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Entry Level Luxury Performance Sedans

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  • shiposhipo Posts: 9,152
    Smoothness comes in two flavors, the first is engine balance, and the second is power delivery.

    Engine Balance:
    - The only match I know of for an I-6 in this metric is an H-4, an H-6, or a V-12. Pretty much every other engine configuration suitable for an automobile will develop ordered vibrations at some level.

    Power Delivery:
    - Engines of the 4-Stroke / 4-Cylinder (or fewer) variety suffer from noticeable "torque reversal" events; in the case of the four pot motor, there are two such events per revolution of the crank. What is a "Torque Reversal" event? A state where the power delivery of the last cylinder to fire has waned to the point where it can no longer sustain engine rotation and when the next cylinder to fire has yet to wax to the point where it can sustain said rotation. Considering 4-Stroke engines apply over 90% of their power between a point twenty degrees after TDC and twenty degrees before BDC, there are two forty degree periods per rotation of the crank where the engine mechanicals and the flywheel are driving the engine.

    Remediation:
    - The remediation of natural engine imbalance of I-4 engines has been known for a very long time, simply keep displacement to roughly two liters or less and apply two (im)balance shafts rotating at twice engine RPM (one to either side of the block), and the natural vibrations of the engine are effectively cancelled out.

    - The remediation of torque reversal events is both easier and not as complete; it is easier because the manufacturer only needs to add a heavier flywheel to effectively dampen out the events. The thing is, dampening isn't as "complete" (for lack of a better word) as cancelling; the torque reversals will always be there, it will just be very difficult to sense them.

    Final thoughts:
    All intermittent combustion engines exhibit torque peaks and valleys, even the monster 18 cylinder R-2800 "Double Wasp" and the even monsterer 28-Cylinder R-4360 "Wasp Major". That said, once beyond the 6-Cylinder threshold the "valleys" don't step into the realm of negative torque and are thus imbued with a property called "smoothness". Six cylinder engines, even BMW's vaunted I6 models, do venture briefly into the negative torque territory three times per revolution, but the excursion below the line of zero torque is so shallow and so short in duration, they too have been given accolades for their smoothness.

    For my part, if BMW's new(ish) turbocharged 2.0 liter I-4 is engineered to be "only as smooth" as the 2.0T in our new GTI, it will be more than smooth enough for me. :)
  • markcincinnatimarkcincinnati Posts: 5,069
    edited January 2012
    Great post -- I nominate it for "one of the great posts" awards (as if there is such an award.)

    If the new BMW turbo 4 is as smooth as the 4 that was in my 2009 A4, I would be delighted. Knowing how time and tide tend to mean incremental improvements are possible (because of the passage of time -- plus a stack of $100 bills), I would assume this new BMW engine will be even smoother. Love the higher HP (and slightly higher torque) than in the Audi 2.0T -- makes me wonder if the tuner shops won't be bringing out some Fritos to up the torque, big time and even boost the HP by at least another 10 or so.

    31 months to go on my '12 Acura TL lease. Of course Audi may well come out with their new and improved 2.0T, in that time period too.

    And with $4.00/gal gasoline coming soon to a pump near you, these 4-cylinder engines keep getting more and more attractive.

    Drive it like you live. :shades:
  • sweendogysweendogy Posts: 1,106
    I agree on the 4cly blurb- 31 months that's tough
  • flightnurseflightnurse 35K feetPosts: 1,590
    I never said, "crappy" engine, I was expecting the new turbo 4 to be a power house and it is. However most people know that BMW has 6 cyl engines and to sell a $46K call with a 4 cyl is a tough sell, but the little engine produces some good number but in 0-60 and MPG. BMW learned it's lesson with the 318i, talk about "crappy" engine.
  • flightnurseflightnurse 35K feetPosts: 1,590
    Not really, since Mark has owned 29 Audis in the past, his local Audi dealer will make him a great deal to get him out of that TL.
  • sweendogysweendogy Posts: 1,106
    I would love to see the deal one would get with 31 mths remaining on a lease on a 2011 TL and reselling that TL on an Audi lot. That sounds like a "leader ad".
    Back on the 4cyl . the old 6 was a fine engine and it sold very well(leased even better) but BMW and the world is looking at 100 (98 and change close today) oil- which will continue to rOll into the pump prices. Even at 45-50k people hate the 80 dollar gas hit 2-3 times a month. 4cyls are here to stay. For 40k I'm willing to pay for a strong 4 that performs better the current 6 and gets me 30mpg highway in the /012 3- add the sports pack and you have major performer with stick.
  • fedlawmanfedlawman Posts: 3,118
    It will be a sad day when BMW does away with the I-6. I love my M, but I do really miss that sweet M20 I had before I went 4-cylinder. That M20 was a sweetheart.
  • kyfdxkyfdx Posts: 27,640
    That M20 was a sweetheart.

