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Thread: Launch?

  1. #1
    Senior Member Phx99Cobra's Avatar
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    Launch?

    I just bought a slightly used pair of et drags. I have a stock 99 irs system. I know it is not very strong but I am still going to go out and see what my car can do. What is the maxium rpm I should or rather can I leave at that is a safe level.
    jlt cai, o/r bassani x-pipe,magna pack cat back, tri-ax, sct tune by keith @ az dyno chip, solid axle w/ 4.10 gears
    Best time...12.797 @ 108.5 mph w/ 1.76 60ft
    New Best Time....12.3911 @ 106.3 w/ 1.589 60ft
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    New Toy - 2003 GT stroker, procharger and to much other s**t to list ***SOLD***

  2. #2
    Administrator BurnTire's Avatar
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    Give it a try at 3000-3500.
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    2004 Cobra, Whipple ,TH-400
    Burning Corn
    9.97 - 135.5

  3. #3
    Senior Member 93mustank's Avatar
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    Launch off the limiter

  4. #4
    Member 99_venom's Avatar
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    A 99 IRS and slicks is a double edge sword...
    Wheel hop is the fastest way to break and axle in an IRS.
    Slicks stop wheel hop...
    But with a 99 IRS if you go out to see what it will do, it'll break.
    93mustank has the best information of the two, then it will break right there at the line and you won't have to worry about it breaking when you power shift second and then smacking the wall.

    Really, be very careful with the slicks. Condsider them to be there ONLY to stop the wheel hop. You still want to slip the clutch a little to launch it easy. Try about a 3000-3500 launch and see how it does. Don't dump the clutch but don't let it slip very much either, just takes a little practice.

    Before you go I would suggest the following stub shaft check procedure:
    http://www.lx.net/jlynch/stub_inspect.html
    Then if it holds together check it again when you get home. Breaking a stub shaft is nasty business because only the brake caliper is holding the wheel under the car after that. And the wheel will be pointing a bad direction for cruising down the track at 100 mph.

    I have the Raxle Axles in my 99 IRS and I have done a best of 1.69 on ET Streets with the IRS. I have been too chicken to really launch it hard even with the better axles, cover brace, locker, 4.30 gears...good luck
    '11 Mustang 5.0 GT Premium Convertable
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  5. #5
    Senior Member 93mustank's Avatar
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    I was just messin..........get solid.......

  6. #6
    Senior Member Phx99Cobra's Avatar
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    Wow, now I feel uncomfortable about driving. I dont want to be going down the track and have a wheel fall off.
    jlt cai, o/r bassani x-pipe,magna pack cat back, tri-ax, sct tune by keith @ az dyno chip, solid axle w/ 4.10 gears
    Best time...12.797 @ 108.5 mph w/ 1.76 60ft
    New Best Time....12.3911 @ 106.3 w/ 1.589 60ft
    SOLD

    New Toy - 2003 GT stroker, procharger and to much other s**t to list ***SOLD***

  7. #7
    Super Moderator Gene's Avatar
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    Quote Originally Posted by Phx99Cobra View Post
    Wow, now I feel uncomfortable about driving. I dont want to be going down the track and have a wheel fall off.
    You should forget about it and buy my seats

  8. #8
    Administrator BurnTire's Avatar
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    Quote Originally Posted by Gene View Post
    You should forget about it and buy my seats
    Yes the seats are more form fitting than the 99's.

    A broken half shaft does not mean a wheel will leave the car. The hubs are pressed into the bearings and the calipers also retain things.
    Sold
    2004 Cobra, Whipple ,TH-400
    Burning Corn
    9.97 - 135.5

  9. #9
    Super Moderator Gene's Avatar
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    Quote Originally Posted by BurnTire View Post
    Yes the seats are more form fitting than the 99's.

    A broken half shaft does not mean a wheel will leave the car. The hubs are pressed into the bearings and the calipers also retain things.
    Yea, just ask Ethan. He knows how it feels.

  10. #10
    Junior Member 169stang's Avatar
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    IRS+Slicks=carnage!
    In an 03 Cobra, I've left at 3800rpm on ET Streets with a 1.68 60' and it lived many passes...........but has had all bushings replaced. No wheel hop at all. This was at a FFW event and had to run the time! I wouldn't leave that hard for just a T&T night!
    Lethalperformance.com

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