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dwightlooi

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Everything posted by dwightlooi

  1. dwightlooi
    In light of the new information that is coming to light let's take a poll on the ATS-V power train configuration. In 1/2 year we may look back and see how close we got it. It is down to two realistic possibilities:-
  2. dwightlooi
    I hope they don't put this in the ATS-V. It's essentially inferior in every measure compared to the LT1. It costs more, weighs more, takes up more room, has more things to break, is more maintenance intensive, while making less power, less torque and is less desirable to a performance oriented driver (presence of turbo lag). The fuel economy advantage is either non-existent or minimal (0~1 mpg). For forced induction to be worthwhile you need to do way better than 116 bhp/L The engine will essentially appeal to those who blindly worship alphabet soup. But such individuals are likely to buy that Bi-turbo six BMW M3 anyway unless they perceive the Cadillac brand differently. And, the only way to change their minds is not to do what BMW does but do what BMW does not do and kick their butts for a couple of generations of models. Short of that matching alphabet soup won't do you any good because they'll believe that "BMW DOHC Bi-turbo" is naturally better than "GM DOHC Bi-turbo". BTW, I stand by my prediction from 1.5 years ago for the ATS-V -- Pushrod 6.2 V8 (LT1) 470 bhp / 450 lb-ft (SAE) 8-speed Automatic 17/25+ mpg
  3. dwightlooi

    Noisy GM 3.6?

    dwightlooi replied to tomg's topic in Powertrain

    12 of them. 6 Port and 6 Direct Injectors. One high pressure piston pump for the direct injectors and another for the port injectors. There is no clear cut over between the two. Basically, the port injectors remain in use even after the direct injectors are activated such that they are both in use at some points on the fuel map.
  4. dwightlooi
    What they can do -- without much cost -- is to use slightly higher compression pistons and a slightly different cam grind on the Caddy versions. Being a luxury marque you can get away with a disregard for 87 octane compatibility and make the engine Premium Fuel only Let's call it the LT2 for humor sake. With 12.5:1 compression vs 11.5:1 you get about 20 additional lb-ft across the board. This translates to about 23 hp @ 6000 rpm. Move the torque & power peaks slightly higher by 200~300 rpm with a cam grind with slightly more lift and overlap to (ala LS7) and you get about 30~40 extra hp. Nothing earth shattering but enough to make the engine somewhat more desirable. Total actual extra production cost to GM is ZERO.
  5. dwightlooi

    Noisy GM 3.6?

    dwightlooi replied to tomg's topic in Powertrain

    Actually, I find all the Direct Injected 3.6s to be noisy. It's noisy in the Camaro, it's noisy in the Buick Lacrosse, it's noisy in the CTS and, yes, it's noisy in the ATS 3.6. I have not driven that engine on the Impala (new or old). It seems that the DI engines are significantly noisier than the 3.6 DOHC w/ port injection (Saturn Aura). It is sort of a "gggrrrr" noisy in the low-mid frequency spectrum. The 2nd gen DI (LFX) version as opposed to be 1st generation (LLT), do not seem to be significantly better. They seem to have succeeded in moving the noise frequency to a slightly higher frequency but it's still noisy. Which was kinda disappointing because they took an active effort in dealing with DI noise during its development -- or so they claim. In this regard the non-DI 3.6 DOHC was a more refined engine. In fact, the 3.5 and 3.9 Pushrods were more refined engines. In the ATS, the engine is actually pleasant sounding when pushed because of the exhaust note and because induction noise drowns out the DI clatter at higher rpms. At 1500~2500 rpm under load though, the engine is annoying. This is particularly bad because that is your "cruising" RPM at legal freeway speeds. GM is not unique in this regard. Go drive a DI turbo 2.0 GTi or A4 and you have the same "ckckckck" sounds at idle and a "gggrrrrr" at lower mid rpm ranges. I used to not believe that this could be an issue but having driven all these cars over time, I now understand will Lexus uses both Port and Direct Injection in their engines. Port Injection for quiet idle and low-mid throttle, low-mid rpm acceleration. DI cuts in at higher revs and wide throttle positions for the additional performance.
  6. dwightlooi
    Well, I think most of you are missing the point... If the ATS-V gets the LT1, it is not an engine you find in a Malibu or Sierra. You ONLY find the LT1 in the C7 Corvette. And, that, even if the engine is adopted as is, is not a bad association. Yes, it's a Chevy engine. But it'll be like an Infiniti G-series performance model getting the VR38DETT GT-R engine.
