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dwightlooi

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Everything posted by dwightlooi

  1. dwightlooi
    Your proposal seems to be fantastic on its face. 2 different displacement diesel engines for the half tons which would *easily* give them best in class fuel economy across all models. What are the drawbacks to doing something like this? Is there any limitation from attempting to shrink the current duramax architecture? How difficult would it be to add balance shafts to a V6 at that angle? Does it being a heavier diesel engine make any difference with balance shafts / NVH? Very genuinely curious since on its face your idea seems to result in engines that put out near *perfect* power/torque numbers for a half ton pickup, all built on an engine architecture that already exists and could be extremely modular - thus significantly reducing costs. It is not hard to add balance shafts... you can simply put one in the oil pan or above the camshaft. There is a difference between shrinking -- as in making the pistons, combustion chambers, valves, etc. smaller -- and simply removing two cylinders and changing the crank pin angles. The latter is easy because all the combustion and aspirational work is done. A diesel has heavier pistons and rods. They need bigger weights on the balancer. It doesn't affect refinement as much as it affects engine resposiveness. Still... the same applies to the 4.5 DOHC and the difference is immaterial between a 4.5 and a 4.95L engine. In fact, the 4.5 is trickier because it is a 72 degree Vee engine -- which is worse from a balance standpoint than a 60 degree (unbalance shafted) or a 90 degree (with balance shaft). This is why V6es are usually either 60 degree (for good intrinsic balance) or 90 degree (when derived from a 90 deg V8 or when it is desirable to stuff a supercharger or turbo(s) in the valley.The 72 degree angle was chosen entirely for packaging reasons to make the fat DOHC heads fit in the same width as a 90 deg pushrod design, and still be wide enough in the valley for the single turbo to fit
  2. dwightlooi
    It's a Delta! Look, drop the Voltec drive train, stick the 272hp 2.0T (LTG) engine in there and sell it for $40K. Or, do something revolutionary with it -- like a Diesel-Electric Hybrid that beats the Prius and sell it for $50K. Whatever it is, do something other than trying to sell it as a $76K Volt with a Caddy crest and leather upholstery.
  3. dwightlooi
    There is a justification if the Volt is sold at a heavy loss... Then own up to it, stop selling it and call the "green" experiment a misstep. Or try and have it (and the ELR as well) as an greenimage booster for a company known for full-size SUVs... Which is the role the Volt+ELR play IMHO... They're PR machines first and foremost. Just do a pure electric then! Drop the ICE, power split device, secondary motor, etc. Quadruple the battery capacity. Should get you a 64 kWh car with a range exceeding the Tesla Model S's "160~200 miles"... probably about ~240 miles or more or less one full tank of gas -- simply based on the merit that this is a lighter and smaller car. Lithium batteries are about $600/kWh, so 64 kWh should be about $38,400. That's definitely within budget even when you don't count the cost savings from dropping the ICE and power-split transmission. There is also plenty of room under the hood for the additional batteries with the ICE and tranny gone. Probably 1/4 the entire battery can go there, another 1/4 in the tunnel and the remaining under the rear seats and where the gas tank was.
  4. dwightlooi
    Well... LOL... I guess the Italians never figured out that FCA is short for "F--king Cheap Ass" to American instant messaging users.
  5. dwightlooi
    There is a justification if the Volt is sold at a heavy loss... Then own up to it, stop selling it and call the "green" experiment a misstep. @ $76K you better have a 60kWh battery, a 160~200 mile range and do 0-60 in under 6 secs -- because that's what a Tesla Model S will do (Tesla's internal range estimates albeit being a little optimistic). That, or perhaps a 30kWh batter an 80~100 mile range, an on-board ICE generator in series and a big enough electric motor for under 7 secs to 60 performance. Because that is what's gonna fetch $76K.
