dwightlooi

You'll need to get DI and VVL on the small block first. Those are pre-requisite enabling technologies for HCCI. It may also be a challenge to design the combustion chamber's roof for maximum knock resistance and predictability with a pushrod head. The main problem is that the wedge head with a heart-shaped combustion chamber (2-valve OHV heads) are not symmetrical with a squish deck on one side only. A DOHC 4-valve head is symmetrical about 2 axis can be engineered with squish decks on both sides.

2850 lbs is a very ambitious goal. 400 lbs does not come easy. Going aluminum or composite this and that, and using a smaller engine, practicing better weight discipline can at best get us half way there. The Corvette is already a very light car for a vehicle it's size and for the powerplant it packs. Really, 3250 lbs is pretty light. If you want to get significantly lighter, one of the most accessible methods is make the car smaller. Smaller car, less enveloped volume, less material overall, less weight. Having said that, the car does not have to be smaller on the inside. Instead, the rear over hang and front over hang can be trimmed significantly -- the Corvette has an abundance of the latter in particular. The other thing that can be done is to move the transmission from its current location ahead of the rear axle to behind the rear axle using a longitudal-engine, front-drive style transmission like those Audi and Subaru uses but putting it in the back and driving it with a torque tube like it is currently done. This not only improves weight distribution (the Corvette is currently slightly front heavy), it also allows the wheel base to be shortened by 6~8 inches without compromising passenger volume. Since we are talking a new transmission instead of the current breed of T6060 or 6L80Es, let's also take the opportunity to make it a 6~8 speed dual-clutch automated manual.

This is a revision which gets rid of the roller, pin and forked push rod. The concept is the same -- we are moving the point of contact between the rod and the rocker -- but the implementation is different. The effect is the same but this is perhaps more robust and "clean". It's a evolution of the same idea, very much like Toyota's VVTL-i is different in implementation but similar in it's cam switching concept as Honda's VTEC. Instead the rod is simply flared out to a block like cross section with a cylindrical face at the tip. A spring loaded tensioner in riding the fulcrum shaft is used to keep it against the eccentric shaft when at rest. Once it gets moving the angle of the rocker's face keeps it naturally against the eccentric shaft's lobe. This particular pairing of eccentric and tensioner size allows a variance in rocker ratio between 1.73 and 1.45. By using larger eccentric lobes and tensioners we can achieve even greater changes in rocker ratios at the expensive of greater VVT mechanism size. I think we can achieve a 1.90~1.20 variation if we want. That's literally the ability to shift between twice as docile as a typical LS engine and Winston Cup rocker ratios! And that is without any "steps" as the mechanism is continuously variable. However, NONE of the size and weigh increase in the VVT gear is the actuated valvetrain mass -- neither the eccentric or the tensioner moves up and down with the valve, rocker or pushrod so such increases in mass won't hurt high rpm performance or require higher valve spring rates.

The small block V8 has powered the Corvette and many other GM performance cars for decades. Among its advantages is its relatively compact size and modest weight compared to overhead cam engines of the same displacement. In fact, an aluminum small block like the LS3 can often be slightly lighter and smaller than a DOHC 32-valve engine of Teutonic pedigree boasting the same power output. Most of its advantages stems from the elimination of a pair of bulky and fat DOHC heads and its belt or chain drives. However, the small block is not without its demerits. The need to utilize a higher displacement to achieve comparable output to a state of the art DOHC powerplant means that it tends to be a little behind in economy and civility. While a pushrod engine will never breathe as well as a well designed 4-valve OHC design, some of its disadvantages can be mitigated with technologies which can be incorporated into a push rod small block V8 but hasn't been done by GM yet. With the next Corvette being a most likely a smaller, lighter car and with Bush's new CAFE mandates filtering in over the next decade, it makes sense to produce an advanced small block which will continue to give the Japanese and the Germans a run for their money in terms of power per unit engine dimension or weight if not hp/liter. I believe the next Corvette (C7) should be powered by a micronized 4.8 liter pushrod aluminum V8 with the following features:- (1) Independent Continuously Variable Intake and Exhaust valve Timing (Cam-in-cam setup already used in Dodge Viper) (2) Direct Gasoline Injection (easier to implement on a 2-valve head in fact than on a 4-valve head) (3) Active fuel management (already proven and in service) (4) Ionic knock detection (based on spark gap sensing) (5) Reduced displacement (~4.8 liters) (6) Belt-less accessory drive (water pump, A/C, alternator runs off 300,000 miles maintenance free roller chain) (7) Continuously Variable Valve Lift (Yes, it's possible on a push rod too; see illustration below for an implementation idea) Bore x Stroke: 94 mm x 85.6 mm Compression Ratio: 11.8:1 Power: 360 hp @ 6200 rpm Torque: 360 lb-ft @ 4200 rpm Redline: 7000 rpm The Corvette should become smaller and cut about 500 lbs off the curb weight. At 2750 lbs, power to weight ratio should be identical to the current C6 Vette. Acceleration should be similar whereas all other aspects of performance should improve due to the reduced mass. EPA numbers will be quite good too with the lower vehicular weight, direct injection and cylinder deactivation.

