Modern suspension

[tgif]

I'm sure this has been covered before, but what is the general opinion of the various coil over replacement K member suspension setups, especially for a street car.  I'm sure for a race car that the benefits are unquestioned, but is the change from the factory torsion bar suspension really noticeable on the street?  Same question for leaf springs vs. four link rear suspension.  Worth the $$$ for the street?  As long as I replace the joints, rubber parts, etc. and go to better shocks and sway bars am I really giving up that much for the $6K or more it will cost?

[WHITE AND RED 69]

On this site 95% will say stay with the torsion bar setup for the front. You can make these old cars handle pretty decent with the right parts. It all comes down to getting the right parts and alignment for what you plan to do with the car. Adjustable upper arms, big torsion bars (Over 1"), subframe connectors, sway bars, and a great set of shocks (not $50 parts store shocks) will make a huge difference. Then make it better by a better steering box, other stiffening mods, brakes, and tires to match and you'll be happy for street cruising.

I do think that some companies (RMS suspensions is top quality) make a fantastic product. My only gripe with the coilover suspensions is that is increases the turning radius. And on these old cars it is already too large. But these setups do allow for wider tires and adjusting them is a bit easier. And stay away from the ones that uses the stock shock mount to support the coilover. It was never designed to take the whole weight of the car.

For the rear, leaf springs are ok but a 4 link is the way to go. I have leaf springs on mine but wish I had a 4 link to make adjustments to get it just right. I wish I could lower the rear with a turn on the coilover instead of lowering blocks. Might happen one of these days for me.  

[WHITE AND RED 69]

I also should add that I think everyone who has added a Reilly Motorsports front end kit (or other companies products) have been thrilled with it. So I don't want to sway you against these products. Just wanted to say that you can make the stock setup work pretty well with the right parts.

Either way you are going to be spending a good amount of money to make it handle right.   

[tgif]

I hear you.  I also keep remembering what Richard Ehrenberg said about the kits not being designed for everyday street driving. 

[WHITE AND RED 69]

I hear you.  I also keep remembering what Richard Ehrenberg said about the kits not being designed for everyday street driving. 

I wouldn't question the reliability of most kits. They use steering racks, spindles, steering linkages, and other parts from cars in production so the reliability is there.

[Mike DC]

  
E-berg's complaints are because he looks at things like an OEM designer would.  

They have to worry about what happens when the car has 240,000 hard miles and no maintenance for the last several years and then it starts making a big scary noise.  The 19yo meth-addict owner keeps on driving it for another 3 months until a wheel literally falls off in traffic.  Then the owner calls an ambulance-chasing lawyer he saw on a TV commercial and they see if they can get some money out of the car company with a nuisance lawsuit.  

Most restored muscle cars with an RMS suspension won't ever get treated like this.


E-berg has valid points about the RMS using stuff like Heim (spherical) joints & poly bushings.  Those don't last as long as stock sealed ball joints, it's just an established fact.  Exactly how long they last . . . that depends a lot on the kind of street miles and the weather/dirt/grimy conditions.  Lots of guys do run these things on the street.  Lots of guys run lots of things on the street that the factory would not.  

     

[pipeliner]

You know who the coil over systems were made for? That's right the shitty non driving, non handling  old Fords and Chevys. Now it's monkey see and monkey do. I was one of the monkeys until I did the research. T-Bar set ups are great now that we have tubular Upper and lower CA,s, different T-Bar rates, sway arms and Borgeson Steering. You'll be highly disappointed if you do a coil over as I even had messages from guys who done them telling me not to do it unless I just wanted to be one of the monkeys.

[HPP]

Coil overs are great if  you need A) lighter weight, B) quick changes of spring rates, C) spring rate selections from  200-1200#,  D) quickly adjustable ride heights.  Some systems, mostly rear, come with the ability to adjust geometry as well, but most front systems do not have this same adjustability. 

