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Mainstream Large Sedans Comparison

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Comments

  • jaymagicjaymagic Member Posts: 309
    LOL, Cap, if you think the Avalon raises flags, pity us poor Azera owners -- I know the ads are running, but most of America has no idea of what an Azera is. They MIGHT have heard of Hyundai, but only in terms of small economy cars or at best "a long warranty."

    A Hyundai Azera is a true stealth car when it comes to public recognition. People get a ride in it or see it and ask what it is, and you tell them and they still don't really seem to get it. They just say its really nice and, wow is that all it cost?

    If they ever figure out what the Avalon and the Azera really offer, Buick, Ford, and Chrysler will be even further in the dumper.
  • captain2captain2 Member Posts: 3,971
    the difference being that Avalon (and Toyota) have all kinds of name recognition (I have never seen any sort of ad for the Av) and granted for being a vehicle that it largely isn't anymore ( a tame 'old folks car'). The Azera is more like - 'who?', despite being a good looking and driving vehicle. The Avalon will continue to outsell the Azera if for no other reason than it is a Toyota, a situation a tad unfair to those looking for less costly alternatives upfront. Neither car, though, really high volume sellers. As far as B/F/C in the dumper, maybe a bit strong, Chrysler does better selling the 300 than either the Av or Azera.
  • ykangykang Member Posts: 88
    Do you know those thieves are working in Irvine, California and they are well known desiners previously worked for other big companies? Do you have any documents or articles which can support your theory? :mad: :sick:
  • joe131joe131 Member Posts: 998
    Well of course the issue is sematics and graphs. It's the only way people can, or try, to communicate with each other in a forum like this.

    OK. OK.
    If you want to differentiate the basic meanings, here it is: Torque is most closely associated with acceleration. Horsepower is more important as a limiter of top speed.
    Torque = Acceleration
    Horsepower = Speed
    Right?
    Well, yes and no.

    Like you typed before, "...torque is indeed a measure of instanteous twisting force available (lb. ft.) and it is what you feel in the seat of your pants when you intially hit the accelerator..."
    Agreed. The pressure you feel after you hit the accelerator, BUT BEFORE the speed of the car changes in response to you hitting it, is the torque being produced by the motor re-routed to your backside. And, as an infinite number of instaneous static pressures are felt in the seat of your pants, the car accelerates. But the increasing speeds of the car is a result of horsepower, while the pressure you feel at any instant during the acceleration is due to torque. Torque is measured statically, but not felt as acceleration. You don't feel acceleration unless you are feeling force over time which is horsepower. If the torque numbers are high during the acceleration, then the rate of acceleration will be greater than if the torque is lower.
    But, in spite of your next point made in that post, that "...you should also be able to accept that it (torque?) is not a prime determinant of how fast a car accelerates, that would be HP, of course (or torque applied over time)...", I'll suggest that torque IS the prime determinant of how strongly you feel the acceleration of a car, while horsepower (and gearing) is the thing that determines how high a real or theoretical top speed the car can reach.

    Bottom line, though you can measure torque, you cannot feel it as acceleration nor see it as speed. Torque is invisible. It is only a force felt as pressure or weight. Horsepower is not measured; it is calculated by the formula, horsepower= torque x rpm / 5250, which means torque and horsepower figures will always be equal at the 5250 rpm point. Horsepower is force in motion visible as acceleration or speed.
    Without torque there can be no horsepower. Without horsepower there can be no movement.

    Do we have a deal?
  • captain2captain2 Member Posts: 3,971
    well thank you for the intelligent responses to what I was trying to talk about - a whole lot better than arguing whether torques curves are really 'flat' - don't you think? :D
  • patpat Member Posts: 10,421
    Now that that is resolved, we can get back to talking about the actual mainstream large sedans. ;)
  • joe131joe131 Member Posts: 998
    ...horsepower formula...which also means if a motor develops torque of 525 ft. lbs. then the horsepower of the motor would equal to one tenth of the RPM at which that amount of torque is developed. Something like a Viper V-10 motor maybe?
    You can find 1650 ft. lbs. of torque developed at 1500 RPM in a motor of some diesel powered tractor trucks pulling trailers down the highway. They have torque values way higher than horsepower, in this example about 470 horsepower. That high torque is needed to supply the force to accelerate the great weight of the tractor and loaded trailer and to keep the vehicle at highway speeds fighting huge weight and drag factors. High top speed is not needed, so neither is high horsepower. Usually they have 9 to 18 gears in the transmission since the torque and horsepower curves are limited to very narrow (compared to cars) RPM ranges.
    Large sedans sometimes are delivered by auto carrier tractor semi-trailer rigs employing high torque motors with characteristics like those mentioned above.
    You can plug in any numbers to calculate horsepower if you know torque @ rpm. That's what a dynomometer does, measures torque @ rpm. If a whole lot of readings are taken at various rpms, then a torque / horsepower / RPM graph can be plotted, which will result in the familiar curves we like to compare.
  • joe131joe131 Member Posts: 998
    Announced last week: Toyota Motor Company officially took over bragging rights from General Motors as the world's largest automaker.