Actually, we do have means of determining approximate temperatures and ice cap extents eons before the advent of modern meteology. Ice core samples, extent of temperate and non-deciduous vegetation through fossil excavation or in more recent times -- like Roman or crusader eras -- historical records of climatic conditions. We know for instance that a not insignificant part of the reasons the crusades happened was not religious in nature. Rather, Europe was shrouded in some of the worst and longest winters known an the resultant crappy harvests and near famine conditions drove lords and monarchs to seek their wealth through plunder and occupation of the "holy land".

BTW, over the past 12 months or so, we have seen a sharp DROP in global temperatures based on the most accurate method of measurement we have -- satellite IR thermographs. In fact, we have cooled so much in the past 1 year that it effectively erased ALL of the warming we saw in the past 12 years (1996 thru 2007)! Androgeneous CO2 output has unquestionably increased in the past 12 months, so any scientifically minded individual has to ask -- just how much of a role does it have to play in global temperatures. Also, unquestionable is a sharp fall off in solar flare activity of our Sun, again we have to ask how much the rather abnormally higher level of solar flare activity in the past couple of decades has to do with our recent warming trend. Now, I am not saying that the warming trend has ended and will not resume. But it is true that all of the warming since 1996 has been wiped out. Not by some Kyoto Accord, not by carbon credits, but rather it just happened due to non-androgeneous reasons we have yet to fully comprehend. Based on the same kind of argumentative basis used by Global Warming yanters to support their theory, I should be forecasting the re-emergence of woolly mammoths by the time our kids grow up! Jeez!

OK... this begs the age old question... WHY? Fossil Fuel is still the most abundant and cheapest energy source bar none. It is cheaper than any of its alternatives by a margin of several to ten of times even at $100/barrel and $3.50 a gallon of gasoline. There is no question that at some point in the future it will become expensive enough that alternatives will start to make sense. But why shouldn't we allow the market to decide that instead of putting that decision in the hands of a class of bungling and often highly misinformed politicians? In the meanwhile, why shouldn't we be talking instead about increasing domestic oil exploration and extraction? How about drilling in Alaska, off the coast of California and elsewhere which we know has the geographic features that tends to yield oil reserves? Also, in large part the gasoline prices of today are the result of refining capacity shortfalls rather than crude prices. At $1.40 a gallon in the mid 90s, crude was at $40 a barrel. In otherwords, about $0.95 of that $1.40 was the cost of crude. It cost us a little under 50 cents to turn crude into gasoline served up at your neighborhood pump. Today, the crude costs $2.38. Now, why does it cost $1.12 to turn that into gasoline? In part it is due to refinery shortages. We haven't built a new refinery since the 70s thanks to radical environmental lobbying and feel good politicians! Why shouldn't we revisit this issue? At some point, when oil becomes hard enough to get to because the easily accessible reserves have all been tapped and exhausted, oil will become more and more a fuel of choice for applications which absolutely have no practical alternatives -- such as commercial and military aviation. At some point we will have to find some way to get our energy and to transport it. And we already know what the answer to that is because there is only ONE answer -- thermonuclear power production and battery storage. Yes, you can forget hydrogen or ethanol or wind or solar or tidal or geothermal. The reason is that Hydrogen is NOT an energy source, hydrogen has to be produced for more energy input than you will ever get out of it which means that it is at best an energy storage medium -- and a real crappy one at that. Most of the hydrogen produced today is produced by cracking hydrocarbon fuel(s). The other way to get it is by applying corpus amounts of electric power to electrolyze it out of water -- electric power which needs to come from somewhere. At -423 deg F it is ridiculous to store or transport as a liquid. Carrying hydogen at 5000 psi as a gas, using all your trunk space for explosive tanks still carrying less energy than a 1/4 tank of gasoline. Ethanol is struggling to get to 1:1 in terms of energy input into its production and it's energy yield. In other words, it is also not a practical energy source although it is a more practical energy transport medium than hydrogen. In addition, we don't really have enough farm land to grow enough sugar & starch crops to produce enough ethanol to replace oil! That is not counting the fact that we'll need to account for the energy that needs to go into ethanol production which -- right now -- is roughly the energy you get out of the process. The argument around ethanol really should be whether we should convert energy to ethanol for carriage purposes rather than whether we can get energy out of ethanol production. Solar, Tidal, Wind, hydro-electric, geothermal and all of the other "free" energy production schemes combined cannot produce enough energy to cover 10~20% of our current energy needs even if we we discount their unreliable nature and the impossibility of populating every practical inch of or our country with devices that produce power sometimes when the weather and season permits. Again, these are feel good technology with no shot at all in addressing mankind's energy needs at present levels much less future demands. So the only answer isNuclear. Add about 500 to 5000 reactors to the map (depending on the type and size of the plants) and we'll take care of our energy production problem. You get electricity out of it which you can then distribute with an evolved and beefed up version of the current electrical grid. The "new" middle-east in a Uranium economy will be in Australia -- not exactly an explosive land packed full of Islamo fascists and tinpot despots. For storage in vehicles, you utilize batteries. Combustible fuels like ethanol and crude distillates will provide high energy fraction fuels for aviation and space applications. That is the ONLY plausible future given what we know today. The question is when do we make that transition? If you ask me, I'll say that the market will tell us when, and it'll do so in an unbiased and perfectly informed manner which we can only dream of when it comes from career legislatives.

