dwightlooi

Developed on their own, no. They are not worth the effort. But as derivatives of a V8 they are a relatively low cost means of getting a big displacement six or a big displacement four. The intent is that a 3.1 liter pushrod four may be a better engine than the current 2.4 liter DOHC four, 2.9 liter DOHC four or 3.0 DOHC V6 when used in light trucks. The 3.1 liter four promises over 210 lb-ft of torque and should have better economy numbers than a 3.0 liter V6. Similarly, a 4.7 liter V6 offers the same basic performance and towing capabilties as today's 5.3 V8 while possibly offering fuel economy number close to that of a 3.6 liter DOHC V6.

Generation V - Pushrods for the Future The pushrod layout is chosen for the following reasons:- o In the interest of fuel economy, engines should have minimum internal friction. o In the interest of fuel economy, it is better to decrease cylinder count than to decrease displacement. o In the interest of performance, engines should have best in class power-to-weight ratios. o In the interest of packaging, engines should have best in class power-to-size (external dimension) ratios. o Advanced Technology like Direct Injection, Independent VVT and roller followers can be applied to pushrod engines Gen V 6.2 V8s have the highest power-to-weight and power-to-size (external dimensions) of any mass production V8 in their power class. They also have the lowest fuel consumption in their power class. Gen V 4.7 liter V6es replaces the 4.2 liter I6, 4.8 liter V8 & 5.3 liter V8 with a physically more compact engine that boasts similar power and torque output while reducing fuel consumption. The Gen V pushrod four cylinder is essentially a V8 with one bank of cylinders. It replaces the DOHC 2.9L Inline four with an engine with both improved performance and enhanced fuel economy. All Gen V engines can be manufactured on the same production line using shared tooling and assembly procedures.

It's relatively easy for that crowd to understand "Horsepower" & "MPG". Even without advertising to this specific regard, when "470hp" & "17 (city) / 26 (hwy) MPG" appears on the same sticker or the same ad, they ought to say "Wow! Really?" You don't really have to talk about camshafts and pushrods until after the fact.

Actually, that may not be the case. Let's put it this way... There are in general two types of car buyers -- the tech savvy ones and the those that are not. It is easy to sell technical merit to the tech savvy buyers. Just tell them how your solution is better -- better power to weight, better power to size, better economy, whatever. Most of the time you don't even have to tell them. Bury that marketing in a brochure and they will find it even before your sales guy does. And then, there are the typical buyer who doesn't even know what DOHC stands for and thinks push rods is something that's part of the door. These types will probably look at the MPG numbers on the stickers and some may go as far as to ask you if it is a "Vee 6". If you tell them it's an I4, they may tell you "Oh, that's cool, just like an iPhone!" But that's about it. They'll go for a test drive, listen for road noise, feel the ride a little and they'll check out the amenitities in the car. How valves are operated in the engine won't come up in the conversation. For the former, as long as the engine has merit it'll do fine. For the latter, whether an engine has merit or not probably doesn't matter as much as the seat cushions.

Just doesn't sound very good. Definitely in a different class than the Passat's. But also worse than the Premium Stereo in the Accord or Camry. Not very full, lacks punch, a little muddied, vocals that do not stand out.

