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Is there an advantage to a concrete filled bumper ?

Discussion in 'The Hokey Ass Message Board' started by swade41, Sep 25, 2010.

  1. So should I still make the bumper out of heavy wall pipe ? I know it would be better in an accident but sheeeees you guys are making me rethink everything...lol
    Right now the fuel cell and battery are the furtherest back in the bed they can go. The horizontal center of weight of these two is higher than the horizontal center of the engine. I had a thread about that placement as well and got some great feed back. Here's a look at the back of things.

    [​IMG]
     
  2. granny
    Joined: Apr 1, 2009
    Posts: 56

    granny
    Member
    from WA state

    If ya gotta add weight to stick a rwd car, adding it as far back as possible will get you the most weight transfer for the least amount of added weight. 5lbs added far enough behind the axle can transfer as much weight as 500lbs added near the axle, that's why weighted bumpers were so popular when tires and tracks were not so good.

    I've got two rear bumpers for my street/strip car, a lightweight stock one if i'm going to run on a sticky track, and one that has 95lbs of lead added that I use when the track (or street) is not so good. I also change spring rate and shock settings when switching back and forth...175lb/in with the heavy bumper, 100lb/in without. Unless you're sprung like a dump truck, ride height is going to change a bit, so i pair my spring sets w/ shims to get repeatable setups w/o needing to scale the car.
     
  3. Even if it did prove advantageous on the strip (which is very doubtful), for a street driven vehicle (especially a pickup, which is already hard to keep under you while turning hard) I'm willing to bet if you load that much weight all the way at the rear you'll be spending a lot of time going back the same direction you just came from... and if its raining you'll want to have a cutting torch along to cut it off with so you can get home alive.

    Nice truck by the way.


    JOE:cool:
     
  4. slepe67
    Joined: Jan 22, 2008
    Posts: 1,146

    slepe67
    Member

    what about filling SBC valve covers with lead? (the valve cover is actually the mold) pop out the huge lead slug and make another

    This would ensure you only used as much as you need. Install or remove as required...just thinkin out loud
     
  5. I'll be steel shopping tomorrow, have to see what wall thickness they offer 3 inch in.
     
  6. Brad54
    Joined: Apr 15, 2004
    Posts: 6,008

    Brad54
    Member
    from Atl Ga

    I'd think playing with tire pressure, spring rates and shocks would be a better plan.

    What suspension do you have in the truck now?

    It better be sealed tight, or they'll bounce you from the track for dripping water on the starting line.

    -Brad
     
  7. lewislynn
    Joined: Apr 29, 2006
    Posts: 1,473

    lewislynn
    Member

    Pipe bombs?
     
  8. prost34
    Joined: Mar 28, 2009
    Posts: 347

    prost34
    Member

    ,,isnt that where the term sand bagging came from?!!!:D
     
  9. shmoozo
    Joined: Aug 14, 2007
    Posts: 672

    shmoozo
    Member
    from Media, PA

    Looking on page 17 of The Rodder's Journal number twenty there is a picture of the rear of Ohio George Montgomery's 33 Willys gasser taken in about 1959. Bolted onto the back of the car is a 250 pound concrete "spare tire" which had been added to increase traction.

    The text of the article on page 16 describes the result as experienced at the 1959 NHRA Nationals which were held in Detroit:

    The caption for that image on page 17 does mention that the NHRA outlawed that particular form of ballast so it's probably a good idea to check the rules of the organization that sanctions the class you run to see the specifics on what can and cannot be done with respect to ballast.
     
  10. aaggie
    Joined: Nov 21, 2009
    Posts: 2,531

    aaggie
    ALLIANCE MEMBER

    Back in the '60s we were running a 392 Chrysler A/FD and used dental plaster to fill the blocks. We ran water in the heads only. The advantage was when you broke a rod it just dinged up the bore instead of shattering the block. Put in a new sleeve and you were back racing.
     
  11. mustangGTS
    Joined: Sep 18, 2010
    Posts: 28

    mustangGTS
    Member

    The tire compounds that you have available today, with what has been learned along the way about suspension geometry is the best answer. There are tons of guys that add weight, and tons that use chassis set to overcome these issues. The choice is really up to you.
     
  12. I ended up just capping the ends off with nothing inside. The pipe was a little over 1/8 wall X 52" and I used 1/4 for the mounting brackets, it can't weigh much more than 25 lbs.

    [​IMG]
     
  13. Falcon Gasser
    Joined: Aug 29, 2007
    Posts: 940

    Falcon Gasser
    Member

    I did not use concrete but used wheel weights in a 3 inch tube bumper, I did not notice any improvement in my 60 foot but it did slow the car down about a tenth and half and that worked out good at Milan running in the 11.50 index class but as soon as I removed it I went into the 11.30's. The entire bumper came in at 93 pounds. I was working to get a better 60 foot times with it and allowing me to keep the tire pressure up so it does not squirm at the top end.

    Jon
     

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