    It still is.... ;)

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  • fedlawmanfedlawman Posts: 3,118
    Yeah, yeah...
  • dino001dino001 Tampa, FLPosts: 3,475
    ... is available with manual. It is basically "no-cost option" as opposed to standard automatic. So no need to go to 335 is one doesn't want to. Yiiihaaw.

    2012 BMW 328i wagon, manual and sports package. No. sold in the US: 1. Probably.

  • Kirstie_HKirstie_H Posts: 10,822
    Are you a 20-something who recently bought a new car or who is right now in the market for a new car? A reporter is looking to talk with young Americans to see what they are looking for in their next new vehicle. Please contact pr@edmunds.com with contact information and a brief description of your experience by Friday, January 20, 2012.

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  • nyccarguynyccarguy Stamford, CTPosts: 7,395
    One of the major gripes I have with my 2010 Acura TSX is its lifeless electric power steering. The complete lack of feedback doesn't help when trying to navigate the snowy, unplowed, unsalted roads of Stamford, CT on my way to work this AM.

    Up until today, I haven't had the chance to put the TSX through its paces in the white stuff with its Michelin Pilot Arctic Alpin snow shoes. For those of you who've been paying attention, up until this past May the TSX was my wife's car and my DD was my Prelude (15" snow shoes in the winter of course).

    The only way I knew the wheels broke traction was by the flickering stability control light on the dash.

    FWIW, 4 driven wheels don't help you if you don't take it easy. I saw a couple in a Range Rover who must've spun out & hit the guardrail.

    2001 Honda Prelude Type SH/ 2011 BMW 328xi / 2011 Honda Pilot EX-L w/ Navigation

  • tlongtlong CaliforniaPosts: 4,737
    One of the major gripes I have with my 2010 Acura TSX is its lifeless electric power steering.

    There was a time when one of Honda's strengths was the nimble handling and steering agility of its vehicles.

    That was a long, long time ago. :cry:
  • nyccarguynyccarguy Stamford, CTPosts: 7,395
    My 2001 Prelude Type SH :)

    2001 Honda Prelude Type SH/ 2011 BMW 328xi / 2011 Honda Pilot EX-L w/ Navigation

  • cdnpinheadcdnpinhead Forest Lakes, AZPosts: 3,237
    That was a long, long time ago.

    Maybe not so long -- my TSX is the previous version and has conventional steering and what I consider pretty decent handling for a FWD car.

    That said, Honda's recent offerings are bloated beyond belief.
  • sweendogysweendogy Posts: 1,106
    Have faith brother - the Ilx is coming along with a new rdx- they'll be fine.
  • m6userm6user Posts: 2,950
    I thought I read that the TSX V6 version still has the hydraulic steering. I wonder if the new RDX with the the same V6 will have electric or hydraulic steering.
  • nyccarguynyccarguy Stamford, CTPosts: 7,395
    The TSX V6 does have conventional, hydraulic power steering. While its no BMW, it does provide decent feedback. The problem is that the V6 weighs so much more than my 4cyl TSX that it adversley affects the vehicle's handling. The 280 horsepower was nice though.

    2001 Honda Prelude Type SH/ 2011 BMW 328xi / 2011 Honda Pilot EX-L w/ Navigation

  • sweendogysweendogy Posts: 1,106
    I'm sure the 10 people that bought one would agree the 280hp is nice.
  • sweendogysweendogy Posts: 1,106
    edited January 2012
    Now we all know how I feel about this category - just because you have a brand does not get you entry to this group- many disagree- hosts have no solid answer why certain cars are here- but since BMW, the standard is ditching its work horse 6 for a better 4- let's throw this car into the mix a well-http://autos.yahoo.com/newcars/future_cars/audi_a3_2013.html

    Yep new a4- rocking the turbo 4- lets make some room and finally delete the tsx from this forum - why 2 acuras, with combined sales of a housing suburb.
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