Long story short: I wrapped up my rear end (http://www.jalopyjournal.com/forum/showthread.php?t=184446&page=2&highlight=triangulated+bar) and am building a triangulated 4bar set-up to work w/ radius rods. My question is, should the upper bars be parallel horizontally with the radius rods or tilt down slightly? Thanks. Jonny
It all depends on what you want the car to do under launch. Some things that come into play are your center of gravity, and wheel base. Quick answer, usually the lowers angle up, and the uppers are pretty close to level.
A better arrangement would have the lower bars level or down in front by about 2 degrees. The upper should be about 5 to 7 degrees down. If you drew a line to extend each forward, you would want them to intersect somewhere between the the front bumber and the back of the driver's seat, no higher than the front mount of the lower bar. This is general info for street applications with modest power. The more power and traction you have to work with the farther back and lower you want the intersect point. Every car varies, so this is a big ballpark. Race cars are very adjustable to find out what the car likes and street cars never have consistent conditions, so they use a more general approach.
I dont know about this, it seems like your car would squat alot. I'd have to draw it out though to really get an idea. You take a line from the contact patch of the rear tire to the intersection point of the two links, and where this crosses a vertical line through you front tire, you figure your amount of squat/anti-squat. This is based on how high it is in relation to the center of gravity of your car.
Whenever I think of setting up a 4bar suspension I think of the old gassers with the loooong ladder bars. Same concept, the farther forward the intersection point the more weight transfer to the rear axle. In theory, with the fourbar setup you have the ability to move that intersection poit for and aft of the car to tune the suspension for launch conditions and pinion angles. But typically the the lower bars are on a slight upward angle pointing up to the farme somewhere around the tranny area and the uppers are more flat.
<TABLE id=HB_Mail_Container height="100%" cellSpacing=0 cellPadding=0 width="100%" border=0 UNSELECTABLE="on"><TBODY><TR height="100%" UNSELECTABLE="on" width="100%"><TD id=HB_Focus_Element vAlign=top width="100%" background="" height=250 UNSELECTABLE="off">on my model a the triangulated bars are parallel to each launches good for a street ride. </TD></TR><TR UNSELECTABLE="on" hb_tag="1"><TD style="FONT-SIZE: 1pt" height=1 UNSELECTABLE="on"> </TD></TR></TBODY></TABLE>
Here's what I have done. Want to make sure it will work before solid welding everything. I bought a parallel 4bar from a local shop, and promptly cut it up to work with radius rods, as I didn't want to compromise my original look. Also the parallel set up interfered w/ the spring mounts. Figured it saved me SOME fabrication.. maybe not, having everything tapped out and brackets drilled etc. I separated the shock mount/rear bushing mount and cut off the upper tab to weld to the inboard of my rear end. I measured an equal distance in toward the pumpkin and tacked them on. The shock mounts went back in the box as I already have them welded on from before. I then put in a set of bars and saw where they landed in space. I angled them down slightly to intersect an imaginary line to the frame mount. Is this correct? I understand if they are tilted downward they essentally lift the center of the car under acceleration and take the forward shock of braking forces. I have built a chassis cross-brace to accept the front mounts of the upper arms, gusseted foward to the trans cross brace and mount. Please let me know if this is right, or if the upper bars should be parallel with the lower bar. From there, I ground the casting of the original radius rod, and the lower bushing mount slid right under it, as so I may solid weld it for the radius rod bushing to be recieved. I then sliced a long section out of the bottom of the radius rod to accept the heavy steel tubung from the 4bar setup. This will be solid welded, with tie rod ends at the frame. I'm open to any suggestions. Biggest thing is if the uppers should tilt out and down or out and parallel to the lowers. It's been jumped on and dropped from the jack to see if anything acts wierd while just tacked together and it all moves and nothing broke. Pinion angle seems pretty static. Thanks.
That's not what I did... I understood it that the lowers are level and the tops pitch slightly down toward the front, like Littleman's coupe (See pics). Are there just numerous ways to do this? I want to make sure my setup's going to be viable before laying too much welding rod into it tomorrow. Jonny
on my a the instant center ( the point where the top and bottom bars intersect) is about at the tranny and motor.....bad picture but you get the idea.....brandon
Excellent! Thanks. Looks like what I'm going for, except that I have shorter tops. I have them pitched so that an imaginary line extenting from them would pass through the lower bar's frame mount. Any more examples/suggustions are welcome. Jonny
I know mini truckers are somewhat looked down upon on here, but there is a guy by the name of Max from Biokustomz who has written several articles on the subject. And just so he's not type casted, he builds everything from rods, mini's, muscle cars to rock crawlers. Here's a link to one of his articles, as well as him trying to explain it, on another custom site. I would copy and paste the entire article but it's pretty lengthy. http://www.streetsourcemag.com/foru...85853&forum_id=16&forum_title=&M=False&S=True
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