If you do not NEED these items, then coil overs are not all they are cracked up to be. IMO, most of the "signicantly improved handling"  of these systems comes from them being engineered with increased and  balanced spring and shock rates that most layman can't calculate.

Coil overs also come with cost. It will cost over $5k front and over $2k rear to convert. By contrast, a complete Hotchkis or Firm Feel system can be installed front and rear for around $3k.

Is the stock stuff great, no, but it aint too shabby. With some minor changes, it can be made to perform  beyond  the capability of most drives.

[sixty-niner]

im in this predicament as well, do I update the old style suspension or go full coil over and 4 link out back??  Header room would be nice, less weight would be nice, and full disk brake set up would be nice.  The only not nice in the coil over set up is the price.  However, I have priced out the complete hotchkis+shocks+torsion bars+upgraded K frame+upgraded lower control arms+borgenson steering+disc brake set up and the savings of an upgraded torsion bar set up is minimal after you add all the other stuff that isn't included in the "full suspension kit"  kind of disappointing.  I have factory discs and therefore have to change the spindle and knuckle if I wanted upgraded brakes which is added cost.   it comes at around 300-500 dollar difference between the 2.  too much to spend on a suspension if you ask me. 

[JR]

I think the torsion bar/leaf spring suspension can be modified in a way to provide decent enough handling for the large majority of owners. Im happy with mine as someone who autocrosses and drives his car pretty hard.

My major complaint is the steering. The original steering boxes suck! I have every intention of buying a borgenson box, but I wish there was a bolt on, replacement K frame that kept torsion bars, but allowed rack and pinion steering. Without ruining the geometry.

There must be a reason why no one offers one, I'd love to know why.

[Derwud]

I want something better then Mustang II geometry and parts..

[Mike DC]

I want something better then Mustang II geometry and parts..

Meh.  A good aftermarket rig like the RMS is a "Mustang II front end" in the same way that an all-aftermarket Ford 9-inch rearend is a "1965 Ford Fairlane axle."

The RMS's geometry is good.  As for durability, they are surviving on the Fast & Furious stunt cars.  

My major complaint is the steering. The original steering boxes suck! I have every intention of buying a borgenson box, but I wish there was a bolt on, replacement K frame that kept torsion bars, but allowed rack and pinion steering. Without ruining the geometry.

There must be a reason why no one offers one, I'd love to know why.

I kicked the idea around a few years ago but it's just not very practical.  The conflict is the whole OEM front end layout overall.  


The stock susp is a rear-steer setup with the steering box & linkage behind the front wheels.  Modern stuff usually puts the steering rack in front of the wheels.  

The rear-steer setup is better for Ackerman angles.  But it demands a heavy-duty linkage of tie rods & stuff because it has to push the outside wheel during cornering.  The front-steer & rack setup on modern stuff can pull the outer wheel so it can be a physically smaller/lighter linkage.  Modern rack setups also use shorter steering arms on the spindle (paired with less travel distance on the rack).  


Unisteer already makes a rack kit to drop into the stock rear-steer position.  But the rack's range of travel is too short for the stock steering arms on the spindles (like with most modern racks) and nobody is very happy with it.  If the rack was big enough not to have this problem then it's probably close to the weight of a Borgeson aluminum box conversion.  No real benefit anymore.  

If you put the rack into front-steer location then you need to cut/weld the hell out of the K-frame.  And you still need shorter steering arms on the spindle.  The most practical way to do that is to change the whole spindle.  But another car's spindle won't mate with the stock LCA without some cutting/welding on the LCA (or maybe switching to a mid-70s Mopar LCA?) . . . anyway, now we have modified & replaced almost enough stuff to have done an RMS setup.  Most people would probably elect to go the rest of the way to RMS to get the coilovers.  I like the stock torsion-bar front end too but it's a mixed bag.   It costs a lot of header room and it limits the LCA length & geometry.  


Verdict: Just buy the Borgeson box.

---------------


There is also electric-assisted steering now.  Combine it with a manual PS box.  

