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Selecting and Buying My First Car



  • ateixeiraateixeira Posts: 72,587
    First post, by the creator of the thread:

    partyboye1 Oct 31, 2003 5:05pm

    So I guess there's more than one person shopping.

    I wasn't confused then nor am I now.

  • steine13steine13 Posts: 2,714
    Let's take two run-of-the-mill vehicles; 2001 Explorer XLT (4045 lbs) and a 2001 Corolla LE (2445 lbs). Say they're both going the same speed (v) and collide head on, and say they will just crash into each other and fuse into one piece of mangled metal. It happens.

    The force on the people inside is determined by their acceleration, and the acceleration is different in the two vehicles... inasmuch as right after the impact, the whole mess will be moving in the Explorer's original direction, because the Explorer is heavier.

    If you work it out, you'll find that the force on the poor people inside the Corolla is 65% stronger than the force on the people in the Explorer.


    Warning: Math below.
    The total momentum before the impact is equal to the momentum after the impact. Explorer: P1= m1 * v; Corolla: P2= m2 * (-v). Therefore, the momentum of the whole mess is P=P1+P2=v*(m1-m2).
    Note that if the two cars have the same mass, their individual momenta are equal and opposite, and the total momentum before the crash is indeed zero.

    Immediately after the crash, the momentum is conserved, and the mess of mangled metal has momentum P=(m1+m2)*u, where "u" is the speed of the mess. It's in the original direction of travel of the Explorer.
    Since P is constant, u*(m1+m2) =v(m1-m2) or u = v* (m1-m2)/(m1+m2). Things will be more legible if we define e=(m1-m2)/(m1+m2). In our case, e = 0.2465.

    The Explorer people accelerate from v down to u... said another way, they experience a change in velocity that is v*(1-e). The Corolla people accelerate from v down to u -- in the opposite direction. That means their change in velocity is v*(1+e).

    Therefore, the people in the Corolla experience a change in velocity -- and therefore, accleration, and therefore, force -- that is (1+e)/(1-e) greater than the change experienced by the people in the Explorer. Using the numbers from the example, they get hit 65% harder.

    This is all very schematic and makes some very simple assumptions, but the basic physics behind it is sound. It's like the Corolla is crashing into a solid wall at v(1+e) and the Explorer crashes at v(1-e).
    Survivability is still very much a function of the design of each car and the design of the restraint systems.

    Exhaustively yours, -Mathias
  • ateixeiraateixeira Posts: 72,587
    I have a major problem with that example - the cars are not comparable in cost or category.

    Basically the chances someone is cross-shopping those two vehicles is nil, so it's just not a useful example.

    If someone comes here and says they are cross-shopping a 2002 Corolla with a 2001 Accord, then I can see the Accord being recommended due to its larger crumple zones, greater mass, and perhaps even extra safety features.

    But a Corolla and an Explorer? Doubtful.

    Most people shop a certain class of vehicle within a certain price range. So if they're shopping for a Corolla, they might also consider a Protege and Civic. You might be able to talk them up to a Camry, perhaps a couple of years older, on the basis of having the extra mass to protect you.

    But I don't think you'll talk the same person into an Explorer or Grand Marquis.

    "You want a compact sedan? Sure, here's a large truck you'll just love".

    If you were a salesman they'd laugh in your face and drive off.

  • Kirstie_HKirstie_H Posts: 11,077
    steine13, you CANNOT just include math and physics like that without a warning in the header! "Ye math-impaired, avert your eyes."

    It seems like we're veering kind of far off topic here. Some of you may recall a little-known discussion about liking & disliking SUVs over on the SUVs board. I think this subject was covered about as exhaustively as possible in that topic, but if you have a fresh idea, please talk to tidester & steve over in SUVs. This is getting more technical than the interest level merits in our first-time buyers discussion.


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  • manamalmanamal Posts: 434
    You are assuming an elastic collision. Any deformation of the cars will absorb some of the energy. With that said, I would rather be in the exploder than the corrolla in your example. However, I would rather be in a modern car with Airbags and cruple zones at 3000 lbs than a 1966 Chevy, which will transfer much of the energy to the occupents.
  • ateixeiraateixeira Posts: 72,587
    Sorry, let's try to steer back on track.

    I think an SUV is probably not the best choice for a newbie driver. Combining inexperience with all that top-heavy mass and less agile handling makes everyone else on the road less safe. ;-)

    Truth is, the best vehicle for a 16 year old is probably a bicycle. Or the bus. LOL

  • steine13steine13 Posts: 2,714
    "Basically the chances someone is cross-shopping those two vehicles is nil, so it's just not a useful example."
    I'm not talking about cross-shopping, I'm trying to flesh out the "marble/bowling ball" argument.

