dwightlooi

This big nostril G6 GXP is not only much worse looking than the Orange GXP, it is so bad looking that it stands to drag down the image and sales of other Pontiac models. I mean the very existence of this vomit inducing car in the lineup makes one feel embarrassed to own or drive Pontiac. You may drive a nice looking Solstice or a clean looking "regular" G6. But when asked what kind of car you drive you'll be reluctant to say "Pontiac" because the response may be "Oh... that car company who makes that ridiculous car with nostrils?

Using E85 doesn't really depend on the engine type or valve train design. In fact, whether the engine has a Air Flow Meter or not doesn't matter either. What matters is that the fuel system must incorporate certain corrosion prevention measures because alcohol is a lot more corrosive than gasoline. In addition, because the calorific value and stoichiometric ratio for ethanol is different from that of gasoline (~9:1 for ethanol; 14.1~15.2:1 for gasoline depending on additives), it is an engine that runs on E85 or Gasoline or a combination of both must be able to determine what kind of gas it is currently burning. In general this is done using a broad spectrum O2 sensor to detect whether the engine is running rich or lean and quickly adjust the fuel injectors' opening duration to adapt. An E85 capable engine can be mass-air-flow based or speed-density based, and they can use all the existing MAF or SD implementations.

I don't see how DOHC valve trains increase maintenance at all. Generally speaking there is very little maintenance. A modern DOHC engine needs no more than once every 15,000~20,000 mile oil changes and basically no additional maintenance from 0 to 200,000 miles other than keeping an eye on fluid levels. It is in fact not uncommon for the accessory belt(s) to last that long and usually those are the first things to go. In fact, in terms of valvetrain longevity pushrods tend to be a somewhat worse. The reason being that in a OHV engine the spring has to be strong enough to prevent valve float against the heavy mass of the valve, rocker, rod and lifter. In a DOHC engine the each spring support a smaller valve, smaller rocker, no rod and (if a lash adjuster is used) no lifter at all. That means that for the same redline capability you can apply a lighter valve spring tension and this causes less wear. The pushrod OHV design has certain advantages. The most significant of which is cost. In the case of a V8 a 6 liter OHV aluminum engine will make 400hp with less weight and take up less space than a 4.0 liter 400hp V8. It also has tend to have a less linear torque curve, but in big HP engines where traction is a challenge being a little "soft" on the low end is sometimes not a bad thing. However, an OHV engine is incompatible with the refinement expectations on today's luxury car buyers and even that of some performance enthusiasts.

What do you mean it doesn't have a drive shaft? I am pretty sure that it has shafts in there to locate the gears. In a transverse automatic it is common to arrange sun-ring-planetary sets in parallel rather series. This is similar to 3-shaft manuals which has one input but two output shafts in parallel. The objective is naturally to shorten the width of the transverse mounted gearbox so it can be mounted beside the engine rather than having to sling it in a "L" arrangement to put it behind the transverse engine. Unlike longitudinal RWD trannys, the transverse transmission for FWD applications typically has the differential housing integrated into it and driven directly with a gear coupling. In AWD adaptations the transfer case is usually attached tangent to the differential housing and driven off the differential's ring gear. This is normally decoupled, but when fully coupled transfers 50% of the available torque to the rear wheels. The mechanism for coupling can be viscously controlled (typical viscous LSD type setup), electronically controlled via clutch packs (ala haldex) or by using a torque biasing type arrangement (either Torsen style worm gears or Quaife style helical pinion gears). Transverse FWD setups are lighter, more compact and more efficient than longitudinal drive trains. They also tend to have less "slop" and less vibration issues related to the shaft connecting the transmission and the rear differential. A transverse FF tranny tend to have around 10% drive train loss vs about 15% for FR setup with separate transmission and differential axle. This is one of the original motivations for going FF. Manufacturing costs and weight reductions being the other major factors.

