Took our Prius to the race track...

Discussion in 'Gen 2 Prius Main Forum' started by snijd, Sep 28, 2008.

  1. snijd

    snijd DIY or die

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    I signed up my 18-year-old son for the Street Survival course, sponsored by Tire Rack, the BMW CCA Foundation, and the SCCA, and thought I'd share some of our experiences--from my son as the driver, from the instructor (and race car driver), and myself, as observer and, briefly, passenger.:eek:

    The training consisted of maneuvering for optimum cornering and obstacle avoidance, and emergency braking. While the car performed better than I expected, it clearly didn't match some of the performance vehicles on the course. Some observations:

    The VSC really works.:D It's nearly impossible to make the vehicle spin out of control, despite the most aggressive driver inputs. It may not make the corner you want it to, but it won't end up going the wrong direction (backwards or sideways), which was something I saw a lot of from the other vehicles in the program. He eventually learned to determine maximum cornering capability by just reaching the point where the VSC began beeping, and keeping it there. The tires were smoking at this point, so it really was about as far as the vehicle was going to go, in terms of lateral G.

    There is no pedal feedback from the ABS, unlike the older designs, where you can feel it in the pedal. I hadn't realized this until he started doing panic stops.

    He experimented repeatedly with different methods of entering a rapid lane-change scenario as fast as possible without hitting any cones. The most successful strategy was to use the brakes at the same time as steering into the other lane. This contradicted what I'd always heard about making rapid turns, since I thought the correct method was to slow first, and then make steering inputs. He could achieve the highest speeds by combining inputs. Maybe this has to do with VSC--I don't know.

    The instructor thought the primary problem with the vehicle was weight transfer during braking, when combined with turns. I asked if the stock Integrities could be the cause, and he agreed they might have something to do with this sensation of front-end instability.

    It was an interesting opportunity to compare the performance of cars with different technologies. You could really see the difference when watching non-ABS vehicles make panic stops--they would skid, and take much more distance to stop, on average.

    The instructor thought the VSC limited the usefulness of the Prius as a teaching tool, because it prevented reaching really out-of-control conditions, which they want the students to see. But I could see a big difference in my son's confidence level with the car, comparing his driving habits before and after the training. I hope that translates into safer driving skills, and doesn't simply turn him into an aspiring A.J. Foyt!

    I'm not entirely sure I'd recommend the training for everyone, although I thought it was a positive experience for my son. In any event, it probably served as an effective method of removing tread from my not-so-well-loved Integrities.;) When the winter tires come off next spring, I'll find some better rubber to put on the car.
     
  2. efusco

    efusco Moderator Emeritus
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    great report...I shutter to think what that little jaunt did to your tank MPG!!
    Still, it's something I'd enjoy going through one day for the experience of it.
     
  3. Stev0

    Stev0 Honorary Hong Kong Cavalier

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    What are you talking about? That sounds like my daily commute.
     
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  4. Bob64

    Bob64 Sapphire of the Blue Sky

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    A side effect: You can now hypermile more effectively by taking those 25mph turns at high speeds :)
     
  5. priusuk2008

    priusuk2008 New Member

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    Very interesting post, thanks. I think I would be so reluctant to put my Prius through that experience, particularly the smokin' tyres bit - I shuddered reading that... however I wouldn't mind doing it in someone elses Prius, any volunteers ?:rolleyes:
     
  6. jpadc

    jpadc Type before I think too often

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    Be careful when your son drives a car without VSC or without anti lock breaks. Such safety features are great, but if you are use to them and have little to no experience in a car without them, stuff that seems safe - just ain't
     
  7. snijd

    snijd DIY or die

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    The closest comparison I could make between this experience and everyday driving is a visit to Naples, Italy, where red lights are considered advisories to slow down a bit before continuing through the intersection...

    I had never thought much about the benefits of VSC, and some folks seem to dislike it a lot. I suspect my next car--and that of my son--will have it, though. He wants to buy our Prius, BTW.
     
  8. Tideland Prius

    Tideland Prius Moderator of the North
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    Great report! Yes you should slow down then turn but I'm guessing because of ABS. ABS allows the driver to steer while braking but I'm sure it has its limits and will understeer if you push it.

    It is also very front heavy. Look under the hood. The engine is in front of the front strut towers. Most cars have it over the strut tower or behind it (usually those are FR cars). So yeah the tyres played some role but the design of the Prius is also to blame.


    But the important thing is that you and your son know the limitations of the car which is something not everyone knows. After this, you can react when the situation arises and know how your car will react.
     
  9. donee

    donee New Member

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    Hi All,

    I have experienced the front-end instability phenomena on reverse crowns left turns in the Prius. All of a sudden the car goes tangent, and does not respond to steering inputs. I know the wheels were turned, as it snapped left once under a certain speed. I do not have VSC.

    After adding the BT Tech plate, this changed dramatically. And the car then responds similar to other front-wheel drive cars.
     