Well, a few things of note here... The first being that you can skew things significantly wit the choice of gearing. The 6.2 Small Block turns in 16/25 on an Automatic Camaro SS for instance. The second being that you are looking at about 60 more horses and two more cylinders on the small block so it is not exactly an apples to apples engine comparison. Overall, there seems to be a difference in fuel economy between DOHC and Pushrod engines of similar output, cylinder count and/or displacement. And, it seems to favor the Pushrod engines. For instance... the 6.2 liter Gen IV Pushrod turns in significantly better numbers than the Mercedes 6.3 liter DOHC V8 (AMG) or the BMW 4.8 liter (N54) NA engines. Better by about 2~3 mpg in city cycle and 3~5 on the highway. Despite perceptions to the contrary, there is a very good reasoning behind this. The Pushrod layout has less valves, less cam lobes, less cams, less bearing surfaces in the valve train. This in general translate to lower frictional losses. They do not have as much valve area and do not breathe as well at higher RPMs. But, engine breathing has practically nothing to do with fuel economy -- at part throttle and at cruise, the engine is making partial power based on an intentionally reduced amount of air actually being aspirated. Any amount of restriction not presented by the intake and valves, is intentionally created by the throttle plate! Similar pumping losses + higher frictional losses means higher consumption, all else being equal. Reducing displacement in and of itself also sounds better than it actually helps. A 3.0 V6 in the CTS is no more economical than a 3.6 V6. A 1.4 turbo is only 2MPG better in a 38 MPG car than a 1.8 NA while making the same amount of power (albiet a bit more torque), and only with the help of lower rolling resistance tires. This shouldn't be that surprising either. Think about it, same cylinder count, same # of valves and cams means nearly the same frictional loss save of that associated with the very slightly smaller bore. Hence, the gains in frictional reduction is small to begin with. While the turbo brings additional power to make up for the power loss due to displacement reduction, it also brings with it a reduction in compression ratio which hurts cruise economy. All in all, if you want to build the most economical engine, you'll want the minimum cylinder count, highest compression ratio, the least number of valves and the smallest number of camshafts that will still give you the required output. There are certain contradictions in this in that big bores and lower cylinder count tends to also hurt the maximum compression ratio you can run with a given fuel octane number. For example, a 3.0 liter I-4 for instance with say 11:1 compression on 91 octane, a single overhead cam and 8 valves will be more economical than a 2.5 V6 with quad cams and 24 valves. Another example will be a 1.8 liter 3-cylinder 2-valve SOHC ought to be more economical than a 1.5 or 1.8 liter 4-cylinder. When the objective is all out economy, Honda went for a 1.0 liter three port with 1 cam and 2-valves per cylinder in the original Insight. This is from a company who championed DOHC and cam switching VTEC on their sport compacts at the same time. On the big end of things, we see that a 6.2 liter V8 with 16-valves and 1 cam can be more economical than a 4.8 liter quad cam 32-valve V8. The question is whether you are willing to live with the increased vibrations of having bigger cylinders and fewer of them.

In general:- Pluses Nice looking car -- especially from the front and sides. Impressively tight body panel gaps Very good handling and composure along with very good ride quality Impressively low road noise during cruise Smooth engines (both the 2.4 and 3.6) Much better interior than the lack luster previous generation Malibu. Minuses Head room is about an inch tighter than Camry or Accord. This is especially bad in the back seat. Seat height doesn't adjust to a low enough height to mitigate the headroom deficiency (and I am only 5' 10"). Leather is of so-so quality -- relatively hard and slippery with vinyl looking grains even though it's not vinyl. Steering wheel is butt ugly and low quality -- the car urgently needs a retrofit with the 4-spoke wheel from the Equinox or Cruze. Interior still half a step behind Toyota, Honda or... Jeez... Hyundai in terms of perceived quality or tactile feel. No GPS navigation option (On-star doesn't count) Comparatively inferior stereo compared to the competition. Verdict This car urgently needs a face lift to stay in the running until the next generation bows. For the interior, I'll revise the seats so they drop closer to the floor boards, improve the interior materials, replace the steering wheel. Outside, I'll re-touch the rear and leave the rest -- they are good enough. Under the hood, I think it is about time that GM switches both engines to the Direct Injection versions. Acoustically, I'll put the double pane windows on the back door windows as well, instead of just the front. Plus I think the 2.4 can use a Helm Holtz in the intake to damp out a low frequency moan in the 1200~1600 rpm band (the V6 is fine).

It really comes down to cost vs benefit. A high revving 3.6 can give GM a clearly class leading NA V6. In fact, even the "modest" version with nothing more than a compression bump, camshaft change and tuning for 91 octane will put the 3.6 in the #2 spot amongst "big" V6 class -- trumping the Ford, Hyundai, Toyota and Mitsubishi 3.5~3.7 liter mills, and fall in in just behind Nissan's 330hp CVVL 3.7 liter on power and beating it on torque. It'll do so without incurring the cost and complexity of a twin turbo setup. A twin turbo DOHC V6 offers good power, but I am not sure it is more economical than a small block pushrod V8 -- not in terms of fuel economy, not in terms of power-to-weight, not in terms of power-to-size and certain not in terms of simplicity. For instance, the SHO's Ecoboost 3.5 makes 350~355 horses and turns in 17/25 mpg with an automatic tranny. A 6.2 liter small block offers 400~426 hp and turns in 16/24 mpg with an automatic tranny in an SS. Granted the SHO is some 300 lbs heavier and AWD. But it also makes 50~76 less horsepower and is basically FWD until the tires slip.

