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New Cadillac twin turbo V-8


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#1 mariner

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Posted 25 March 2018 - 11:45

A new 4.2 litre V-8 from Cadillac with twin top mounted turbo's a la F1 !

 

http://www.enginelab...urbo-v8-engine/

 

I wonder if it is new corporrate GM engine? Seems a lot of money for just the low volume Cadillac range.

 

Also interesting they decided to go V -8 for just 4.2 litres not V -6 when they have compact V-6 of 3.6 litres already.



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#2 MatsNorway

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Posted 25 March 2018 - 14:38

As the comments suggested it is probably due to the new corvette getting a radical makeover. So using the same platform for the luxury cars is a no brainer. No one wants a V6 anyway. Straight six maybe.

 

Corvette becoming a mid engine sucks.


Edited by MatsNorway, 25 March 2018 - 14:40.


#3 Bob Riebe

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Posted 25 March 2018 - 20:11

All the twitter about the RE Corvette, if it is a reality getting the new quad cam Cadillac engine is about as accurate, probably , as the RE Corvette scuttlebutt for the past fifty years.



#4 MatsNorway

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Posted 25 March 2018 - 23:48

I sure hope the rumor mills are wrong. But it seems more real now.



#5 Canuck

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Posted 27 March 2018 - 00:16

I never cease to be amazed by new engine developments. Who would have guessed that a reverse-flow engine with turbos in the valley would work better than on the outside.

 

I'd be curious to know the average age of a current 'Vette buyer. What's the rate of repeat buyers - how often does a current Corvette owner buy a new one? How many owners? How many people with the means and the plans to buy a current Corvette would not buy an RE version? How many are ambivalent? How many people who are not buying now, would if it were to undergo a RE transformation?

 

Perhaps the new RE 'Vette, assuming it's actually a thing, will be only as successful as H-D's V-Rod series - which means somewhat, but not enough to keep it alive. Or perhaps it will be to Chevrolet as the Cayenne was to Porsche (though I can't imagine how given the inverse relationship there).

 

I like the current Corvette and would own one if circumstances permitted - it's beautiful, it's fast - what's not to love?



#6 Greg Locock

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Posted 27 March 2018 - 08:38

61

 

They aren't terrible cars, if I were in the USA and wanted a that sort of thing I'd buy one, and drag the average age down a bit! The reality is that it is a car that is good at stuff that i only want to do on a race circuit (and I'm not very interested in that) and is otherwise just an inconvenient heater with a nice sounding donk, mixing my slang there.



#7 MatsNorway

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Posted 27 March 2018 - 10:53

I suspect you would prefer a AMG Greg.

 

As for the Corvette, they are terribly cheap for the performance you get. At least they used to be if you compared to a 911 or a GTR

 

Here is some claimed spy shots of the mid engine corvette. Looks generic and not very interesting proportions. I sure hope that is some other car.

https://www.roadandt...photos/?slide=8


Edited by MatsNorway, 28 March 2018 - 09:47.


#8 sblick

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Posted 27 March 2018 - 20:27

The Cadillac engine is sweet.  Driven it, but not very fast.  Start up was awesome though.  I would assume there will be a quiet start up mode a la the Mustang.  It is stuffed pretty tight into the engine bay like most engines these days.  Cadillac has promised sedans that will beat BMWs and Mercs at the Nurburgring so maybe we will see this in an ATS-V.

I wouldn't pass up the chance at a Vette anymore.  The performance is amazing.  They ride and handle now like a sports car should.  120k US for a ZR1 is a bargain these days for the performance you get.

Average age is still old, average buyer does not have one very long they are always trading up to another one, I would say there are a fair amount of buyers with multiples in the garage.  Vette buyers are very loyal.



#9 gruntguru

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Posted 28 March 2018 - 00:11

Interesting that it has divided turbine housings and each turbine is fed by one bank. Unless they are using an unconventional firing order, the pulses to each turbine will not be evenly spaced. Not a deal breaker - the pulses to a particular turbine inlet only need to be more than about 240 degrees apart, ie 270 or 450 would be OK but 360 would be ideal.



#10 MatsNorway

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Posted 28 March 2018 - 09:49

Could the pictures be early prototype? Are you saying they should run a single turbo and make the pulses mix from each bank?



#11 sblick

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Posted 28 March 2018 - 11:41

That is like a diesel set up with a single between the banks.  I sometimes wonder why there aren't more dual turbo set ups in diesels.  Someone could probably tell me why.  Is there durability or performance issues with pulses being uneven?  I can see a slight performance problem, but was wondering with uneven pulses if turbo is spinning fast then slow, fast then slow and causing weird wear patterns.



#12 gruntguru

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Posted 29 March 2018 - 03:58

Could the pictures be early prototype? Are you saying they should run a single turbo and make the pulses mix from each bank?