Well... Global Warming IS A CROCK OF SH!T and Hybrids DO NO MAKE ECONOMIC SENSE AT $3~4 a gallon! Cheers Bob! Before you start accusing me or Bob as a redneck moron, consider the following:- Global Warming is an alarmist hoax because... back in the Cretaceous when dinosaurs walked the earth, Global temperatures were about 18 degrees (F) warmer than it is today. Many cooling and warming cycles have occurred afterwards, and back when Imhotep built the Step Pyramid (~4700 years ago) global temperatures were about 3 degrees warmer than today. Back when Genghis Khan consolidated out the Mongol Empire and the Norse explored Greenland (~800 years ago; circa 1200 AD) global temperatures were 3~8 degrees warmer than today. The Earth, again, had many warming and cooling cycles in between and thereafter. Late-1800s to ~1940 was a warming period, 1940 to 1977 saw rapid cooling (an the Al Gores of the day were predicting an imminent Ice Age) and finally the 1980s to present had been a MILD warming period (less than during the 1200s and way short of historical peaks). There is no question whatsoever that androgeneous CO2 output consistently increased between 1850 and 2008, there is also no question that Dinosaurs and Genghis Khan didn't drive SUVs. We can therefore say that our current climate is smack right in the middle of historical fluctuations and that it should be seen as perfectly "normal". More importantly, we have ZERO evidence, scientific or statistical, that androgeneous CO2 output due to industrialization has any tangible effect on global climate change. Of course, this won't stop the Nobel Committee from giving Al Gore the Peace Prize, but then again they gave it to a bona fide terrorist, corrupt hate monger and murder Yasir Arafat, so I guess they have very unique "standards"! Hybrids do not make ECONOMIC sense because... a Corolla averages 32 MPG whereas a Prius costing $6000 more does about 48 MPG in typical mixed driving. Say you drive the average 12000 miles a year. You'll burn 375 gallons in the Corolla and about 250 gallons in the Prius -- a difference of 125 gallons. At $3.50 a gallon you have saved $437.50 a year. It'll take you about 13.7 years to recoup the price difference between the two cars! That is assuming that the maintenance cost is no different between the two and that $2000~3000 battery lasts you that long. Having said that, there may be a decent business case for Hybrids because there are a considerable amount of individuals who want to buy them for "green" pride or out of shear inability to do grammar school math.

How about a 1.8 liter 3-cylinder Dual-VVT direct injection turbodiesel? Should make in the vicinity of 150hp and 240 lb-ft of torque on Unleaded #2. Probably need urine injection to meet emission standards though...

Figure a 1.8 liter 3-cylinder DOHC 12V engine to be about 127hp w/o DI and about 150hp w/DI some advanced features like Dual VVT. That's in the same bracket as the leading 1.8 liters in the FWD compact segment. Thats assuming regular 87 octane and the same architecture (bore/stroke, combustion chamber shaping, etc) as the LE5 2.4 liter 4-cylinder engine currently in use in the Malibu, G6 and others.

Weight, not engine size, engine technology or #of cylinders is the BIGGEST contributing factor to fuel consumption. However, having said that, a 3-cylinder engine will be more efficient, more compact and lighter than a comparable 4-cylinder of the same displacement. The reasons to increase the # of cylinders has nothing to do with fuel economy, engine packaging or weight. It is just you get more firing pulses with more cylinders and with large cylinder sizes it is harder to control engine knock because the distance from the spark to the furthest reaches of the cylinder wall is greater. However, a 1.8 liter 3-pot will have the same knock resistance as a 2.4 liter 4-pot which we know to be perfectly manageable.

