Driveshaft Loop Needed?

Discussion in 'Street/strip 400/430/455' started by Bogus919, Aug 22, 2022.

  1. Bogus919

    Bogus919 Silver Level contributor

    I'm thinking of taking the GS to the local track and visited their website for a quick rundown on rules/regulations. It's telling me if I run a quarter in under 14 seconds I need a driveshaft loop. I looked an example up online and was wondering what you guys are running and how you have it mounted? The stock 70GS stage 1 was running under a 14 quarter and I figure I'm at least at that point in my build so will probably have to follow these rules.

    Also, how strict is this? I figured if I ran fast enough I might have to wear a helmet and my car would need to meet the basics like a good windshield, tires, brakes... etc.

    This is for test and tune also, if that matters... this isn't competing in a bracket or anything... if you can't tell, I've never done this before lol.

    Thanks for the info
     
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  2. Brett Slater

    Brett Slater Super Moderator Staff Member

    It's cheap insurance to make sure your driveshaft doesn't end up sitting next to you in the front seat should the unthinkable happen.

    There's a couple options out there as well that you'll find with a quick Google search, too.

    You can either drill through your floorboards or get one that bolts between the transmission and the mount. Ideally, the Steve Caruso units are the best - they bolt under the crossmember - but he's no longer making them.

    James Weinman recently did a batch of them, so maybe reach out to him and see if he has any left.
     
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  3. Bogus919

    Bogus919 Silver Level contributor

    I like the idea of drilling and mounting on the crossmember vs drilling into the tub of the car. Thanks Brett.

    Something I noticed on another website (and not he site of the track I'm going to) is that this requirement is for cars that run better than 14 in the quarter with slicks and 11.5 in the quarter on street tires. I'll for sure be in street tires.
     
  4. Stevem

    Stevem Well-Known Member

    Its needed, period!

    On a buddy of mines car the driveshaft tore right in half and came up thru the floor board right next to his seat with the car doing over 128 mph.
    It was only 1.5 inches away from grabbing his seat belt which would have wound the belt up and cut him in half, this did not happen to him due to the driveshaft loop being where it was!
    Be safe and alive because you 100% never know what the day may bring.
     
  5. hugger

    hugger Well-Known Member

    Not many tracks tech ,...and unless your making over 450hp I myself wouldn't worry,..and 9 out 10x if it breaks its in the first 5ft
     
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  6. hugger

    hugger Well-Known Member

    It's obviously not a bad idea but on street tires and low hp,...ehh
     
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  7. Brett Slater

    Brett Slater Super Moderator Staff Member

    Here's an option that requires no drilling: https://www.opgi.com/drivetrain/dri...loop-driveshaft-1961-72-gm-th400-g240622.html
     
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  8. Bogus919

    Bogus919 Silver Level contributor

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  9. FLGS400

    FLGS400 Gold Level Contributor

    It's been 20-years or more since I ran a car there, but the only thing they checked in tech at Bradenton was that I had a drive side seat belt, no rear hubcaps, and an over-flow catch for the radiator. I ran a 3rd gen Camaro, a 1971 Nova, and a 1972 Monte Carlo there on street tires back then.
     
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  10. Mark Demko

    Mark Demko Well-Known Member

    I kinda sorta agree it’s needed if your hooking at the start.
    ESPECIALLY with questionable overseas U joints.
    Who knows how good the metallurgy actually is.
    I might put one on mine:cool:
     
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  11. D STAGE 2 455

    D STAGE 2 455 Well-Known Member

    I wonder if that driveshaft issue at over 128mph wasn't a critical speed issue. Either way, the drive shaft loop did its job.
     
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  12. Tomahawk

    Tomahawk Platinum Level Contributor

    That's what I'm thinking too. $100ish seems worth it for a tangible insurance policy.
     
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  13. Gary Bohannon

    Gary Bohannon Well-Known Member

    The best way to lose a driveshaft is to pull apart your u-joint at the alumite. Any greasable u-joint MUST be installed with the rotation pushing on the alumite opposed to pulling. Many get pulled apart right at the threaded hole.
    You may need a driveshaft loop at 300 hp and street tires if the u-joint is not installed correctly. Seen it happen.
     
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  14. sean Buick 76

    sean Buick 76 Buick Nut

    Yes do a loop and while your at it resolve the stock driveshaft they aren’t very strong. I just had a new driveshaft made and it was crazy how thin the old one was.
     
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  15. Bogus919

    Bogus919 Silver Level contributor

    That's good info Rich, I appreciate the first hand experience with that track. Just looking to do a few high speed passes to see where I'm at. I run it up to 80 here on the street because everybody else is driving that fast on the highway but I feel guilty doing any more in a bright orange car that sticks out like a sore thumb! :eek:
     
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  16. Stevem

    Stevem Well-Known Member

    The failure had nothing to do with the mph.
    I made a video of my buddy's run that day and at the moment he crossed the line and heard him let off the throttle, the shaft then gave up.

    The shift in rotating load from compression to expansion final took its toll!

    A driveshaft loop is like a handy fire extinguisher, you never really think about or wish you had one until in the after math you wish you had such!
     
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  17. Jeremy Zepnick

    Jeremy Zepnick STEELMAN

    Hi, not much info on drive shaft loops on here. As to front placement or rear placement, or as to photos of what ppl have done, or what products are best.

    I don't want to read about retired fabrication products. Can people post a product that is currently available on the market with specifications/pictures of said product installed?
     
  18. Tomahawk

    Tomahawk Platinum Level Contributor

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  19. cjeboyle

    cjeboyle Gold Level Contributor

    I’ve been out to Bradenton Motorsports a couple times, same as Doc, for test and tune. I was also very concerned about tech so I put a driveshaft loop in, bought a good helmet, changed out the coolant for water with a wetter and headed to the track. I signed my life away and headed for the line. They checked nothing! The only thing I heard was “Roll up your window”. I did see one guy they wouldn’t let run because he did not have long pants. I ran mid 12’s on drag radials.
    Cliff
     
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  20. hugger

    hugger Well-Known Member

    On a stock chassis you're limited to a front mount shaft as there is too much suspension movement to mount one in the rear

    The best location imo is welded to the floor brace that's about 8in behind the yoke iirc,.. simple bolt together unit heat and bend the tabs to match the angle of the floor brace,..or piece of sch 80 pipe welded to the brace
     

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