    By Micheline Maynard Published: April 25, 2007
    International Herald Tribune

    http://www.iht.com/articles/2007/04/25/business/25auto.php
  • plektoplekto Member Posts: 3,738
    The easiest way, IME, to explain torque to people is a long hill. You know - the kind that grinds on for a few miles.

    If your car starts going slower up the hill as it goes on, you'll eventually reach a speed where it will more or les keep the same speed despite the accelerator being floored.(half throttle or full - hardly any differnece) You may have 200+ HP, but you ran out of torque.

    It's the ability to maintain speed and change it. And honestly torque is far more important than power, because if your speed drops too low going up a hill, you have to downshift until it hits its optimal torque range.

    Going 35-40mph up a mountain highway(Grapevine, etc) is a huge problem compared to storming up it at 65-70mph. Automatics exacerbate this problem(silly tall gearing as a rule) so that you need massive numbers to achieve what a small engine with a manual can manage.

    Me? I'll go for torque over HP any day. Even the slowest turbo-diesels, for instance, still go 0-60 faster than most cars ten years ago did.
  • captain2captain2 Member Posts: 3,971
    Me? I'll go for torque over HP any day
    and I, of course, the opposite - part of that debate that has raged since the advent of internal combustion engines, torque vs. HP. Why HP? Because that is where there is a direct correlation between what I use (acceleration) and vehicle weight/size. Give me almost any vehicle's weight and claimed HP, I can accurately predict a 0-60 time and even a 50-70 time. It applies to this group of cars as well, why do the Av/Azera/Max get into the 6s 0-60? - because they all pull about 14 lbs per HP - why do the 500/Lucerne 3.8 need 8+, how about close to 20 lbs/ per HP.
    Drivability, as you note, can definitely be improved with a lot of accessible torque in lower RPM ranges (you long grade example) but, in my mind, HP is still going to be what dictates my car buying decisions, at least until the point that the diesel engine becomes unobtrusive (and clean) enough to find their way in cars like this.
    Found the MB 3 liter diesel (actually the ML320CDI) to have enough HP that it is a 'fun' vehicle to drive, although that high compression engine that creates all that torque would have me having to adjust to engine braking - your hill, BTW, no sweat!
  • martin22martin22 Member Posts: 53
    Gentlemen: Let me reiterate a post I made some months ago.

    Consider the formula from Newton's second law of motion..

    Force (in this argument, torque) = mass x acceleration

    Put another way, Acceleration = Force divided by mass.

    It's as simple as that: Acceleration is directly proportional to force (i e torque at the driving wheel) and inversely proportional to mass.

    That's the Law!
  • plektoplekto Member Posts: 3,738
    The reason HP is nearly meaningless these days is because we have artificial limits on how fast we can go in this country.

    Ie - There's no point to the 4th, 5th, or 6th gears in a 911. Because you get a ticket at anything over 70mph. So having 300hp on tap is worthless, really, except maybe if you manually shift it and only drive in 2nd gear or something.

    AND the race for ever-more HP leads to them constantly reworking the engines for it instead of torque - so the gearing gets taller and the thing gets "peakier". I personally can't stand the new Avalon, for instance. It drives like a Towncar - almost a binary throttle response because they are worshiping HP to beat the competition instead of just leaving it alone.

    Computer makers *finally* figured this out. Now we see a torque type race - same speed, but more cores and better multitasking. Graphic cards have been doing this for decades, though - raw speed is moot. How many pipes, buffers, and such makes the real difference.
  • rockyleerockylee Member Posts: 14,014
    Well they are only #1 for this quarter. I predict they will stay #1 but it's not set in stone yet until the final quarter sales come in. :P

    -Rocky
  • tjc78tjc78 Member Posts: 15,852
    "It drives like a Towncar"

    There are almost no similarities between the two. The TC is powered by a fairly sedate (230 HP?) V8 and has numb handling and steering. The Avalon for a big car handles fairly well and the engine is no comparison. If you want to compare the fact that they are both big quiet sedans, fine. However, the driving experience is totally different. And, for the record I have owned a TC and fairly often drive a newer GM which is basically the same thing.

