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Discussion Starter · #1 ·
I was wondering if anyone has connected front to rear unibody for added regidity, For two reasons i want this when im driving with the top of its obvi bouncy and I will get strut tower bars wich may help, if not for top they will for handlin, please if you have these or know where i might get some lmk, post pics if you can please!!! I searched and only found strut bars :(
 

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Madd Tyte JDM yo ®
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no one makes subframe connectors, or Unibody connectors as you call them. we have full length "Frame rails", albeit sheetmetal. the rocker panels provide a good deal of rigidity as well as the formed channels 8" inboard of the pinch rails on the rocker panels.

the only way to connect the front and rear is w/ a roll cage. strut tower braces do nothing to control torsional flex, neither do floor braces or trunk braces or anything else. a 6 point cage is the only real way to improve the stiffness.
 

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this has been discussed many people have tried stuff such as the foam injection stuff. I do belive there are other ways to make the frame stiff besides a 6pt cage. I have been considering making my own subframe connectors that would continue back to the trailing arms just got to work around quite a few clearances
 

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Madd Tyte JDM yo ®
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how would adding 2 bars tying the front subframe to the rear subframe stiffen the overall body?

you cant strengthen a bridge by adding material that runs parallel to its main length. you need to triangulate the pieces in a way to prevent movement on the parallel axis.

i guarantee you wont significantly strengthen a ruler by stacking another ruler on top of it and joining it at the ends. you need to take the parallel structures andjoin them on a vertical axis or triangulate them.
 

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if it doesnt work then why do so many people use them on so many other types of cars. The main thing holding the cars center is thin sheet metal by adding thicker bars or turbes across the main structural support of the car it resist saging in the middle of the car such as when the targa is off. You are correct this does not completly solve twist however it does prevent alot because it extends most the lenght of the car... look if you have a kleenex box for example it twist very easy now tape two pencils along the bottom of the box running parralell and tell me it does not make it harder to twist the box. It spreads the pressure elsewhere


Actually Im completly bs'ing my way threw this and dont know shit about structural support but I dont see why it would hurt to try and seeing as how they supposably work for so many other people with cars such as f-body's I dont see why it wouldnt for ours. My goal with this is to get rid of targa flex. Im willing to possibly run a 4/6pt roll bar but I will never accept having a full cage and targa bars to me are disgusting.
 

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Madd Tyte JDM yo ®
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the reason why it works on other cars is because they are made out of 0.120" wall 2"x3" box tubing and bolt to factory body mounts, or more effectively, weld into the subframes. when our cars are lowered, we have very little room under them, especially to have square steel tubing chilling under our floor boards.

we already have a 2"x3" box tubing spot welded to ou floors, its thin gauge sheet metal, but this is already in addition to the rocker panels. our rocker panels have gussets spot welded inside them.

the reason why your pencil method works is only if you tape the pencil along its entire length. this effectively attaches it to complete "Underbody" of the box and equally transferring its stress.

since our floors are only sheet metal, its not a feasible option to weld the box tubing the entire length of the floor... especially considering that there is sound deadener, wiring, undercoating, carpet and padding inside the car.
 

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okay Im starting to get it, however take a look at these http://www.bmrfabrication.com/F-bodyChassis.htm they do not weld onto the floor pan, if you use round tubing you can also have alot more clearance then using 2x3. The main portion of flex in a car would be in the direct center of the wheelbase would it not? Putting the bars there would bassicly connect the whole front to the rear. The bars would work as resistance against twist or flex. Even in the case that this does not work do you relise how many people run strut tower bars/ c-pillar bars or harness bars in our cars? So whats the harm of couple more useless bar as you see it.

anyways here is the thread I started bout it a couple months ago

http://www.supraforums.com/forum/showthread.php?t=340948
 

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Discussion Starter · #10 ·
I was just looking for something to help stop topless rattle and that bend feeling when i jam on it, ty guys
 

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DDDDUUUUUBBBBBZZZZZZZZ
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My friend runs a 388 stroker Chevy motor making 700+ in his mk3. Stock body/chassis/rear end. You have nothing to worry about
 

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TheFastCoonAss
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Targa brace stays mounted with or without the top on the car. Unfortunately I had it built by PROJECTSUPRA and he has no real desire to build any more. It was real labor intensive for him......
 

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I Love Lamp...
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Hardtop mod ftw!

If i recall correctly wasnt jawsgear designing some type of alternative subframe? I cant remember exactly what the deal was though...

Tim
 

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Madd Tyte JDM yo ®
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well, i hate to say it, even the MKIV's get cowl shake and torsional twist when getting on the throttle. ask anyone who has tried to launch/accelerate briskly from a stop w/ a topless MKIV; you develop 2 dimples right behind the driverside rear targa bolt. my friend's car has this problem because he tried a quick launch from a stop light when he first got his car.

just keep in mind, targa off= for show, cruising, etc. top on=go fast, launch hard.

you could do what the MKIV guys have done before; buy the a targa car, hard top sheet metal and convert the targa car to a hard top. a targa car converted to hard top will be stronger than a stock hard top because of the additional bracing on the targa car.

floor bracing isnt gonig to stop the cowl shake though...
 
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