  6. dwightlooi
    To be totally honest, I was and am very luke warm about the Volt. It was supposed to be revolutionary, it is anything but. Sure it is a plug-in but it didn't have enough electric range to cover daily driving for many people without kicking on the ICE -- you need about 60~80 miles for that. As a hybrid it's efficiency is bottom of the barrel. As a matter of fact, it's not any better than a Cruze on it's ICE. I see the ELR as a missed opportunity. Instead of restyling and poshing up the Volt, GM could have aimed higher and bring out an alternative to the parallel/plug-in formula to challenge the Prius at it's own game and win. It's really not that hard to beat the Prius in the MPG game -- especially when you have a $76K budget to play with. Heck, you can easily do it with $50K. This formula is guaranteed to both out-run and out-mile the Prius:- New "modified" version of the new Opel 1.6L CDTi Turbodiesel engine as the ICE The engine "modification" adds 2-stage cam switching VVL which enables the engine to shut down ALL cylinders when triggered New "modified" version of the 6T45 6-speed automatic and call it the Electramatic 6E45 The transmission "modification" replaces the torque converter with an electric motor (40hp@1000~4000 rpm, 210lb-ft@0~1000 rpm) Battery consists of two of the Volt's nine modules with 32 cells each and a total capacity of 3.6 kWH, or which 3.0 kWH is actually used Without a torque converter, the engine cannot and does not ever idle; power from standstill is always electric. Once under 600 rpm or when pure electric propulsion is prescribed, all valves on the ICE close and the engine freewheels. When decelerating, the ICE again shuts off all valves allow for full regenerative braking from the motor-generator Once underway, power is electric or diesel or both with the total not exceeding amounting to 176bhp@4000 rpm/232 lb-ft@1000rpm The battery (when fully charged) as enough juice for 8 miles of pure electric driving. As the engine doesn't ever idle, the A/C compressor is electrically driven
  7. dwightlooi
    You can't. The is no justification that a more luxuriously appointed Volt is going to fetch $36K more over the already over priced Volt. Remember, the Volt was supposed to be a $30K Hybrid that came in $10K over the original price target. Without subsidies, a $40K Volt does not make any economic sense simply because the $20K premium over other comparably equipped Deltas (eg. Cruze) is enough to buy 188,500 miles worth of gasoline @ $3.50/gallon. The Volt is neither fast nor particularly long legged on battery power (40 miles). The ELR is no much better except perhaps for looking a little sleeker and having a nicer interior. $35K for that and a Caddy badge!?!! No fly a kite! If I am interested in saving money fuel expenses I won't buy a Volt much less an ELR. If I am a Global Warming koolaid drinker or I want green creds with my liberal friends, $76K is pretty darn close to the Tesla Model S and that has a lot more cool factor, green factor and it is actually fast! Really, a $76K Delta? At the very minimum they should have put a 270hp LTG engine in there and give it twice the battery capacity. Perhaps not even then.
  8. dwightlooi
    Yes, you can do a 90 deg V8 by using two banks of cylinders and components otherwise identical to the 2.0T. You won't be building it on the same line as the line-4 though because the banks will be facing 45 degrees away from the inline-4's cylinders. A 4.0V8 will make about 540~550 hp and about 550~600 lb-ft of torque running about 22~23 psi of boost on 9.5:1 compression. Essentially twice that of the 2.0T (LTG) engine. It will however weigh more and take up more room than a pushrod V8 of equivalent output. It'll also cost more and may not offer any fuel economy advantage. Mercedes never had a 4.6 liter bi-turbo. The current E63 has a 5.5L bi-turbo of 517 bhp / 516 lb-ft. The next C63 (why they insist of calling it a C63 baffles one) is a getting a 4.0 bi-turbo V8 with ~450 bhp / 500 lb-ft -- the focus here being on response rather than the highest practical output. Still one has to ponder how this powerplant is any better than a 6.2L LT1 pushrod? Horsepower is about the same as the 455~460hp LT1, torque is somewhat higher by 40~45 lb-ft but subjected to turbolag. The engine will undoubtedly weigh more, take up more room and have more potentially maintenance issues. And, it'll be hard press to equal much less beat a projected 16/27 mpg the LT1 can deliver in a C-class sized vehicle.