  7. dwightlooi
    Cadillac had the Northstar... that didn't help either. Fact is that the valve train layout and alphabet soup is not important to the overwhelming majority of buyers. Performance, apparent refinement, etc. does. Advertising is simple when you have the facts on your side... "0-60 in 4.0 secs -- 27 mpg -- faster around Nurburgring than an M3" All you have to do is say it.
  8. dwightlooi
    Actually, it depends... Germans are not very good with some of their high performance models. For instance, nobody dares to own an E60 M5 without an extended warranty. The SMG replacement or failed V10 means a $20K repair bill. This severely affected the resale value of the E60 M5. The E63 AMG is another car whose resale value is in the dumps because of unreliable hardware. All E63s come with Airmatic shocks -- air springs basically which allow dynamic ride height adjustments. Every single owner of E500, E55s and E63s I know have had an Airmatic issue -- either the bags leaked, the fittings leaked or the pump goes kaput. For this reason the E63s sell for less than the C63s of the same vintage -- sometimes by as much as 5~8K less even though this was a $20K more expensive car when new. The Germans have a habit of putting stuff into production -- especially their high end models -- which hasn't been perfected. That hurts them really. GM has an ACE up their sleeve for the ATS-V. It's called the pushrod small block V8. More compact, lighter, cheaper and generally more reliable than DOHC V8s and Bi-turbo sixes of a similar output, it allows the ATS-V to be a lighter, faster, more balanced, better handling car, while at the same time permit a price tag advantage over the more expensive to build engines the competition relies on. That it is also probably have better fuel economy compared to Bi-turbo sixes and smaller displace DOHC V8s comes as a bonus. The question is... will they play the card or will they be dumb enough to try to simply do what BMW does and put a V6 with a pair of turbos in the car.
  9. dwightlooi
    To be honest, the ATS's interior beats the 3-series and/or the 5-series. The stitched dash and overall perceived material quality is superior. BMW is also notorious for being cheap on really basic stuff... the entry 3-series and 5-series don't even have leather -- they have vinyl leatherette. Seat heaters are optional. Even the arm rest is optional! BMWs are also notorious for electrics and switch gear failures. In fact, you'll be hard pressed to find a BMW owner who -- new or used -- have owned a BMW for a total period of 5~6 years without something electronic or electrical failure.
  10. dwightlooi
    I have never been a big fan of big wheels, just wide tires. 18, 19, 20" wheels really don't do much for handling or traction. In fact they can hurt these qualities by being excessively heavy. Some of my favorite tire sizes are the 255/40 R17 and the 275/35 R18. Generally, I prefer to go to the widest available width for a given wheel size before going to the next wheel size. And I prefer to go with the smallest wheel size that still has the width and rolling diameter I am looking for. For a rear drive car with over 400 hp, there is never enough tire width. If there is a tipping point beyond which no additional practical traction benefits exists, its beyond 400mm width and no such production tire exist. The problem is that you need to increase the front width as you make the rears wider to maintain proper balance in cornering traction. And you can only go so far... when you go from say 245 in the back and 225 in front to say 275 in the back, you need to also make the front 245 or 255. The problem is that if you go too wide in the back -- say 335, you cannot proportionately increase the front width because those wheels need to turn and pretty soon they start to rub unless you complete change the suspension geometry and widen the effective tracks.
  11. dwightlooi
    I'll take any bet that this will not happen. They'll go one way or the other, but not one then the other. If the ATS-V end up being a bi-turbo V6, it'll stay that way until the next model generation at least (5 years from now). There will not be a ATS-V+ or whatever with a different engine, even if the ATS-V ends up being an inferior car to its competition because of bi-turbo power. If they are smart, they play the ace up their sleeve which is the pushrod small block V8 and have a superior powerplant to anything BMW and Mercedes can or will field. If they are dumb trend followers chasing after non-existent presumptions a fuel economy from reduced displacement, alphabet soup or simply trying to make the same mistakes BMW makes, they'll pick the the heavier, more expensive and less powerful V6 with two turbos. But whatever it is that they do, that is the ATS-V and that will remain the ATS-V for this cycle.
