dwightlooi

I am sure they can, but it'll mean starting over and doing something they haven't done before. It'll take longer and cost more money. And it may not be very good the first time they tried it. It'll be like GM doing the Quad Four back in the 80s. It took GM four engine generations to get from that to where they are today. It'll take BMW and M-B at least two product cycles or about 12 years to catch up to GM. There is also the inherent risk of such a departure. They will continue down the path they are currently on -- which is delivering year over year mpg and performance improvement anyway. And, if it means being unnecessarily expensive -- like going to bi-turbo DOHC V8s to compete -- well, their market segments can afford it.

Well, let me just focus of three facts... (1) The overwhelming majority of car buyers (probably in access of 70% -- perhaps 90% of women and 60% of the men) don't even know what a camshaft is much less what Pushrods do or what DOHC stand for. So, the argument that the market expects DOHC is a tenuous position simply based on the notion that consumers cannot care deeply about something they don't have an idea about. (2) DOHC, 4-valve cylinder heads and high specific output does not directly help you in meeting CAFE or fuel economy goals. It doesn't for all the reasons we have already discussed, the most important of which is that they are not more miserly on fuel, period. In fact, the one design choice that results in the highest return in MPG (for any fixed hp target) is to enlarge the engine by about 30% in displacement and adopt an Atkinson Cycle camshaft. This is not an opinion, this is a fact. (3) From a consequence standpoint, not meeting CAFE really isn't that consequential. Do you know the penalty? It's $5.50 per 0.1 mpg, $55 per 1 mpg and $550 for a whopping 10 mpg of non-compliance. Also, it is important for everyone to realize that CAFE mpg is not the same as EPA mpg. This is important because it is a lot more lenient and most manufacturers are ALREADY ahead of the curve. Eg. Passenger car CAFE today is 28 mpg, with the exception of hybrids and the most efficient compacts, today's cars are not going to average 28 mpg! But, do you know what GM's CAFE score is? It's 31.7 in 2011 -- and that includes every passenger car they make. Guess what Honda's CAFE score is? It's 42.8 in 2011. That includes Accords, Acura TLs and even their unibody crossovers. A window sticker MPG average of 21 mpg is equivalent to 28 CAFE. A Window sticker of 34 is equivalent to 46.These are also not opinions, they are facts.

Or, it could simply be that overwhelming majority engines sold are DOHC designs simply because the majority of makers do not know how to build a pushrod engine! Again, look at this table and tell us how the DOHC designs are better? Can you? Red = Best in category. In fact, the Pushrods hold the crown in 4 out of 5 categories and is a very close 2nd on the 5th.

The problem is that while the notion of "larger displacement = higher fuel consumption" is quite widely accepted, it is a huge fallacy. It's not very different from the entire global warming and CO2 regulation nonsense. It is based on utter rubbish, but it hasn't stopped misguided politicians, media and individuals from jumping on the band wagon -- but that is another topic for another day. The basic fallacy of displacement being correlated to fuel consumption can be debunked with three fundamental facts:- (1) Displacement is measure of the volume of air an engine is capable of sucking in per revolution -- assuming that volumetric efficiency is equal on all engines. The amount of fuel that is injected and burned is generally proportional to this volume. However, there is no saying that all engines turn at the same speed for a given speed the car is moving at, hence there is no direct correlation between displacement and actual aspiration! Example: If a 2.0 liter car in top gear runs at 3000 rpm at 60 mph, while a 3.0 liter car runs 2000 rpm at 60 mph, they are actually displacing (ingesting) the same volume per unit time. The 3.0 liter engine may be able to be geared to turn slower because it makes more torque and can make an equivalent amount at 2000 rpm as the 2.0 liter can at 3000. (2) Static Displacement is NOT an accurate measure of actual aspiration even at a given engine speed because some engines simply breathe more air than others at the same speed. This can be due to better or worse intake and exhaust restriction, valve opening duration and depth. It can be due to the presence of forced induction -- a turbo or supercharged engine cramps more air molecules into each cylinder and burn more fuel by breathing pressurized air! It can also be different simply because of the operation cycle of the engine -- cylinders in a 2-stroke engine breathes once every revolution, whereas those 4-stroke engines breathe once every two revolutions! There are many engines employing an Atkinson type cycle where the intake valve remains open even as the piston is coming up during the compression stroke. This causes part of the intake charge (usually about 30%) to be pushed back out of the cylinders, hence the engine breathes less than the static displacement will indicate. In other words, knowing the displacement and the rpm of the engine, without knowing its design, does not tell us how much air is actually being sucked in. (3) In real life, lower displacement engine are not necessarily lower fuel consumption engines. Factors like transmission efficiency, vehicular weight and aerodynamics comes into play. Even when these are similar, the market is littered with examples of larger displacement engines with better fuel economy. For instance, our table a few posts ago demonstrates that the two biggest displacement engines the 6.2 and 7.0 pushrod engines actually have the best fuel economy numbers, while the smallest displacing units (4.0 and 4.2 liter) have the worst. Casting aside these high performance engines, we can draw on the example of the Toyota 1.8 liter (2ZR-FXE) in the Gen 3 Prius. This engine has a lower brake specific fuel consumption than the Toyota 1.3 liter (1NR-FE) that makes the same horsepower because it operates using the Atkinson cycle. The Mazda Renesis 13B Rotary is a 1.3 liter engine -- I'll let you look up the fuel economy numbers for the RX-8 that uses it (clue: it's not very good at all, in fact it is exactly the same as the 5.5 liter C55 AMG). Examples that contradict the notion that lower displacement generally means lower fuel consumption are so widespread and prevalent that using displacement as a gauge of fuel economy is simply ridiculous and focusing on displacement reduction as the primary means of improving MPG is dubious at best. Using displacement to levy taxes is outright injustice because it accomplishes neither basic fairness nor whatever environmental goals the legislators aspire to.

