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Building the Ultimate Hybrid Let’s face it, Hybrids are not about sensibilities as much as CTS-Vs are not about sensibilities. A sensible buyer will understand that a Prius does not save you any money over a Corolla and a CTS 3.6 gets you around with better comfort while burning less gas than it’s V brethren. Hybrids are about making the owners feel good. And, while CTS-V owners feel good about getting pressed to their seats, being able to carve mountain roads at highly illegal speeds should they choose to do so and secretly musing about the parody of driving to the supermarket in a 556hp rocket sled in sheep’s clothing, Hybrid owners enjoy watching the MPG gauge return ridiculously high numbers and brag about the efficiency of their powertrains in front of their Global Warming coolaid drinking buddies while patting each other on the back. The Problem with GM’s Hybrid strategy is that it is too sensible and insufficiently sensational. The Mild Hybrids and the Dual Mode SUVs are make the most economic sense. The Volt strikes a balance between zero emissions of electrics and the practicality of being able to take long trips and drive without worry of being stranded. But BAS cars aren’t posting Prius numbers and are in fact bottom of the class in MPG bragging rights. The Volt, well, it’s not spectacular looking, it’s not fast, it’s electric range is a paltry 40 miles and it’s hybrid mode highway MPG is no better than a Cruze or Focus. In short, it’s not a Model S. In a way, I guess one can say the same of Honda’s strategy – it’s too sensible. What GM really needs is a no excuse Hybrid that blows away it’s competition in the MPG game in its price class. As far as price class goes, $30K is not bad place to be. It’s $4K more than a Prius but it’s cheap enough to draw the Prius buyers if they really want one. What’s needed is substantially better MPG numbers than the Prius. And, that is actually a walk in the park from a technical standpoint with $10K to play with over the $20K price tag of a loaded Cruze LTZ. Here’s how I’ll do it… Chevy Slipstream Platform: Aluminized Delta / 4-door Sitting arrangement: 2+3 Engine: 1.6L Naturally Aspirated Diesel -- 70 hp @ 5200 rpm / 110 lb-ft @ 2600 rpm (Opel 1.6 CDTI Ecotec Diesel w/o the turbo) Motor-Generator: Permanent Magnet DC motor -- 70 hp @ 5200 rpm / 141 lb-ft @ 0 rpm Combined output: 140 hp @ 5200 rpm / 216 lb-ft @ 2600 rpm Auxiliary Generator: 15kWe Exhaust Gas Turbine Generator Transmission: 9-speed Automatic without torque converter or clutch Battery: 5.5 kWh, 360 V Lithium-Manganese-Oxide battery w/ 96 cells (basically one of the three parallel 96-cell modules used in the Volt) Target MPG: 70 mpg City / 70 mpg highway (w/o plug-in usage) The Powertrain concept is very simple really. Instead of a gasoline engine we use a diesel which is immediately about 20% more efficient at the same output. But we are not going to just stop there. We’ll use the smallest diesel GM has and make it naturally aspirated. The reason for dropping the turbocharger two fold – first it allows for higher static compression which improves cruise and low output fuel economy which is what we need for those EPA test cycles, second it allows all that exhaust gases to be used for something else. That something else is the hallmark of this hybrid drive train – a second source for energy to charge the battery apart from regenerative braking. Instead of using the otherwise wasted exhaust to increase the specific output of the engine through turbo charging, we recover it as electricity via an exhaust driven generator. Any additional power for the wheels come from the electric motor if and when warranted. The transmission system is an utterly conventional 9-speed Automatic currently under development with one catch. It doesn’t have a torque converter or an automated clutch. Instead, the transmission input is coupled directly to the engine’s crankshaft and the 70hp electric motor-generator -- all three turn at the same speed or not at all. Basically, this engine is incapable of idling. At about 800 rpm, the VVL system basically shuts off all the valves and allow the engine to freewheel without pumping losses. Below 800 rpm all propulsion is electric. The motor spins the transmission as well as the freewheeling engine. Above 800 rpm, fuel is injected into the engine and the valves start working again reactivating the engine. During all deceleration the VVL system again deactivates the engine eliminating engine braking such that all of the powertrain braking is regenerative. A torque converter is no longer needed because the engine does not need to idle and during shifts the electric motor pitches in with a little torque input or regenerative outtake to unload the transmission – basically rev and load matching such that the gears are not experiencing significant accelerative or decelerative loading. A 5.5kW battery with about 4kW actually used provide the assurance that there will be plenty of juice for puttering around under 800 rpm in 1st gear. The car has a 12~15 mile all electric range and is capable of an emergency recovery mode in the extremely unlikely circumstance that charges are drained below the minimum allowed on the battery (about 15% charge). If a the battery gauge ever reaches the regulated “0”, the car can run the engine in neutral to bring it back up to drive away levels and the car will never leave the driver stranded. At full throttle the system sends all available engine and electric motor power to the wheels. But at part throttle it is smart about it. When the battery is above 33% it uses more electric power before increasing ICE power. Below that, it moderates electrical assist at part loads to build the bias towards charge recovery and storage. An optional SAE 1772 receptacle allows those with patience for the hassle to recharge the battery via a wall 110v socket in 10 hours or a 220v in about 4 hours. The charging kit is exactly the same as the Volt’s. If the owner doesn’t plug it in the vehicle is designed to function like a traditional Hybrid recovering which decelerative energy from regenerative braking, as well as slowly build up the battery charge from the a the gas turbine generator driven by the diesel engine’s exhaust. The diesel engine adds about $1000 to the cost. The gas turbine generator is basically the exhaust half of a turbo coupled to an alternator and is about the same price as the 1.4T’s turbo, intercooler and pipings. The battery is a good $4K (slightly more than 1/3 the volts battery price). The 74 kW electric motor is about $2500. There is no inverter and expensive multi-phase power controller since we are going to a DC motor. The torque converter-less transmission is actually cheaper than it’s traditional equivalent. That’s about a $7500 premium in costs, making a $30K car perfectly doable. The logic here is that we are using the money saved from eliminating the Volt’s battery, 149 hp motor to put together a conventional hybrid with that beats the Prius at its own game with a $30K vehicle (the originally intended price point of the Volt). This setup is more efficient than the Prius's because:- It uses a Diesel ICE It has two energy sources for the Hybrid system -- regenerative braking + exhaust gas turbine generation It has complete cylinder deactivation allow full regenerative braking using the motor It has a much higher battery capacity It has a multi-speed transmission instead of a planetary power spliting device.