Of the many things that govern how "civilized" an engine is, three things matter the most. Engine vibrations due to harmonic imbalance, Engine virbations due to block flex and the number of power impulses coming from the engine per unit time for at a given RPM. The ONLY advantage a 4-cylinder has over a 3-cylinder is having 33% more power impulses per unit time. That is you will see the same spacing of power pulses from a 3-potter as a 4-potter running at 33% greater speeds. In otherwords, at 1500 rpms the 4-cyl makes as many power pulses per second as a 3-cylinder at 2000 rpm. Similarly, a V6 or I6 at 1000 rpm already produces power pulses with equal proximity as a 4-cyl at 1500 rpm. This we cannot fix, but really do you feel that an engine is much smoother at say 2600 rpm compared to say 2000 rpm? Probably not. This leads us to the other factors -- harmonic balance and block stiffness. The 3-cylinder engine produces 1st order vibrations with a frequency equivalent to the speed of the crank producing an end-to-end rocking moment. This is caused be a shifting Cg of the reciprocating assembly. We can balance this out with a single balancer shaft turning at crank speed. The 4-cylinder engine produces 2nd order vibrations with a frequency twice that of the speed of the crank producing vertical up-down moments. This is caused by the fact that the pistons accelerate at different speeds* when coming down from TDC and those going up from BDC! We can balance this out with two contra-rotating balancer shafts turning at twice the crank speed. When un-balanced, the 4-cylinder has the advantage in that its 2nd order vibrations are less severe the 1st order vibrations in a 3-potter. In general, 4-potters at 1.8 liters or less tend to achieve decent civility w/o balancers, at 2.0 liters they sometimes have it, at 2.2 or greater displacement they almost always have it (one exception, I believe, being the pretty truck like Nissan SR24DE in the older Altimas and 240SXes and that is one pretty rough motor). With proper balancers however, both the 3-cyl and the 4-cylinder can be smooth and civil engines. The issue of block stiffness is really quite independent of the number of cylinders. Wobbly blocks flex in response to pulsatile pressure applied on the crank journals. This leads to relatively low frequency vibrations that yell DIESEL! A stiff block resists flexing and comes through with a higher pitched metallic whirl which we so endear. *If you don't believe that pistons move at different speeds at the top and bottom of their travel, draw a circle with a long line going through its middle. Mark say a 20 degree point clockwise at the two points past the bisecting line. Now draw two lines of the same exact length signifying the connecting rods from these two points to the center line. Note the difference between the distance covered by the pistons.

GM has been sucking for years. I know many of you don't to hear that or admit that, but it's true. GM sucked in the 80s. They sucked in the 90s. They have been dong all the bean counting and quality skimming possible in order to remain the "value leader" while operating out of a high cost country (USA). It's a moronic formula, but for over two decades they stuck to it. Today, GM vehicles (and most American cars for that matter) are viewed as technologically and qualitatively inferior products with a dubious reliability record, poor economy and resale values in the toilet. GM has finally awaken -- the GMT900s are OK, G6es are decent enough, the Aura is yet another step forward, the Solstice is a looker, the new CTS is world class, the Malibu has all the markings of a comeback car like the Taurus was to Ford in 1988. But to press the offensive, it's time GM think out of the box and aim not to simply match the competition or edge ahead slightly but to totally surpass them. In order to beat the Civic and the Corolla in fuel economy numbers and perceived technological superiority it's time to pull out all the stops. And it's a tall order. The R18A engine in the Civic for instance is not only a VVT unit, it is a part time atkinson cycle engine. Meaning that at part load, the VTEC system engages a second set of intake camlobes which keep the intake valves open well into the intake stroke. This allows the engine to kick part of the intake air back out of the cylinder. The throttle body remains nearly fully open while the engine breathes easily through the unrestrictive intake system while providing cruise economy. Combined with a 5 speed automatic and impressive weight discipline in chassis engineering yields a car that is bigger than the G6 on the inside while weighing 2750 lbs and delivering 30 mpg in the city and 40 mpg on the freeway under the 2007 EPA standards. Going through GM's list of new technologies and the latest parts bin we can give the new Cobalt the following:- Direct Injection Dual Cam VVT 4-valve DOHC valvetrain with roller followers 36 volts electrical system with alternator-starter-motor HCCI -- Homogeneous Charge Compression Ignition 6T40E 6-speed automatic transmission But is it enough to beat the Civic? Well, maybe it's time to think 3-cylinder! A 3-cylinder engine has the following advantages over a 4-cylinder of the same displacement. Lower frictional drag -- lower cylinder wall area, less valvetrain and reciprocating parts Lighter and shorter block Less parasitic loss from harmonic balancers (if equipped) -- one balance shaft at crank speed, vs two at 2 x crank speed. In addition, the 2.4 liter Gen II Ecotec is a perfect candidate for building a 3-cylinder. The LE5 engine with one cylinder lopped off makes exactly 1.8 liters -- right where the Cobalt should be if it wants to play in the Civic/Corolla club. In addition, the HCCI engine with its tricky combustion management process is being engineered right now around the big Ecotec engine and keeping the same combustion chamber, piston and rods from the big 4-potters will reduce engineering time and costs. Personally, I won't mind seeing a new Cobalt come on stage with a 3-cylinder Ecotec with mild hybridization (alternator-motor), Direct Injection HCCI and the 6T40 6-speed as standard. Such a 1.8 liter three-banger should deliver about 150hp, 140 lb-ft and help leap ahead of the Asians.