  12. dwightlooi
    The ATS 2.0 and 3.6 does not suffer a handling deficit against the 3-series. In a way they are better -- more like the E46 than the E90 -- which means they are more connected to the road feel and more direct (before the active steering rubbish isolated the bimmers like they traditionally weren't). That is a good thing. The problem with the current ATS variants is that they are slower than BMWs of lesser engine power and weight. Not by a tad but about a full second. This suggest that the power train is not being employed efficiently. Either the gearing is sub-optimal, the transient response of the engines are lacking or (most probably) the trannies just suck compared to BMW's ZF supplied mill. The LT1 will go a long way towards addressing the performance deficit, but hopefully the 6L80 or TR6070 transmissions will keep up! One thing I didn't see on the test mull -- which disappoints me -- is significantly flared fenders and/or much wider tires (ala Audi RS4). RWD cars in this power and weigh class are typically very traction limited. The C55 was, th C63 is. The M3 not so much because of the low torque 4.0 V8. But they can all use the widest rear tires you can mount on the car. Judging from the photos the tires are between 245 and 265 in width. I would have very much preferred 275 or 285s in the back with 245 or 255 fronts.
  13. dwightlooi
    http://blogs.automotive.com/spied-2015-cadillac-ats-v-caught-testing-on-winter-roads-130545.html#axzz2N07Jrykt Four exhaust outlets distinguishes the test mule from a "run of the mill" ATS. V8 sounds reported from the vehicle.
  14. dwightlooi
    At least 200~300 lbs of extra weight for the motor, inverter and battery assemblies. That's a lot of weight for 160hp extra hp. Simply increasing displacement to 8.0 liters would have achieved the same power goals with less weight. It is remarkable that this thing weighs 2,767 lbs. But 2,500 lbs will be even better. Quite honestly, nobody in the market for a 950 hp, $1.7 million, Ferrari is going to care about fuel efficiency or environmental creds.
  15. dwightlooi
    If the whole point is to intentionally field an "inferior" engine so the LT1 can shine, the 5.3 is a horrible idea. The cheaper and better idea will be to simply de-content the LT1 and keep the engine's core components. It's cheaper that way and you'll still get the "inferior" engine you are looking for. Eliminate VVT Eliminate AFM Eliminate the variable muffler system Switch to a 15% "mild" Atkinson Grind on the camshaft for better fuel economy and lower output* DI is retained to keep the architecture, pistons, injection and fuel system common 385 bhp @ 6000 rpm 385 lb-ft @ 4200 rpm *A 15% Atkinson Grind closes the intake valves 15% into the compression stroke reducing the effective displacement by ~15% (to 5.2L). It also consequently made the power stroke virtually 15% longer than the compression stroke increasing energy recovery from fuel burned with each ignited mixture. Generally speaking such an engine will be more fuel efficient than a "true" 5.2L V8 and just about every single parallel hybrid uses an Atkinson cammed engine instead of a smaller displacement engine.
  16. dwightlooi
    How's that supposed to be cheaper? Displacement reductions save zero dollars in terms of production costs. If they really want to make a "cheaper" corvette, the simple thing to do will be to drop VVT, drop cylinder deactivation and drop Direct Injection. Displacement stays so tooling and reciprocating assemblies can be common for economies of scale. Going to a V6 makes even less sense. Any V6 powerful enough for a vette -- even an entry vette -- would have to have two turbos and an intercooler assembly (or two of them). Any bi-turbo V6 will cost more than the V8. But honestly, I don't think they will touch the engine. Simply eliminating the removable roof panel (which most drivers don't care for anyway) is a given. I'll actually pay extra for a fixed roof since I have zero desire for the sun and very much prefer additional stiffness and elimination of a source of leaks and noise. Switching from carbon fiber back to fiber glass for the hood, eliminating magnetorologic shocks, dumping the variable muffler system and going to smaller wheels w/ taller sidewall tires will save enough money to drop the price tag to "early" C6 levels. Want to save more money? The stitched leather dash can be replaced by Cruze style fabric coverings and the leather seats can be decent vinyl instead (contemporary vinyl can be pretty good actually and they use it on about 1/2 the BMW 3-series or C-class sold). Next comes the stuff that start to hurt desirability but are not particularly essential -- dropping power seat adjustments (which actually saves weight), dropping powered steering wheel adjustments, dropping seat heaters (the base BMW 528 doesn't have it either), dropping auto-dimming mirrors, dropping Navigation, going to halogen projectors instead of HID and, yes, eliminating non-regulatory airbags (you only need the two front ones to meet regulatory requirements). The point here is that all of the aforementioned save money to help make the car more affordable. Changing displacement does not. In fact, changing displacement actually adds to the overall cost of corvette production by adding a discrete engine model (which cannot be the Vortec version because the intake manifold would have been too tall).