Actually, if you pull back the torque peak from 5200 rpm to 4000 rpm while keeping static compression constant you'll probably GAIN a few ft-lbs of torque. Let me explain... What are normally done to help an engine breath better at high rpms include increasing the valve lift, increasing the valve size, increasing the intake passage sizes and, perhaps most prominently, increasing the duration the intake and exhaust valves stay open. Unless you are making a tractor motor the duration of the exhaust valve opening will be longer than the exhaust stroke itself and that of the intake opening longer than the intake stroke. There will also be some period during which both are open towards the end of the exhaust stroke and the beginning of the intake stroke. For an engine to breath well at high rpms, it is beneficial that the exhaust valve open before the piston reaches the bottom of the travel -- you sacrifice some energy recovery for a little extra time for the exhaust to leave the cylinders. You also open the intake valves early before the exhaust stroke is complete and do not close the exhaust valve for some time while the piston is going back up during the compression stroke. You do this because at high rpms air is being sucked in at a high rate and they "stack" momentarily behind the intake valves when they are closed. When they open the air is actually coming in at a slight positive pressure. You will have the ability to expel exhaust gases before they fall to their lowest pressure at the top of the piston stroke and you will be able to continue to aspirate air into the cylinders for a short time after the piston has already started to come up. In short, long duration and overlap is key to proper engine breathing at high rpms. These tuning techniques is how naturally aspirated engines can actually achieve OVER 100% volumetric efficiency. Now... what will those same cam lobes that open the valves in the aforementioned manner do at low rpms? Well, first it'll waste some propulsive force tom the pressurized combustion products by wasting the last 5~15% of the power stroke opening the exhaust early. The overlap is horrendous for emissions at low rpms and reduces engine output. This is so because at low rpm, air is not flowing all that fast and when the intake valves open early the lack of stacking pressure behind the valves means that exhaust simply regurgitates into the intake -- making them dirty and make the engine suck back some of its own exhaust rather than fresh air at the beginning of the intake stroke. Also keeping the intake valve open past bottom dead center of the intake stroke turn the engine into a pseudo Atkinson cycle unit -- basically you push some of the intake charge back out the intake causing you to lose "effective" compression ratio and "effectve" displacement -- except that unlike an engine designed to function in this cycle you do not have a very high static compression ratio to compensate for the compression loss. All of these means that you LOSE torque at low rpm and hence lose horsepower at low rpms. In fact sometimes it's so bad the engine stumbles because there is so much EGR that the mixture fails to ignite properly. Emissions also goes to sh!t because now you have less complete combustion before you pop the valve and sending the gases into the exhaust. Variable Valve Timing (VVT), especially independent exhaust and intake timing control, allow you to dial out much of the overlap. But when both cams are of a longer duration that their respective piston strokes whatever dialing you do is a compromise. Open the exhaust earlier and you increase hydrocarbon emissions. Close the intake late and you lose compression and reduce effective displacement. You usually end up doing both but more of retarding the intake than advancing the exhaust -- because the latter is means you'll fail SMOG. You are not so much restoring power lost -- you really can't with those cam durations -- but rather adjusting the cams such that the engine doesn't stumble and doesn't fail emissions. If you ever wonder why high revving engines (which doesn't switch cam profiles) like the M3's S65 are somewhat soft under 4000 rpms, it's because they have long duration cams and the VVT system is retarding that intake cam way way back to reduce overlap, causing the engine to lose compression and displacement until intake velocity builds enough with rpm for it to start dialing the intake cam forward! Another example is the Nissan VQ35 in the 350Z. The engine debuts at 287 hp @ 6,200 rpm / 274 lb-ft @ 4,800 rpm. It was later updated to improve specific output to 308 hp @ 6800 rpm, but the extended cam durations caused torque to fall to 268 lb-ft @ 4,800 rpm. So much for all that... basically, the LFX is a relatively high revving tune with 321 hp @ 6800 rpm and 275 lb-ft @ 4800 rpm in the ATS. The transverse engines are slightly worse off mainly due to the asymmetrical exhaust contortions. If you dial it back to have a torque peak at 4000 rpm by using shorter duration cams, you will gain a few lb-ft of torque. If you do it by doing that and making physical changes to the head and intake to narrow the ports and runners you'll gain even more. How much? At least 4~5 with just the former, perhaps as much as 10 lb-ft by doing both. So a properly "defanged" 3.6 will probably be about 280 lb-ft @ 6000 rpm 280 lb-ft @ 4000 rpm. Which is about the same result as you'll get with the Camry or Accord engines if you simply add Direct Injection and crank up the compression ratio by a point or so.

