenced by dropping boost numbers by most all superchargers as the revs climb toward redline. GM's 'chargers are not immune to this. Add in all the additional drag loss it takes to drive said supercharger, and you can easily see things are not tilted in the supercharger's favor. Now, before you get all defensive, I'm not saying superchargers don't have valid uses. Just when you are talking flat-out stupid amounts of HP/liter, there is no comparison. R&T has a list of the highest power per liter cars, and all top 14 are turbocharged, with the highest at 187.5hp/liter. Even the vaunted, king-of-the-hill Demon in race tune at 840HP is merely 135.5HP/liter. If you achieved the same specific output of the Mercedes CLA 45 AMG in the Demon, it would make an absurd 1,163HP with turbos (or the LT4 with twins).

This doesn't even take into account all of the aftermarket applications. Or diesel applications. When you look at parasitic losses, efficiency limitations, packaging constraints, etc.... superchargers just are not anywhere near the cutting edge of internal combustion engine power production any more.

 

[SteveSRT8]

Imagining that turbos have no parasitic power loss is just plain wrong. They are an obstruction in the exhaust and are very difficult to package properly in a modern car with a larger engine. Sure they fit on a 4 banger easily, especially a flat one! They also have under hood heat issues unless mounted remotely.

Conventional superchargers fit nicely where an intake is on most V-8/V-6 applications. No packaging changes needed.

Personally I like them in the cheap centrifugal style because they have a power curve like an engine should IMO, rising steadily to a peak point at higher revs. Just feels more natural to me.

Totally agreed that properly sized/installed they are great at producing power, but they are not the end-all for modern vehicles. Any dyno queen can have big numbers to brag about, but let's see those time slips! You used the word "streetable" which to me means smooth, quiet, idles well in traffic, pulls all my accessories with ease and doesn't overheat or release ridiculous heat into the engine bay thus stressing other components.

And we all know about those absurdly small engines with outrageous hi output. Highly stressed small engines seem to fail a lot in my world...

 

[john_pifer]

Originally Posted By: Quattro Pete
Originally Posted By: john_pifer
Yeah, and all those German cars are entirely too complex and unreliable, and cost a fortune to maintain, too.

Let's see how reliable these new complex American engines will be.

That's my point!

 

[SubieRubyRoo]

SteveSRT, I never said there was "no" parasitic power loss from turbos. But it has been tested that the large, belt driven superchargers sometimes take upwards of 200HP to turn them fast enough to make the power they do at redline. Centrifugals do mimic a good N/A power curve, but to my knowledge its been a loooong time since centrifugals have been used in road cars because they are soft on the bottom compared to either screw-style superchargers or turbos. As far as time slips, I don't think you'd have to look far to find incredible ones- especially if you are talking aftermarket. By your description, I'd be willing to bet that any of today's production twin-turbo V8s would hit all of your requirements. As far as the high-strung 4 cyls, maybe not so much.

Like someone referenced in the Navigator TT EcoBoost thread, it's not like manufacturers are just taking 4 or 6 cyl engines and slapping 30lbs of boost on them- they are engineered from the ground up to support the rated power levels. I completely agree though that if you took an N/A 4 cyl making say 200HP and put a honkin turbo on it to make 450HP with no internal changes, it's insides would not remain so for very long...

 

[PeterPolyol]

Originally Posted By: michaelluscher


This line of thinking brings back bad memories

This same line of thinking birthed the Northstar


The Northstar and the Aurora V6 are great engines, very underrated. Any achilles heel they had was that it was a premium engine built by a cheap-@$$ company- such engines are not their forte.

Oldsmobile engineering was always a bit too esoteric for GM

 

[nthach]

Originally Posted By: PeterPolyol
Originally Posted By: michaelluscher


This line of thinking brings back bad memories

This same line of thinking birthed the Northstar


The Northstar and the Aurora V6 are great engines, very underrated. Any achilles heel they had was that it was a premium engine built by a cheap-@$$ company- such engines are not their forte.

Oldsmobile engineering was always a bit too esoteric for GM

Toyota's introduction of Lexus in the late 1980s put the auto industry on notice - it not only introduced higher engineering/fit & finish/NVH levels for the world to try to imitate, it set a standard at Toyota themselves years later.

Mercedes and BMW had to respond to it, but I think Lexus also gave GM a wake-up call that it just can't match the level of QC, fit & finish and engineering for Cadillac to compete against. The Northstar was probably GM's answer to the Lexus V8. It's a very good motor on paper and a lot of those concepts are sound - but GM back then was reeling from Roger Smith almost steamrolling them out of existence.

 

[dailydriver]

Originally Posted By: SubieRubyRoo
I completely agree though that if you took an N/A 4 cyl making say 200HP and put a honkin turbo on it to make 450HP with no internal changes, it's insides would not remain so for very long...

Granted, it was built 'for street reliability boost' (up to 23 PSI allowed by the ECM) from the ground up (albeit absolutely NOT anywhere near a 'full race' engine), my little "smaller than a 2 liter bottle of soda" as we used to say mockingly on the LSx sites to all of the imports, WILL handle up to 425+ WHP on the factory long block, before the internals outright require strengthening.

Of course, this IS with ALL of the ancillary 'supporting mods' (4 port injection added on, HUGE intercooler, usually E40 fuel, cooler plugs, higher capacity radiator, and possibly water-meth injection, etc.)

 

[PeterPolyol]

Originally Posted By: nthach
Originally Posted By: PeterPolyol
Originally Posted By: michaelluscher


This line of thinking brings back bad memories

This same line of thinking birthed the Northstar


The Northstar and the Aurora V6 are great engines, very underrated. Any achilles heel they had was that it was a premium engine built by a cheap-@$$ company- such engines are not their forte.