Let's put it this way... The LZ family of 3.5 and 3.9 V6s is VERY GOOD as far as pushrod sixes go -- especially the 224hp 3.5 with CVVT for its single in-block cam. Defnitely an entirely league above the 3.8 clunkers. But there is really no good reason for them to exist anymore. Buyers who care about the engine will get the 3.6 DOHC even if a car equipped with it is $1500 more. Buyers who don't care are better served with the 2.4 Ecotec. Having driven both the 3.5 LZ4 and the 2.4 4-potter, I can honestly say that both are just as smooth in normal driving. And both make an unpleasant clatter when revved hard -- albiet in a different way. The 3.5 makes crude and uninspiring groaning noises, the 2.4 simply vibrates more than a balance shafted four should and you feel it more than you hear it. For cars like the G6 or Malibu or whatever, it doesn't make sense to have both the 2.4 and the 3.5 in the lineup along with the 3.6 DOHC. And if you have to eliminate one, the 3.5 is the natural one to go... at least the 2.4 is economical to run!

Interference is not an issue. In fact it is often necessary given today's compression ratios of ~10.3:1 for regular gas engines and ~10.8:1 for premium gas ones. And this is going to get higher with the popularization of direct injection. It'll get to ~11:1 with Regular, 12.5~13:1 with Premium, even turbos will run about 10.5:1 (eg, VW's 2.0 FSI Turbo in the Rabbit, Jetta and Passat -- 10.5:1 compression, ~14.5 psi boost). If you use a timing chain, the chain is not going to ever break thus there is never an issue with bent valves. Chains are become more popular because manufacturers want to get rid of the 60~90,000 mile timing belt replacement intervals -- a significant number of customers are not going to replace it and when it breaks they are going to say the manufacturer's engine is unreliable. The problem with timing chains is that they are noisier than belts. The new slim roller "silent" chains are quieter, but still noisier than belt drives. If not for the noise issue all the accessories would have been chain driven too.

Yes, pretty much. Like the Integrated Power System on the DDG-1000. And, if a gas turbine as well as a secondary closed cycle steam turbine is used in a COGAS-E arrangement, like the the arrangements used in some of the latest cruise ships like Celebrity's Millenium class and a few others.The system has all of the advantages of a gas turbine with none of its disadvantages. Simple powerplant with minimum moving parts, no reciprocating assembly and no coolant requirements. Ultra compact powerplant with power densities several times higher than a piston engine. Basically no vibrations. No turbine lag and intertial overdrive because the turbine is not directly coupled to the drive train. No inefficiencies at part load and non-optimum turbine speeds because the turbine ALWAYS operate at ideal speed. With a steam recuperative auxiliary turbine, thermal efficiency can equal or beat the finest diesel piston engines. The engine can run on multiple fuels or even a combination of different kinds of fuels without physical modifications -- although emissions may prove a problem because catalysts usually are not that adaptive. Energy conversion is also very efficient -- a good generator is over 95% efficient and good Permanent Magnet motor is also over 95% efficient. The presence of a battery -- even a modest one good for 10~20 miles of driving is makes it at least partly a plug in chargeable car for short hops and allows for energy recovery through regenerative braking. Most importantly, unlike traditional hybrids the small size and miniscue weight of the turbine power unit offsets the added mass and space requirements of the electric drive drive components and the battery. No matter how you look at it, the ability to throw the radiator out and make the engine 1/4~1/6th the size is very significant. In fact, it changes the design paradigm of a car significantly because the engine is small enough that it no long has to occupy a big compartment in the front of the car! This may mean the end to the tradtional 2-box/3-box design paradigms. Imagine a 100hp engine which fits in the glove box and you get the idea. I am not saying you'll put it there, but you can tuck it in a whole host of places.

When the G6 came out I thought... wow, Pontiac can make pretty cars once again. The G6 was clean, sleek and handsome looking. Interior quality was still lacking as was the 3.5 and 3.9 L pushrod clunkers. But, GM seems to be getting on the ball with interior quality and styling -- the GMT900s were good, the Malibu was better and I think the new Caddys and Buicks may have a chance at matching Toyota and Honda grades. And, the 3.6 is now available. When the orange G6 GXP concept came out, I thought thats neat -- slightly beefier front fascia, clean muscular looks. If they would put in the 3.6 DOHC or better yet a 300hp rendition of the 2.0 LNF it will be a genuinely nice car. Then they came up with this black, horrendously ugly thing with a Darth Vader grille and Hippopotamus Nostrils. The Firebird was a puking ugly car, flippingly tacking and extremely low quality car don't remind us of it PLEASE! Please, Pontiac you are just starting to remake yourself into a respectable marque. Don't trash it by putting out this GORGON!