There are advantages.  No PS pump/belt/pulley/etc.  No parasitic horsepower draw from the pump.  The manual gearboxes are lighter than power ones too.  But I don't think you would keep the "road feel" of an old-school setup.  The modern OEMs are having to simulate road feel in their electric PS by using sensors & software.  I doubt any of the aftermarket or junkyard retrofits are gonna go through with all that.

Another potential disadvantage of electric PS - you wouldn't have the PS fluid pump anymore if you wanted to run hydro-boosted brake assist.

[JR]

That is a very helpful post Mike, thanks.

[Mike DC]

 

[Derwud]

I want something better then Mustang II geometry and parts..

Meh.  A good aftermarket rig like the RMS is a "Mustang II front end" in the same way that an all-aftermarket Ford 9-inch rearend is a "1965 Ford Fairlane axle."

The RMS's geometry is good.  As for durability, they are surviving on the Fast & Furious stunt cars.

Verdict: Just buy the Borgeson box.

---------------


There is also electric-assisted steering now.  Combine it with a manual PS box.  

There are advantages.  No PS pump/belt/pulley/etc.  No parasitic horsepower draw from the pump.  The manual gearboxes are lighter than power ones too.  But I don't think you would keep the "road feel" of an old-school setup.  The modern OEMs are having to simulate road feel in their electric PS by using sensors & software.  I doubt any of the aftermarket or junkyard retrofits are gonna go through with all that.

Another potential disadvantage of electric PS - you wouldn't have the PS fluid pump anymore if you wanted to run hydro-boosted brake assist.

Building a 9 Inch or a Dana is one thing. Trusting your front suspension to just anyone with a welder and some steel is a bit different...

Judging suspension by if it holds up to movieland is an even bigger stretch.

I would agree with you on the Borgeson box though.

Also driving a Electric steering car, yes minimal road feel/Feed back, but handles like it is on RAILS!!

[Mike DC]

Building a 9 Inch or a Dana is one thing. Trusting your front suspension to just anyone with a welder and some steel is a bit different...

Judging suspension by if it holds up to movieland is an even bigger stretch.

Depends on the show. 

The F&F crew started using RMS stuff in 4th movie and the next one will be the 9th.  They have been pretty brutal on their old Mopars.  It's way beyond the footage that makes it to the final cut.  If the RMS stuff was gonna be fragile then they definitely would have uncovered it.  They haven't.  I've heard that some of their RMS setups have been around for several movies, pulled off wrecked cars and reused on later ones.   

Is it as well-tested as the factory stuff?  No.  But nothing aftermarket ever will be.  That's setting the bar pretty high IMO.   
 
----------------------

Electric steering is weird on the cars I've tried.  They can do a pretty good job of faking 'road feel' but I could believe it's a problem if you are really into precision handling.  There were moments where I did think the system was a little confused.       

It seems like a lot of technical advancements - better than the old way when it's working just right, but worse than the old way if it isn't. 

[Kern Dog]

The guys that install these replacement suspensions seem to be happy with them but I wonder how many of them had driven similar cars with an optimized torsion bar car. If you take a 200,000 mile car and install a RMS setup, of course it is going to handle better.
Me? I just cannot justify the expense. I would bet that the lion's share of the improved feel comes from the steering rack. I have a 304,000 mile 2007 Ram truck and the steering still feels sharp. The traditional Mopar power steering feel was loose, overboosted and sloppy. Even a Firm Feel rebuild sometimes has some on center slop to it. Mine does. I have a stage 3 with fast ratio arms. Once you get past the on center slop, it feels nice. I'm not to the point where I'd lay down $900 to install a new Borgeson chuck but maybe someday.
Changing spring rates? How many guys do this often?
Header clearance? TTI and Doug's make headers that fit.
Lighter? Maybe...if you go from power steering to their manual steering rack. The K member isn't that heavy.