    P.S. If you hate the Avalon and think it drives like a TC how come you always recommend the GM? It would stand to reason that you would hate that too.

    2023 Mercedes EQE 350 4Matic / 2022 Ram 1500 Bighorn, Built to Serve

  • alexstorealexstore Member Posts: 264
    well look with your own eyes. put 2005 Honda accord and 2006 Sonata next to each other and look at them from the back.
  • captain2captain2 Member Posts: 3,971
    HP is nearly meaningless these days is because we have artificial limits on how fast we can go in this country
    now you know I can't let you get away with that one! :D The reason why an Avalon, let's say, will seriously outaccelerate a Lucerne in any measure (0-60, 45-65 or whatever) you choose, has nothing to do with a lousy 18 lb.ft. of extra torque it might have, but everything to do with the 70 extra HP it has. And it has everything to do with the fact that the Av engine will pick up revs (and HP) like no pushrod engine ever dreamed of. If you don't think that acceleration capabilities mean anything, everything is all about ultimate (illegal) top speeds, then you really need to drive that diesel E320 I waas talkng about - perhaps the ultimate illustration of what gobs of torque can do, while still watching the taillights of its gas engined counterpart.
    Nobody has yet to explain to me - why, if acceleration is all about torque, then why is there only a correlation between vehicle HP/vehicle weight and there is no direct correlation between between torque/vehicle lb. relative to acceleration capabilities. In summary, torque only 'gets you going' or FTM 'keeps you going' and will only provide that acceleration if the engine involved revs quickly - the definition of HP. Don't fall back on 'it's all about gearing' because within this class drive ratios are all similar, but the Avalon is in the next county 0-70 at 13 lbs/HP, the laggard Lucerne (at 19 lbs./HP) can't be seen in the rear view mirror. And both engines are spinning at about 2000 rpm at that speed (in top gear). And I would be willing to bet that you will find the same 2000 rpm at 70 or so in the Azera, the Maxima, the 300 V6, as well as the LaCrosse 3.6 - those cars all having reasonably good HP/wght ratios and what else? - acceleration capabilites (that has nothing to do with top speed) that the Lucerne 3.8 (or the 500) could only dream of.
    Besides which, if 'HP is nearly meaningless' then why do we even have 'HP wars' ?
  • joe131joe131 Member Posts: 998
    Yes, it IS all about TORQUE. Torque is force. Horsepower is torque over time.
    Remember, TORQUE is measured, HORSEPOWER is calculated by using the torque number. Without torque there is NO horsepower. But not the other way around.
    Torque is simply the amount of pressure created by a motor that tries to twist the crankshaft. It is force only. It is a static measurement. It is measured at a point in time, not over a moment, not a second, not over any span of time. It is measured as if the motor was not even turning over at all.
    Knowing the torque at any one point in time does not necessarily give you the ability to predict how quickly the RPM (speed) of a motor will increase because of that torque. There is no time component in a torque measurement so there is no uniform or predictable effect it will have (over a period of time) on the acceleration (which does have a time component) of the car. Torque does not concern itself with time in any way.
    But torque is all about the potential of a motor to begin movement of the car from its static position at a point in time at whatever RPM that torque value is measured.
    Maybe this, in conjunction with my previous post can help explain torque to you.
    Does this make sense to anyone out there?
  • kublerkubler Member Posts: 7
    It's almost correct, except that one needs to know the torque curve vs. rpm and the HP in order to judge the power of a car. The formula is torque = (HP * 5252)/rpm.

    If we look at a large waterwheel, we may find that turning at a leisurely 12 rpm and produce 2600 ft lbs torque! Using this formula we calculate that the wheel is only producing 6 hp!

