New 4.2L V8 from GM and Cadillac

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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.
 
The LT4 produces 650HP/650FT-LBS with supercharging.
I think Cadillac marketers want to go elite, up-scale, Cadillac-unique to sell their cars on emotion. Might work if they can get a high price.
Even though the LT4 is better. Mass may be similar too.
 
Originally Posted By: oil_film_movies
The LT4 produces 650HP/650FT-LBS with supercharging.
I think Cadillac marketers want to go elite, up-scale, Cadillac-unique to sell their cars on emotion. Might work if they can get a high price.
Even though the LT4 is better. Mass may be similar too.


This line of thinking brings back bad memories

This same line of thinking birthed the Northstar
 
Was behind a new or newer Cadillac yesterday. It had a 2.0L Turbo emblem on the back. Sorry not talking about what the OP stated though.
 
"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.
 
Sorry - Barra is not moronic. She may be able to lead them to better profitability.

I'm sure the Caddy buyers have been polled (no pun intended). Branding needs an edge
smile.gif
 
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Luxury-performance-high$$$ cars need to have 4-valve cylinders and twin turbos. Its a selling point.
Never mind that the LT4 performs better. Doesn't matter except to engineers like me who like the best, optimal way to achieve performance.

BMW, Mercedes, Lexus, Infiniti, Jaguar, Alfa Romeo, Audi are the competitors, and all their engines are more complicated than a million Swiss watches.
It gives the owner bragging rights and an inflated sense of self-worth the more complex a machine they can own.
 
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.
 
Originally Posted By: michaelluscher


This same line of thinking birthed the Northstar

This time around, GM is run by an engineer(Mary Barra) and not the train wrecks before the government takeover. I think GM did learn quite a bit from the Northstar and applied what/what not to do for this motor.

The hot-V design is probably a first outside of diesel V8s - GM probably made that move to maximize thermodynamic efficiencies with the turbocharger setup. If the engine is DOHC and headed into the Corvette or another GM product, having a smaller space claim helps as well.
 
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.
 
Originally Posted By: ARCOgraphite
Sounds like a mid engine vette is near.
That is not a Caddy only engine unless GM corporate is moronic.
Oh, maybe they are moronic!

The mid engine Vette has been near since the the early 1960's
 
Got pretty good distribution with the transaxle and torque tube … pushrod engines have a low CG … they did good adding a huffer & puffer (and blow your doors off)
 
Originally Posted By: CT8
Originally Posted By: ARCOgraphite
Sounds like a mid engine vette is near.
That is not a Caddy only engine unless GM corporate is moronic.
Oh, maybe they are moronic!

The mid engine Vette has been near since the the early 1960's


It seems to have died along with Z.A.D., helped along by the purist, die-hard front-engined, fan base of the car.
frown.gif
 
Originally Posted By: 4WD
Got pretty good distribution with the transaxle and torque tube … pushrod engines have a low CG … they did good adding a huffer & puffer (and blow your doors off)


But they seem to suffer from 'huffer in the valley heat stroke' (soak) on long runs under high revs/power output.

A twin snail (with proper valley/turbo/manifold shielding and a large enough intercooler) will not.
wink.gif


This powerplant (probably tuned/boosted/cammed even more radically yet) would make the mid-engined y body a TRUE 'exotic', at STILL a fraction of the cost of most of the others out there (albeit yes, MUCH more coin than the current 7th gen of the car).
 
Originally Posted By: nthach

The hot-V design is probably a first outside of diesel V8s - GM probably made that move to maximize thermodynamic efficiencies with the turbocharger setup. If the engine is DOHC and headed into the Corvette or another GM product, having a smaller space claim helps as well.


Only if you are talking production motors. Ford a Turbo Windsor hot-V in the 1960's for racing applications.
 
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.
 
I'll bet they make it work just fine. BMWs are [censored]. We had a 540il that was a tub. It had constant electrical problems. My brother has a Z4 that he just dropped 6 grand into for electrical and some mechanical issues. It has left him stranded a couple times. One transmission issue was so bad, BMW had to send a rep out to see it for himself. I wouldn't trust BMW to do something like that very well, to begin with.

GM has tremendous engineering capacity to make it work. Just because something BMW tries to do fails doesn't make it a bad idea.
 
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