Well, a turbocharger is not a simple add on either. You have about $500~600 for the turbo alone, the exhaust plumbing to feed it, then you need the IC, the pipings to and from it, etc. Also, turbocharging typically is not fuel economy neutral mainly because you have to drop the compression ratio and go to an intake plenum/runner that doesn't promote cruise efficiency. An alternative would be a "milder" makeover of the 3.6L DI V6 such as... Proposed changes:- Increased Compression Ratio (11.3:1 --> 12.3:1) Revised Camshaft Profile (Slight increase in intake duration) Revised exhaust system (metallic high flow catalysts, larger cross section pipes) Better Spark Plugs (Iridium Electrode Sparking plugs) Accompanying Transmission Modifications (6L50 --> 6L50E) Improved Power Rating (315 bhp --> 325 bhp) Reduced Input Torque Rating (332 lb-ft --> 312 lb-ft) Increased Maximum Shift Speed (7000 rpm --> 7200 rpm) Target Performance:- Output: 321 bhp @ 7000 rpm Specific Output: 90 bhp / liter Torque: 278 lb-ft @ 5700 rpm Specific Torque: 79 lb-ft / liter Rev Limiter: 7200 rpm Fuel Requirement: 91 Octane Unleaded Gasoline Oil Requirement: 5W-30 Synthetic Oil (Factory Fill --> 5W30 Mobil 1 Extended Performance

The 3.6L Direct Injected V6 is a fine engine, making between 288 and 304hp is a wide variety of applications while ingesting an unfussy diet of 87 Octane. However, given that Ford and others have upped the ante on V6 performance, there may be a place for a high output 3.6 to compliment the "Regular" 3.6. This engine shall be targeted at sporty car applications. It is modified for an 18% increase in specific output at the expense of slightly higher costs, a little low end grunt and expects a diet of 91 octane. Proposed changes:- Increased Compression Ratio (11.3:1 --> 12.3:1) More aggressive cam profiles (increased lift, duration and overlap) Revised Intake (Larger Throttle Body, Increased air box volume, trumpeted velocity stacks, larger filter area) Improved Bottom End (Lightened H-section Connecting Rods, Forged Crank, lighter pistons, ladder style main bearing griddles, Piston oil jets) LF1 (3.0L) style exhaust port (3:1 collector integrated into aluminum cylinder head) Revised exhaust system (metallic high flow catalysts, larger cross section pipes) Better Spark Plugs (Iridium Electrode Sparking plugs) Accompanying Transmission Improvements (6L50 --> 6L55) Improved Power Rating (315 bhp --> 369 bhp) Improved Torque Rating (332 --> 345 lb-ft) Improved Max Gearbox Torque (480 lb-ft --> 521 lb-ft) Increased Maximum Shift Speed (7000 rpm --> 7200 rpm) Marginal reduction in Ratio Spread (6.05 --> 5.94) Target Performance:- Output: 360 bhp @ 7000 rpm Specific Output: 101 bhp / liter Torque: 283 lb-ft @ 5800 rpm Specific Torque: 79 lb-ft / liter Rev Limiter: 7200 rpm Fuel Requirement: 91 Octane Unleaded Gasoline Oil Requirement: 0W-40 Synthetic Oil (Factory Fill --> 0W-40 Mobil 1)

I wasn't advocating building the ATS in as a 1-series or A3 sized vehicle. What I was trying to say is that bigger is not always better, and there is an optimal size with "Compacts". Personally, I feel that this optimal size is around where the previous 3-series and C-classes were at. Based on that opinion, I do not believe that caddy should play one-up-manship on size and try to make the ATS a bigger vehicle than the current 3-series and C-class. In fact, I think they can make a slightly smaller car and focus on getting weight out of the platform. If size is the leading concern for a buyer, that buyer can be directed to a CTS.

Based on that reasoning, there is no reason to do a compact! Just do a ATS at the CTS's size and a full size to go up against the 5-series! Bigger is not always better. There is an optimal size which as small as it can be while being comfortable to the average person under 6 ft. That is where the E36 was, that is where W203 C-class was and that was where the B5 A4s were. Overtime, in an effort to be slightly bigger than the competition and their own previous generation offering, sizes have crept up. This created extra space that isn't needed by the purality of buyers and extra weight which hampers performance, handling and fuel economy. If bigger is better, there won't have been initiatives to introduce a new model slotted below those models that have grown pretty big over time... BMW won't have tried with the 1-series to complement the 3-series. Audi won't need the A3 to complement the A4. Honda won't need the Fit to complement the Civic. Nissan won't need the Versa to complement the Sentra. Toyota won't need the Yaris to complement the Corolla. Granted, not all of these efforts were sales successes. But an argument can be made that the "optimum" size for a compact would be between the two offerings these companies ended up with. This is especially true when you have to do one car and not two. Personally, I don't see a problem with a 1995 325 or a 2002 C230. It's a comfortable size without excesses and I think that's about wear the the optimum size is.