Problem with Scion since then has been that it has too many models! Back when it was new, Scion only had the xA, the xB and the tC. Now it has the xD, xB, iQ, tC and the FR-S. Maybe they should drop the xD and the tC and focus on cars that are unique in the market place within or without the Toyota umbrella. And make those car more unique... maybe a Turbocharged 3 cylinder for the iQ or AWD for the xB?

Like I said... such reputations took decades to build and takes decades to dispel.

Or, they can simply ignore the law and pay the fine. It'll amount to about 6000 Euros for their 3.0L V6 diesel cars and 12800 euros for their V8 supercharged models. About a 12~13% price increase. That is a lot stiffer the US CAFE penalties which is really negligible -- a manufacturer which misses the 54.5 mpg "target" by a whopping 53.5 mpg by making cars which gets no better than 1 MPG will pay a fine of roughly $2,900 per vehicle. That of course is ridiculous unless the automaker makes 70 ton main battle tanks exclusively. If GM does absolutely nothing to improve fuel economy and is still at it's 32.9 MPG CAFE number from 2012, it'll have to add $1,188 to the price tag of its cars. If you have ever wondered why the US automakers don't fight CAFE rules, it's very simply:- (1) It doesn't really matter how strict or how lose they are. It doesn't matter how high an MPG rating CAFE demands. If it applies to everybody then it doesn't really put anyone at a disadvantage. In 2025 if 54.5 MPG is not achievable in the kind of cars consumers want to buy then they simply won't meet CAFE, sell mostly whatever the consumers want and pass along the fine. (2) Fines from CAFE are relatively mild and tolerable. This makes them basically immaterial in vehicle sales and choice. Eg. A consume may still choose a 40 mpg CRUZE over a 55 MPG hybrid because the $800 fine is cheaper than $6000 Hybrid drivetrain. In fact whatever state or federal tax incentives may be available will most like have a greater bearing than whatever CAFE penalty exists. A Corvette buy may still buy a 23MPG corvette over a 55 MPG hybrid because he will willing pay the $1700 fine to go 0-60 in 3.8 secs.

Affordable, dependable, comfortable. That defines the Camry and its reputation. You can sell a lot of cars on that definition and reputation, unfortunately you cannot design or engineer a car that immediately takes on that persona in the minds of Camry shoppers. You wanna be a Camry? Go build a Malibu with 99% of the owners not having to see a dealer or a mechanic for 15 years and 200,000 miles, then come back in 2028 and be the new Camry. OK, I may be exaggerating a bit. But such exaggerations may not be too far off from the perception of Camry owners and buyers as far as the reliability and low maintenance of the car. Such legendary reliability may be legend indeed, but we have a Camry in the family... it's a 2003 model with 190,000 something miles. Never broke, never fixed never failed emissions. My in law takes it to an oil change place maybe twice a year paying little attention to mileage between changes. Never done any inspection, never changed the brake fluid, never replaced the transmission fluid, never touched the powersteering fluid, never services the A/C, never went to the dealer or mechanic for routine maintenance. The steering is a little lose from worn tie rods, the parking brake is out of adjustment & essentially does nothing when pulled, the CV boot is torn but they decided to ignore it until the joint makes noise (it hasn't yet) and the windshield washer tank has been dry for years. I think his philosophy is that if the car runs he's not going to fix it. The car has seen a mechanic exactly twice -- to get new brake pads. And they did it the quick and dirty way without turning the rotors or replacing them for about $100 each time, I think the chinese shop they went to probably didn't even measured the disc thickness but hey it's $40 an hour and the cheapest joint in town. The car just won't die, won't even leak oil!