Oldsmobile engineering was always a bit too esoteric for GM

Toyota's introduction of Lexus in the late 1980s put the auto industry on notice - it not only introduced higher engineering/fit & finish/NVH levels for the world to try to imitate, it set a standard at Toyota themselves years later.

Mercedes and BMW had to respond to it, but I think Lexus also gave GM a wake-up call that it just can't match the level of QC, fit & finish and engineering for Cadillac to compete against. The Northstar was probably GM's answer to the Lexus V8. It's a very good motor on paper and a lot of those concepts are sound - but GM back then was reeling from Roger Smith almost steamrolling them out of existence.

If I had a dollar for every time I've heard an identical romantic Toyota mythos story.
The fact is that Lexus was nothing special. Lexus as a brand name didn't even exist in Japan until 2005. The Japanese majors during the bubble era all concurrently launched their 'foreign luxury' brands at the same time. The UZ V8 was run of the mill at the time, no more technologically advanced than the Nissan VH V8. Both 'bragged' 6 bolt mains, aluminum construction etc etc; this wasn't Toyota's gift to the world, it had the standard features of a new engine architecture during that era of automotive engineering. I've read so much [censored] propping up the UZ it's ridiculous. The Lexus wiki even says that "it's (UZ) race heritage was confirmed by some TRD guy in 2003... LOL what a crock of romantic horse hockey! 14 years later, some american that was never involved in the UZ development project now "confirms" it's based on a race engine just because it has 6-bolt mains? Wow. Now they're teaching the Germans how to make low power density V8s? hahahaa wow.

The differences you speak of to 'quality' between the German and the Japanese brands are exactly that- cultural differences between engineering and manufacturing between Germans and Japanese, not MB/BMW etc vs "Lexus", a purely marketing brand borne out of North American customer research and brand positioning with the intent of maximizing profits on luxury vehicles.

The luxury brands from the Japanese majors began as marketing strategies to take advantage of trade deals in which the higher end models could be re-branded and sold to higher profitability in the US and other markets, instead of domestically. They all wound up selling existing Toyota/Nissan/Hondavehicles/hardware from the oversaturated Japan Domestic market re-branded as Lexus, Infiniti and Acura. For instance, the LS400 was nothing but a Toyota Celsior.

If Ford didn't cut Mazda's Amati brand (for fear of poaching sales from/shaming 1990s Lincoln), we could have had a magnesium-alloy W12 from them as well as yet another Japanese V8. Too bad.


tldr; Toyota is not a mentor to any other brand, apart from sales volume aspirations. There is a metric poop-tonne of mythos and romantic stories surrounding them, however.

 

[A_Harman]

Originally Posted By: oil_film_movies
"Cadillac says the new 4.2 is actually a little lighter and a little more compact than the LT4. We find this hard to believe, considering compact dimensions are among the biggest selling points of GM’s small-block. Engineers point to the shorter block (by 50 millimeters), made possible by bore spacing down to 96.0 mm from 111.7 mm in the small-block."-- Car and Driver magazine

So they saved some mass. Doesn't sound like much.
We have to think of this as appealing to the kind of rich buyer that responds to "gee-whiz, twin turbo's!!". GM might make money on this one, so I guess there's no sense in saying the LT4 is better and what idiots GM are for producing this newer design that doesn't beat an LT4.
Maybe this beats an LT4 for NVH. That would be a justification for it I guess. The LT4 is pretty good there now, so I dunno if this a leap forward.


GM's new 4.2L V8 has a bore spacing of 96.0 mm. How funny. Exactly the same bore spacing as the Ecotec 2.0L I4 that has 275 HP in the Camaro. Just double that engine, and you have 550 HP. Hmmmm....

GM's 3.0L High-Feature V6 has 400 HP in the CT6, and that engine has the same bore diameter as the Ecotec 2.0.

Sort of beginning to see a pattern in GM engine design. 500cc DOHC cylinder with 4 valves, turbocharged up to 20 psi (or thereabouts).

Did anybody ever check to see how expensive a 2.0L Ecotec turbo crate engine is? $7200 on Crate Engine Depot the last time I checked, and that only gets you 275 HP. Meanwhile, you can buy an LS3 with a Hot Cam and 480 HP from the same place for $6300. The point is, DOHC engines are expensive to produce, so they're expensive to buy, and all the extra mechanical bits whirling around inside make them less efficient.

I'm still waiting for GM to do a twin-turbo version of their 4.3l V6 and use that to blow Ford's Egoboost V6 off the road.

 

[A_Harman]

Originally Posted By: SubieRubyRoo
Originally Posted By: LEADED
Is this Powerplant DOD ? . Will see if anyone have info . Thanks


The engine also will be General Motors’ first to apply Active Fuel Management cylinder shutoff to an overhead cam engine. Preliminary numbers are 550 hp @ 5,700 rpm in high-output form, and 500 hp @ 5,000 to 5,200 in “standard” form.


Not so. GM has AFM on the Gen2 High-Feature V6. That engine shuts off one cylinder on each bank to make a V4 mode.

 

[A_Harman]

https://www.sae.org/news/2018/03/all-new-cadillac-v8-for-2019-ct6

Some nice technical information on the engine.

 

[SubieRubyRoo]

“Most significant is Active Fuel Management in its first use for a GM-made DOHC V8. The setup operates the engine in 4-cyl. mode when appropriate, shutting down the outboard two cylinders of one bank and the inner two cylinders of the other engine bank. “

That sure sounds like Northstar stuff to me...