Thanks guys. I have the hotchkis adjustable strut rods as well, lower control arm stiffening plates, firm feel solid tie rods and a new borgenson power steering box so this should drive 150% better than the factory setup. The only things left are a new sway bar and T-bars....still trying to decide on which ones to use. Any ideas on those? I am thinking the 1.03 pst or the equivalent firm feel bars
Sounds like you've got a good plan! :thumbup:
The 1.03" PST bars are a good choice for most people I think. PST has NEVER given the actual wheel rate for those bars, but based on the generic spring equation it should be around 220 to 230 lb/in. With that kind of rate I would still want a good set of shocks like the RCD Bilsteins. The closest Firm Feel bars would be their 1.06's, which have a 252 lb/in wheel rate. That's what I bought for my Dart. My Duster has FFI 1.12" bars, with a 300 lb/in rate. But that car was built with the intention of running autoX. I do drive it almost daily, as it's my primary transportation. It's definitely stiff, but not intolerable. I actually like it the way it is. I do run Hotchkis Fox shocks on it though, and they do work better for the larger 1.12" bars than the Bilsteins did (I ran them previously).
good question on the t bars.
Do Firm Feel,PST and Just Suspension 1" torsion bars
have identical resistance to twist?
No, not at all. The problem is that neither Just Suspension or PST actually publish the wheel rates for their bars, so the best you can do is use a generic constant for spring steel in the torsion bar wheel rate equation based on their diameter. If you compare the published numbers for the larger Mopar Performance bars and the Firm Feel bars though you see that even bars of the same diameter can have different wheel rates based on the steel used. I worked the equations backwards to get some different constants from the companies that actually publish their wheel rates, which is where I get my wheel rate ranges for a given diameter.
But I've run the Just Suspension 1" torsion bars. They were pretty soft for their diameter, and based on the equations and my experience running them compared to other torsion bars I would say they're probably closer to 185 lb/in or so. Based solely on diameter they should be between 185 and 200 lb/in. I have not run the PST 1.03's, but based on their diameter and a generic constant for spring steel they should be somewhere between 220 and 230 lb/in or so. Firm Feel actually publishes it's wheel rates, their 1" bars are 195 lb/in, their 1.06's are 252 lb/in, and their 1.12's (which I run now) are 300 lb/in.
Just depends on how crazy/accurate you want to be. For the most part the numbers are tied to the diameter of the bars. For large changes in diameter you really only need to consider the diameter. It's when you start comparing bars that are the same diameter but from different manufacturers, or bars that are close in diameter from different manufacturers that things get interesting. I mean, .03" doesn't sound like much, but it could mean a difference of 20-30 lb/in on the wheel rate (or more!), which is more than a 10% difference in the wheel rate if you're comparing 1" to 1.03" bars.