The simplest answer is the pursuit of specific output (hp/liter). In some countries, silly government legislation tax displacement rather than poor fuel economy. In those markets specific output as a tax advantage. Then there is the 4-cylinder factor. Traditionally 4-potters are limited to 2.0 liters due to poor refinement at larger displacements, high specific output of DOHC engines allow refined and high revving 4-cylinder engines. With 4-cylinder (or I6 engines for that matter) the pushrod advantage is diminished. There is only one head, so you are saving one camshaft and not 3 by using pushrods instead of DOHC. Also, there is no width advantage since it is not a Vee engine and no matter how wide the head is i is not wider than the intake plenum and exhaust manifold. This leaves some weight and height advantages to using a pushrod arrangement, but 2/3rds of the design advantages simply doesn't apply with inline engines. If you wanted fuel economy in an inline engine, you'll simply use a SOHC 2-valve layout to save on frictional losses -- as did the Honda Insight for instance. With most of their development dollars and accumulated experience comes from 4-valve DOHC 4-potters. The natural progression from that is to apply these core competencies in V6 and V8 engines.

A comparison of contemporary V8 engines I report, you decide.

Is the best debate line you have "everybody is doing it, so it must be right"? At one point everyone believed that the world was flat, is it? At one point it is a capital offense to claim that the Earth orbited the Sun, doesn't it? That's the same line of argument you hear a lot from the Global Warming crowd! Do you want to have an argument about that based on facts or based on "I have more scientists on my side, or my gang of PhDs are better than yours"? I prefer to let the facts do the talking. Here are a list of contemporary V8 engines, their outputs, their weights and their fuel economy numbers. Look at it and tell us how DOHC or reduced displacement is superior (based on the statistics please)? Comparison of Contemporary V8 engines Remember, the two Pushrod engines are out going models that is being replaced next year. The pushrod engines lack VVT and DI, both of which are used in abundance by the DOHC mills in the chart. Even then the engines are more than competitive. These features can be incoporated in a Pushrod design, and will be in fact used in the Gen V Pushrod V8 arriving next year.

Actually they did use the DOHC configuration for V8 engines. Twice actually. Once in form of the DOHC 5.7 liter V8 in the Corvette ZR1 and once more in form of the Northstar 4.6. They were discontinued because they were generally inferior to the Pushrod alternatives. As far as "faith" based takes go, one can just as easily assert that "sooner rather than later, the superior performance and economics of Pushrod V8s will force BMW, M-B and everyone else to develop a pushrod engine or face market oblivion.

The problem is that the V6 Bi-turbo is not something better. It is something worse than what the Chevy will have. Hence, you need to amend your line of justfication to "It doesn't matter if it is inferior. It doesn't matter if it is bigger, heavier, more complex, less powerful and guzzle the same amount of gas. It doesn't matter if it makes the car less balanced and somewhat slower. People will buy it as long as it is more expensive and more exclusive."