Personally, I believe that the ideal future vehicle configuration is one built around a gas-turbine generator and electric drive. I say this for the following reasons:- (1) A 100 kW gas turbine (~134hp) is roughly the size of a 100 disc stack of CDs. Even with the generator attached it is no larger than a waste paper basket. You cannot match the space and mass efficiency of a turbine with ANY kind of piston engine. (2) An advanced centrifugal gas turbine is about 30% thermally efficient at its optimum speed. This is better than gasoline piston engines in general. If higher efficiency is desired, a combined cycle arrangement where the gas turbine exhaust is used to create steam to drive an auxiliary steam turbine will boost efficiency past 40% (better than direction injection turbodiesels). The entire setup is still smaller and lighter than a 1.6 liter piston engine. (3) A gas turbine requires no coolant, no radiator, no coolant pumps, etc. A simple cycle turbine itself has only ONE moving part and zero inherent vibrations. This again reduces complexity, space requirements and maintenance hassles. (4) The main disadvantages of a turbine -- horrible throttle lag, inertial overruns on throttle release, poor efficiency at all but ideal speed range, etc are ALL irrelevant when the turbine is completely decoupled from the drive train and use only at optimum speed and only to generate electricity for the battery bank. (5) A gas turbine is inherently multi-fuel. You can feed it Diesel, Gasoline, Kerosene, Ethanol, natural gas or even hydrogen without making any physical modification to the turbine itself. A gas-turbine electric vehicle with a 20 mile electric reserve can be used as an electric car for short commutes and will be able to generate its own power with greater efficiency than a piston engine based hybrid for longer trips. The basic architecture is extensible to an Ethanol, Gasoline, NG, Hydrogen or electric future. The vehicle will also be extremely refined in terms of NVH as the engine as effectively no vibrations and no exhaust pulses. I also believe that -- like computer components such as memory and harddrives which have become "non-serviceable" items -- automobiles will go down this path very soon. Instead of having a mechanic diagnose and fix increasingly advanced systems, I believe that at some point it'll make sense to simply move on to an automobile with no serviceable parts. Instead, the drive train will be broken into half a dozen "modules" such as the powerplant, the electric motor, the battery, the inverter, etc. Each is not serviceable and completely sealed from the factory. If there is a failure or an impending one, the "modules" can be removed and swapped with a functional one in 10 minutes. All servicing and refurbishment will be done at the factory in an automated, large scale process for greater efficiency and quality consistency. Labor is reduced to the minimum and one will sign maintenance contract for a particular period which covers all component swaps needed instead of paying for repairs as needed.

Well, CIB or IBC, is more accurate. But the acronym OHV has stuck and is more commonly understood. In anycase, it is not incorrect. Pushrodders are OHV nothing more. SOHC and DOHC add single or dual overhead camshafts. In anycase, if the LZ4 is dying... good riddance! Nobody wants a pushrod engine. It is perceived as unrefined (true), inefficient (true), low tech (not always but usually also true), heavy (not true but people think so anyway) and unreliable (true for domestic stuff of the 80s and 90s). In fact, I think GM should drastically cut their engine lineup and do what Nissan does. Build ONE great engine and use it everywhere. There is just way too many engine models in GM's lineup. about 1/5th or 1/6th of the current numbers should be ample. As far as NA goes, I suggest the following six engines. Everything else should go. (1) 2.0 DOHC Dual-VVT DI (base engine for compacts and midsize) (2) 2.0 DOHC Dual-VVT DI Turbo (High performance compacts, small sports cars) (3) 3.6 DOHC Dual-VVT DI (premium engine for midsize, base for luxury) (4) 6.2 OHV (SS class engine for midsize and standard for large sports cars) (5) 5.0 DOHC Dual-VVT DI (Premium engine for luxury) (6) 7.0 OHV (Z06, premium engine for large sports cars) For the global scape, add a 1.6, a 2.0 turbo diesel, a 2.8 DOHC DI VVT, a 2.8 turbo diesel. Thats all, 10 engines for the whole world. My favourite engine in GM's lineup is the LL8 4.2 Inline-6, but unfortunately it won't and shouldn't make the cut. I also think that GM needs to set a high bar in terms of reliability. Do it because it'll pay off in the decades to come. If you think that there is only a small difference between domestic reliability and Toyota/Honda reliability in the 80s and 90s, you are kidding yourself. A Toyota is basically a chnage the oil and fix nothing for 200,000 miles car in general. I cannot say the same for GMs, Chryslers or Fords. Sure, GM has done A LOT to make up on lost grounds. But when you are fighting a rotten reputation, good enough simply isn't good enough. The bar must be set higher. I think that a car TODAY needs to go at least 200,000 miles with ZERO maintenance other than once every 15,000 mile oil changes. If more than 1% of the cars need a starter, alternator, gasket, waterpump, oil pump, or anything but expendables like batteries and bulbs fixed over 10 years or 100,000 miles then the engineering simply isn't good enough.