  9. dwightlooi
    The basic issue with building a V8 (as opposed to a V12) out of the 3.6 LFX engine is that it is a 60 degree engine and a 60 degree V8 -- while interesting and in fact beneficial from a packaging standpoint -- is not a well balanced design. For an engine destined for a flagship model this is fact may have a greater negative impact than using a big displacement small block V8. Afterall, the degree of vibrations from a 6.2 liter class 90 degree V8 is very much acceptable in cars like the C/E/S63 AMG models. A V12 on the other hand will be able to not just share the 3.6L engine's internal parts but also be made on essentially the same assembly line. A V12 -- even for M-B or BMW -- was, is and will always be a specialty model with limited volume. It helps when it does not need or have unique pistons, valves, and everything else. Most importantly though, a V12 -- like an Inline-6 -- is naturally of perfect harmonic balance without relying on counterweights and/or balance shafts. One thing many people fail to recognize is that the Pushrod V8 -- irrespective of costs -- is not inferior to a DOHC V8. It is in fact superior in most aspects. It produces more power for a given external dimensions and/or engine weight. It has better fuel economy than DOHC designs of the same displacement or output. In fact, it tends or have equal or better fuel efficient compared to turbocharged DOHC designs of a similar output but significantly lower displacement. The only thing is not good at is in delivering very high specific outputs and than only matters with regards to displacement taxes. But, as good as GM's LT1 and LT4 direct injected, VVT packing pushrod engines with cylinder shutoff, they are products that cut a balance between performance and costs. For instance, they could have had cam-in-cam independent valve timing, but they don't because a synchronous VVT setup has 70~80% of the additional benefits for half the additional cost. They could have had a variable cam profile setup (ala VTEC or Variocam plus), but they used the oil galleys and collapsible lifters for shutting down half the cylinders for fuel economy benefits instead. They could have been lighter had they splurged on magnesium block and/or titanium rods, but they stuck to aluminum and steel so they can have a $52,000 Corvette which not only beats the 911 but beats it at half the price. They dould also have got 30~40hp more out of those engines by increasing compression ratio by another half point or 1 point, but that would have mandated 91 octane fuel all the time when GM wanted 87 octane compatibility. Such concerns and the balance sort are somewhat different when you are talking about a Cadillac as opposed to a Chevrolet. Cadillac can, and should, have a dedicated version of the Smallblock V8 which eschews some of the cost and fuel considerations and strive for maximum performance. An LT2 for Cadillac for instance can have cam-in-cam independent VVT, 12.5:1 compression, cam switching VVL replacing AFM, quieter Piezo direct injectors and a magnesium block. Such an engine could push about ~500 bhp / 475 lb-ft from 6.2 liters while weighing about 20~30 lbs less than the 465 lbs LT1. You can probably also "afford" better under the hood dressing than the cheap black plastic covers you find on a Vette -- a cover wrought from an acoustic sandwich which can have a magnesium casing and inner layer with a rubber liner in between, which is not purely cosmetic but also a instrument of refinement. It'll probably cost about $3000~4000 more, but that may be just fine for a Caddy.
  10. dwightlooi
    They already have a proper V8 in the LT1. No reason for a DOHC mill that weighs more, makes less power and does not exactly have better fuel economy. I see no imperative to do a DOHC V8. However, if they wanted a flagship engine, they might do a V12. By sharing the pistons, rods, valves and the majority of parts with the ubiquitous LFX, they can easily put together a 7.2L V12 which doesn't cost too much to develop and won't cost too much to build. Most of the development cost associated with a new engine is actually in getting the combustion and aspirational systems right. If you are using combustion chambers, pistons, valves, intake geometries and fuel maps that are identical to that of the proven LFX 3.6L V6 it all comes down to just tooling for a V12 block crank casting and a longer crank forging. The engine won't exactly be "Supercar" grade -- something befitting a LaFerrari -- but it'll be more than competent enough for a luxury cruiser which is what Caddy is building. Expect about 640 bhp @ 6800 rpm and 550 lb-ft @ 4800 rpm, which is exactly double that of the LFX V6. It'll drink regular 87 octane just fine too. This also opens the door to a renewed XLR based on the Corvette platform, but powered by this V12 instead of the LT4 supercharged V8. The corvette will actually be faster and lighter, but the V12 Caddy XLR will sit more comfortably next to an Aston Martin on the boulevard.
  11. dwightlooi
    3.6L Twin-Turbo doesn't make for a fitting power plant for any flagship. The car needs a V8 or better yet a V12 -- or at least have the option for one.
  12. dwightlooi
    Three things... (1) The L86 is used in the Silverado pickup truck. If the ATS uses the V8, it'll much more likely be the LT1 used in the Corvette. The LT1 makes 460 hp @ 6000 rpm / 465 lb-ft @ 4600 rpm. (2) The LF3 3.6L TT V6 actually has 10.2:1 compression (not 9.5) -- per GM official statistics. (3) Contrary to what many people think, the Twin Turbo V6 is the heavier engine. The 6.2L LT1 V8 weighs 465 lbs vs the 3.6L LF3 V6's 485 lbs -- both GM's official numbers. For comparison, BMW's S65 4.0L DOHC V8 weighs 445 lbs whereas the previous generation LS3 port injected pushrod V8 weighed 403 lbs. BTW, the ATS is only very slightly lighter than the F30 3-series. The ATS 2.0T weighs 3,373 lbs equipped with the Hydramtic 6L45 6-speed auto. The BMW 328i 2.0T weighs 3,410 lbs equipped with the ZF 8HP 8-speed transmission. Still, it's the first time a GM platform has a weigh advatnage over Bavarian and Stuttgart stuff.