I think this is a lousy stylistic element... The upward sweeping trim line and under tray makes it look as if the tail is jacked up and the suspension isn't level. That brings two pretty uninspiring pictures to mind -- that of a dancing low rider and that of an unloaded pickup with leaf spring suspension. Neither of which fits the identity of a classy luxury coupe.

But... if I am to write the specifications for the most economical (gasoline) engine for the Chevy Cruze, it’ll probably look something like this… Configuration: 70% Pseudo Atkinson Cycle Inline-4 Valvetrain: SOHC 8-valve w/ cam-in-cam independent intake/exhaust VVT Bore x Stroke: 94 mm x 97 mm (Same bore and piston dimensions as 3.6 LFX V6) Displacement: 2.7L (2693 cc) Fuel Injection: Direct Gasoline Injection Ignition: Coil-on-spark direct ignition with dual iridium plugs per cylinder Power: 140 bhp @ 6000 rpm Torque: 142 lb-ft @ 4600 rpm Redline: 6200 rpm This is the absolutely lowest specific fuel consumption 140hp 4-cylinder engine you can build (in theory at least) that doesn’t involve a hybrid drivetrain or compression ignition. For marketing reasons, you may want to pull a “Mazda” and call it a 1.9L engine by calculating displacement based on the fraction of the actual piston stroke AFTER the intake valves have actually closed* *Mazda pulled that fast one on the 1998~2001 Millenia / Euros. The so called 2.3L Miller Cycle V6 is actually a 3.0L V6 but because the intake valves remained open for the first ~20% of the compression stroke, Mazda states the displacement as 2.3L. With a Lysholm screw supercharger recovering some of the lost power it made 210hp. This is exactly the same as the 3.0L Mazda V6 of the period, but it was about 13% more fuel efficient and torque was slightly higher. Apparently US, Japanese and Europeran regulators either didn't know any better or didn't care.

The LFX is a 84hp/L engine. It peaks at 6500 rpm. You cannot quite match that with a 3.6L pushrod or SOHC 2-valve engine. To get about 300hp you'll need about 4.3 liters from a pushrod 2-valve engine optimized for 87 octane. The new Ecotec3 4.3L Pushrod engine will more or less match a 3.6 DOHC if it was tuned for a car. This engine gets 18 (City) /24 (Hwy) mpg pulling the 5000 lbs brick that is the full size Sierra 1500 pickup. I will think that it'll at least get better than the 18 mpg (city) rating the Impala gets with the 3.6L LFX. But, if you simply drop a modern 3.6 Pushrod in the Impala, it'll be down about 34 hp although fuel economy will go up. If you are wondering why the GM 3.6 is slightly worse than even the competition's 3.5 and 3.6L V6es in fuel economy... well there is usually an inverse relationship between specific output and fuel economy even amongst DOHC 4-valve engines. The fat intakes, high lift and generous overlap periods required to get you high specific output through good high rpm breathing also equals inferior charge mixing and homogeneity at low rpms. It means that more fuel needs to be burned to make the same power at cruise and consequently inferior fuel economy. GM is actually near the top of the classin the specific output of their DOHC V6es, they are also near the bottom of the class in EPA fuel economy with these engines (Eg. LF1, LFX). What I was getting at is that engines like what you find in today's Accord and Camry really don't need to be DOHC 4-valve. They would have delivered the same performance with better economy and lower cost if they used a 2-valve setup. Conversely of course, you can use a 4-valve setup to build a 360hp 3.6L V6, but fuel economy will be inferior. It is also debatable whether a larger displacement 2-valve engine would have served up 360 hp with better economy and lower costs.