    "It seems like we're veering kind of far off topic here."
    No we're not. When someone is looking to buy a car with a fixed price in mind, there will be trade-offs in economy, safety, reliability, etc.
    Since the discussion very properly veered into the safety aspects of weight, I thought I'd put some numbers to it.
    In the example, it was a difference of two thirds, not something terrible like a factor of ten. I find that relevant.

    I picked an SUV simply because they are heavy, I was not trying to get into THAT argument. Have it your way: Crown Victoria it is.

    "You are assuming an elastic collision."
    No, a plastic collison -- it's ONE body afterwards.

    "Any deformation of the cars will absorb some of the energy."
    Actually, nearly ALL the energy goes into deformation of cars and occupants. The rest goes to heat the pavement, as wrecks screech to a stop.

  • Manamal:

    Momentum is conserved in a collision energy is not. Big difference ! So in spite of all the energy lost to metal deformation (etc) the jolt to the small car driver is still significantly greater and is described by the momentum equations.


    When I looked up the specs on a 2004 Exploder XLT it weighed just under 4500 pounds. Therefore your little calculation may just be somewhat low.


    I don't know why I am wasting my words on you. Nonetheless, nobody is comparing buying an Exploder to a Corolla. These are the vehicles you are literally and figuratively likely to run into driving around. If you are driving a Corolla you better watch out for the Explorers.
  • ateixeiraateixeira Posts: 72,587
    I still don't see a Corolla cross-shopped with a Crown Vic. ;-)

    But I do get what you're saying.

    Still, I'd pick the agile car to escape the collision completely. Quicker acceleration, better braking, and higher handling limits can help get you out of trouble.

    Noone keeps statistics on "close calls" and accidents that don't happen.

    I just can't accept the thought that you are a sitting duck and cannot avoid most collisions. Drive defensively, always leave yourself an "out", and practice good situational awareness.

    The Miata is a puny car, just 2300 pounds, yet death rates are average. It's not a death trap like you might assume.

    Why? It's agile and can avoid accidents, plus drivers are mature and experienced (median age in the 40s).

  • ateixeiraateixeira Posts: 72,587
    you better watch out for the Explorers


    More mass can do more harm to other cars, particularly small ones, but telling everyone to go out and get large cars does not make the roads safer for the general public.

  • I actually hadn't been considering any of the F-body cars, until I drove a '97 Camaro the other day. I really liked it. I thought the clutch was great :) I'm still wondering about reliability/gas mileage/insurance, though. (I'm just looking at the V-6, or possibly the base V-8.)

    Any input?
  • Between a '97 Mustang and a '97 Camaro, which would be the better option as far as reliability? Assuming they both have similar mileage, options, and engine types, of course. (Please, try to keep the violent Ford vs. Chevy arguments to a minimum :)
  • qbrozenqbrozen Posts: 25,961
    well, asking for reliability of Ford vs. Chevy is just asking for trouble. ;)

    Well, let's say its a GT vs. a Z28. The Z will cost a bit more (according to Edmunds numbers), but will be quite a bit faster (almost a full second to 60), but its a couple hundred pounds heavier. BUT, you want to know about reliability. I'd say flip a coin. I've always been partial to the Chevy 350 in terms of parts availability, ease of repair, and general reliability, but the Ford 4.6 has proven itself over the years to have pretty stout internals. I've found you can usually count on all the pumps needing replacement on the Ford at about 140K miles, but that's really not a huge deal, if you are a mechanic that is (IIRC correctly, that oil pump that will fail at 140K needs to have the engine jacked up and oil pan removed).

    '18 BMW 330xi; '67 Coronet R/T; '14 Town&Country Limited; '18 BMW X2. 47-car history and counting!

  • Well I might be a bit biased on this topic.

    I've owned 6 F-bodies (3 Camaros, 3 Firebirds) and no Mustangs.

    The V-8 Z-28 Camaro or Firebird Formula/Trans Am are the performance bargain of the century. These cars are a rocket. That Corvette derived LS1 or LT1 engines are remarkable in that they have mucho horsepower down at the low RPM's where you can use it.

    The difference in the V-6 versions and the V-8's are:
    The power difference (of coarse)
    The V-8's have a tighter suspensiona and handle better around corners
    The V-8's have that cool V-8 growl

    Think of the V-6 as a sporty looking car with a little more power that handles better than a family sedan. Think of the V-8 as a little rocket waiting for you to unleash it.

    Expect reliability to be about average compared to a wide selection of cars (much better than a Hyundai or VW but not as good as a Toyota). I would think that reliability of a Camaro versus a Mustang would be about the same. Check the reliability ratings here on Edmunds. My one little comment is that (in my experience) Ford parts tend to be expensive relative to GM parts. So just maybe it will cost a bit more to repair a Mustang.