  13. dwightlooi
    How about... Vrrrrmmmmhhhhh.... (Corvette Stingray Cut Scene) 0-60 mph 3.8 secs. 30 mpg (EPA Hwy MPG) Single Integrated Cam Because simple is simply better
  14. dwightlooi
    Well, it is "easier" to make a OHC engine rev to stratospheric RPMs compared to a pushrod engine. The elimination of the rod mass and the individually smaller valves which are lighter run into valve float at greater opening and closing speeds given the same spring tension. The CX500 also has 250cc cylinders (roughly comaprable to what you'll find in a 1.0 liter 4-cylinder engine. Smaller cylinders mean smaller valves and also generally lower piston speeds (they tend to have shorter strokes as well as smaller bores). Still, the point is that the kind of engine speeds above which DOHC 4-valve heads really shine are not really employed in many, if not most, of today's DOHC powerplants. You really need to get to about 6000 rpm before you see any tangible benefits, 7000 rpm before it is significant and 8000 rpm before it is really worth it. With a few exceptions -- Such as Honda's B-series or F-series, Toyota's 2ZZ-GE, GM's LF1/LFX, BMW's S65, etc. -- most of today's DOHC 4-valve engines are DOHC 4-valve for no good reason! For example, Toyota's 2.5L DOHC I-4 used in anything from Camrys to Scions makes 178 bhp @ 6000 rpm and 170 lb-ft @ 4100 rpm. That's 71.2 bhp/L. Their mainstream 3.5 V6 makes 268 bhp @ 6200 rpm and 248 lb-ft @ 4700 rpm. That's 76.6 hp/L. You can achieve that kind of numbers with Pushrod or SOHC heads, along with 2-valve per cylinder. The LT1 V8 is at 460 bhp @ 6000 rpm with 465 lb-ft @ 4,600 rpm. That's 74.2 bhp/L. Even the Ecotec3 6.2L pushrod V8 used in Silverado trucks makes 420 bhp @ 5600 rpm with 460 lb-ft @ 4100 rpm. That's a not so shabby 67.7 bhp/L. If you implement a DOHC 4-valve setup, it should at least rev to 7000 rpm and make it's peak power at close to 7000 rpm (like GM's 90 bhp/L LFX V6) or preferrably do what Honda did 22 years ago with the B16A 1.6L which makes 160 bhp @ 7600 rpm with 111 lb-ft @ 7000 rpm and a 8200 rpm rev limit. Anything less and a DOHC valvetrain is simply not worth the weight, the bulk, the cost, the complexity and -- if you don't care about any of the above -- the extra parasitic drag and fuel economy penalty. The problem with all the extra high revving designs is that they have emissions, tractability and/or efficiency issues down low which really takes a cam switching valve train to properly address. Over the years manufacturers had, instead, simply watered down their DOHC mills by reducing passage sizes, valve lift, valve overlap, etc. to make them civil and efficient at typical driving conditions. In doing so, they had also made the entire design choice moot. But, by now, they are so used to it that they carried on the tradition anyhow.