When you trim valve lift, passage sizes and overlap periods back so the DOHC motor reaches it's power peak at around 6000 rpm, it is no longer able to rev without running out of breath any better than a SOHC or Pushrod motor with a similar power peak. Volumetric efficiency peaks at the torque peak on all engines and volumetric efficiency falls off faster than rpm is rising at around the power peak. This is true of every internal combustion engine regardless of the number of valves or cams. It is even true for a wankel. Hence, 24-valve V6es like the Altima's 3.5 (270 bhp @ / 251 lb-ft @ 4400 rpm), the Toyota Camry's 3.5 (268 bhp @ 6200 rpm / 248 lb-ft @ 4700 rpm) or the Honda Accord's 3.5 (268 hp @ 6200 rpm / 248 lb-ft @ 5000 rpm), no longer have any statistically breathing or volumetric efficiency advantage over a Pushrod or SOHC 2-valve design with a 266bhp 3.6L V6. Now, a little history how this came about... back in 80s when DOHC 4-vavle designs first entered the mainstream, the engines typically revved close to 7000 rpms and made about 80 hp/L. An example of this is the Toyota 4A-GE used in the high performance versions of the Corolla and Levin, as well as the MR2. If this doesn't sound all that impressive, remember that this is an age when many cars are still carburetted, fuel injection is primitive, compression was low, lead just got removed from gasoline and finite element analysis of combustion is something done on supercomputers for the Steath Fighter. In anycase, even at 80hp/L the engines won't idle right, exhaust would have been sooty and the engines would stumble under 1500 rpm if you floor the gas pedal if not for devices that blocked off half the intake to increase swirl (see Toyota T-VIS). Even so low end torque and civility is is marginal. Some time in the very early 90s, Honda popularized cam switching in form of VTEC. Basically, this allows the engine to run two sets of cam lobes, one for high rpm power and one for proper low rpm running. Specific output went to 100 bhp /L and low rpm character was no worse than the 80s DOHC engines -- which is to say passable but not all that great. The late 90s saw an interesting trend... Everybody went DOHC because the past decade and an half of marketing had backed the manufacturers into a corner they created. Marketing and alphabet soup now drove specifications as much as engineering realities -- perhaps more so. Yet, specific output fell. A 1998 Maxima had a 190 hp DOHC 24-valve 3.0 V6. The Accord had a 200 hp 3.0 V6. That's about 67bhp/L or less. Why? Because the automakers realized that the typical family car driver has no interest in winding the engine to 7500 rpm, while they appreciate an engine that pulls from a stoplight with smoothness and authority. By narrowing the intake tracts, reducing valve lift and getting rid of much of the valve overlap, they could defang the DOHC mills such that they performed just as well as the SOHC or Pushrod 2-valve designs in the regimes which customers and emission regulators cared about the most. In short, the priorities of the engine's performance characteristics no longer call for the airflow potential only a DOHC 4-valve design could have provided. But, because they and their customers are so used to DOHC setups by then -- and they didn't want to appear retrograde -- they stuck with it and made 4-valve engines that performance like 2-valve engines instead. Yes, it cost more, it took longer to build and its more of a hassle to service. No, there were no technical benefits, and in fact fuel economy is a little worse. But it kept the marketing department happy and the engineers were too lazy to argue or were overruled by the MBAs who ran the company that didn't know any more than what the brochures said. In the meanwhile, the convictions of the DOHC proponents were reinforced by lackluster market performance of those US brands which stuck to pushrods and SOHC modular engines. That this has more to do with complacency, bean counting and a lack of technological content in their 2-valve engines rather than the 2-valve layout itself is lost to the decision makers and the consumers alike. At some point in the 2000s all the US makers relented to the tide. And this brought us to today. All the mainstream consumer engines are essentially all DOHC 4-valves -- not because they have to be, but because things when done long enough take on a life of their own. There are some exceptions of course... Honda in particular fancies SOHC 4-valves as a compromise and dared to use a 2-valve SOHC design when it comes to delivering the best fuel economy they can in their Insight and Civic Hybrids. GM soldiers on with the Pushrod LT1 V8, but only in the high performance Corvette where the buyers either know better or subscribe to a different tradition, and the engineers know that it is the smallest, lightest and most fuel efficient path to 460 hp.

Honda uses SOHC designs on the Civic 1.8 and the TL / Accord 3.5 V6es. They use a DOHC design in the 2.0L and 2.4L Inline-4s you'll find in the Civic SI, CRV, ILX and 4-cylinder Accords. They also use a SOHC 2-valve per cylinder / twin spark 1.3L engine in the 2nd Generation (2009~present) Insight Hybrid and the Civic Hybrid (Designation: LDA). The selection of a SOHC 2-valve design in the Insight gives it slightly better fuel economy than a DOHC engine would, hence the design choice. Somewhat lower cost, slightly better fuel economy and -- only in the case of pushrod Vee engines -- notably more compact packaging and lower weight. But, all of these come at the price of slightly lower performance. Let's put it this way, a Pushrod V6 of 3.6 liters (266 hp) will essentially match the Toyota Camry's 3.5L V6 (268hp), but it'll be cheaper to build and give slightly better fuel economy. The use of a DOHC design in such powerplants are technically difficult to justify. In GM's case for instance, they took the middle road. GM's LFX V6 revs to 7000 rpm and peaks at 6800 rpm with ~90hp/L. Not quite full DOHC potential, but somewhat better than a SOHC or Pushrod 3.6 could achieve. Their 2.5L I4 peaks at 6300 rpm with 82 hp/L and is only slightly above the potential of a SOHC 2.5 design. The moral of the story really is this... If you use a DOHC design better wind it to 7500 or 8000 rpm and get about 100+ hp/L out of it like the various engines of this genre (Eg. Honda F20C, B16A, B18C, H22A, Toyota 2ZZ-GE, BMW S65, etc.). It will do that for you. But, if you are going to temper that screamer with narrower intake passages, lower valve lift and minimal overlap -- like most "mainstream" DOHC engines of today does in the interest of low end torque, idle civility and emissions (because fat intakes, valve overlaps and low intake velocity is really bad for hydrocarbon emissions) -- you are better off using fewer cams and lesser valves. Doing so will lower cost and reduce parasitic friction, giving you better fuel economy and still meet the airflow requirements of an engine with a 6000 rpm power peak as well as a DOHC layout will.

