a couple ?'s on custom a-arms

[62fairlane]

My design team and I are going to be finishing our suspension design in about a month here and got a few things we need to sort out.

1. bushing selection on the lower arms- I was looking at the suicidedoors.com bushings as I have heard good things about their products and would most likely grab some airride stuff from him at the same time.

2. Arm construction- we are placing airbags on the lower arms and the shocks off the upper arms. on these lower arms they will have to carry the load of the car and didn't know if an alloy steel .120" tube say 1.25" would really be enough?we have also been playing with the idea of an L arm on the bottom as it seems to be pretty common on most passenger cars now. With L arms the bushing in the joint of the L is firm (IE poly or similar) while the bushing on the leg is a softer rubber. the length of the leg takes up the deflection from the rubber but keeps harshness down. The other design we are looking at is a fabricated steel box section arm that would have a much higher bending moment to it. Since our new software package at school for CAD has built in FEA maybe we will just do both designs and have "numbers" to back up our choice.

3. Upper arms- we were planning on a modded circle track arm (GM style arm) The mod we were making was just a plate/bracket to allow mounting the shock end on the arm close to the UBJ. BUT the arms we are seeing seem to have solid metal bushings in them? I have seen poly bushings offered for these (speedwaymotors.com) but didn't know if they would go into the tube style uppers? Being a driver we would like to have a livable ride out of it hence the softer upper bushings....or will the solid bushings ride just fine?

[79T/Aman]

solid bushings are fine they are much more free than other bushings therfore they allow less transfer of road shock

[MoeBawlz]

fair warning about FEA analysis... if you arent proficient in it and really know what your doing, the numbers you get may not be what they really are and you could get yourself into trouble.