There is NO DI pushrod at this time although there is no reason there can't be. In fact, a concentric cam-in-cam VVT (ala Viper 8.4 V8) and with DI may be the next step in the small block evolution. Other "feasible" technologies to incorporate on a small block includes a camlobe switching system modelled after the Porsche Variocam 2 and a continuously variable pivot system for the rocket arms which will provide continuously variable valve lift. Other non-performance related changes possible is a belt free engine. Basically, you eliminate the accessory belt drive by running the water pump off the camshaft via helical gears or a secondary chain and replacing the alternator with a generator/motor that fits in place of the flywheel. The onlly thing left then is the A/C compressor and you can run that electrically of the battery and alternator motor output. Such an engine will have the side benefit of being able to shutoff at stoplights and give or take about 20hp worth during acceleration and braking using a not too expensive 48v battery. And, or course, there won't be any belt to change and -- with long life fluids -- essentially no service intervals for 10 years or 150,000 miles except for oil changes every 15,000 miles or so.

Well, we need to separate weigh due to technology and weight due to architecture. Let's just put some numbers in to this discussion for comparison. The LS7 (7.0 liter 505 hp OHV V8) weighs 458 lbs fully dressed. The recently replaced 6.0 liter LS2 was 322 lbs undressed (w/o the alternator, accessory drive, A/C compressor, etc). The AMG 6.3 liter DOHC V8 weighs 439 pounds not sure if that is dressed or not. However, I do not believe that the two engines are equal in terms of fabrication technology and/or the designer's liberty to sacrifice cost for weight. The 7.0 is in fact the "smaller" engine physically thanks to the much smaller heads and not having to carry four camshafts topside. In general, for the same level of construction technology, an OHV engine is smaller and lighter for a given power output. That is its advantage. The disadvantage is that it is lower in specific output, lower attainable rev limits, less willingness to rev and in general inferior in brake specific fuel consumption (lbs/hp-hr or g/kW-hr) compared to a DOHC powerplant of the same output. The OHV engine also lags in refinement -- idle quality and the turbine like whirl factor in general. This is either a good thing or a bad thing depending on your perspective and the application. In a Camaro the primal roar and slightly rough and bubbly idle is probably looked at as a mark of prowess under the hood. In a Lexus, such an engine will probably turn away most of the buyers.

Well, for one, the Cobalt uses a DOHC 16v 2.2 or 2.4 liter engine (both has the same EPA fuel economy numbers w an automatic tranny) and uses a 4-speed automatic. It is also about 100 lbs heavier than the Civic despite being a smaller car on the outside and especially on the inside. The Honda Civic (2008) uses a SOHC 16v 1.8 liter engine with both variable camlobe switching and variable camshaft timing, is about 1 passenger lighter comparably equipped and uses a more modern 5-spd automatic. A 3~4 mpg differential is about what I expect. If Chevy wants to play the economy game (and win) its time to not be stingy on technology and get better at managing weight growth in product development (not traditionally GM's strong suit). For starters, pile on what you have in your arsenal and utilize the technologies you have at your disposal but had previously bean-counted out. Whatever the Cobalt replacement is should use an improved version of the 2HO 1.8 liter engine with Dual VVT, HCCI, Direct Injection, all roller cam followers and most importantly the 6T40 6-spd transverse automatic transmission. The alternator-motor + 48v electrics based "mild hybrid" system should not be on a special Hybrid model, it should be standard on every Cobalt. The car should weigh in at 2600 lbs not 2800. It should have an interior at least equal to the CTS. Do that and you have a winner. The costs should fall wherever it falls as long as it is reasonable. The selling points will be:- (1) Best interior in class. (2) Tightest construction in class. (3) First Compact Car with Direction Injection, Variable Timing and HCCI (Homogeneous Charge Compression Ignition). (4) First Compact Cart with a mild Hybrid drive train as Standard. (5) Best Fuel Economy in class. (6) Best NVH suppression in class. (7) Best warranty and service in class. It'll also be the most expensive Compact FWD in class -- say $4K more than a Corolla. The USA is a high cost country. US manufacturers cannot and should not compete on price or value. We'll never win against the Koreans and soon the Chinese and Indians. GM has been casting herself as the "value leader" for the last decade or two. That in and of itself is the BIGGEST strategic blunder. The only way you can be the value leader is if you bean count out all the quality, technology and attention to detail that the consumer expects. You end up with an inferior product line which -- due to high US labor costs -- will still be no cheaper or barely cheaper than the competition. You then slap on rebates and discounts and take it out of your bottom line. It doesn't take a PhD to understand this basic flaw in their business model. A US car company can be a BMW or a M-B, it cannot be a Hyundai or a Chery! It's time to wake up!