Forget the "new platform", how about just stretching the Stingray's aluminum frame rails to make it a 2+2. Weight can go up from 3200 lbs to 3700 lbs and still be decent.Then tag on Caddy bodywork like they did with the XLR. Heck just call it the XLR if they can't think of anything else. You get a choice between the LF3 3.6L Bi-turbo with about 420hp or a supercharged variant of the LT1 V8 with about 600hp depending on how fast you want to go. Sell it for $68K~$88K depending on the configuration. That price point along with the utility of the rear seats and a more luxurious cabin will make is an attractive alternative for anyone looking at stepping up from a vette or is looking at Panameras, 6-series, SC or S-class coupes.

Not coming to he USA...

It can be, but the 4.5L displacement makes it unlikely. Why go all the way down to 4.5L when the 6.2 already has enough cylinder wall thickness for a decent amount of boost? Also, why just 500hp if you are going to add two turbine-compressors and an intercooler assembly, especially when a naturally aspirated LT1 is already 460 hp? More likely though, its an engine that doesn't exist (yet) and they just coin those numbers because 500hp and 4.5L is more or less where the competition is. They also said the Volt would have a turbo I3 and Caddys may be getting a V16... all of which is utter rubbish when it comes to the actually production lineup.

What if GM goes back to 2-valve per cylinder -- either with a Pushrod design in a V6 or SOHC design in I4s and/or I3s? With today's technological content, the engines will perform more or less like this:- 1.5L SOHC 6-valve Inline-3 w/ VVT & Direct Injection -- 111 bhp @ 6000 rpm / 113 lb-ft @ 4600 rpm 2.0L SOHC 8-valve Inline-4 w/ VVT, & Direct Injection -- 149 bhp @ 6000 rpm / 151 lb-ft @ 4600 rpm 1.5L SOHC 6-valve Inline-3 w/ VVT DI and turbocharging -- 170 bhp @ 5200 rpm / 180 lb-ft @ 2600~5200 rpm 2.5L SOHC 8-Valve Inline-4 w/ VVT & Direct Injection -- 183 bhp @ 6000 rpm / 185 lb-ft @ 4600 rpm 2.0L SOHC 8-valve Inline-4 w/ VVT, DI and turbocharging -- 237 bhp @ 5200 rpm / 240 lb-ft @ 2200~5200 rpm 3.6L Pushrod OHV 12-valve V6 w/ VVT & Direct Injection -- 266 bhp @ 6000 rpm / 269 lb-ft @ 4600 rpm This is based on the same power density as the LT1 V8 (74.65 hp/L) and a fuel expectation that is 91 Octane Recommended / Not Required. We are keeping displacement as is compared to the DOHC mills. On turbocharged engines it assumes the same boost level and turbine/compressor efficiencies as on the Malibu's 2.0T engine (for the 1.5T I drop it a little to account for the fact that small turbos tend to be slightly less efficient. We are also assuming that we are not using a cam-in-cam dual VVT setup which is technically a feasible option. It is actually... not that bad even compared to today's typical DOHC engines. Definitely on the lower end of the spectrum, but not embarrassingly bad. Fuel Economy numbers though can be expected to be superior to GM's or the competition's existing DOHC engines. This doesn't surprise me, and it shouldn't surprise anyone. Think about it... most passenger car DOHC fours and sixes reach their peak torque in the mid 4000s and their peak power rating between 5800 and 6400 rpm. That tells us two refutable facts -- they reach their peak volumetric efficiency around mid-4000 rpm range, and they reach a point where volumetric efficiency falls off faster than RPM is rising at around 6000 rpm. Whatever theoretical advantages of a DOHC 4-valve design might bestow, most modern passenger car engines are certainly not capitalizing on it since a 2-valve setup can already achieve the same approximate performance. The reasons may vary from not wanting to compromise the idle or low rpm torque, wanting to keep intake velocity high (hence narrow intake passages) for emissions reasons and/or simply not wanting to warranty a 8000 rpm engine or transmission. This then begs the question... why put up with the increased complexity, additional friction and added cost of a DOHC design when you are not going to build a Honda F20C (S2000; 2.0L 240 bhp Inline-4) or BMW S65 (E90 M3; 4.0L 414bhp V8)?