    Expect your insurance to be higher on a sports car than on a econobox or a family sedan. That V-8 Camaro likes to idle down the road at about 80 miles per hour. If you are young and unmarried with a poor driving record then expect to pay through the nose for insurance. I had a (young) friend who after getting three or four speeding tickets was paying more for his insurance than his Z-28 car payment. The V-6 version insurance rates are much better since the horsepower is less. Since I'm a good driver my rates were just a bit higher than for any other car. You'll need to talk to your insurance company to find out the rates for you. Do this on any car that you are considering Camaro or otherwise.

    Gas Mileage on either the V-8 or the V-6 are pretty good - much better than you would expect. I used to get 24-25 miles per gallon in a V-8 Firebird formula on my 45 miles commute to work. The V-6 Firebird that I had was a bit better and got maybe 26 mpg. You can look up the EPA mileage numbers on these cars here on edmunds.

    The other thing about these cars is the fun factor - and they are great in this category. Life is too short to drive an econobox.
  • ateixeiraateixeira Posts: 72,587
    Watch out for insurance rates, those can kill you with pony cars.

    Death rates are also horrible, but I think a lot of that is just the demographic they appeal to, mostly young males.

  • Real world injury rates for the Camaro are average when compared against all cars. Camaro injury rates were 20 percent less than a Mustang. pdf - see the end of the document for the sports cars

    For what it's worth the Camaro received the best barrier crash test rating of ANY car when it was crash tested in 1994.

    I will concede though that performance cars tend to attract a reckless demographic skewing accident statistics
  • ateixeiraateixeira Posts: 72,587
    Yeah, my neighbor's kid owned a few of both those cars, and he kept telling me Camaros were cheaper to insure, despite being quicker.

    Still, I think there are better choices for a first car.

    Ironically, my first car was a used Mustang, a 1981 Mustang Ghia with a 3.3l I-6 engine. It was junk, though, slow and still had sky-high insurance rates. I really think it was a poor decision on my dad's part to give me that particular car (it was a surprise).

  • asafonovasafonov MinneapolisPosts: 409
    I am looking at the PDF sheet that you posted a link for, and I am a bit puzzled. I see that "twin" models (Corolla-Prizm, Villager-Quest) have substantially different rates on all three parameters, injury, collision and theft. I can see how theft rates can be different, but different injury and collision rates in vehicles that differ only cosmetically?
  • steine13steine13 Posts: 2,714
    Different demographics, different drivers, different accident rates. Life's messy. -Mathias
  • Asafonov:

    Well that twin paradox is puzzling isn't it ?

    I can only guess:
    Perhaps the demographics and ability to drive a car of the two driver populations (Corolla & Prism) are different. Perhaps the cars are similar but they are not exactly the same. Their differences result in different collision and and likelihood of accident characteristics.

    Maybe another poster has some ideas ?
  • joey16joey16 Posts: 2
    Hey everyone, I'm coming to the point where I'm going to be getting a car fairly soon. I'm 16 going to be 17 in June. And I'm starting to look around for vehicles. I know that whenever I go to a dealership or something they see how young I am and think "Oh boy, time to take advantage of a young ignorant kid." But hopefully with the help of some elders here I won't be the ignorant kid they think. I overall just would like for people's advice on what I should and shouldn't do. Like for example already a dealer tried to tell me I should finance, but I know I don't want to end up paying more. So if anyone could give me pointers it'd be great! Thanks.
  • ghuletghulet Posts: 2,628 aren't legally allowed (in most, if not all states) to sign a contract to finance a car until you're 18. Also, if you don't have any credit established (also virtually impossible til after you're 18), most lenders wouldn't loan you the money for a car anyway. I'd save your money or, if you're parents are willing and able, let them buy you a car. Don't buy anything too fast, too expensive, too large, or piggish with fuel. Don't forget about insurance (check rates before you consider ANY car, it's a MAJOR expense for a guy your age), upkeep, repairs and gas. Actually sit down and budget to see if you can reasonably afford what you'd like to buy (while still being able to eat, go the movies, buy clothing or whatever else you like to do). Are you going to college? If so, are you paying for some or all of it? I've seen more than one person forced to drop out of college to pay for some old car. Think about the future. Most people your age (myself included at that time) tend to buy cars based on emotion rather than reason. Try to avoid doing that. Do some research, ask your parents or another trusted relative for guidance if they've had decent luck with cars.