  17. dwightlooi
    Thanks for this very cool insight. Question for you and everyone else. If the 6.8 can get you 550HP and about 525Lbs of torque, why not use it to supercharge rather than the 6.2? Seems you can get allot more out of this 6.8 than the 6.2 based on what I have been reading? Second question, what about reliability and long life using 6.8 versus the 6.2? Lengthening the stroke while shortening the rods increases the piston side loads. You can avoid that by raising the deck, but that'll be a new block architecture and basically uneconomical. You can also raise or lower the crank height which creates and offset at TDC and accomplishes the same goal, but again that's a new block design. The 101.6mm stroke is tolerable up to 7100 rpm as shown in the LS7 so I guess that have "proven" that they can get away with it. Traditionally, they used the 6.2 instead of the 7.0 because of the thicker cylinder walls which are more tolerant of forced induction's extra heat and pressures. With the 6.8 having exactly the same wall thickness (in fact it can be the same exact block) they can supercharge the 6.8 instead of the 6.2. The reason I don't think they will is because of the presumption of a 700 hp target -- there is no need to increase the displacement. Besides, with forced induction -- within reasonable limits -- increasing displacement and running lower boost has the same power result as not increasing displacement, running higher boost with lower compression. With turbocharged engine the latter produces more lag. With superchargers there is zero lag so it really doesn't matter except that higher displacement with higher static compression and lower supercharger pulley ratios is probably slightly more fuel efficient at cruise.
  18. dwightlooi
    The LT1 doesn't really have a lot of bells and whistles. They decided against cam-in-cam independent VVT. They decided against a variable valve lift system (which would have displaced AFM). So, yes, I expect any of the LT1's derivatives to have DI and synchronous VVT. AFM is a maybe. AFM limits revs because of the mass it adds to the actuated valve train. Eliminating AFM gets you the ability to go maybe 500~600 rpm higher on the redline. But, you don't need that to make 550 or 575 bhp out of 6.8 liters. In fact, if you look at the LS7 (which revs to 7100 rpm) most of the upper rev range doesn't contribute to a faster car -- power peaks at 6300 rpm and falls off quite rapidly after that. Short shifting that engine probably get to better acceleration.
  19. dwightlooi
    Right, but the Germans don't try to operate on a business model of trying to undercut the Japanese and match the Koreans on price like GM tried to do in the 90s and 2000s. Not even Volkswagen did that. The average Golf and Jettas were $2K more than the Civics & Sentras, while being about 4~5K more than the Hyundai's of the day. And those were Puebla, Mexico, made Golfs and Jettas. If they tried, they would have failed. I believe the ATS-V will get LT1 power; there is no reason to move to a less powerful, heavier, yet more expensive engine which is arguably less desirable to at least half the buyers of this type of vehicle. The ATS getting a 2.0T - 3.6 - 6.2 engine options spread allows the CTS to logically move to a 3.6 - 3.6TT - 6.2SC engine spread. Alternatively, the ATS can go to 2.0T - 3.6TT - 6.2, which allows the non-V cars to meet BMW head on, whereas the 6.2 out do the M3's I6T in every respect (weight, mass, power, cost and fuel economy)
  20. dwightlooi
    This is my prediction:- ZR-1 goes on a hiatus and will not return until 3~4 years into the C7's life cycle. When it does, it gets a supercharged version of the LT1 6.2 -- let's call it an LT9 -- making about 700 bhp. Z-06 goes on a hiatus until the 2nd model year, returning with a stroked version of the LT1 -- let's call it the LT5 -- displacing 6.8 liters and making about 550 hp naturally aspirated. The reason I believe that it'll be 6.8 liters in particular is because this is what you get from using the LT1 bore with the LS7 stroke. This allows them to not have to redesign the piston or remodel the combustion chamber; shorter rods will allow the chamber geometry to be identical to the LT1 at top-dead-center while increasing compression ratio to 12.7:1 (right about where it needs to be and where it can be tolerated with 91 octane). Getting to 550 hp isn't hard. The displacement increase alone gets you from 450 to about 493 lb-ft, a 1.2 point bump in compression alone is worth about 30~35 lb-ft for a total of about 525. If that torque peaks at about 4800 rpm and with the same fall off as a the LS7 you get about 550 bhp. Bump the torque peak slightly to ~5200 rpm and you actually get closer to 575 bhp. Not bad for an engine that's 485 lbs dressed and wet.