Actually, it is not true that DOHC engines make less torque. They don't. They actually make MORE torque at the same displacement. A DOHC 3.6 will make more torque, more power and burn more fuel than a Pushrod 3.6 -- the burn more fuel part comes from it's higher parasitic losses from valvetrain friction. The problem of course is that while hp/L scales with the flow rate of your heads, valve area and RPMs, lb-ft/L doesn't (it really only scales with compression ratio). At any given hp rating, a DOHC engine will tend to be of a lower displacment and hence lower torque output. But, at any given displacement a DOHC engine will be superior in both torque and power output, but losing out in fuel economy. An interesting paradox very few people understand is that the above is true only for gasoline engines. The OPPOSITE is true of DIESEL engines! You see... the reason DOHC 4-valve GASOLINE designs make more power is that despite having higher frictional losses, the gains from reducing pumping losses more than offsets the parasitic friction losses. This is ONLY true when the throttle is wide open. When driven modestly and/or at cruise the engine's pumping loses is caused not by the flow capacity of the head or valve train, but by the partially closed throttle plate. Because in any kind of standard test where fuel economy is measured -- and in any kind of scenario where the driver gives a damn about MPG -- the throttle is not wide, open DOHC 4-valve engines are almost always less fuel efficient than a pushrod or SOHC 2-valve design of the same capacity and similar technological content. A Diesel engine doesn't have a a throttle body. It runs wide open all the time. It simply meters less fuel, burns lean and produce less power when you prod the pedal part ways. Hence, in a Diesel the pumping loss advantages of a DOHC 4-valve design that applies to Gasoline engine only when you floor the pedal, applies all the time. In a Diesel, a DOHC 4-valve design tend to be more fuel efficient than a 2-valve design of the same displacement.

Forget the 4.5 Bi-turbo DOHC V8. The architecture doesn't exist yet. It'll cost a lot to develop and it has very limited applications. It'll costs more to built and it burns more fuel than a pushrod large displacement V8 of the same output. Just use the LT1 V8 (or a 6.8 or 7 liter derivative; similar to the LS7 but with Direct Injection, VVT and AFM) should make 460 (6.2L) to 525 hp with a like amount of twist. Lighter, smaller, cheaper, more uniquely American and more MPGs. If GM still hasn't gotten it's 8-Spd Auto off the ground by then, just use an Aisin or ZF 8-Spd.

The 2800 V6 (L44) was 140 hp / 160 lb-ft; the MR2's 4A-GZE 145 hp / 140 lb-ft. Just about ANY GM pushrod 60-degree V6 will fit the fiero and there have been transverse V8 swaps -- up to an including the fat Northstar and not just the small blocks. Anyhow, back to the 3500/3900 V6es... I believe that their major flaw was that they weren't large enough in displacement and there weren't enough commonality with the Smallblock V8s. Ultimately, this meant that between the V8s and the 60 degree V6es, GM would keep only one of the two engine lines. They kept the V8 and univeralize the high feature V6 in 6-pot applications. It is unfortunate, because a 4600 V6 using the same feature set as the LT1 will make about 340 hp / 345 lb-ft. With AFM its is likely just as fuel economical than the 3.6 DOHC. The 3.6 DOHC's 18/29 mpg is not that hard to match. It would have made a very good Impala engine and a better base engine for the Camaro than the 3.6 DOHC.

It doesn't take a tail out situation for the traits of AWD to make itself felt. And some of those traits are quite dampening. In the 90s, I went through two AWD cars in succession -- a 1988 Toyota Celica All-Trac Turbo (ST185), followed by an Eagle Talon TSi (basically a rebranded Mitsubishi Eclipse GSX). In the mid 2000s I was driving an Audi S4 2.7T (B5). So, I had my share of AWD cars. In general, they behave with significant understeer going into a corner and if you give it just enough throttle it adjusts to neutral. However if you floor it, it understeers again and stays that way crawling its way out. You are usually stuck with an understeering car scrubbing its front tires most of the time. More importantly there is a lack of the ability to adjust the attitute of the vehicle with the throttle. The car is dead set on being stable and throttle inputs simply increase that stability. I am not talking about breaking the tail loose, just alter the understeer/neutral/oversteer attitude of the car. This problem is exacerbated by the fact that a FWD or RWD car typically have one differential. AWD cars have three. Some of these are usually limited slips and if they are viscous it reduces the agility of the car by counteracting (at least partially) the desire of the inside and outside wheels and/or the front and rear axles to turn at slightly different speeds. This trait is present even when decelerating. Until the advent of active differentials such is the general driving dynamics of an AWD. The upside of course is tremendous launch traction and the ability to drive on low traction surfaces (like snow) with a greater degree of poise. Subarus in particular are bad in this regard. To keep their AWD system simple and because they have a transmission layout the makes this easy to implement, run of the mill Subaru do not have a center differential. The transmission output is geared directly to supply the front and rear differentials with 50% of the torque each. This makes the understeering problem worse by forbiding axle speed differences.. What I am saying is that Subaru can and should make RWD the standard for $1000 less than their AWD vehicles. That consumer choice doesn't hurt. That discount doesn't hurt. And, about 1~2mpg of mileage improvement certainly doesn't hurt.

