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Last Post 30 Mar 2006 01:13 PM by  gidtup
Switching from RWD to FWD
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Slowdude
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21 Mar 2006 03:45 PM

    So as the first step in our family planning process, we gave the Miata to mom last week bought a Mini Cooper S. This is the first FWD car we have owned in a decade and it really feels strange. The handling is awesome at regular speeds but, in closed course testing, I feel like I am constantly understeering when hard in corners and I can’t seem to get the rear of the car to pivot no matter what ham fisted things I try. The car is totally stock and likely to remain so. Anyone have an autocross primer on FWD driving?

    I will probably run in STX this year because my wheel/tire budget will be going to finishing out my garage/auto mecca, plus these run-flats need to die ASAP.

    Thanks,

    John

    Lynn
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    21 Mar 2006 04:19 PM
    What?!!!! No Chevelle in STU? NOOOOOO. Oh, wait a minute, there's no Mercedes there anymore either.

    I hate FWD cars and have managed to avoid owning one. But I hear that you need to put a lot more air in the rear tires and pick up the throttle later in the turns.
    paulpro
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    21 Mar 2006 06:33 PM

    Front tires get more air in FWD, Lynn...AND you can brake all the way into corners (something I still can't get rid of in a Miata :) )

    Lynn
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    21 Mar 2006 07:54 PM
    I never said anything about braking. There is really no difference between RWD or FWD there. But most FWD cars don't allow as early a throttle application as most RWD tires. Inflating the rear tires past its optimum pressure will lessen understeer. Making the tires harder increases the effective spring rate of the rear suspension.
    Slowdude
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    22 Mar 2006 08:51 AM

    Lynn I saw that little "Nothin' but motor and tires" machine you are going to run and I have to say that looks like a TON of fun!! With the Mercedes being a hatch back, you can just put it in there and still use the car as a tow vehicle/rain racer.

    I am retiring the Chevelle due to boredom and with autocross alignment settings, it really tries to commit suicide driving to car shows in Tulsa, KC, Memphis, Nashville, etc. It really is a tramliner special on anything but the smoothest pavement. Does anyone know if the Mini alignment specs in this months Grassroots Motorsports are too aggressive for the daily driver?

    John

    Lynn
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    22 Mar 2006 09:17 AM
    John, you might want to ask about the Mini alignment specs in the Stock class forum. I'm sure guys like Craig Wilcox, Brian Garfield, and Jake Nygaard will have some good advice.
    96SM2
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    22 Mar 2006 09:41 AM
    Jerry Crump, Jan and Bryan have talked to Craig Wilcox, they probably have the specs for Minis also.
    DNPWWO
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    22 Mar 2006 10:44 PM

    The April GrassRoots Mag had the setup for MINI S, and yes Jan and Bryan have the setup.

    Why not run GS til you run the runflats out. They do handle good for the first 20,000 miles. I ran 6 Solos, 2 Wicks and a PDX on mine before getting new set. Bought same for street and bought a set of Khumos on BBS wheels for comp. FWD less air in front more in back. Try 30- in front and 55+ rear, then go from there.

    Larry K Green MINI S #6 GS

    ConeFusion
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    22 Mar 2006 11:29 PM

    Too bad that you won't bring out the Chevelle anymore. It certainly isn't the ideal autocross car, but it's beautiful. I always enjoyed seeing it.

    No need to argue [;)] about the higher/lower tire pressures. Both of them can work. A tire has its optimal grip at a certain pressure. From that point, you can reduce grip by running either higher or lower pressure. Which direction you want to go seems to be a matter of personal preference.

    Other ways of reducing understeer in Stock: Maximize front camber. Larger front swaybar (helps on many cars). Front toe-out (improves turn in). Rear toe-out (helps car rotate, but you'll probably want to set it back for street driving). Reduce rear camber. Shock adjustments.

    Imitation can be a very good car setup strategy. If top drivers are willing to share their setups, copying what they do is much easier (and most likely better) than figuring it out yourself. But keep in mind that tire pressures only apply to the tires they're running. You may need dramatically different pressures if you run different tires.

    DNPWWO
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    23 Mar 2006 12:26 PM

    I only mentioned 35F and 55R as the GoodYear Eagle runflats seem to like it. They will be slick enough to bring rear around as most like. At the arena I ran Khumos and had a 40F and 50R and wound up 35F and 35R and brought my time down 1sec. My size is 245/45/17 Stock Runflat and the Khumos are the same. Most run 16" in comp.

    Larry K.

    Slowdude
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    29 Mar 2006 10:05 AM

    OK, I am feeling STOOOOPID. [:$] Blame it on the fact that I normally drive older cars, but in this weekends closed course testing, it occured to me to turn off the Dynamic Stability Control. Holy cow what a difference. You can toss the car almost at will and traction is back to being a function of right foot pressure!! Woo Hoo! [:D] Now brakes on a turn rotate the car and too much gas sends you to the outside.

    I didn't realize how smoothly the DSC was compensating on twisty sections. Before this, the only time I had noticed the DSC light or felt the effects was on straight line 1-2 shifting/tire spin where it abruptly KILLS the power and tosses you forward, before kicking you back as it regains traction. I had no idea it has been smoothly keeping the back end in shape until I did the same section a few times with it on and off. It's like driving a different car. Gonna need stickier tires.....

    John

    mtuhro
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    29 Mar 2006 02:10 PM
    How did your times compare with DSC on vs. DSC off?
    DNPWWO
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    29 Mar 2006 09:36 PM
    I found a difference of 4-5secs difference in DSC on and off. You felt the difference right away, as with the DSC on it seemed as if you had no power on accelerating in turn, as the wheel spin created the DSC function. If you need put a post-it note on dash to remind you. Also, if you change tires at track, remember to reset tire monitor, it's worse than the DSC as it makes all sort of noise and turns DSC, tire and engine lights on, an really creates havoc when trying to push it to the limit.
    mtuhro
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    30 Mar 2006 07:27 AM

    It is unfortunate that the Mini does not have a DCS switch with multiple functions. In some vehicles the driver can select to turn off Traction Control only, or turn off Traction and Stability Control.

    I imagine that the more advanced drivers would turn Traction and Stability Control off before every run. However, when given a choice, I will turn Traction Control off and leave Stability Control on. This way I have control over the throttle, and still have Stability Control available if I get too far out of shape.

    gidtup
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    30 Mar 2006 07:43 AM

    I think the Grassroots Set Up will be a bit to much for everyday driving. We are just going to drive it at Walnut Ridge for its maiden outing. We are then going to ease into the alignment settings and see how much the street tires are affected.

    The car, stock is great and I can't wait to be on stickey tires this weekend. Driving Maupin's last year on sitckey's was so much fun. But then again Front Wheel Drive makes sense to me in my head. In fact did a few years in a red FWD and loved it, so this one will be great. Pulling around a turn is much better than pusing around a turn. [;)]

    Patrick Washburn
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    30 Mar 2006 12:46 PM
    Slowdude wrote:

    Does anyone know if the Mini alignment specs in this months Grassroots Motorsports are too aggressive for the daily driver?

    I don't live with one, I just borrow it occasionally, but it seemed fine on the road to me with an AX setup. (As far as drivability) I used to run my Neon with WAY more aggresive alignments than this, and I did live with that as a daily driver. Long term wear wasn't an issue. It was fine.

    gidtup
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    30 Mar 2006 01:13 PM

    Patrick

    Thanks - I was hoping not to wear out street tires monthly. I want to spend all my tire money on Khumo's [:D]

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