    Therefore, we need HP and torque to move a car.
  • joe131joe131 Member Posts: 998
    Yeah, everything true that you said, I already said more than once in different ways. But what you added did not change anything I said. (What part do you think was incorrect?)
    And, like I've said, multiple plotting of torque vs RPMs is precisely how the horsepower curve is calculated. If you don't know torque at RPM then you can't calculate horsepower to begin with. Because a horsepower curve is only a mathematical derivative of the torque curve, the torque curve (which contains the time component in rpm) is, BY ITSELF, totally sufficient to judge the power of a motor. And if weight and gearing and other factors are known, acceleration and top speed of the car can also be estimated closely. Adding a horsepower curve to the graph is superfluous. It does, however, give the marketing department another more easily accepted and persuasive number to publish. A horsepower curve may also, to some anyway, more dramatically illustrate how peaky is the power delivery of the motor. So in that way the horsepower curve can be useful even though it is unnecessary. And sure, so long as torque does not drop off steeply (like it always does eventually), added RPM will result in increases in calculated horsepower.
    Again, horsepower is work/movement performed during time. Torque is force irrespective of time. Torque is force that has work potential but no movement.
    Waterwheel is just another example of torque and rpm being used to calculate horsepower. No news there.
    Say what you want, but if you ain't no way got no torque, you ain't no way got no horsepower.
    Got it?
  • plektoplekto Member Posts: 3,738
    P.S. If you hate the Avalon and think it drives like a TC how come you always recommend the GM? It would stand to reason that you would hate that too.
    ****
    Only because you can get one at the end of the year for about $17K. Dirt cheap for a relatively decent commuter-box.
  • captain2captain2 Member Posts: 3,971
    Only because you can get one at the end of the year for about $17K. Dirt cheap for a relatively decent commuter-box.
    truth to the old adage that you get what (you are willing to pay for)? The generally most expensive Avalon is BTW the cheapest car to own in this group (Edmunds and Intellichoice) and you are not likely to buy even a 'stripper' version for under about $25k. Perhaps you can explain that one, as you espouse on the virtues of antiquated (and cheap) cars?
  • plektoplekto Member Posts: 3,738
    I was talking about the GM. $17K after rebates at the end of the model year is common(about 18K right now via carsdirect).

    For that price, it's not a half bad car.

    I just don't like big, bloated things to drive. Cars are all so heavy now that it's like the 60s again. Bigger and bigger and more HP... And it all is just as horrid to drive.

    Give me a 2600lb little sports sedan and I'd be happy as a clam.
  • joe131joe131 Member Posts: 998
    If you don't have enough cash or credit to get an Avalon, the Crown Vic might be a good choice if you need a new big car. Not everyone has the means to buy or make payments on a 25 or 30 thousand dollar car. The Crown Vic or Sonata might be the best cars for lots of us who think we need a new car but can't afford the more expensive ones.
  • captain2captain2 Member Posts: 3,971
    OK that's fine but this is a LARGE sedans forum so therefore I must assume that your $17k 'bargain' must be an Impala with a 'really solid' (sarcasm intended) pushrod V6 in it. Same COO and value comments apply although the Impala is much closer to the Avalon in these regards.
    Would also suggest to you that as FE becomes more and more of an issue with the autobuyer, that this size boom that cars in almost all classes have unquestionably been experiencing, MUST slow down or even reverse. FE already sells, just wait for those gas prices to go up even more - we may all be driving diesels b4 you know it.
  • captain2captain2 Member Posts: 3,971
    The Crown Vic or Sonata might be the best cars for lots of us who think we need a new car but can't afford the more expensive ones.
    True, but if things are that tight that an extra hundred or even two hundred dollars or so a month, is going to make or break it - then I would tell you NOT to buy a new car at all. That CV or Sonata a year or two old - now that would be cheap. Or conversely, you could drive something a whole lot better, let's say that Avalon you couldn't afford to buy, on a lease for possibly even less money than had you bought (or leased) either of the other two cars.
  • joe131joe131 Member Posts: 998
    I covered that, and its up to them whether they get a new one or not.
    New cars are often much better deals than used cars cuz used prices are so high. most people selling nice newer ones are upside down and can't afford to see them for a fair price.
    Good to amazing incentives and loss leaders on new ones sometimes and loan rates lower on new too usually. And the better warranty might pay off over a used car.
  • captain2captain2 Member Posts: 3,971
    those end-of-year clearance prices very rarely do anything but 'screw' those buyers that bought the car earlier - in resale values. 'Program' or lease cars dumped back onto lots can be very reasonably priced, and usually are both low mileage (with warranties remaining) and well maintained simply because those are the terms of leases. An 06 Taurus right off the Hertz lots can currently be had for about $11k with something under 20k miles on them. Don't think there is a more defendable choice, value wise, than buying any car (Avalons included) after somebody else has taken that first and/or second year depreciation hit. To purchase a new car is certainly a luxury that all of us can not afford, but when we do, I think it is important to understand that cheaper up front does not necessarily mean cheap to own.
  • joe131joe131 Member Posts: 998
    I already explained: cheaper up front is the only way some can afford to get a car, regardless of true cost to own over the years. And that goes for used and new cars.
    With maintenance costs high for parts and labor ($105 per hour in many cities) that first 20,000 to 30,000 miles while under warranty might be the cheap miles in spite of the new car depreciation. And if you get a LOT of incentives when buying new, the depreciation ends up being much less than if you paid whatever most people paid for the same model year car.
    I had a brand new 1996 Ford and its transmission self destructed EVERY 20,000 miles. I sold it when it was on its 3rd transmission and second motor. It had 58,000 miles on it. Best $800 I ever spent was on the $0 deductible extended warranty I got from the credit union lady. OVER $10,000 in major defect repairs in under 60,000 miles.
    But I bought it WAY under INVOICE and sold it privately for a good price so cost to own was not so bad. Time in shop was inconvenient, but I got a free rental under that warranty too. Over the years I've had total failures of 5 Ford transmissions and ZERO for all other brands. Fords have made up 20% of all my cars.
  • barnstormer64barnstormer64 Member Posts: 1,106
    If your car starts going slower up the hill as it goes on, you'll eventually reach a speed where it will more or les keep the same speed despite the accelerator being floored.(half throttle or full - hardly any differnece) You may have 200+ HP, but you ran out of torque.

