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Old 10-04-2011, 08:27 PM
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Zedn Zedn is offline
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Join Date: Jun 2009
Location: Sydney, NSW
Cobra Make, Engine: RCM, Jag front and rear, LS3
Posts: 1,640
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Hi Mike,

Thanks for the feedback.

I was concerned about those points also. I spent a lot of time exploring options by looking at other cobras, and also a lot of hot rods. Also drew up a few sketches to calculate the displacement caused by the arc for various trailing arm lengths. The ideal situation is to have long arms that intersect with the axis of the inner fulcrum on the control arm. These virtually have to mount halway down the car next to the gear box (or to the rear of the car). This works on a hot rod but no chance on my chassis without hanging below and limiting ground clearance. Laurie (RCM) said that he used to use the jag arms modified to run on an angle by cutting them and rewelding. I chose not to use the jag arms because i dont like the look of them and i already had the parts to make my own, but apparently that works ok.

I considered Rose joints but thought they wouldnt provide enough movement to compensate for the arc and hence cause toe in. I couldnt run the arms straight cause they would clash with seat mount and exhaust holes in the chassis. I also considered going rearwards except the fuel tank gets in the way and there would also be no room for undercar exhaust.

With the shocks removed i can move the suspension through the full travel without any binding or noticeable drag so i dont think there will be any bump steer issues. Durability of bushes is a concern though. Only time will tell how this goes. If the jag bushes wear out i can replace them with Rose joints quite easily by just cutting and welding in a bung to the tube.

The patrol bush on the front provides a lot of flex as these are used on arms about 2/3 the length of mine and there is double the travel on 4x4 suspension when compared to a cobra. The tube for the rear bush is welded on at a slight vertical angle so as to match the angle of the control arms at ride height.

I think it should be ok. Only time will tell!
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