The Northstar was introduced in 1993. It made 300 hp / 295 lb-ft out of 4.6 liters at the time. The Northstar ended its production run in 2010 making 320 hp / 315 lb-ft owing mostly to an increased (10.5:1) compression and the addition of Varaible Cam Phasing. The LH2 Northstar weighed 195 kg and it delivered 15/24 mpg out of a 3900 lbs Cadillac STS. The LT1 engine (Gen III) was its pushrod contemporary engine at the time (introduced on the 1992 Corvette). The LT1 made 300hp / 330 lb-ft out of 5.7 liters. The 6.2 liter LS3 engine (Gen IV) in 2010 made 436 hp / 428 lb-ft out of 6.2 liters. The LS3 weighed 183 kg and it delivered 16/24 mpg out of a 3850 lbs Camaro SS or 16/26 mpg out of a 3300 lbs Corvette. Between 1993 and 2000, the Pushrod engine has seen more significant developments than the DOHC Northstar. Amongst the greatest change is the adoption of an Aluminum block with the LS1 (Gen IV) engine in 1997. The Northstar was a relatively light DOHC engine for its time and has always been an aluminum engine. At 195 kg the Northstar is actually lighter than today's 201 kg Ford 5.0 DOHC (Coyote) V8, although its output of 69.5 hp/liter has always been on the lower end of the DOHC V8 spectrum. I report, you decide.

Berkshire Hathaway is an obsolete organization that knows nothing about modern investments...

Yes... BMW S65 Oil Pump Assembly (Below)

In case you are still wondering why it is possible for a 6.2 liter pushrod engine to be smaller and lighter than a 4.0 liter DOHC V8, here are the two engines side-by-side. Notice the amount of room and extra material needed by the DOHC heads, quad cams, their sprockets and gears? BMW S65 4.0 liter DOHC V8 (Left), GM LS3 6.2 liter Pushrod V8 (Right)

The key qu Why is hp per liter of any importance? If both engine makes (let's say) 400 hp. If the pushrod engine is externally smaller, lighter and have better fuel economy. Why is it of any importance if it makes that 400hp out of a static displacement of 6 liters instead of 4 liters? The most common argument for the relevance of hp/liter being important is that a 4 liter engine is smaller and lighter. But this isn't true. In fact, the wide DOHC heads, 3 addtional camshafts, 3 times as many cam phasers and double the number of valves often causes the 4 liter DOHC engine capable of 450hp to be actually bulkier on the outside and heavier on the scales. Yes, it is possible for a DOHC engine to be lighter, but that only happens when there is a drastic inequality in the amount of lightening technology and advanced materials applied on the two engines being compared. It's just like saying that it is possible for a mid-sized car to be lighter than a compact. When construction techniques and materials are equal, the pushrod engine is always lighter. The other argument is that if you make that 400 hp out of 4 liters instead of 6 liters, you get better fuel economy. That too isn't true as displacement is pretty low on the list of features the most affect fuel economy despite popular misconceptions. The problem with DOHC designs is that when you have three times as many camshafts and twice as many valves, these components along with their bearings and chain drives incur extra parasitic frictional drag that otherwise isn't there. In addition, when you rely on small displacements to make the same power output as a larger, lower revving engine, you end up with less torque. The lower torque output often requires a lower gearing for equal performance and/or drivability. Higher frictional losses + lower gearing often result in inferior fuel economy despite a lower static displacement. As a matter of fact, if you want to maximize fuel economy the most effective thing you can do is not to reduce displacement, but to increase it while adopting an Atkinson Cycle cam. An Atkinson cycle engine of the same output, but larger displacement is always more economical on fuel. A good comparison of two engines can be found with the BMW S65 DOHC 4.0 V8 and the GM LS3 Pushrod 6.2 V8 in the Camaro SS. The S65 with 414 hp / 295 lb-ft in a 3704 lbs M3 posts an EPA rating of 14 mpg (City) / 20 mpg (Hwy) . The S65 engine itself weighs 202 kg. The LS3 with 426 hp / 420 lb-ft in a 3849 lbs Camaro SS posts an EPA rating of 16 mpg (City) / 24 mpg (Hwy). The LS3 engine itself weighs 183 kg. The Pushrod, low hp/liter engine of a larger displacement is lighter than the DOHC, high hp/liter engine of a smaller displacement. It produces slightly more power, a lot more torque and better mileage from a heavier car. How is that embarassing? The entire notion that DOHC is "modern" and Pushrods are "ancient" also begs a history lesson. The DOHC design was invented BEFORE the Pushrod design was. The DOHC design was pioneered by Bentley in 1919. The Pushrod OHV design was invented in 1930 by Arthur Chevrolet. So, which is more modern?