Nope, the license plate is not on, and the two square slots where it should be doesn't look like a gas cap. Maybe they got REALLY silly and put it in the TRUNK! Or maybe under the driver's seat!!!

Nah, Chevy already has the Malibu. There is no need to overlap the "Camry" market with yet another car. The RWD Impala or Caprice or whatever you want to call it should be situated one step above the Malibu, priced accordingly and configured suitably. A 3.0 DI does not exist. And a 3.6 is not going to be any more or less expensive. Engine complexity costs money, slightly larger bores does not. If fuel economy and tree hugging is the goal a 4-potter is superior. They are not only cheaper (1/2 as many cams, a simpler block, exhaust on one side, etc) they are also more efficient at a given displacement due to lower parasitic loss. Think about it for a minute, between a 4 camshafts, six pistons, 18 rings, 24 valves, and 2 camshafts, 4 pistons, 12 rings, 16 valves, which do you think has less friction (for a given displacement)? The 4-potter! Out of consideration of this being a big and relatively heavy car, let's pick the biggest 4-potter in the General's arsenal. The truck portfolio's 2.9 liter LAV 16-valve Inline-4. Give it direct injection, DVVT and a mild hybrid treatment and it should be good for 230 hp. That is incidentally the same as the output as the 3.0 liter I6 in the BMW 328. Sure, it won't be the silkiest engine in the world, but if you care about that more than economy and looking green, you'll get the 3.6 V6 DI for the same money.

No, you won't be able to order one. This is FICTIONAL. But it is a realistic projection of what can be done with the 2.4 I4. What you do is throw in Direct Injection and Dual VVT. The 3.6 liter DI-VVT (LLT) in the CTS makes 304 hp and 273 lb-ft on Regular 87 with a 6400rpm power peak. A 2.4 liter (2/3 the displacement) should make roughly 203 hp and 182 lb-ft -- perhaps a little more given that I4s in general have less parasitic drag per cylinder than a V6 due to having half as many camshaft and a less complex camdrive. The Gen II Ecotec block (found on the 2.0 liter LNF and 2.4 liter LE5 engines) and its current internals winds out to 7000 rpm just fine (the LE5 2.4 in the base Solstice/Sky does just that). By using a set of camshafts, ports and runners biased for slightly higher RPM (by about 600 rpm) it should be plenty easy to make another 10hp. This may cost you some low end torque and perhaps a little peak torque. But I believe that be can match the port injected 2.4's low to mid range output while improving its top end dramatically. The graph reflects that. The power delivery is deliberately tuned to create the impression of an engine which wants to rev and is never out of breathe -- the power peaks at the redline and nowhere on the powercurve will the driver feel the power fade. Regardless of the power or performance of the engine, this "never fade till you bounce of the rev limiter" feeling is quite alluring. Try driving an Audi RS4 and you'll experience such a powerplant.

Forget the Camaro! This is the Chevy I want. Call it a Caprice or call it an Impala, I don't care really. Forget the 2nd rate Aussie powertrains though. It's time to modernize the powertrains and keep it one step above the Malibu (RWD or not). Let's say... (1) A DI version of the LLV 2.9 liter I4 with ~230hp mated to an alternator motor, NiMH batterypack and a 6L50 6A for a "Hybrid" for the tree huggers. starting ~$29K (2) A LLT 3.6 liter (DI) V6 with 304hp and an 6L50 6A for the mainstream trims. starting ~$29K (3) A LS3 6.2 liter V8 with ~420 horses for the SS with a 6L80 6A ~$36K There, you have a flag ship model for Chevy.

This is what they "could" have done... Almost like an E30 M3's S14 engine, accept it makes a little more power and it runs on Regular!

