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Thread: 620R vs. Atom 3.5R on track

  1. #11
    Join Date
    Feb 2009
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    NYC
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    Quote Originally Posted by BruceBe View Post
    ...it's just more difficult to click off consistent fast laps, in race traffic, when all that "milking the cow" is going on through the corners.
    Having observed quite a few people from this club forum on track, I can attest to that euphemism in their cornering styles.
    However, the end results are more like 15 year old teenage boys!


    Quote Originally Posted by BruceBe View Post
    It *is* a driver challenge to become confident, competent, and fast in a download car. Lovely stuff, if you can invest the time and get comfortable with the very dynamic handling characteristics.
    Yes, I failed!

    Quote Originally Posted by BruceBe View Post
    The CSR is a different beast - it feels like a more modern car. Once a CSR takes a "set" in the corner, it's easier to maintain composure, apply power, and keep mechanical grip.
    Thats very well said - exactly how it feels in my CSR.
    Mike
    2010 Caterham CSR with Cosworth 2.3 Duratec
    2018 Caterham 420R with 2L Duratec 210hp at Donington UK
    1975 BMW CSL Group 4 (restoration - engine and dry sump install time)
    1977 Holden Torana "A9X" (awaiting restoration)
    1985 Holden Commodore SS Group A
    1985 Holden Commodore Group A
    1982 Ferrari 400i
    1965 Ford Mustang Fastback "Holman Moody"
    1992 Ford Escort RS Cosworth WRC (fettling after long period of storage)
    1990 Range Rover 2 door Classic
    and another project car coming....

  2. #12
    Join Date
    Oct 2006
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    Cincinnati
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    3,671

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    I always have assumed that, with its 50-50 balance, a se7en would be more manageable on the track than the tail heavy Atom, esp in the hands of we amateur drivers. The Atom's 40-60 front/back distribution is similar to the 911's.
    Kitcat:AKA, Sir Spinsalot
    '97 Caterham Super Sprint, 1700 Crossflow-sold
    '09 Birkin S3, Duratec-sold
    '03 Caterham Zetec track car
    '19 Honda Type R, sold
    '19 Miata Clubsport

  3. #13
    Join Date
    Apr 2007
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    Bozeman MT
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    497

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    It seems to be fairly simple - the Caterham has more torque than the tires can put to the ground given it's weight and weight distribution. The Atom has wider tires and much more weight on the rears so it can put power to the floor and it doesn't battle power-on oversteer and wheel spin every time the driver gives it the boot.

    I autocross against a well driven supercharged Atom at nearly every event I do (owned by a local friend of mine) and its ability to put power down far surpasses my Westfield S2000. It weighs just a bit more, makes much more power and can put it all down so the acceleration can't be challenged. Yet it's extremely rare for it to post a faster time and it comes down to two key things....first is that the Westie is narrower and in slaloms and sweepers that makes my course shorter and that adds up quickly. Secondly the Westie is much better in violent transitions with much less tendency for it to wag its tail or spin due to having a more even weight distribution and a much lower polar moment of inertia.

    I'm sure that on an open track like the Atom and Caterham were on my friend's Atom would just walk away from my Westfield with ease.

    dave

  4. #14
    Join Date
    Feb 2010
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    The weight distribution argument, with respect to putting power down is valid. One is a rear mid-engine car (Atom), and the other is a front mid-engine car.

    I would guess that the Westie's lower tendency to over-steer has more to do with roll-couple distribution, and managing weight transfer due to driving style/skill. The biggest speed part in a car is behind the wheel.

    Cheers,
    -Bruce
    Beachman Racing
    Authorized Caterham Cars dealer

  5. #15
    Join Date
    Feb 2009
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    NYC
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    In my track tag times with non-wing Atoms at NJMP, I have always observed them to have a nervous front end that washes out somewhat in corners. So the weight distribution argument works both ways in terms of advantages and disadvantages. It will depend on the track format. On an open track, 350hp vs 309hp in similar weight cars usually has a predictable outcome.

    Still, I enjoyed watching the full Fifth Gear episode last night to see what happened to the Xenos and Radical. They should show that more on tv. There are only so many re-runs of Ancient Aliens I can take!
    Mike
    2010 Caterham CSR with Cosworth 2.3 Duratec
    2018 Caterham 420R with 2L Duratec 210hp at Donington UK
    1975 BMW CSL Group 4 (restoration - engine and dry sump install time)
    1977 Holden Torana "A9X" (awaiting restoration)
    1985 Holden Commodore SS Group A
    1985 Holden Commodore Group A
    1982 Ferrari 400i
    1965 Ford Mustang Fastback "Holman Moody"
    1992 Ford Escort RS Cosworth WRC (fettling after long period of storage)
    1990 Range Rover 2 door Classic
    and another project car coming....

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