(1) I didn't say that a GM turbocharged engine will be objectionable in reliability. However, all else being equal, it'll have more common points of failure that an NA powerplant. Pressurized Intercooler plumbing, a bunch of hose clamps, bypass or blow-off valves and the turbocharger itself (thrust bearings, journal or ball bearings, oil seals, wastegate control pneumatics, etc ) are articles that do not exist on an NA engine, and things that don't exist cannot fail. Most engines degrade over time. Valve cover gaskets seep a little oil, piston rings wear out a bit, rubber hoses harden, oil pans leak a little, etc. Most 5~6 year old engines exhibit a bit of these and most owners ignore them. They seldom cause a catastrophic failure or notable decrease in drivability. However, similar degradation on a turbocharged system can cause a show stopping, repair warranting issue. (2) I didn't say 300hp from 3.0 Normally aspirated liters is impossible. I said that 300 lb-ft is impossible. This means that a 100hp/liter engine will necessarily be rather peaky and soft on the low end. The 3.0 at 90hp/liter is already making its peak torque at 5700 rpm and its peak power at 7000rpm. Any higher and becomes really objectionable, plus you'll need a new transmission since the 6L45 and 6L50 has a maximum input shaft speed of 7000rpm. (3) I don't think the ATS has to be bigger, more powerful and all that compared to the 3-series. In fact, slotting below the 3-series and above the 1-series in sizes is not a bad way to go since it is fills a niche that the progressively oversized "compacts" from BMW and M-B has grown themselves out of. That everyone is ding one thing is sometimes a good reason for you not to -- defacto differentiation. 270hp (between a 328 and 335 in power), slightly smaller, 150~200 lbs lighter than the 3-series or C-class at ~$33K is not a bad place to be. It's where the 3-series/c-class (E46/W203) was at the turn of the millenium. Not everyone wants a bigger car and those who do can always get a 5-series, CTS or E-class.

The Lacrosse is a large mid-size FWD vehicle in the same segment as the ES350 and TL. It could have made do with just one engine -- the 3.6. In fact, starting august next year that is exactly what it'll do. You know that 100hp/liter and more incredibly 93.5 lb-ft per liter is not going to happen on the 3.0. No NA V6 can make those numbers, not GM's not, BMW's not anyone's. The 3.0 with it's 270hp is OK for a 3300 lb car, it differentiates the ATS from the CTS, is more inline with the 3.0~3.2 liter class displacement of the other compacts in the segment and is marginally smoother than the 3.6 mainly because of it's shorter stroke* The ATS, no matter how good, is not going to generate 3-series volume from day one. That's 80,000 cars -- more than the VW Jetta and Passat combined. If GM can get to 30,000 a year by 2015 -- roughly comparable to a TL or IS -- the program will be a resounding success. Going with fewer engine choices and configuration options, you cut down on logistical costs and make available a few hundred dollars per car to throw into the interior. That's the difference between a leather wrapped dash and a plastic one. The M3 or C63 is not and "up level" car but a niche vehicle mainly because of their price. $60K is simply too much to ask of most 3-series buyers who bought 335s. Given the choice -- at the same price -- I am sure most 335 buyers will pick the M3. As for those who don't care about performance much they'll buy the 328 and sink the extra money into a navigation system or something if they want to splurge. If you have a $30~35K ATS and a $45K ATS-V the ATS-V then becomes the defacto up level car for enthusiasts -- the V the salary man can afford if you will. Back in the mid-90s the M3 was almost that and accounted for a good 1/5~1/4 of the 3-series US sales. Then it got more and more expensive, and further and further away from the young working enthusiast. The question then becomes, if you need to limit yourself to one engine will it be an I4 turbo or a V6? That's a tough one even that the I4 will make the same amount of power, more torque with slightly better economy. The V6 has better main stream acceptance and is possibly a little less problematic 12 years out. One thing I'll like to see GM do is update the 2.0T. It is a world class engine as is. But it can be the best there is and it is relatively simple to get there. The first thing they can do is go to a slightly more efficient turbo -- like the Honeywell-Garrett small frame, ball bearing, twin scroll units like the GT25RS and GT28RS. More importantly perhaps, they can ditch the air-to-air intercooler for an air-to-water one which they have a good deal of experience with in the ZR1 and CTS-V. An air-to-water intercooler can be kept small and close to the engine, eliminating big intercoolers up front and fat hoses going to and from them. This drops pressurized volume dramatically and pressurized volume is just as important if not more so than the turbocharger itself in causing lag. * The 60 degree V6 exhibits an end-to-end rock in terms of operating vibrations due the shifting center of gravity as the pistons move up and down. This is most affected by the stroke length because kinetic energy needs to be reversed twice with each full stroke and kinetic energy is 1/2 x mass x velocity^2.

