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Re: Subframe connector options and opinions
#1161188
01/21/12 11:53 AM
01/21/12 11:53 AM
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Joined: Dec 2003
Posts: 22,784
Bitopia
jcc
If you can't dazzle em with diamonds..
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If you can't dazzle em with diamonds..
Joined: Dec 2003
Posts: 22,784
Bitopia
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Quote:
Quote:
The first question should be IMO, could someone describe and BACK UP at least, with sound reasoning, what actual forces sub frame connectors resist? I am not questioning many many positive reports of their improvements in ride etc. So are they resisting compression as the rear leafs push forward upon acceleration, are they resisting twist individually, if just under tension we can just use a steel cable, are they preventing a bending moment as front of leaf pushes up upon acceleration with a bending moment provided by the front mass of the car, ie engine, etc, are they just straightening out the force path thru 4 right? angle turns from the front hanger to the doorsills back to the TB crossmember, etc?.
If we knew what they are resisting, it would be a lot easier to design a solution. I suspect they are doing all the above, but some more then others, but which one? Say if twist was the main force, a large dia tube would be first choice, if bending moment, a tall I beam, yaw? bending, an I beam on its side, etc. My understanding is it needs to be the smallest and lightest shape/size that gets the job done. Anyone can oversize a solution, only a smart designer knows just how much is needed, if you way oversize, you look.....?
Years back member AAR? (patent attorney) had a lengthly thread on Subframe connectors, and main conclusion was the larger the crossection of the subframe, the stiffer, wall thickness provides a lot less stiffness then crossection increase gives. The installation advantages are numerous with the contour cut-out connectors, and installation ease IMO is thier only advantage. Performance wise, compared to a full tube they leave a lot on the table. 
Aren't the factory rockers in effect thick gauge sorta-square tubes connecting the front and rear subframes? If so, what do aftermarket subrame connectors do that they don't? Just add strength to the connection because you now have four subrame connectors instead of two? Perform some other function?
And although it might present clearance issues for driveshaft and/or exhaust, wouldn't an X-shaped subframe connector be much more rigid than two straight tubes?
IMO you are correct, add on sub frame connectors are just straighter factory rockers, on steroids.
An "X" design is usually just a replacement for a flat shear plate, for many reasons, some obvious, but an X would mainly be beneficial in this application would be if a force was being say applied by only one wheel during acceleration, and therefore trying to "shear" the car, however if an "x" was on four planes, bottom, top, sides, you would then have a very large "tube", and that would resist greatly any twist/torsion forces, which is of choice what most race cars accomplish with a full cage, but an x on one side doesn't seem to me get very much buck for bang.
Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.
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Re: Subframe connector options and opinions
[Re: domingo]
#1161198
01/21/12 01:10 PM
01/21/12 01:10 PM
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Joined: Jan 2003
Posts: 9,670
Lima, Peru
domingo
EL Master
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EL Master
Joined: Jan 2003
Posts: 9,670
Lima, Peru
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e brake bracket that needs to be modified....thats it!
Then if you want to you add the torque boxes I sell below and YOU ARE ALL SET. Super strong and you dont ruin your car as this is a mod I dont think you will regret or that will prevent you from enjoying your car as if it was unmodified. You can use your e brake cable, you have leg room on the rear seat, etc.
I do steer away from cutting up or modifying my cars, speciually if they are street cars. Of course I would not do this to an original HEMI car, or an RT or something rare....because you are cutting and welding. But on all my "clone", "tribute" or modified cars I do this. Its a nice upgrade and you cant really tell they have been modified unless you really know how these cars look from, the underside from the factory.
I was thinking about offering these connectors already bent, trimmed and ready to install, along with the modified E brake brackets to go along with my torque boxes offerings....
What do you guys think?
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, is that comparing a car with a cage and no frames ties, with a car just with just frame ties, or is that comparing car with a cage and no frame ties to a car with a cage and frame ties?