    Nope, you ran out of horsepower. Either that, or you ran out of gear ratio (which affects torque at the WHEELS).
  • barnstormer64barnstormer64 Member Posts: 1,106
    It's as simple as that: Acceleration is directly proportional to force (i e torque at the driving wheel) and inversely proportional to mass.

    You forgot about pulleys!

    If you want more torque at the wheels, just apply a different gear ratio. That's what they're there for.

    Just like a pulley system allows you to lift more weight than you can with a straight lift. Or a lever. Remember the statement "give me a long enough lever, and I can lift the world"?

    Granted, you'll have to pull the rope twice as fast on a system of pulleys with a 2x mechanical advantage . . just like you'd need to get twice the rpm if you changed the gearing 2x. Either way, it's WORK (or HP) that keeps you moving/accelerating.
  • barnstormer64barnstormer64 Member Posts: 1,106
    the torque curve (which contains the time component in rpm) is, BY ITSELF, totally sufficient to judge the power of a motor.

    Not true at all. That only tells you how much the engine can "lift" . . but not how fast it can do it.

    What if the engine has gobs of torque, but can't exceed 1000 rpm because it get "winded"? That means it has very low HP . . all the torque in the world isn't going to help it . . unless you don't mind simply lifting heavy stumps out of the ground, instead of using it to power a vehicle.
  • jim101jim101 Member Posts: 252
    Ran out of torque, hmmmmmm, ja ever consider that maybe the catalytic converter might be dirty and or need replacing. As they become clogged they rob horsepower and torque.
  • bhmr59bhmr59 Member Posts: 1,601
    Who are you to decide an an extra hundred or two hundred bucks or so a month should determine whether one should be able to buy a new car?

    My property taxes went up $130 per month, electric bill will double from January to July (~550 Kwh just over $100), cable bill up $22/ month, gasoline $3.159 (up from $2.949 a week ago). Property taxes will go up about $280 on July 1.

    Different areas of the country have different costs of living and affect people's disposable income. Just don't give us the "only" $1 or 2 hundred bucks a month stuff.
  • joe131joe131 Member Posts: 998
    I think if you read my previous posts more carefully, you will understand why your post is wrong, but I'll repeat some of the info here for you in a little different order and using a few simpler words in another attempt to clarify it.

    I'll comment on your post from finish to beginning.

    Last you ask, "What if the engine has gobs of torque, but can't exceed 1000 rpm because it get "winded"?
    Read the answer here, ok? If the engine cannot exceed 1000 rpm then the graph of torque vs rpm (the torque curve) will reflect that. The curve will end at 1000 rpm. The calculated horsepower curve will also end at 1000 rpm since that is the maximum speed of the motor.

    Previous to that you guess that the torque curve only tells you how much the engine can "lift" but not how fast it can do it.
    Now why you bring that up I do not know. I never claimed the torque curve alone can tell how fast an engine can lift anything. And, by the way, in spite of your notable imagination, a horsepower curve does not tell you how fast an engine can "lift" either.