There are three arguments against that. (1) The first being that variations are logistically expensive. And the ATS in the first year of its first model cycle may not have the volume to justify having three or four engine choices. The money saved -- probably a few hundred dollars is better employed in spiffing up the interior or making an LSD standard. Acura has pretty decent success with a 2 engine strategy on the TSX, Lexus has a decent one on the IS (before the advent of the IS-F) and Infiniti makes very good inroads with just one when it introduced the G35. (2) The second being that between a 2.0T making 260~290 hp and either a 270hp 3.0 or 304hp 3.6 V6 there isn't a tangible power gap unless you artificially create one by limiting the output on the 2.0T. Hence, from a plain performance stand point it may be better to simply choose between the 2.0T and the V6 but not offer both. (3) The third being that in offering 3 engines you are also necessarily creating stratification in price within the lineup since a 2.0T and 3.6 priced within $1000 of each other doesn't make a lot of sense. Creating a $20K gap between the base car and the top of the line car either makes the top of the line car hard to sell due to its price or makes the base car too cheap to be profitable.

What's more interesting is that the combination of a V6 for the regular car and the V8 for the ATS-V got ZERO votes. This, is in fact a VERY likely choice by GM! Perhaps the most likely.

Yes, and the initial assumption is that GM may be moving to a 5.5 liter displacement. But this is not to be. It appears that the Gen V (production) engines will retain the 6.2 liter and 5.3 liter displacements. If you distill it down to the basics -- assuming the bottom end holds together and the engine doesn't pile on additional parasitic drag -- power "potential" of a motor is a function of airflow. The amount of air ingested per unit time governs the amount of fuel you can burn, and this by and large determine your gross output. Hence, if you keep the bore constant and destroke the engine you can end up with the same output, albeit higher in the rev range. This is because a 10% shorter stroke and a 10% INCREASE in rpm results in nearly identical airflows given the same bore, valve, lift and runner geometries. That said, fuel economy from the destroked engine will not be tangibly (if at all) better because the amount of friction and aspiration losses are relatively equal save for a small amount of bore drag from the shorter travel of the pistons, and this is offset by a reduction in the stroke length reduces the engine's ability to capture the energy from expanding combustion products. This is why most engines targeting maximum economy are long stroke designs. Whereas engines with very short strokes (eg. the Ferrari 4.3 V8s; 94 x 77.4 mm) also have pretty sub-par fuel economy ratings to match their exceptional specific output. But a "held back" (aka less peaky) 6.2 compared to a loftier 5.5 has its advantages too. Weight is about the same and the torque curve can be flattened out and dialed in lower such the maximum torque arrives 500~600 rpm sooner. This is significant because it allows the engine to go from a 2000 rpm cruise rpm (@ 70 mpg ) to the vicinity of it's torque peak of 4200 rpm in two gear jumps instead of three. Important because regardless of the transmission's snappiness, the engine takes time to make up the rev difference during downshifts.

Actually, that is more of a transmission issue... I pegged the 6.2 DI at 450hp / 438 lb-ft is mainly because the torque limit of the 6L80 transmission is 439 lb-ft. This presents a unique problem because while you can go to the 6L90 to get past 439 lb-ft, the 6L90 also has a maximum shift speed of 6000 rpm (vs 6500 on the 6L80) which makes it impossible to exploit a peakier torque curve anyway! For example, a tune making 480hp @ 6600 rpm and 455 lb-ft at 4800 rpm won't work because it'll need to use a 6L90 transmission and that transmission will have to shift at 6000 rpm.