Without going into paragraphs and paragraphs of technical discussion, the V6 TT vs Pushrod V8 argument comes down to one thing and one thing only. Why should GM put a heavier, bulkier, more complex and more expensive engine into the ATS-V that happens to have less power, less responsiveness and similar fuel economy? If it is because they believe that V-car buyers care more about having turbochargers and dual overhead cams than the resulting performance of the vehicle, then they are seriously misguided indeed.

But before they do that, they need to ask a simple question. Why is a 3.6 Bi-turbo V6 better than a 6.2 Gen V DI V8? Because a Nissan GT-R lays waste to anything GM has ever made? Because of the active torque biasing AWD system and everything else? Or, because of the Bi-turbo 3.8 liter V6? Just based on the numbers won't a GT-R be faster and better handling if it used the LS7 Pushrod V8 instead of the VR38DETT V6? The LS7 was 505hp / 470 lb-ft vs 480 hp / 434 lb-ft (when introduced). The LS7 was also 32 kg lighter, does need intercoolers, doesn't need a myraid of intake plumbing and has zero turbo lag. Similar power output, better weight distribution, less throttle lag, less spagetti under the hood and, yes, less money. How is that a bad thing?

But before they do that, they need to ask a simple question. Why is a 3.6 Bi-turbo V6 better than a 6.2 Gen V DI V8?

Which brings us back to the point that a 3.6 450hp Bi-turbo does not exist and will be a new engine that has to be developed solely for Cadillac while the Gen V V8 in a sports car configuration already exists in form of the engine that is already being developed for the C7 with or without its application in the ATS-V. Not should, not if, not perhaps, not whether it can be -- it is already there with the development funds already spent. Also, when you talk about an engine for a car whose primary role is as a performance flagship for the series, the priority is always performance. Not particular valvetrain choices, not the presence or absence of any particular technology or component. Performance, period. The Gen V V8 has the 3.6 TT V6 beat in terms of power-to-weight, torque-to-weight, power-to-size, torque-to-size, cost, simplicity and responsiveness. It also promises to be just as good or at the minimum pretty darn close to the 3.6TT V6 in terms of fuel economy -- based on the fact that even the current generation of Pushrod V8 equal or exceed the the fuel economy of its generation of Bi-turbo V6es of equivalent output. So why will you want to invest additional funds (which you otherwise don't have to invest) and incur higher production costs to install an engine which is inferior or equivalent in every regard? If Cadillac cannot compete based on a superior engine, what makes you think they can on an inferior one? Because the DOHC Bi-turbo label will make buyers disregard everything else? I think you underestimate the intelligence of performance car consumers. The BMW 335xi tops out at $56K fully optioned, that doesn't stop the M3 from having a base price of $61K -- a $5K difference. Fact is that they are different cars. You don't get AWD with the M3, you don't get some of the options on the fully optioned 335xi unless you also check the option boxes which can then take the M3 to almost $70K. The ATS 3.6 stops at $48K, but it starts at $42K. When making comparisons you have to compare base price to base price! The ATS-V should start at ~$52K -- $49.99K if they want to price it aggressively. Yes, you can pay just as much for a 3.6. But, that is a loaded 3.6 into which you added $6K worth of options magnetic ride control, Brembo Brakes, polished wheels, premium package and AWD. In fact, you would have added most of the performance parts in an ATS-V -- the brakes, the Magnetorologic shocks -- and more (AWD). The only thing you would have not added is the powerplant and a $4K difference is about right in that regard. At 52K, the ATS-V does not have AWD and it probably does not even have a moonroof (which is a plus for some buyers who don't want sun on their head but can use an additional inch of headroom). There's nothing wrong with that. Half of the budget going to alternatives and fuel efficiency. How much is that is simply evolutionary development of their diesel lineup?