The difference is that the 3.5 RL has just another V6 in a market crowed full of V6es. So you can it doesn't have the product differentiaton part of the equation. And, it was neither particularly big (3.5L) nor particularly powerful (225hp initially) nor can it claim to be smoother than a V8. In addition, like the previous caddies, the RL was a nose heavy, understeering FWD car that was not particularly inspiring to drive and not exactly up to Lexus standards in silent plushness. A 4.2 liter Straight Six oozing all the latest tevchnology, pumping out ~350hp, pushing ~300 lb-ft and turning the rear wheels is a whole different animal -- especially when it is probably smoother and more turbine like than ANY V8 can hope to be. If anyone ever needs a reminder as to the creamy smoothness possible only with an Inline-Sixunless you move up to a V12 all they have to do is drive a BMW 6-potter then drive one their V8s... the BMW straight sixes beat their V8s in smoothness.

I think that GM should consider building at least one line of premium cars around the LL8 Inline-6 (aka Vortec 4200) instead of either the Northstar or LSx V8s or the 3.6 VVT. The reason is simple -- it is smoother than any of these 8-potters and it's different from whats being offered by the rest of the pack. More cylinders doesn't always produce a smoother engine. Sure you have more power pulses in closer proximity, but that isn't the biggest contributing factor to a refined and smooth engine -- vibrations is. Think about it for a second. Is a V8 at 3000 rpm less smooth than the same V8 at 4000 rpm? How about an I4? Is it less smooth at 2400 rpm vs 3200 rpm? The answer is no. The Inline-6 is one of the few engine configurations that's completely balanced in terms of both 1st and 2nd order forces -- only horizontally opposed engines and V12s can claim the same. Neither the I4 (2nd order vibrations on the vertical plane at twice the rotational frequency), any degree V6es (end to end rocking moments at the rotational frequency) nor V8s (smaller than I4 but nonetheless present 2nd order vibrations on the vertical plane at twice the rotational frequency), can claim the same inherent perfect balance as an Inline-6. This is why the straight six is legendary for its creamy smoothness in the BMWs and is also the configuration of choice for very large displacement diesels in big rig trucks. The LL8 is already a modern all aluminum engine. It makes a decent 290-ish hp as is. It is smooth as silk as is. For the next generation engine where DI and dual VVT are expected, it is inherently less complicated to implement these features on an I6 where you have just one cylinder head, one fuel rail and two camshafts, instead of a V8 with twice as many of these. The 4.2 liter displacement is also in the sweet spot of its own. Big enough to produce 300~340 hp and 290~320 lb-ft with the aforementioned technology, but not so big that it becomes too big an engine. This torque bracket can also be handled by the smaller, lighter and more efficient 6L50 6-speed auto instead of the heavier and less efficient 6L80 6-speed auto. If more power is needed, a pair of KKK K04s, Mitsubishi TD04-15TK or Garrett GT20 turbos will create a motor that will blow the BMW N52 turbo in the 335i out of the water. A 4.2 Dual-VVT DI Inline-6 with a pair of any of the above turbos will be able to put out about 500 hp @ 5250~6200 rpm with 500 lb-ft available from 2000~5250 rpm. Thats good enough to build a super car or super sedan out of. The big straight six has a lot to offer -- sweet spot performance bracket, ease of advance technology integration, unparalleled natural smoothness and unique market positioning. I think GM should really give it a good look.