Re: AMC Handling
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Re: AMC Handling



There is understeer built into the rear leaf setup; the front spring perch is higher than the rear shackle pivot, so there's a geometry change when a spring gets compressed.

Recurving the rear springs flatter, with taller shackles to achieve the same height will undo this. You will absolutely need to add a panhard etc to counteract the side slop, especially with tall shackles.

Lowering blocks between the axle and spring will drop it safely, easily, and cheaply; however it increases axle wrap-up, so you'll need a "traction bar" setup or equiv. I was gonna use flat stock to sneak beside the spring front pivot bolt and a braced bracket bolted under the spring U-bolts for the far end.

Braking forces will make the rear axle oscillate (shudder) by wrapping the springs up (reverse of a drag racer's problem :-) so the traction bars are required with lowering blocks.

I did this on my '79 AMX I used to autocross; but I broke the car before I ever got the panhard and bars built. Instead of taller shackles, I made 2" blocks and bolt extensions for the shackle chassis mount. There's very little force on them, hence the factory pair of 5/16" studs.

I may go back and do all this to my 70 hornet.



On Dec 29, 2005, at 11:35 AM, Sandwich Maker wrote:

" From: farna@xxxxxxx
"
"
" You'll also need to tighten up the rear springs. Either add a leaf or
" use one of the short "half leaf" bolt on stiffeners. Also add a panhard
" rod or Watt's link to control sideways movement -- yes, even with leaf
" springs. A nice four link would be even better. A 1/2"-3/4" sway bar
" would be a good idea also. You don't want the rear as stiff as the front
" though, it will handle funny then!


the rule of thumb for camaros, with a generally similar geometry to
'70s amcs, is fronts 50% stiffer than rears.

" One more thing -- get wheel weight down! Weld Draglite wheels or similar,
" and lighter calipers. I've been exploring the lighter caliper bit. There
" are aluminum replacements for the 82-83 style Concord/Spirit GM calipers,
" but they state "for off road use only". They are ISCA certified for
" racing though. Speedway carries them (www.speedwaymotors.com). I wonder
" why not for street use when they are cetified for road racing and circle
" track? That's got to be harder use!


that just means they're not dot [or whatever] certified for road use.
racing use is harder, but they get more maintenance. snow/salt
corrosion isn't a problem for instance.
______________________________________________________________________ __
Andrew Hay the genius nature
internet rambler is to see what all have seen
adh@xxxxxxxxxxxxxxxxx and think what none thought













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