I think buyers are smart enough to look at the window sticker and read the MPG numbers even if they are pretty dumb otherwise. And those too stupid to do that are probably too stupid to know what displacement and/or cylinders are. As I mentioned earlier, all the surveys surrounding the Ecoboost F150 point to the fact that buyers paid extra for the towing capacity not the presence of turbos or smaller displacement. The 1 mpg advantage came as a nice little bonus but it was the $750 difference in pricing and the towing capacity that convince most. No, nearly 65% of the car market is comprised of 4-cylinder vehicles not just half. But, no, they are not full of turbo fours. These in fact are fewer than V6es by a large margin. These cars are mostly NA fours with pedestrian power output, low price and good economy. They cater to the majority of car buyers who, BTW, are not particularly interested in performance. Buyers of I4 Accords, Camrys and Altimas bought them because they didn't care if the V6 had more power, the I4 is cheaper and it has better fuel economy. A Turbo four is not cheaper and it does not have better fuel economy compared to a lower powered NA four. Once you get into the buyer category where performance matters and cost take a back seat, fuel economy also to a greater or lesser extent take a back seat. You keep saying that automakers WILL invest in far reaching technologies to comply with CAFE without logically or factually supporting that claim. Businesses are just that, businesses. And a business case has to be made for investment decisions. $1500 in additional hardware to avoid $55 in penalties does not compute in any business case because consumers don't want to pay for it. As I have said, if consumers are all on board with the current regime's "green agenda" Hybrids won't be 3.7% of the market despite generous rebates and other nonsense they hand out. Let me tell you when a $5000 delta in vehicle cost for a Hybrid makes sense -- when gasoline is $20 a gallon or if the regime makes it mandatory (as in illegal to sell unless in compliance). The regime does probably have that kind of twisted idea of a command economy, but unless it has a the congress the senate and the white house nothing but gridlock will result.

A Twin turbo V6 is unique because GM doesn't even make a single turbo V6 right now, let alone a twin turbo. Using the engine from a Camaro may make the ATS different than BMW, but it makes it too much like a Camaro. Why pay $65,000 for an ATS-V when a $36,000 Camaro has the same engine. The ATS's interior isn't lined with silk and cashmere to justify that big a price gap. And a loaded ATS 3.6 is near $50k, the V-series will be over $60k. And I don't care if they use a V8, but it shouldn't be the engine out of a Camaro or Silverado. BMW and Audi also sell in countries where gas is $7 a gallon or taxes on displacement exist, etc. And they both are selling over 1 million cars a year, what they do seems to work. Based on that same logic, why would anyone pay $60K for an ATS when it uses the same Bi-turbo V6 that will be found in an Impala SS, Acadia Denali or Silverado? The one thing you are missing is that the Bi-turbo V6 was not conceived for the ATS-V and there will never be exclusivity associated with it. The LF3 was conceived as an upgrade engine (above the 3.6 LFX) for large cars, SUVs and trucks -- very much like the Ford 3.5 Ecoboost except that with the LF3 at least GM choose the 3.0 liter displacement. GM would have been unable to justify the development costs and/or produce enough to have reasonable economies of scale if it did an "exclusivity engine" of any kind for the ATS-V. If the ATS-V uses the Bi-turbo V6 it will be on the backs of these other applications not the other way around. By the way, your price estimates are a little excessive. The ATS-V cannot be $60K without completely encroaching on the CTS-V and Cadillac is in no position to dramatically rachet up their pricing of the CTS-V. The ATS-V will be closer to $50K than to $60K.