  15. dwightlooi
    I don't think GM publishes a "drafting grade" drawing of the LFX. But you can get the majority of the official statistics here. http://www.gmpowertrain.com/VehicleEngines/PowertrainProducts.aspx
  16. dwightlooi
    I am still of the opinion that none of these publications actually know what's under the hood of the ATS-V. Unlike the Z06 there had been no actual credible leaks, just rumors. To me, it's still 50/50 between the LT1 V8 and the 3.6TT. Here's why... Case for the LT1 V8 This maintains the Cadillac V-car tradition of using Corvette motors and makes the V-car powertrain philosophy consistent if they use the 625+ bhp LT4 in the CTS-V (which I am quite sure will be the case) While the 211 kg LT1 is 28kg heavier than the LS3, this is by far the lighter, more compact, more powerful and more torquey motor (compared to the LF3 V6 which weighs 220kg) That LT1 is also somewhat cheaper than the LF3 allowing for money to be put into other performance equipment Fuel Economy will be 1~2 mpg worse than in the lighter & sleeker Corvette, but 16/27 mpg is more than competitive in a 455 bhp car Case for the LF3 V6TT The XTS and CTS already use this motor, using it adds fewer discrete engines to the Cadillac lineup There are those who believe that Cadillac should do what the Europeans do, the BMW M3 is now a turbo 6 For markets with a displacement tax, the 3.6 liter powerplant may have a tax advantage over the 6.2 liter I project the 3.6TT beating the 6.2 V8 by 1 mpg in the City, although it remains to be seen if there is any advantage on the Freeway. Given the ATS's lighter mass over the CTS Vsport, expect 1~2mpg better mileage -- at least 17/26 mpg, perhaps 17/27. Again, very good numbers, but not clearly superior to the pushrod V8. As far as the Alfa Romeo 3.2 based TT? I don't know where that came from. That was and is never in the cards.
  17. dwightlooi
    The new crest looks neither as pretty nor as "premium" as the old one. Making it "oversized" doesn't help either. The older crest with the round outer wreath fits better on the ATS's Grille or any grille. It also has more fine details which projects a more premium feel.
  18. dwightlooi
    It's beyond that... calling a Holden Epsilon a Commodore, while also calling a Holden Alpha a Commodore is just nonsensical.
  19. dwightlooi
    A year or two? No worse than resurrecting the 4.5 Duramax H.O. DOHC V8.
  20. dwightlooi
    Doesn't make any sense. If they are going to go through the expense and time to do an Alpha for Holden, just put an LFX 3.6 and/or LTG 2.0T in it and sell it as a mainstream commodore. HSV can drop an LT1 or LT4 in there and sell it as a super sedan. Now, none of these have to be Made in Australia. But making a FWD commodore and a RWD Commodore makes zero sense.
  21. dwightlooi
    For the WRX STi to be "significant" today, it either has to make 400+ bhp or it needs to weigh 2,800 lbs. It is neither. Whether it is based on their 3.0 H6 or a 2.0 H4 Turbo, or whether it is an aluminum car, how they achieve that is largely irrelevant.
  22. dwightlooi
    Forget the 4.5 Duramax Diesel -- the cost, complexity and mass of a four cam V8 isn't worth the specific output improvement. A very simple solution is to simply build on the Pushrod-32v Duramax 6.6 architecture. Instead of building a smaller V8, just take two cylinders off the Duramax 6.6. The resulting 4.95L V6 will make about 300 bhp / 575 lb-ft. That's close enough to the projected 310 bhp output of the 4.5 they were developing and more importantly superior in stump pulling torque (which is what really matters in a truck). While they are at it, why not a 3.3L V4 with 200 bhp / 383 lb-ft? The beauty of a cam-in-block + pushrod design is that you can use a V configuration with no penalty in terms of number of camshafts or phasers needed. The Duramax 6.6 and/or it's 6 or 4 cylinder engines are already reverse flow engines where the exhaust exits the valley of the Vee permitting the efficient use of a single turbo instead of two smaller ones flanking the engine. Unlike the 4.5, the 4.9 and 3.3 Duramax 6.6 derivatives will share the piston, connection rods, wrist pins, valves, springs, lifters, pushrods, bolts and a huge number of other parts with the 6.6L sibling.
  23. dwightlooi
    There was a time when 280~300 hp, AWD and Compact was interesting and unique -- or at least a rarity. We are talking about the 1990s. This used to be the exclusive domain of the WRX STi and the Lancer Evo. Today, any number of cars have a turbofour with 240~300 hp, many have AWD and many aren't any bigger or heavier than the Subie. 305hp isn't enough to be noticed. And, quite honestly, WRXes have become fatter and heavier over the years to the point where I am not sure if there is a reason to get one over say an ATS 2.0T AWD.
  24. dwightlooi
    That new crest is butt ugly
  25. dwightlooi
    Another interesting note... this marks the first application for the Hydramatic 8L90 automatic transmission. GM's first 8-speed auto. To beat the clock, the 14' CTS vSport uses an Aisin sourced 8-speed auto. It remains to be seen if they will switch the CTS line over to the Hydramatic. If they do, it'll probably not be the 8L90; an 8L50 would been more appropriate and more efficient.
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