A few points:- (1) There are two problems with wheel hub motors... the first is that electric motors can be heavy. And, for the most parts the size and weight of the motor is a function of how much torque it can produce. If you eliminate the reduction gearing the motor's size increases. Because electric motors tend to be able to rev up to very high speeds, it is a good trade off to reduce the speed range it can achieve in exchange for torque multiplication. Let's put some numbers into play here. A 225/45 R17 tire is about 78.5 inches in circumference -- thats roughly 0.00124 miles. At 60 mph the wheel is turning at 806 rpm and at 120 mph it is going 1612 rpm. A typical DC motor will easily turn at 10000 rpm or more and their torque output decreases linearly with rpms, so it is beneficial to use reduction gearing to reduce its speed range from 0~10000 to say 0-3300 rpm while tripling the torque output. Hub motors don't do that. If you try to get 3x the torque without gearing, you'll need a bigger motor. The following diagram illustrates the torque curve of a DC motor -- I think it is self-explanatory. The second problem is that motors can be heavy and fragile. The last thing you want, if you are after great handling and dependability, is to put all that mass in the wheel so it bounces up and down as unsprung mass and subject the motor to all the shocks and rigors of not having a suspension to ride on. Putting the motors at the differential isolates them from the shocks of wheel movements, and reduces unsprung mass dramatically -- instead of motors going up and down, only the half-shafts go up and down with the suspension. (2) The ARROWS in the previous post DO NOT indicate the rotation of the wheels or the motors. They indicate the direction of the application of force -- which may or may not be the same as that which the components are turning. Think of it this way.... When you are braking from 60mph to 0 mph, the wheels are always rotating forward. The Brakes apply force in the reverse direction even though they don't rotate at all. In a similar vein, you can have a motor act to apply force in the opposite direction while turning in the same direction as the wheels.

To date, gasoline-electric hybrid vehicles have been designed primarily with improving fuel economy as the primary goal. Although some implementations -- such as those in the Lexus LS600h and RX400h -- have sought to create vehicles with no compromises to performance or even a little gain in this department, no hybrid vehicle to date has been designed with improving handling dynamics as the primary goal and with economy gains as a secondary (but very tangible) benefit. Here, I propose such a concept. Concept Premises:- (1) Hybrid drive trains can be used to enhance handling as well as improve fuel economy. (2) By adding two motors directly to an open differential, we can create an advanced differential with the ability to not only bias torque through computer controlled resistance application on the less tractive side (traditional active differentials) but also add torque on the opposite side. The biasing of regenerative braking can also be used to provide artificial stability (modulate over or understeer) when braking in a turn. (3) By using two DC PMMs of modest output, we can keep the entire motor and battery assembly small and light. That the motor's torque output falls linearly with wheel speed -- hence diminishing their usefulness at high vehicular speeds -- does not matter much because electric assist has the greatest utility at low to mid vehicular speeds (0-60mph), and most handling issues related to power application during on-limit cornering and braking also happens at low to mid vehicular speeds (<60 mph). (4) On a 3000 lbs vehicle, a mild 148 volt Li-Ion battery pack and two 15 kW (20hp) can easily be fitted with a weight penalty of ~250 lbs. An estimated 20~25% improvement in fuel economy and a dramatic enhancement of the vehicle's handling dynamics can be expected. (5) When coupled with a derivative of the 2.0 liter DI VVT turbo engine (LNF) or a derivative thereof, this may be an ideal "sporty green propulsion" package for GM's Alpha (compact RWD) platform. The idea is very simple. This is a direct drive parallel hybrid with a twist. Instead of putting the electric motor on the flywheel (ala Honda Insight) or coupling it with the engine via a planetary resistive-assistive type CVT (ala Prius), we put two smaller motors on each of the differential output shafts. The differential itself is a traditional open differential. This arrangement allows electric assist during acceleration and regenerative power recovery during deceleration. But on top of that, the motor totally transforms the differential into what is probably the most advanced active differential ever. When powering out of a corner, one motor will add power to the outside wheel while the other puts resistance on the inside wheel. The effects of this is amplified by the mechanical open differential which naturally wants to bias engine power to the side with lesser resistance. In doing so we can prevent or at least delay the onset of inside wheel spin while we add to the power application on the outside wheel which naturally has more traction (due to its higher rotational speed and weight transfer). When decelerating we can enhance vehicle stability by applying differing levels of power generation on the two wheel. The following diagram illustrates the setup.

