Looking at Tubular K member

AAndrews said
Hey Rassnasty82,

Just so you can see what the RMS kit looks like in a real car and not an advertisement, here's pics of my install.

I previously had the original K-Frame welded and gussetted , 11/16 tie rods and sleeves, boxed lower control arms and revamped power steering box , all new strut rods and bushings, K&N shocks, re-arched rear springs. Took the whole works out and sold it to use RMS Suspension.

With the new setup , header install is a breeze, , steering is fantastic with great feel, no more wandering, car is absoultely locked in in the turns and is a blast to drive fast in the twisties.

I know there are several members on here who really know how to make the factory stuff perform well and I wish I had been on this site longer as I might have learned how to make it perform better but now I don't have the time to be fu#king around with suspension setups trying to "get it right". My cruising season is short enough as it is. 5000 miles later and I'm very happy with the new setup.

That being said, if budget is an issue , its cheaper to modify your existing suspension but you will need to follow the suggestions by 72bluNblu, AutoXcuda and a couple of others on here who can really dial in the stock suspension. Just be prepared to experiment a lot to get it right.

Heres the whole setup for the front end . Notice that the coil-over mount is integrated into the k-frame and does not use the inner fenders for anything. I actually filled the holes in the inner fenders when I did the body work.

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RMS Alter K ation installed!

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Frame rails tied and torque boxes installed.
United Car tool Components used. Very beefy and fit well.

This is a must to get the car rigid enough for good handling.

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Good luck with your project and post some pics of your car!

Cheers!!

If the car was wandering there was probably an easy solution. The proper alignment is the biggest culprit, if you use the factory alignment specs for bias ply tires with radials it will wander all over the place. With tubular UCA's you can add more positive caster than you can get with the factory stuff, and that will cure the wandering issue. Unless it's a worn out steering box or parts.

Rack and pinion vs original worm and ball shouldn't be that different either. The worm and ball stuff will always have a small on center "dead" spot, but if everything is in good working order and properly adjusted it should be small. New or rebuilt steering boxes should make it small enough that it shouldn't be worth the expense of the upgrade for a small change in feel.

And it shouldn't take a lot of experimentation to get it right. It's really a simple formula- larger torsion bars, high quality shocks, a modern alignment with the proper amount of positive caster (the SKOSH chart plus some if you can get it), and you should be in good shape. Coilovers and torsion bars + shocks are both just springs and shocks.

The coil over conversions are just modified MII suspension. So, you can upgrade your Mopar suspension, or you can upgrade Pinto suspension. An RMS is just Pinto based suspension with all tubular aftermarket parts on a modified K frame. There was a time you couldn't get all those parts for a Mopar, but that time is over. Everything on my Duster is tubular, aftermarket, adjustable, etc. It's as different from factory Duster suspension as an RMS is from Pinto suspension.

pishta said
How's the turning radius with the rack and pinion? That's the only downside I've heard but it should be an easy fix? I'd run a tubular K only if anyone offered it. Cleaner looking, pan clearance and has to be lighter and better welds.

Turning radius with the RMS at least has been documented as being wider. It's because of the specs of the rack and pinion used, you don't get the same turning angle. Remember the rack is for a different car. I suppose you can have a custom rack made, but with off the shelf parts your turning radius will suffer.

Rassnasty82 said
I would like to take it to the track couple times a year, but mostly street driving. I would be interested to know how to set up the torsion bar suspension to make it handle just as good. I have upgraded torsion bars, and the adjustable race struts up front with factory upper and lower control arms with new ball joints.

Sounds like you already have most of what you need. What size are your torsion bars?

Adjustable strut rods are nice, as long as you've set them up properly so there's no binding in the LCA. Making them the right length should eliminate any binding, especially with poly or Delrin LCA bushings.

Tubular UCA's are probably the biggest thing you don't have. The factory UCA's don't have enough caster adjustment for radial tires. They were designed for bias ply tires and those use no or even negative caster, which is terrible for radials. If you use Moog K7103 offset bushings in the stock UCA's you can get better numbers, usually up around +3.5° or so of caster. At that point it depends on your tires. That's good enough if you're running 225/60/15 or narrower tires with the all season radials most guys run. On my car I run 275/35/18's, and +3.5° is not enough because of the tracking tendencies of tires that wide. I run +6.5° of caster, and that solves it. But you usually need adjustable tubular UCA's to get that much. I run SPC's from BergmanAutocraft.

Oh, and a good set of shocks. Bilstein RCD's, Hotchkis Fox shocks, maybe Viking or ride tech depending on your preferences. I run the Hotchkis Foxes and Bilstein RCD's on my cars.

Steering should be rebuilt or new. Worn out steering boxes will cause a looser feeling, but there are plenty of options out there now for new replacements. PST for manual boxes, Borgeson for power.