No, Capturing blowdown energy requires having separate passages all the way to the turbine wheel, with each passage shared by cylinders that are at least 200+ degrees apart ie no more than 3 cylinders sharing each passage. This engine has 2 cyl per passage but they are probably not equally spaced (360* apart)



#13 sblick

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Posted 29 March 2018 - 13:08

Cadillac is saying that Chevy can't have their 4.2 liter.  Autoblog story.  Find that hard to believe that GM won't disperse the technology through their divisions



#14 Greg Locock

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Posted 29 March 2018 - 18:04

You never worked with GM did you?



#15 MatsNorway

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Posted 29 March 2018 - 21:52

You have to tell us more than that Greg.



#16 kikiturbo2

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Posted 29 March 2018 - 23:58

No, Capturing blowdown energy requires having separate passages all the way to the turbine wheel, with each passage shared by cylinders that are at least 200+ degrees apart ie no more than 3 cylinders sharing each passage. This engine has 2 cyl per passage but they are probably not equally spaced (360* apart)

could be a flat plane crank V8 which would be ideal setup with two twin scroll turbos..



#17 Bob Riebe

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Posted 30 March 2018 - 02:32

Cadillac is saying that Chevy can't have their 4.2 liter.  Autoblog story.  Find that hard to believe that GM won't disperse the technology through their divisions

A magazine recently interviewed one of the gents involved with the Corvette and he seemed rather certain that the Corvette should remain with be identified as a Chevrolet.



#18 Greg Locock

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Posted 30 March 2018 - 04:27

The amount of infighting between divisions is quite amazing, and the little empires have their little emperors. That may have changed since the government, sorry, taxpayer, buyout, but it doesn't seem likely. GM needs a Mulally.



#19 gruntguru

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Posted 01 April 2018 - 03:17

could be a flat plane crank V8 which would be ideal setup with two twin scroll turbos..

More likely a dual plane crank and some pulses arriving at 270 and 450 degree intervals. Single plane vibes don't pass muster these days - think of the cost in oil filled engine mounts!



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#20 404KF2

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Posted 01 April 2018 - 06:12

I suspect you would prefer a AMG Greg.

 

 

Oh god not AMG; they sound like my friend's 1968 Mustang 40 years ago.  Super loud, uncomfortable boy racer car for meatheads.



#21 MatsNorway

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Posted 01 April 2018 - 18:09

Some V8 Mercedes then..



#22 Bob Riebe

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Posted 02 April 2018 - 20:44

Oh god not AMG; they sound like my friend's 1968 Mustang 40 years ago.  Super loud, uncomfortable boy racer car for meatheads.

Still good to know there are those who long for the big Caddy Ghetto Cruisers. :rotfl:



#23 Kelpiecross

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Posted 03 April 2018 - 02:51

Interesting that it has divided turbine housings and each turbine is fed by one bank. Unless they are using an unconventional firing order, the pulses to each turbine will not be evenly spaced. Not a deal breaker - the pulses to a particular turbine inlet only need to be more than about 240 degrees apart, ie 270 or 450 would be OK but 360 would be ideal.


How much difference to performance does it make?

#24 sblick

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Posted 04 April 2018 - 17:23

Worked as a supplier to GM, and know many stories of the infighting to keep technology.  In these days though I thought a person called CEO could put their foot down and disperse costs through many divisions even if single turbo or no turbo.



#25 Lee Nicolle

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Posted 09 April 2018 - 04:05

The amount of infighting between divisions is quite amazing, and the little empires have their little emperors. That may have changed since the government, sorry, taxpayer, buyout, but it doesn't seem likely. GM needs a Mulally.

As I understand it the Corvette division is profitable unlike some others. I suspect their 'truck' division is as well.

Though the EV/ hybrid vehicle nearly certainly costs a LOT.



#26 Greg Locock

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Posted 09 April 2018 - 19:18

Back in the day Corvette was one division that was ALWAYS up for the chop (80s,90s, 00s). Getting the next model funded was always life or death for them. Whether this was sadistic board members having a bit of fun with the red headed step child, I don't know.



#27 Almag

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Posted 11 April 2018 - 19:45

More likely a dual plane crank and some pulses arriving at 270 and 450 degree intervals. Single plane vibes don't pass muster these days - think of the cost in oil filled engine mounts!

 

Correct, the Cadillac 4.2L has a cross-plane crank (firing order 1-5-4-3-6-8-7-2) and thus each scroll has 270 and 450-degree firing intervals. This the same as Audi's hot-vee 4.0L twin scroll biturbo V8, and ditto for Benz's.

 

Only the BMW hot-vee 4.4L achieves 360-deg firing per scroll. They do this with exhaust manifolds that are not bank-specific; rather, each turbo is fed by cylinders of both cylinder banks. I have heard that the BMW manifolds were horrifically expensive things to develop/validate.



#28 sblick

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Posted 11 April 2018 - 20:44

GM, as well as Ford's, truck divisions rule the roost when it comes to profit.  Whatever the truck divisions want they get.  They are a money printing machine.  Rumors are 5-10k per truck go in to the coffers.  Ford sells 800k a year and Chevy and GMC are close to a million.

 

On the GM side a next door neighbor of a friend worked on the XLR-V engine. When they reported more horsepower than the Corvette, while in development mode, the Corvette guys squashed that engine.  No one was allowed to be faster than a Vette.