  21. dwightlooi
    I am sorry but that makes ZERO sense. Personally, I very much hope that they realize that the Pushrod V8 represents an ace up their sleeve, not a liability. That they'll go for the lighter, more compact, power powerful, cheaper to build and no less fuel economical V8. And, honestly, I believe they will and that Motortrend doesn't know what they are talking about. But whatever it is that they do, making a Bi-turbo V6 ATS-V then switching to a V8 late in the model cycle makes ZERO sense. The ATS will be a TT V6 or a Pushrod V8, and that will be that from beginning to end. There won't be both.
  22. dwightlooi
    One thing too many auto companies don't understand is that the USA is a high cost country. You cannot cost cut your way to begin a "value" leader doing your engineering and manufacturing in a high cost country -- not unless you can convince the UWA to accept $8.25 an hour. Maybe not even then. You can't match Hyundai's prices without building something significantly inferior to Hyundai's, so you shouldn't even try. Companies have to accept the fact that their products will cost more and sell for more than the competition from Korea, China and elsewhere. Accept that and try to figure out how to command a higher price and successfully operate without being the value leader.
  23. dwightlooi
    I was under the impression that most gasoline blends contain less than 10% ethanol and that 10% is the absolute limit permitted by the EPA without labeling it as an ethanol blend fuel. Typically, the actual blend is between 3% and 8% mostly as a convenient way to meet Octane ratings and oxygenated fuel requirements at the same time. In any case, I find a reduction in fuel economy by a whopping 2 mpg highly dubious. The reason being that Ethanol has roughly 67% (2/3rds) the energy content of typical gasoline class distillates. A blend of 90% gasoline with 10% ethanol will yield a fuel with 96.7% the calorific value. If you average 30 mpg, the maximum you are going to lose due to the fuel blending is 1 mpg (3.3%). In reality it is probably less because fuels have never been 100% gasoline since it existed. Anti-detonants, detergents, etc typically make up about 1/30th of the volume anyway and these stuff typically don't burn to produce energy even as well as ethanol.
  24. dwightlooi
    One thing at a time! And they are focusing on the right priorities. Get into the luxury compact segment first with the ATS -- that's the biggest slice of the pie and they weren't even fighting for it. Get the CTS updated and moved upmarket so it can be a 5-series / E-class competitor. Next up the LTS to be in the S-class segment. Everything else can and should come later. The only mistake they made thus far, IMHO, is the XTS. That should have been the Buick flagship. Lexus and Audi were successful before the LF-A or the R8. And one can argue that they could be just as successful with or without those cars. Adding a XLR is not going to change their market share or balance sheet tangibly. Competing with the LF-A or R8 is not particularly difficult. Drop a 7.0L or supercharged derivative of the LT1 (550~650 bhp) into a more carbon intensive version of the C7 platform and you have a super car that can run with a Ferrari. But, as much of a Halo car as that may be, it is not worth delaying the LTS over.
  25. dwightlooi
    I have never been a fan of the G8's styling -- I hated those Pontiac nostrils (fake intakes on the hood). But this is, well, pretty uninspiring if rather unoffensive. Honestly, even the Malibu's nose look better sculpted and purposeful. Overall the VF Commodore looks better and more coherent -- not that it's that stunning either. Why the LS3 is sticking around is baffling. The LT1 should be standardized across the board. Personally, I don't see why they needed the Impala and the Malibu. These two should be one product. The Malibu should have been on the Impala's longer wheelbase and the Impala should be de-contented to be inline with the Malibu's price point. The car should have a V6 for people who want one. The SS being V8 only isn't a bad idea. Anyone who will rather have better mileage can get a Bu. Anyone who wants more luxury can buy a Buick if the preference is FWD or a Caddy if the preference is RWD. Chevy needs to focus on being the value brand. Buick as the comfort luxury brand. And Caddy the sport luxury brand. There should be as little overlap in products as possible between these. GM is not doing that...
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