    And lastly, you first state that the torque curve by itself is NOT totally sufficient to judge the power of a motor.
    The answer is, "Oh yes it is!"
    Heres a reminder for you: Horsepower is just a label. Torque is also a label. A torque curve is a representation of measured torque over the rpm range of a motor. A horsepower curve is calculated from and totally dependent on the values in the torque curve being applied in a known mathematical formula. The label of force relative to rpm is thereby converted from the torque label to the horsepower label. There is NO additional information magically imparted to the graph by simple mathematical manipulation of the plotted points on the graph which compare force measured at different rpm levels. And before you can calculate horsepower for any rpm level, you must first measure torque at that same rpm value, then convert torque vs rpm to the horsepower label using the formula.
    The addition of a horsepower curve ONLY gives a more dramatic profile of force at rpms and adds another label on the graph.

    I understand your frustration in wanting to see a representation of how much time it takes for a motor to increase its rpms (or torque or horsepower), but the type of graph mentioned above (one containing torque and/or horsepower curves over rpms) just DOES NOT provide that information, whether labeled as either torque or horsepower plotted against rpms.

    To see the rate at which torque/horsepower/rpms values change, which is to say the time span over which a measured value changes, another meter of time in seconds/minutes/whatever would need to be calibrated across one axis of the graph too.

    The simple and most meaningful graph to represent how the power of a motor actually moves the car is to plot an acceleration curve for the whole car as it powers away from a stop up to its top speed. That calls for a stopwatch and a road test, well beyond the capability of a dynamometer (engine brake) machine.

    If you only really wanted to know how quickly a motor can rev up under whatever load, you could do that on a motor test stand. You'd need to connect the crankshaft to a tachometer and use a stopwatch to measure how long it takes for the motor's rpms to change from one level to another while applying your choice of loads resisting the rotation.

    Either way, you MUST add another measurement to the test. And that measurement is elapsed time which can easily be counted with a stopwatch.

    OK now?
  • captain2captain2 Member Posts: 3,971
    What if the engine has gobs of torque, but can't exceed 1000 rpm because it get "winded"? That means it has very low HP . . all the torque in the world isn't going to help it
    Exactly
  • hjc1hjc1 Member Posts: 183
    Enough is enough.....I think we talked this issue to death.
    All I know is my Azera gets me from point A to point B with no problems :=)
  • joe131joe131 Member Posts: 998
    And 2 + 2 = 4. Glad you can count. Big deal! So what?
    Simple math there, guy.
    High torque, low rpm motors exist, like in the over the road tractor-trailer rig mentioned before.
    So a motor that makes 2000 ft. lbs of torque at 1000 rpm also makes 381 horsepower at 1000 rpm. Big deal! So what?
    Torque and horsepower, may they rest in peace.
    And may we too?
  • imidazol97imidazol97 Member Posts: 27,132
    >You'd need to connect the crankshaft to a tachometer and use a stopwatch to measure how long it takes for the motor's rpms to change from one level to another while applying your choice of loads resisting the rotation

    That measurement would be meaningless because the motor has to turn the transmission input shaft and the car's mass is connected to that. In other words more torque will start the car moving better and speed up the car quicker to get to the next gear change to effect the same cycle again.

    Speeding up an unloaded motor is useless data.

    This torque vs. my car makes 350 horsepower so it's better spitting match has been boring for the last many posts. I can imagine new visitors reading this and leaving in droves saying, "I don't wanna be in an arguement..."

    2014 Malibu 2LT, 2015 Cruze 2LT,

  • plektoplekto Member Posts: 3,738
    My point earlier was that while MY vehicle doesn't run out of speed necessarily, all of us have had the situation where we are going up a long hill and it starts to struggle. If you wanted to pass/change speed, you whomp on the pedal and virtually nothing happens.

    That's torque. Going 60mph up a hill and wanting to go 70 - but the throttle just does nothing... You ran out of it/don't have enough. Going 1500rpm in overdrive just makes it worse as it takes time for your engine to spool up to where it's developing enough HP(or you can downshift hard, but that's a poor excuse when the engine supposedly has 250+HP) (GM and Ford are famous for this "wide-open-throttle-lag" scenario, thanks to their transmissions being so tall and the torque converter being so agressive)

    Now, sure, you *do* accelerate, but it's a slow roll-on instead of pushing you back in your seat and jumping NOW for that open spot in traffic.