The problem is that a 6-cylinder Bi-turbo is not in any way special. It is in many cars and is not unique to Cadillac. The LF3 engine -- if it is used -- will also be found in various other GM vehicles most likely including SUVs and trucks. If you look at the Luxury RWD Compact market by itself, a big displacement V8 is actually more "unique" especially after BMW ditches the 4.0 V8 and Audi has already switched to a Supercharged 3.0 V6. The C63 will most likely switch to 5.5 Bi-turbo after the W204 platform sunsets in 2014. This leaves the ATS-V with the opportunity to be the only game in town if you want a small, light, luxurious car powered by a V8 with the immediate throttle response of a NA engine. You are right, they should put in the best engine and the Pushrod V8 is an extraordinary engine unique to GM. On technical merits alone it is better than a Bi-turbo V6 by being lighter, less complex, probably more powerful and lag free, while being equally efficient or within 1 mpg of the V6. It also happens to be more cost effective and does not need additional R&D commitment because it is already being developed for the C7. As far as the type of buyer the ATS-V is going to get, I honestly don't believe either a DOHC V6 TT or Pushrod V8 NA is going to matter to them as much as the performance numbers. Enthusiasts are smart enough to not want a more expensive, no more efficient, lower performance engine just because it has Turbochargers. In fact, when Audi went from the 2.7 Bi-turbo to the 4.2 V8 with the S4 nobody complained about it being less desirable because it is missing two turbos. This segment may not be as price sensitive as the Cruze's, but to say that adding a few grand to the price tag helps sell more cars is also nonsensical. Even if that's true -- that somehow there is a reverse demand curve because expense buys prestige and prestige overrides other considerations -- all Cadillac has to do is raise the price! It doesn't have to make an engineering decision. To put it in one sentence... BMW has to go I6 Turbo and Audi has to go a Supercharged V6 because they do not have a state of the art Pushrod V8. If they did, they could have achieved the same fuel economy and/or performance goals without downsizing to six cylinders and adding forced induction. It is also lack the time, technological know how, patent portfolio and experience to start from scratch and develop a line of pushrod engines.

Perhaps we have to agree to disagree here, but your assumptions are:- Buyers today have a preference for smaller displacement and fewer cylinders rather than actual Fuel Economy numbers Buyers have a predisposition towards Turbocharged engines and perceive them as more advanced and more desirable Buyers place a great importance on a 1 mpg difference over most other factors when making a buying decision Manufacturers deem the CAFE penalty for an additional 1 mpg of non-compliance as actually significant and worthy of significant engineering or manufacturing costs to overcome. All of the above happens to be either flat out untrue or at least unproven. Really... how many buyers bought a Focus over a Cruze because it is 28/38 mpg vs 26/38 mpg? Conversely, how many bought a Cruze because it has a "smaller displacement 1.4L" and "turbocharged"? The truth is that neither are overriding factors in the average consumer's buying decision. The color of the instrument cluster or the shape of the tailights probably have a similar degree of importance! Speaking of CAFE, you make it sound like it is the be all and end all of the "new era" when the penalties are insignificant. Part of the reason Automakers didn't really fight it is because the penalties are inconsequential and if it applies to everyone it doesn't really create an unfair advantage for anyone. Do you know what the penalty is for every 1 mpg of non compliance? It's $55 per vehicle. Do you really believe that it makes business sense to spend $1500 in additional hardware (say a pair of turbos, their intercoolers and their pipings) to try to avoid $55 in cost which they can simply pass on to the consumer? In fact the CAFE penalties are structured in such a way that I have always advocated for automakers to simple build cars that they believe their customers want to buy and completely disregard CAFE. Meeting it is great, not meeting it is no problem at all either. Or put it another way. Will the majority of buyers spend $1500 extra instead of $55 extra to have let say a 17/28 mpg car vs say a 16/27 mpg car? If this is true, most buyers will also pay $5000 in upfront premiums a Hybrid drive train which will save enough gas at $4 a gallon to pay back that investment in 9 years, and Hybrids will have a 90% market share today rather than 3.7%.