    Also, this probably isn't what you want to hear, but consider whether you actually 'need' a car at 16 or 17, or whether you could get by using a family car, the bus or getting rides from family, neighbors, friends and co-workers. Cars are expensive, it's not a decision to be taken lightly. To many younger people, they initially represent 'freedom', but in reality, they take a lot of time (working, worrying) and financial freedom away from you, no matter what age you are. You can talk yourself into buying a car because you 'need' one to get to work (at likely a lower-paying job), only to discover you're working almost exclusively to pay for the car, to the detriment of your grades, your family responsibilities and your remaining social life. Most of us have already learned this the hard way. Be careful, and good luck!
  • tmarttmart Spring, TXPosts: 1,391
    Very good advice.
  • jlawrence01jlawrence01 Posts: 1,828
    I agree with Ghulet. While a car seems to be a necessity, do you really want to go in debt on a car especially when it would be better to save for a college education / trade school?


    If you do buy a car, buy cheap. There is no need for you to own a $20k car at this stage in your life. I would look for a 7-8 year old Escort, Buick, etc. with about 85k for somewhere in the ballpark of $3-4k. The cars tend to be pretty reliable but make sure that you have a mechanic check it out for you.


    As for how to get an advantage on the purchase, do your homework. If you run out and buy without doing the research, you will get an expensive lesson. Dealers are there to make a profit. I am there to get the best possible deal, It is a zero-sum game in that anything that the dealer gets comes out of my pocket.


    Unless you can get a co-signer (parent or relative), this whole discussion is moot. That is, most smart people will not sell to a minor. Why? Because in Contract Law 101, any contract is VOIDABLE. That means that the minor can cancel any transaction or IOW, the seller could have the sale fall through after completion. Your cosigner won't have that option.


    Hope that helps.
  • joey16joey16 Posts: 2
    Hey thanks for all the advice so far, I appreciate it. I understand that many of the things involving buying a car will also involve my parents, I know they will be the ones to sign for things etc. But I just want to gain knowledge so I learn early, I want to go to a dealership and have a salesperson be surprised at my knowledge. Also about needing a car, I think it'd help because I've rode my bike for a year or so and I ride everywhere, from 2-8 miles to get places. But I don't just ride to get around, I ride for fun as I'm into the whole bmx seen. Plus I love being independant and not having to work around others schedule to get around. That's a big reason why I got a job 8 months ago, because I wanted to buy what I want, when I want (as well as start saving for my future).
  • andre1969andre1969 Posts: 23,534
    that you're working, and trying to be independent at such a young age, but just don't let the car purchase consume you, and ultimately hold you back.


    I got my first car a few months before I turned 17. It was free, as my Mom gave me her old 1980 Malibu coupe. But my stepdad made me get an insurance policy in my own name, which when you're 16 or 17 ain't cheap! And if you're male, I don't think it becomes cheap until you turn 25! At least, that's when mine really went down, but I also got married at 25, which helped too.


    But anyway, I still remember that first year of insurance. $1,361. And that was back in 1987! I'm sure it would be a LOT more than that today! I was working at a veterinary clinic part time after school back then, maybe 19-21 hours per week. In the summer, they'd let me work more, like 35-40. It only came out to like $4000 per year, so essentially just the car insurance was taking 1/3 of my take-home! And then there was gas, maintenance, repairs, etc.


    I was still able to save a little money, but at that time there was no way that I would've been able to go out and actually buy something from the dealership! At least, not anything fairly new. And it's not like I could pick up any more hours because of this little time-waster called "school" ;-)


    And that's an important thing. Make sure that you don't get in over your head by over-working yourself to pay for the car, and making your school work suffer. You may not feel the pain now, but ultimately that's something that you could be paying the penalty for, for years to come, as it might be harder to get into a decent college, or even a community college, reduced wages down the road, etc...
  • ateixeiraateixeira Posts: 72,587
    Go to a car show, and narrow down your choices there, by shopping cars that you fit into comfortably and have the room for your stuff.


    Once you've narrowed it down, do you shopping on the 'net.


    At least that way you deal with a car dealership as little as possible. You will need to do test drives, but show your research and hopefully they will take you seriously, especially since you went through all that trouble and even got a price quote.


  • audia8qaudia8q Posts: 3,138
    Good advice
  • jchan2jchan2 Posts: 4,956
    Buy something with lower insurance rates- I'm thinking more Honda Accord, Toyota Camry type cars. That is, if you can find one used in your price range. If not, the Ford Taurus is a decent ride- nothing special but at least it gets you where you're going.
  • ghuletghulet Posts: 2,628
    ...for the record, that Camrys and Accords are cheap to insure, based on theft rates alone. I'm pretty sure Hondas in general are among the most expensive vehicles to insure.
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