  10. hyo silver

    hyo silver Awaaaaay

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    Knowing the limits of your vehicle is always a good idea, and it's much better to learn them in a safe place instead of the street. Theoretically, race training should make for safer drivers, unless of course it only makes faster drivers. I remember showing my little brother once how fast the car could go and how it responded, but I don't think I did him - or the general populace - any favours.:)

    I'd like to see how well the Prius does with better tires, and a few chassis components. Maybe Presto feels like a drive into Washington...
     
  11. hyo silver

    hyo silver Awaaaaay

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    The front end still slides first (understeer), but at higher speeds than before. Don't ask me how I know this. ;)
     
  12. Rokeby

    Rokeby Member

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    What, if any, effect would you expect the BT Tech shock tower brace to have
    vis-a-vis understeer/sliding.
     
  13. drees

    drees Senior Member

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    Heh, sounds like fun. :)

    If the tires were really smoking, he probably could have gone a bit faster by easing up a bit. The slip angle on the tires would have been too big for maximum cornering loads.

    Interesting, I hadn't really noticed, even though I have engaged ABS a few times. Must have been thinking about something else at the time. :eek:

    Yes, it has everything to do with VSC.

    The reason it is suggested to most drivers to slow first, then corner, is because for the average driver, it is far too difficult to balance both cornering and stopping at the threshold without exceeding the limits of the tires and sending the car spinning.

    By first concentrating on slowing, then cornering, you give yourself fewer things to think about.

    But with VSC, you don't have to think about it, the VSC will keep the car pointing in the direction you wish to go while you ham-fist the controls as much as you like.

    If you tried the same thing in a car without VSC, you would do one of two things:

    1. Far exceed the load capabilities of the outside front tire sending the car into a push and hitting the outside cone.

    2. With the car slowing and turning at the same time, unload the rear tires and send the car into oversteer and spin out.

    The stock suspension and tires are far too soft for any serious sporty driving. Stiffer swaybars and even slightly sticker tires would go a long, long way to improving cornering feel.

    Yep, I agree. It's great practice to test and exceed the limits of a vehicle in a controlled environment, and VSC largely keeps you from doing that.

    It sounds like both you and your son learned something new about driving and the Prius, so the course was likely money and time well spent.

    And naturally, you burned about 10k mi off the Integrities at the same time, too. ;)
     
  14. Jack66

    Jack66 Kinda Jovial Member

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    Thanks for the report, snijd. I might take my daughters to one of those schools when they get older, but I also want my wife to read your comments on the VSC and ABS. She doesn't doubt they will work but she doesn't know what to expect if she has to use them. :)
     
  15. Qlara

    Qlara New Member

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    Did the Prius also make similar 'dog-peeing' position (rear wheel is in the air) during the rapid lane-changing routine?
     
  16. hobbit

    hobbit Senior Member

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    My own experience with this sort of thing is here, albeit not
    with my own car. Still quite instructive. They're of the
    "brake first, then start turning" school. And yes, this is a
    great way to buy a lot of new tires -- I wish I'd gotten a
    picture of the extreme tread-block cupping on what they had.
    .
    _H*
     
  17. a_gray_prius

    a_gray_prius Rare Non-Old-Blowhard Priuschat Member

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    This is one of the most awesome threads I've seen on PC. Too bad about the VSC, I'm sure some 4-wheel drifts would have been more productive at burning off the integrities.
     
  18. jelloslug

    jelloslug It buffed right out!

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    I have seen extreme tread-block cupping first hand. I had the opportunity to browse through a large selection of retired Bondurant Driving School Ford Taurus SHO cars and parts a few years ago and there were stack of SHO wheels with Goodyear Eagle +4 tires that were tread block cupped over 1/4" deep. None of the tires (or cars) had over 12,000 miles on them. I imagine that most of the cars spent as much of their life going sideways as they did going forward.
     
  19. hyo silver

    hyo silver Awaaaaay

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    I would expect it to tighten up the handling even more, especially in quick left-then-right turns, but I don't think it would improve the understeer. In fact, it might make it worse. I remember my high school car physics only vaguely, but I do recall something counter-intuitive about changing the stiffness of the opposite end of the car. Like, if the rear end slides first, it's too stiff, relative to the front, and either a smaller rear sway bar or a larger front one will fix it.

    When I first got the Prius, it felt like it was hinged in the middle. The front would turn first, and the back would follow sometime later. Hard cornering was out of the question, and it took awhile to get used to the lack of steering feel. I didn't like the handling at all. After installing a rear chassis brace, the car felt like the two ends were actually attached, and I could begin to explore the limitations of the tires. Which didn't take long - worn Integrities in the rain caused some serious understeer, which is far from my favourite driving sensation. New tires (Goodyear Triple Tread, 195/60/15) made a huge difference, and I wish I'd bought them right away instead of waiting so long. I've yet to slide either end since then, but I've heard some very satisfying noises from the tires. ;)

    As soon as there's a few more zeros in the bank account, I'd like to install more bits. I hear Presto has all the goodies and says it's one of the best handling cars he's ever driven. I should call him up and ask for a ride one of these days.
     
  20. snijd

    snijd DIY or die

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    Not that I observed, but I was a fair distance from this part of the track while observing.
     
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