The problem with your assertions is that it centers around the notion that a Bi-turbo V6 gets notably better mileage than a V8 of equivalent output. The facts is that this simply isn't the case in many cases and even when there is an advantage, it seldom amounts to more than a 1 mpg difference. It is important when making comparisons to make comparisons between engines of similar output and between vehicles of similar weight and with similar transmission efficiency. We know that a 426hp / 420 lb-ft 6.2 Pushrod V8 w/o DI in a 6-spd 3850 lbs Camaro SS is capable of 16 / 24 mpg. Can you name a V6 Bi-turbo powered vehicle between with 400~450hp that does better than that? The Ecoboost powered Taurus SHO gets 17 / 25 mpg. Yes, it's 250 lbs heavier and is hampered by AWD, but it is also making only 365 hp / 350 lb-ft. What will happen to the mpg numbers if you decrease compression, raise boost and switch out the turbos for slightly larger ones to get to 420~430 hp? No clear advantage there. With Ford's F150, the Ecoboost 3.5 V6 gets 16 / 22 mpg. Ford's own 5.0 V8 gets 15 / 21 mpg -- a mere 1 mpg deficit. Despite the fact that the Ford Coyote 5.0 V8 is a DOHC 32-valve design that more complex and costly than GM's it is $750 cheaper than the Ecoboost 3.5. Not widely recognized is the fact that being a DOHC engine is is also likely slightly less efficient than a pushrod design. Customers didn't pay a premium for the Ecoboost engine because they fell in love with the "high tech" nature or the Twin turbos, they bought it by and large because truckers care about towing capacity and the Ecoboost had 11,300 lbs to the 5.0 V8's 10,000 lbs. So in a way you are right, buyer's didn't care much about the cylinder count; they didn't favor less cylinders or lower displacement. They saw a 1300 lbs tow capacity advantage and a 1 mpg advantage and decided that $750 is an OK premium to pay. In GM's case, there will be a direct injected, pushrod operated, probably AFM equipped V8 that has better mpg number that Ford's, also the price difference is greater because the pushrod design is simply cheaper than the DOHC V8. This is not to mention better torque output because of larger displacement than Ford's 5.0 liters. In the end it might be a wash in terms of economy and towing capacity. Why then will buyers pay in excess of $1000 more for the Bi-turbo six?

As far as cost goes, displacement costs nothing. It is complexity that drives cost. Here's a list of differences... Unless you are saying that 2 pistons and 2 rods cost more than 8 valves, 8 valve springs, 8 lifters, 2 turbos, 6 ducts, two intercoolers, one electric pump, 3 cam phasers and three camshafts, the V6 TT costs more!

The is no 450 hp TT V6 under development. GM has a 3.0 TT V6 (LF3) under development, but that is not a 450hp engine, more like a 360hp engine designed to go up against the Ecoboost 3.5. If a 3.6 TT is to be developed, it'll be for the ATS-V and very little else. It will even less sense to turn the LF3 into a 150hp/liter, high boost engine for all the cars and trucks the TT V6 is intended for. In otherwords, while a low boost 3.0 TTV6 does exist, a 450hp class TT V6 does not, that is what an ATS-V needs to be performance competitive with the teutons. Any charged engine will have turbo lag. The only question is how much. This is because no matter how efficient and well sized, a turbocompressor does not go from 5,000 to 70,000 rpm instantaneously and it cannot pressurize the ducts, IC and intake plenum from vacuum to 15 psi (or whatever boost level is used) instantaneously. You may not find it objectionable but that doesn't mean it does not exist. The presence of a slight delay between throttle input and steady state power delivery at that throttle position makes a car more difficult to control in the middle of a turn or during transitions. All else being equal, turbocharged engines always require more frequent maintenance intervals. This is because oil has to be exposed to the turbocharger's bearings which is a lot hotter than anything it passes over in an NA engine. The difference is substantial. A full synthetic like Mobil 1 is good for 15,000~25,000 miles on a NA engine, on an LNF for instance it is between 8,000~12,000. Again, it may not be objectionable to you or any performance enthusiast, but there is very definitely a difference in oil life between a turbocharged engine and one that is not. Also, there is no running away from the fact that there will be half a dozen to a dozen more hose clamps, IC tank(s) that can leak and needs to be checked, not to mention usually an after run electric water circulation pump for the turbo bearings. I am not new to turbocharged cars... I have had a Celica All-trac Turbo (ST185), Eagle Talon Tsi AWD (w/ mitsubishi's 4G63 Turbo engine), NB 1.8T and an Audi S4 2.7T (B5) over the years. In my time I had replaced three turbochargers and dealt with a bunch of non-catastrophic nuisance like pressure leaks and bypass valves that sticks. Yes, the newer designs are better. But to say that you can design out all the additional service and failure modes compared to an NA engine is something I cannot see ever happening. As far as costs go, well displacement costs nothing. It is complexity that drives engine costs. Here's a list of differences... TT DOHC V6 Gen V V8 Camshafts 4 1 Camphasers 4 1 Valves/springs/lifters 24 16 Pistons 6 8 Rods 6 8 Crank 1 1 Direction Injectors 6 8 Water pumps 2 1 Electric water pump 1 0 Oil Pump 1 1 Turbochargers 2 0 Intercoolers 2 0 Intake duct pieces 6 1