[Mike DC]

The guys that install these replacement suspensions seem to be happy with them but I wonder how many of them had driven similar cars with an optimized torsion bar car. If you take a 200,000 mile car and install a RMS setup, of course it is going to handle better.  
Me? I just cannot justify the expense. I would bet that the lion's share of the improved feel comes from the steering rack. I have a 304,000 mile 2007 Ram truck and the steering still feels sharp. The traditional Mopar power steering feel was loose, overboosted and sloppy. Even a Firm Feel rebuild sometimes has some on center slop to it. Mine does. I have a stage 3 with fast ratio arms. Once you get past the on center slop, it feels nice. I'm not to the point where I'd lay down $900 to install a new Borgeson chuck but maybe someday.
Changing spring rates? How many guys do this often?
Header clearance? TTI and Doug's make headers that fit.
Lighter? Maybe...if you go from power steering to their manual steering rack. The K member isn't that heavy.

True.  There has been a lot of unbalanced comparing going on.   And many people complaining about the steering box are really missing the lack of caster in the wheel alignment, which is solved by changing the UCA/bushings rather than anything on the steering itself.  

I think the weight loss with the RMS is significant though.  Front-steer layout = lighter weight, be it power or manual.  BTW a stock K-frame (bare) is about 45 lbs.  The T-bars themselves and the stock LCAs are not very lightweight either.

[Derwud]

I can't wait to see how my QA1, Hotchkis, Borgeson set-up feels.. And yes I know the difference of old sloppy suspension vs freshly rebuilt and properly aligned T/B set-up is.

[garner7555]

I can't wait to see how my QA1, Hotchkis, Borgeson set-up feels.. And yes I know the difference of old sloppy suspension vs freshly rebuilt and properly aligned T/B set-up is.

I have those same parts along with magnum force and PST.   I too am looking forward to testing out how the custom setup works out.   It's more practical to buy a complete kit, but it's more fun to piece together your own.                  

[JR]

 I can say my chassis setup really isn't anything exotic. Subframe connectors, poly bushings, Helwig front/rear sway bars, adjustable UCAs, QA1 single adjustable shocks, stock RT springs, and good rubber, and I feel the body control, suspension dampening does a fairly good job for what it is.

After flogging the hell out of it on many autoX courses and empty backroads, the chassis has gone from a wallowing, understeering pig, to a neutral, composed car that doesn't want to break traction in a fast corner, but can be coaxed into throttle oversteer easily if you want to. I think the majority of members here would be thrilled with an equivalent performing setup.

I don't really feel the aftermarket coil over setups return their cost of investment, unless you're one of the HARDCORE competitors at an optima street car shootout, or equivalent.  Not saying anything is "wrong" with them at all, just saying I doubt it would be worth the cost to most members here.

[garner7555]

I can say my chassis setup really isn't anything exotic. Subframe connectors, poly bushings, Helwig front/rear sway bars, adjustable UCAs, QA1 single adjustable shocks, stock RT springs, and good rubber, and I feel the body control, suspension dampening does a fairly good job for what it is.

After flogging the hell out of it on many autoX courses and empty backroads, the chassis has gone from a wallowing, understeering pig, to a neutral, composed car that doesn't want to break traction in a fast corner, but can be coaxed into throttle oversteer easily if you want to. I think the majority of members here would be thrilled with an equivalent performing setup.

I don't really feel the aftermarket coil over setups return their cost of investment, unless you're one of the HARDCORE competitors at an optima street car shootout, or equivalent.  Not saying anything is "wrong" with them at all, just saying I doubt it would be worth the cost to most members here.

I agree 100%     

[Brass]

Torsion bars seem to perform well:

https://www.youtube.com/watch?v=kASM04zuHlo

[Finn]

My 68 is on bags at all 4 corners with T-bars and a 4 link rear...

It does alright.

Edit: Also tubular arms, poly bushings, frame connectors and torque boxes.

Edit2: And a firmfeel stage 2...wish I would have gone for stage 3.

[Derwud]

Torsion bars seem to perform well:

https://www.youtube.com/watch?v=kASM04zuHlo

AWESOME!!!!!