    What is optimal is when the two values are roughly the same, of course(or what I and others call a "square" engine) So, for instance, a little VTEC with 200hp and 120lb-ft of torque isn't going to drive in traffic any better than a stock 140hp motor with the same torque. Oh sure, on the highway or on a track, it's a whole other animal, but slogging through traffic going 20 to 40 to 30 again - you'd be hard pressed to feel a difference. But a 180lb-ft/180HP engine will drive much quicker despite not having as much HP.
  • martin22martin22 Member Posts: 53
    FYI a "square" engine is one whose bore dimension is equal to its stroke dimension
  • plektoplekto Member Posts: 3,738
    True, in engineering terms, but I'm talking about how the graph looks - both lines almost overlapping each other.

    Perhaps a better term could be made to describe it...
  • joe131joe131 Member Posts: 998
    You say, "If you wanted to pass/change speed, you whomp on the pedal and virtually nothing happens.
    That's torque."
    Did you mean to say that is LACK of torque? That would make more sense.
    If you find yourself in a situation from which your car will not accelerate any more, it just means the torque available at whatever rpm you were at was just not great enough to produce the horsepower needed for the desired acceleration. You did not run out of torque/horsepower since neither went to zero. You just did not have a powerful enough motor to get the job done to your satisfaction.
    The the main thing you need in a motor is a significant amount of torque at low rpms and continuing to have a significant amount as the motor spins towards it's redline. If you have that, you'll have your horsepower and acceleration too. If you have more than a significant amount of torque over that same rpm range, then you'll have even more horsepower and acceleration to enjoy.
    Why you would think a motor which has equal peak amounts of torque and horsepower is optimal, I don't know. A motor that has a higher torque peak than its horsepower peak would be just fine too so long as it winds up to a high enough rpm to please you. But a motor with a lower torque peak than it's horsepower peak would not offer the relatively lively acceleration from low rpms that is so nice to have in normal traffic.
    So long as a motor has a redline allowing at least 5250 rpm, torque and horsepower values will always be equal at 5250 rpm. But peak values reached at differing rpm levels will not be equal.
    If the torque peak is achieved at any rpm over 5250, then the horsepower produced at that same rpm is going to be greater than the torque maximum. Later on in the rpm range of that same motor you eventually will have equal torque and horsepower at another certain rpm as torque begins to decline and horsepower declines at an even steeper rate. If the torque peak is achieved at less than 5250 rpm, then the horsepower generated at the rpm of peak torque will be less than that torque value.
    Best case would be high torque from very low rpm right up to redline.
  • barnstormer64barnstormer64 Member Posts: 1,106
    My point earlier was that while MY vehicle doesn't run out of speed necessarily, all of us have had the situation where we are going up a long hill and it starts to struggle. If you wanted to pass/change speed, you whomp on the pedal and virtually nothing happens. That's torque.

    Nope, that's lack of horsepower.

    You can always apply gearing to get more torque to the wheels. But then THAT would require more rpms from the engine. And if it ain't got the horsepower to do that, then you just can't go any faster.

    You've probably GOT that amount of torque available in the engine (with gearing) . . . but you don't have it at that SPEED (and incline).

    It's a bit of semantics, I suppose.
  • plektoplekto Member Posts: 3,738
    Did you mean to say that is LACK of torque? That would make more sense.
    If you find yourself in a situation from which your car will not accelerate any more, it just means the torque available at whatever rpm you were at was just not great enough to produce the horsepower needed for the desired acceleration. You did not run out of torque/horsepower since neither went to zero. You just did not have a powerful enough motor to get the job done to your satisfaction.
    *****
    This is exactly what I meant. Now, you can always downshift, of course, but there are times when downshifting will over-rev the car.

    The Grapevine in California is a perfect example - you get into a 40-45mph "zone" with a 4 cylinder car and you can't shift up as you lose your momentum, and there's not enough torque available to do more than eek up a bit at a time. Of course, to get enough speed out of it, you'd have to rev it near redline - so catch-22. You crawl up the hill instead of having enough mass in your engine to power your way up.

    Of course, this is a poblem with automatics far more than manuals because of the tall gearing(gaps are too wide to find an optimal torque/rpm ratio). Given that most Americans now drive automatics, the trend towards huge engines and HP is obvious. (of course between you and I, I'd rather have a lighter 4 with a 6 speed gearbox - problem solved.)

