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Sagging Rockers anyone?

Discussion in 'General Mustang Discussion' started by Mach1 Driver, Jul 11, 2018.

  1. Horseplay

    Horseplay I Don't Care. Do you?

    BTW. Mark and Patrick know one another. He's just messing around. That said, Patrick is kind of a putz.
     
  2. msell66

    msell66 Burning Fossil Fuels Donator

    He’s kind of one but you....you’re a full blown putz.


    Mark
     
  3. msell66

    msell66 Burning Fossil Fuels Donator

    Sorry to go OT. That’s not like me.


    Mark
     
  4. Patrick Stapler

    Patrick Stapler Active Member

    You guys are awesome...well most of you.... Truth be told, I haven’t been here lately...spending lots of time herding cats elsewhere. It’s all good though. I do however stand by my previous remarks relative to chassis stiffening in general. I would also agree that all subframe connectors are not made equally. I do especially like the way CA adds connectors. They essentially turn the front and rear rails into one rail. In reality though, you probably couldn’t do it the way they do it on a street car as it’s pretty invasive to the floor.

    I also like the rear seat divider plate. There is no replacement for a full shear plate when trying to combat torsional twist. This is the primary reason why traditional subframe connectors do very little with regards to reducing torsional displacement...not enough cross sectional area and in the wrong location. Anyway, I hope my previous explanations do aid some.

    And Mark...your welcome. Hopefully you learned something as well.
     
  5. stangg

    stangg Active Member

    FYI... http://www.stangfix.com/threads/convertible-inner-rockers-in-a-coupe.10770/#post-134061

    In my opinion... If you are already replacing floors, then it's a practically a no brainer to add the inner rockers. On mine, I ran them the full length of the rockers where Shaun stopped at the leading edge of the rear torque box. Probably not a huge issue, and probably not worth going all the way if the rear torque boxes are good.
    I think I'd only use sub frame connectors if the whole underbody is original and sound.
     
  6. tarafied1

    tarafied1 Well-Known Member

    I have to throw in my two cents. I would think the Vert inners and related parts are better, no argument there, however, proof is in the pudding. I too have the full length invasive welded-in SFC that actually sandwich or encompass the original ends of the sub frames. In fact the rear suspension attaches thru my SFC.They do stick up in the rear floor pan and go thru the seat pans. Anyway, I have had my 67 a LONG time both before and after the SFC and with a big block. At the time I added the SFC I also added the passenger torque box and welded the seams on the shock towers. All of these changes made a noticeable difference. Maybe not as measured by engineering principles but certainly as measured by my "seat of the pants" so I am sure SFC do something. If I had to do it all over again I would do the vert rockers and seat pans though, as I am sure it is the strongest.
    Picture 262.jpg
    Picture 265.jpg
     
  7. phlegm

    phlegm Active Member

  8. Mach1 Driver

    Mach1 Driver Active Member

    Yes I know it well. That's the famous torsion test, which is the one and only such test as far as I know. There is a summary in post 79 on page 4 that is very enlightening. Its a very long thread running over 5 years. An export brace will reduce torsion by a whopping 25%, and the rear seat divider (metal sheet behind the seat) by 11%. He didn't try inner rockers but did try SFCs which did nothing.
     
  9. phlegm

    phlegm Active Member

    I haven't read it completely in quite a while.
    But I remember reading that the SFC helped with "ladder" strength (stopping the body from folding like a taco) but did nothing for reducing rotation
     
  10. phlegm

    phlegm Active Member

    I forgot to ask a follow up questions.

    Since the first post lists the inner rockers at "2.5 x 5.75 x 75"
    Would a section of 2x5 (or 2x6) 0.125 wall rectangular tubing welded above the floor/inner rocker junction be a suitable replacement option?

    And
    Where the inner rocker terminates at the front.
    How much strength would be lost if the inner rocker terminated at the toe board transition and was not cut through the the very front of the outer rocker?
     
  11. tarafied1

    tarafied1 Well-Known Member

    I skimmed thru it, looks like a lot of details. I didn't see where he tested a Welded-in SFC. I saw a picture of an elaborate SFC with all kinds of tubing and other braces but couldn't find any specific info on that being welded in.
    **edit** I found it.
     
    Last edited: Jul 13, 2018 at 2:09 PM
  12. Mach1 Driver

    Mach1 Driver Active Member

    As I recall they were initially bolted in, but I don't remember if they were welded also. It'll take a while to read it.
     
  13. tarafied1

    tarafied1 Well-Known Member

    I found it on post #66. He did weld in SFC and showed the same result as bolted in. I'm quite surprised at that
     
  14. Mach1 Driver

    Mach1 Driver Active Member

    The short answer is no. Those dimensions were given by one of the vendors- who knows how accurate they are. I believe I said approximately because of that. It is basically a C shape with an upward and downward flange on the ends of the C. That would make the body 4-3/4 with two 1/2" flanges. this thing is welded back to back with the outer rocker. If you make it taller than the existing structure you'll have an issue with the sill plate. You need to go to Street or Tracks website and look at their article. The inner rocker welds to the upper and lower pinch welds of the outer rocker. To accomplish this they cut the floor 1/4" from the outer rocker cover and removed the upward turned flange. This allowed the flange on the new inner rocker to stick down and be welded to the lower pinch weld. The floor was welded up to the bottom of the new inner rocker. There wouldn't be anywhere to weld a rectangular tube to the rocker. The outer rocker's inside cover is not a structural part, its just a cover.

    I don't see the point of cutting the inner rocker off before it gets into the front torque box. You couldn't transfer the load directly from the inner rocker via the torque box to the front sub frame. IMO its doesn't make sense to go that far and not finish the job.
     
    Patrick Stapler likes this.
  15. Mach1 Driver

    Mach1 Driver Active Member

    They don't have enough cross sectional area to do anything, they are just a long torque rod. Remember Chrysler's torsion bar suspension? That's the way I think of it, they just twist.
     
    Last edited: Jul 13, 2018 at 3:50 PM
    tarafied1 likes this.
  16. Horseplay

    Horseplay I Don't Care. Do you?

    I guess it should be said that all of this is really not necessary if you are simply building a car to drive. Unless you intend to do some serious track stuff or high horsepower drag racing its not needed. And if you are planning on ripping up the quarter mile you should be looking at installing a cage of some design which would provide WAY MORE affect in controlling all forms of chassis distortion.

    Most guys do a set of SFC because even in basic driving they help to stiffen up the car and reduce any minor flexing that can occur in a unibody design like our mustangs. The only time any "twisting" is happening is when you mash the pedal. And that is only IF, and it's a big IF, your car hooks and has enough torque to create the forces necessary.
     
  17. Patrick Stapler

    Patrick Stapler Active Member

  18. Mach1 Driver

    Mach1 Driver Active Member

    Its true that we don't need 500 hp, and we don't need Truetrac, and we don't need a top loader, but we all want it, and know that its only going to twist things a little more. Besides, I want it and don't need to rationalize it, so there!
    [​IMG]
     
  19. KBMWRS

    KBMWRS What did the moron say today?

    yeah what he said!;):p
     
  20. Horseplay

    Horseplay I Don't Care. Do you?

    I hear ya. Just wanted the more casual or newbie reading this to be clear. Plus, unless you will be ripping it up most weekends you have to balance the cost, intrusiveness of the work, etc. to determine how far to go and the path to follow.
     

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