Personally, I don't see a lot of "middle ground" in the car buying public. Buyers either don't really care for horsepower -- as long as they have enough to get on the freeway smartly. Or, they are people seeking a high performance vehicle for whatever reason -- ego, enthusiasm, or whatever. The only reason 335 buyers didn't buy an M3 is because they don't want to or can't afford to pay that much for a car. And, most 328 buyer don't care for the 300hp engine and much less want to pay for it. With the 3-series you have a 60K base price on the M3, a 45K 335 in the middle and 35K for the 328. For the ATS, with trims on offer, GM can start with a 32K ATS 2.0T or 3.0 V6, and simply round it off with a $45K ATS-V. Basically, you satisfy the 335 buyers with an ATS-V, everyone else you vector to the regular ATS. The former offering more power and performance than the M3 for the price of a 335. The striking a comfortable performance balance between a 328 and 335 while offering an entry price about 2~3K under the Bavarians'.

You are right. 220/258 is for the "non-GS" Regal. The GS is 255hp 290 lb-ft from its uprated 2.0T.

The C-class (W204) and the E90 3-series have grown to be solid mid size cars rather than the compact or large-compact they used to be. The weight estimates assumes that with the CTS offering people who want a larger car what they want, the ATS can be sized like the previous C-class (W203) or the 1990s 3-series (E36) in terms of size. A bit larger than the 1-series, but smaller than a Honda Civic, on the inside.

There is no efficiency difference between the 220hp / 258 lb-ft (Regal GS) tune and a 270 / 275 lb-ft tune. The reason being that the compression ratio will be similar as the torque isn't that far apart (~9.2:1). The maximum torque attainable and hence boost level is a key factor in determining the compression ratio that can be used. To gain cruising efficiency (off boost thermal efficiency) you'll want to increase the static compression. A 270hp / 220-ish lb-ft tune will allow for the use of 10.2:1 compression (of thereabouts) and about 12~14 psi of boost (vs 18~20 psi). The engine can still deliver 270hp, but with the reduced torque limit it'll do so at ~6400 rpm. The torque curve can be very, very, flat (eg 222 lb-ft @ 2400~6400 rpm) but acceleration will suffer due to the notably diminished area under the torque curve. If we stick with the basic turbo sizing you'll probably end up clipping the wheels to gain flow rates at higher operating speeds at the expense of a bit of efficiency.

(1) The 3.0 (LF1) is not being phased out entirely. It is simply being omitted from the US lineup from 2012 model year onwards. It soldiers on overseas in markets where the 3.6 would out the car in a different tax class regardless of actual fuel economy ratings. (2) There is no significant weight difference between the 3.0 and the 3.6. The blocks are the same size as are the bore centers. It has just as many valve train parts. The only "tangible" savings in weight comes from the 3.0's 3:1 exhaust collector which is integrated into the aluminum head and hence not requiring an iron or steel header as part of the exhaust system. (3) The 3.0 is being phased out of the US because the anticipated efficiency gains of 1 mpg over the 3.6 was not realized -- in part due to the peakier nature of the short stroke engine forcing higher average revs -- and because it costs a similar amount to build as the 3.6. The decision was hence to simply standardize on the 3.6.

Assuming that you MUST choose from one of the following power train lineups for the Cadillac ATS, which do you most prefer? (The objective here is to limit the number of different power train configurations offered to no more than two)

The GTO and the Chrysler cars weren't home runs not because they are $35K or that they used a pushrod configuration. Their problem was that they were basically overweight cars outfitted with worse than KIA interiors which didn't handle all that well. It fact, the only reason they sold at all was their big displacement V8s. It is OK for the ATS to use a V6 instead of a Turbo Four -- either the 270hp 3.0 DI V6 or the 304hp 3.6 DI V6. If GM uses a V6, it can be a 3.0 270 hp that slots between the 328'2 230hp unit and the 335's 300hp turbo six. That's not a bad way to go. But ultimately, an turbo I4 is more flexible because it actually performs better, uses a bit less fuel, can be tuned to two different power states without hardware changes and the 2.0 displacement means lower taxes in many foreign markets. I just don't want to see GM proliferate the model with both. Remember, every dime wasted on the logistics of multiple configurations is a dime taken away from that posh interior or a feature struck from the amenities list. Finally, there is also a HUGE difference between no frills and low quality. An interior can be exceeding high quality but devoid of extraneous features. A car can do without active steering, suspension and differentials, as well as steering beam headlights or even HIDs and still be a great, direct, engaging drive.