Honestly, I don't know if AWD as standard is such a great idea. In places where it never snows, AWD does more harm than good. It makes the car less entertaining to drive, makes it slightly heavier, reduces fuel economy and adds cost (about $750~1500 depending on the center and front differentials). Subaru can and should make it optional so they can not just drop prices by a bit and raise the fuel economy numbers by a bit, but also give RWD seekers something they want. There aren't that many RWD options in Subaru's price segment and this is another market for them to exploit. Going RWD is simple for Subaru. Remove the front differential, get rid of the half-shafts, remove the center out-take gear (run of the mill Subarus don't have a center differential but a fixed 50/50 F/R torque split, i.e. symmetric AWD). The rest of the transmission stays the same.

A $10,000 premium over a Prius so you can spend $35 less in fuel costs a month = 24 years to break even on the investment. Nobody expects a 24 year lifespan to the battery pack, so it actually never ever pays itself back. Same thing can be said of a Volt vs a Cruze. $77 savings a month on fuel costs for a $16,000 investment in the propulsion system. 17 years to break even -- again, never going to actually happen with Lithium-Ion batteries. You don't buy Hybrids to save money, you buy it to "feel" good about helping out with reducing a non-pollutant called Carbon Dioxide and make an imaginary dent in a non-existent problem called Global Warming. I have no problems with people wanting to do that for the same reason I have no economics justification for driving a 470hp car with 15/21 mpg and being happy about it. I just have a problem with paying higher taxes so my "wealth" can be transfered to people who make that choice in terms of tax credits or government "green" subsidies.

What will be really interesting might be a Toyota Vitz (Yaris) hatchback in GT-S trim. Power can come from a 2ZR-FZE engine. Basically the Corolla's 1.8L Inline-4 but fortified with an Eaton TVS R900 supercharger. Should be good for about 180~220 hp depending on how much boost they want to run. But more importantly it'll continue the same philosophy as the FT86. A light, agile car with adequate power and zero turbolag. Sorta like a rehash of the "original" VW Rabbit/Golf GTi. Probably won't work too well in the USA, but it should be well received in Japan and in Europe -- where people actually like hatches

Well, I will very much have preferred zero subsidizes for Ethanol, "Green" Energy and no gasohol blending mandates. But on the otherhand, there is no justification for double taxing oil companies when every other business and individual do not have to pay foreign taxes on top of US taxes with no deductions or for saying that capital expenses should not be deductible. But, yes, philosophically I am of the persuasion that US government should be significantly smaller in size and scope.... that it should take less (in taxes) and do less (in services, entitlements and, yes, subsidies).

That's untrue on so many levels... The Federal government does not subsidize Exxon Mobil per say, they provide tax credits for certain energy production activities. And in fact, a lot of the so called subsidizes are not subsidies at all. Every year, we spend about $75 billion on such activities. Of these only about half ($38 billion) goes to fossil fuel producers. The remaining half goes to Alcohol incorporation, renewable electric production and Ethanol production. Of the 37 billion or so that goes to fossil fuel production, most ARE NOT subsidies at all... About $16 billion is foreign tax credits -- credits company receive on US taxes for taxes they already paid to foreign governments. It's like if you worked in Russia and paid 12% (Russia as a 12% flat tax) of your income in Russian income taxes, you get to take that 12% as a deduction on your US income taxes because you didn't actually earn that money -- it was lost to foreign taxation. This applies to you, to any company and to oil companies! Why shouldn't it? About 14 billion goes to credit for producing unconventional fuels. Most of the time, it is for producing fuels the oil companies don't want to produce or cannot make a profit on, but is mandated by the government. Again, I hardly call that a subsidy, more like a compensation for compelled activity. It's like you don't want to ride a bicycle to work, but the government say you must. You claim that this results in 2.5 hours a day of lost productivity and lost wages because of increased commute time and increased tiredness. The government says, OK, we'll pay you 2.5 hours of wages, but you ride that bicycle. The rest, about 8 billion goes to credit for expenses incurred in oil, gas and coal exploration. Again, why would anyone consider that a subsidy? That'll be like saying that if you buy a food truck and install the equipment so you can sell hotdogs, that you shouldn't get to deduct that on your business tax returns as an expense!

This is the wrong thread to persist in this discussion, but I want to emphasis that I have absolutely no qualms with people who feel good about driving a car that gets them 70 mpg or 100 mpg -- nevermind the economics -- just like I have no problems with people wanting to drive cars that go from 0-60 mph in 3.8 secs but doesn't have rear seats. If hyper-miling makes you happy, all the power to you! My quarrel is with the public policy of using tax payer money to subsidized such behavior, especially when the reasoning behind such policy is based on an environmental hypothesis that is totally bogus, founded on fraudulent data and propagated through bullying voices of proper science into silence.