    IME, HP over 180-200 is unnecessary. But 250-300lb-ft of torque is a wonderful thing. Of course, you don't want a 1999 S500 either - big V8 with 4700lbs as well(no joke - really that heavy despite its ~300 HP) - loads of torque but loads of weight as well. It's a tricky process to make a lightweight engine and have enough mass to get enough torque. Of course, this is why I love superchargers. Problem solved. :)
  • joe131joe131 Member Posts: 998
    Heavy load/drag or steep incline; both have the same effect on the engine. The engine will get to a point where it just won't accelerate the car/truck any more. That would be a situation where you'd be better off with a torquer instead of a cammer.
    The torquer will have maximum torque at low rpms which exceeds maximum horsepower. The greater torque being made at low rpms will provide enough horsepower there to accelerate the vehicle despite the load and/or incline.
    The cammer, on the other hand, has very small torque numbers down low on the rpm band, but because it can rev really high it will have maximum horsepower up there which is much greater than maximum torque. The problem with the cammer is that to pull that load or get up that hill you have to be revving the motor up close to its horsepower peak, but at that rpm the motor's torque curve is decreasing which means the power to twist the crankshaft is becoming less and less in supply. And, you can't downshift to get back to the fat part of the torque curve because you'd over-rev the motor. So, it feels like you just run out of steam.
    With the torquer though, even at low rpm, enough horsepower is being made to sustain speed with a heavy load and/or up a hill with power to spare. Why? It is because at or close to the rpm of the torque peak, the horsepower curve is still going up! There is a power reserve with the torquer not available with the cammer in most driving situations.
    Generally, with other factors being equal, the more cubic inch displacement a motor has, the more torque it will have at lower rpms. The less displacement a motor has, the more likely it will spin to a higher rpm which most often results in peak horsepower being much higher than peak torque.
    One solution: turbocharge the smaller displacement motor. That will allow high torque beginning at low rpm and keep torque high for a much longer rpm range than a normally aspirated motor. As some gearheads like to say, its the area under the torque curve that really matters, not how high the curve reaches on the horsepower gauge. Whatever methods used to create that large area under the curve doesn't much matter. More cubic inches or more efficiency; both work fine.

    Is this all making sense to anyone out there?
  • joe131joe131 Member Posts: 998
    So to try to get up that hill a little faster what can you do? You say, " you can downshift hard, but that's a poor excuse when the engine supposedly has 250+HP."

    Yeah it has 250 horsepower, but only at 6000 rpm or so. The motor was probably only making 125 horsepower or so right before the downshift.

    The other thing you might try is lightening your load. Do you really need those back seat passengers? You could politely tell them to bail out.
  • joe131joe131 Member Posts: 998
    I said, You'd need to connect the crankshaft to a tachometer and use a stopwatch to measure how long it takes for the motor's rpms to change from one level to another while applying your choice of loads resisting the rotation.

    Somehow, it seems, you missed that important part of the sentence.
    The load you choose to apply could be a transmission and drive wheels on a resistance roller if you want. I don't see much value in timing the RPM rate of increase for a motor not connected to anything, although someone a while back was interested in it for some reason. And if he wanted to, he could apply HIS choice of load too, which might be no load at all.

    Fair enough?
  • captain2captain2 Member Posts: 3,971
    IME, HP over 180-200 is unnecessary
    unless, of course, you happen to be driving either the Lucerne 3.8 or the Ford 500 - both of which are relative 'dogs' in this class and, at least, in the 3.8s case with relatively high (and more accessible) torque compared to HP in a car that has the most difficulty holding speed when the terrain even gets slightly hilly. You and joe131 can drone on all you want about your precious torque, but any of several cars in this group are much better, faster and safer drives with a simple thing called HP.
  • plektoplekto Member Posts: 3,738
    WEll, of course, if you put a small engine in a huge and heavy car, it'll become a problem. But switching to the 3.6VVT would solve the problem. Just a little remapping otf the VVT controls and presto - isn't a slug anymore.
  • imidazol97imidazol97 Member Posts: 27,132
    >this group are much better, faster and safer drives

    "Safer" drives is a real stretch. I.e., 400 horsepower would make a 500 safer is what you've just stated.

    I disagree. My 3800 with 210 hp and high torque is great driving. And see the post the transmission doing block learn on driving styles and downshifting easily expected a driver who punches it more often...

    >You and joe131 can drone

    The droning is because someone doesn't accept that different people have different driving styles.

    2014 Malibu 2LT, 2015 Cruze 2LT,

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