alloutt

with what and how often?

SlideWRX

If you are staying with Poly bushings, then a panhard bar *brace* is pointless; it's replacing a piece of metal with a heavier piece of metal, while all the suspension bushings will be doing the flexing. A strut tower bar at least replaces air with metal. By the time the panhard brace would be usefull, the car would likely have a cage. The panhard bar will definitely help though.

jayel579

http://www.partsamerica.com/productd...egoryCode=3245

Use what ever you want but every oil change.They call it a LOFR (pronouncedloffer)at your local shop, Lube, Oil, Filter, Rotate(tires).

Norm Peterson

Linear rate is what you want, and you might even consider a coil-over setup. Then you have a much wider choice in spring rates, and the rates themselves are no longertied to the ride height (which affects suspension geometry not necessarily in the right direction).

I think Sam Strano might be the guy to talk to. His focus is autocross, but those items aren't the sort of tuning part that would differ between auto-X and open tracking. I have, however, heard of a PHB that failed through one of the ends where one of thepoly bushings is retained.

I'm not sure what 'slop' you're referring to,so it might be something as simple as wheels that aren't as wide as what the tires can stand.

Poly bushings are a mixed bag - definitely not a magic bullet for handling. The stiffness of that material that provides good fore/aft axle location works against you when the car rolls in the turns. Kind of like an extra, virtualsta-bar, so your tuning with poly is not the same as it would be for OE bushings or any of the various spherical pivots that are available. There are 'Johnny-joints' from Currie, and a poly-ball from J & M, though I'm not sure about availability. And there's a midway step you can get away with on out-of-the-box poly bushings that gains you some of the spherical pivot benefits without giving up too much elsewhere.

More similar than either vs drag racing. Autocross is by far the more transient-intensive event, and rarely involves anything above 2nd gear, so shocks/struts are relatively more important in auto-X if you're at all serious about it. Beyond that, it would be about which class and what modifications are allowed. That road course speeds are quite a bit higher matters, and unless you're actually competing wheel-to-wheel you'll probably want to maintain a little more conservatism in your setup on the road course, where a spin may not go as lightly disciplined as a cloud of tire smoke and minor embarassment. A little looseness that helps get you turned in on a lane change or through a slalom probably doesn't belong with cornering speeds that may approach 3 digits. For example, a little static toe-out can help at auto-X but is apt to make things twitchy at higher speeds.


Norm

Norm Peterson

BTW, poly should not be lubed with petroleum-based products. There are specific lubes for that material(and marine silicone lube works pretty well too).


Norm

UrS4

Norm,

I have been checking out different coilover kits and I found one from MM.

The Sport Box includes the following parts:
[ul][*]MM Panhard Bar with Aluminum Rod[*]MM Caster/Camber Plates[*]H&R Cup kit with springs, shocks and struts[*]Eibach front and rear sway bar kit [/ul]
Its about $2100 bucks so it isn't cheap. Either that or I will call griggs and see what they have that is similar and maybe add in their TorqueArm kit and some LCA.

My concern about the coilover kit, while I really like the ride height adjustability, is picking the best spring rates for my application. I have heard to go stiffer than the non-coilover spring rates but I guess I would have to go with whatever Griggs suggested as I don't know.

My only concern about the TA is that with my one piece DS, if I lower the car how do I correct the pinion angle as I think the TA eliminates the need for the UCA?

Thanks for your help Norm

Norm Peterson

I don't think I'd swap a 3-link out for a torque arm, even one with an upper as short as the S197's OE piece. Too much work for little (if any) gain, and possibly even a small step backward (theoretically speaking).Keep in mind that Sam Strano did quite well in a Stock category Shelby at both the Solo Nationals and the Pro-Solo this past September, and that Pro-Solo specifically involves a dragstrip-style start. IOW, the basic arrangement is pretty good from the get-go, so I think a little tuning of the various bits will get it where you want it. Springs, shocks, sta-bars, and bushings. The next step might be PHB lowering, though that would cause a re-think of at least the rear sta-bar and/or springs in order to restore the handling balance. More difficult would be tinkering with the upper link length, assuming that any extra length could be accommodated without generating any physical interferences or compromising the anti-squat % curve.

All that said, pinion angle correction with a TA would most likely involve either tapered shims or a torque arm design that allows length adjustments of top and/or bottom tubes via something like rod ends.

As far as picking the "best" spring rates is concerned - the best you can get is fairly close with a few spreadsheet calculations, though quite a bit of information is required. But don't be surprised if a test session has you considering changing something - I'm told that this sort of thing commonly happens even at the OE level where much more complex techniques are available. In addition to locating thevarious suspension points, some general vehicle data and even personal preferences concerning ride and understeer/oversteer balance are needed. Coilover spring rates themselves also depend on whether their motion ratios differ from the conventional springs that they are replacing, and for a given wheel rate coilovers can be softer than comparable conventionals if (for example) they are replacing springs midway out the control arm as on either end of a Fox/SN95. The catch seems to be that once you get the spring out nearer the wheel, relatively stiffer springing is still tolerable.


Norm