An automatic transmission upshifts by having the the torque converter act as the "cushion" while one the gearbox slam shifts between two ratios through hydraulic actuation (electronically gated or otherwise). Basically, it'll be like shifting from one gear to another on a manual transmission very quickly WITHOUT taking power off the gas or using the clutch. In a manual, a very intrusive and potentially damaging shock will be experienced up the driveline from the wheels, through axles, through the differential, through the transmission, through the engine itself. However, the torque converter acts like a fluidly slipping clutch -- it is basically one propeller pushing fluid to turn a second propeller -- and permits a smooth transition. The problem of course is that a torque converter is like an always slipping clutch -- it robs power and immediate power conductance from the powertrain. This is why torque converters of today typically have a weak lockup clutch which engages the engine directly to the transmission input (neutralizing the torque converter) at low loads and when no shifting is occuring. The main reason automatics traditionally are less desirable than manuals for enthusiastic driving (not to mention less efficient) is that there is this torque converter rubberband effect. Power application seems to lag by a few fractions of a second as the engine rpms can rise and fall while power to the wheels and change in speed plays catchup. The converter also takes part of the power produced by the engine and turns it into heat in the transmission fluid within the torque converter while performing the hydraulic coupling reducing efficiency. The lockup clutch mitigates this during cruising and that bought us a little efficiency gain. Recently there have been a few developments have cropped up such as clutch-to-clutch up shifting (which eliminates the freewheeling phase during a shift, unfortunately not for 1st-2nd shifts because the torque load is too high) and transmissions which are smart enough to blip the throttle during the freewheeling phase of a down shift. These gets you a more direct feeling and slightly better performing automatic. An automatic meets or BEATS a CVT most of the time in efficiency because despite the latter's ability to maintain optimal gearing all the time, it suffers from one commonly overlooked flaw -- it needs to waste power ALL THE TIME driving a hydraulic pump to keep the two halfs of the CVT's pulleys pressed tighly against the steel belt! This happens even during gentle cruising at freeway speeds where an automatic basically locks up the torque converter. The CVT can't relax the pulleys at anytime or the belt will slip! The rise of the CVT, despite the advent of the tension belt (as opposed to compression Van Doorne type belts) CVTs capable of handling 200~250 lb-ft has been curtailed mainly because of this flaw in the entire concept which prevented the CVT from delivering better economy numbers than a 5A or 6A. The challenge to the modern automatic will not come from CVTs it will come from the twin-clutch automated manuals (ala DSG). Here you basically have an electronically controlled manual using two clutches. one for odd gears and one for even gears. The clutch is slipped for parking lot crawling and basically the transmission shifts from one gear to another by slipping both clutches during the interim period while two gear sets are concurrently engaged. Borg Warner has shown that this can be done smoothly and with superior efficiency and performance compared to both manuals and automatics. With twin clutcch equipped cars on the street for 2~3 years now it has also been shown that these gear boxes aren't konking out en masse. The concern of course is that these transmissions are not serviceable at your local tranny shop and if they turn out to have a higher than normal failure rate at 10~15 years of age it will put a stigma on the car models that use them and their manufacturer. The longevity and reliability of an auto is a known quantity, that of the DSG is a maybe. What disappoints me is that GM is not at least looking at the twin clutch actively at this time.

Three things:- (1) Fuel Economy The possible advantage of having MORE speeds is that you can achieve better fuel consumption numbers by having a very tall top gear without having a very tall first gear and/or big shift gaps between the gears. I say "possible" because having more gears does necessarily mean you can to the aforementioned. What's perhaps as important or MORE important is the Ratio Spread which is the maximum ratio difference between the tallest and shortest gearing a transmission can support. The 6-speed 6L80E/6L50E Hydramatics are 6.04:1 meaning the shortest gear is 6.04 times shorter than the tallest. The Mercedes 7-speed is "only" 6:1. The Lexus eight speed is 7.05:1. If you create an 8-speed transmission which has say a 6:1 ratio spread you are unlikely to see any economy gain. (2) Performance For a given 1st gear ratio and final drive (which you can easily configure) the shift gaps determine the drop in RPM for every shift. To understand why this is important, we need to talk briefly about what moves a car. In one word torque moves a car. The amount of push you get is the torque multiplied by the total effective gear ratio. For any given gear ratio, a car pulls the hardest at the engine's torque peak. Horsepower is merely a measure of torque x RPM. It is important because until the power peak torque is either increasing or decreasing at a rate slower than the increase in engine speed. In otherwords, as long as horsepower is increasing you are better off staying in the same gear even if the engine is past the point where it pulls the hardest in the gear you are in because for ANY % change to a taller gear ratio, you lose more torque multiplier than you lose torque as engine speed increases past the torque peak. In otherwords, a general rule is that a transmission should shift at the power peak and end up in the next gear at or after the torque peak. Depending on the engine's peakiness, a 4-speed may or may not achieve this. A 5 speed almost always achieve this. A 6-speed simply gains you the very marginal advantage of keeping the revs after the shift closer to the power peak. However, it has been shown that the last point gets you very little in terms of performance -- many cars with the same power to weight ratios are no faster with a 6-speed vs a 5-speed. (3) More gears can hurt. More gears = more shifts from 1st to top gear. Shifts themselves ALWAYS hurt performance and economy. Why? Because during a shift, power transfer to the road is either interrupted or reduced (depending on transmission type). During a shift your are burning gas to make HEAT inside the transmission instead of pushing the car forward. Therefore, shifts themselves suck. The only reason you tolerate them is that the gains from having closer spaced ratios and a wider spread are larger than the losses to power interruptions during shifts. Unless this is true, having more speeds can actually hurt acceleration performance or economy or both.