sectioning front struts

[CTR98]

Many non-stock class autocrossers shorten their struts. I shortened mine two inches when I switched to coil-overs and then put in some shorter Illuminas sourced from Ground Control. Pretty easy to do if you can weld or have friends who can weld. Just remember you have to take the inches out of the middle of the strut housing as you need to have the threads on top for the strut caps.

[jmortensen]

There is already a great how-to on hybridz.org but it assumes the use of Koni struts. If you're talking Illuminas, the BZ3099 is the MR2 rear that fits in the front of the 240 and is 1.5 inches shorter. Use the standard 240 front in the rear and it is 2" shorter. Or you could use the BZ3099 front and rear with spacers in the rear.

I think sectioning about 2" from the top of the strut is ideal. I want to say that Ground Control's instructions say to section right at the bottom of the strut, but this seems like a dangerous place to do the work. First off if you totally screw up the weld then you can't grind out the part that you messed up. And secondly, if your weld is really bad and breaks, the bottom of the strut could detach from the strut tube, and at that point it's a matter of what you're going to hit before the car slides to a stop. You could make the argument that if you're that bad at welding you probably shouldn't be welding your strut housings in the first place...

If you section above the spring perch then the loading from the spring goes down the strut tube not up, so the welded area only takes lateral forces and pulling forces from the extension of the strut (if you were to jump the car or have it on a rack with the suspension hanging). If the weld were to break while driving it would make a hell of a noise, but it would be impossible for the control arm to move down far enough for the strut insert to fall out of the tube.

When I did mine I just used hose clamps to attach the strut tube to a piece of angle iron to hold them in line, and tacked them together, then welded it up. It was really easy, and the Illuminas that I'm using aren't nearly as tight in the bore of the tube as the Konis so the fitment isn't so hyper critical.

EDIT--The BZ3099 uses thicker threaded portion at the top of the plate than the stock Z stuff. I bought adapters to fit them into my camber plates from Ground Control, not sure what mods would be needed for stock strut tops.

Jon

[hls30.com]

Jon,

Thanks for the info! I will hunt down that article this evening. I am going to remove the perch weld on a lathe, and probably could just use a parting tool to cut the strut, re-thread the remaining strut tube, and re-position and weld the perch-alleviating the need for tube allignment.

Thanks again,

Will