Modern suspension

[HPP]

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.  

With the Hotckis comparison you are doing, you are replacing a number of parts that don't need to be changed out to step up performance. However, a BIG difference, at the advanced price points you are using, is that most of these changes can all be done incrementally as budget allows, unlike a coil over conversion which is an all or nothing change over.

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.

IMO, if the stock stuff could be built up to stand up to and satisfy Dan Gurney, then it has capability for 99% of the rest of us.

Changing spring rates? How many guys do this often?

In my experience, only hard core racers who compete on multiple tracks. I have never meet a street driver who is routinely changing rates. They might be doing so to dial in their feel, but once they get there, they stop change-ups.

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.  

Mike, you are I are usually on the same page  with suspension.  For many others reading this, this is usually the first point I make about stock based suspensions. Comparing worn out original junk to a brand new coil over system  isn't valid. Even a rebuilt stock system to a coil over isn't equally compared. These aftermarket systems come with balanced spring and shock rates.  Apply those same balanced rates to the stock layout and their performance steps up considerably.

Lets look at it like this; leaf, coil, torsion, or air are the  methods of  suspending our old cars. That hasn't changed  much over the  last 50 years.  Simply changing a torsion bar to a coil over doesn't automatically make it better. Its still just a spring. How you balance those rates has not changed much. How you control them (shocks)and  move them through the range of motion (geometry) is what  has changed.    Mopar geometry was very advanced in the day and there  are only a couple of  things  it needs to improve to really make it shine;  Improved caster (which also improves return to center, road feel, steering resistance, and self alignment tendencies) and reduced bump steer (due to t-bar/tie rod interference) and it is as good as any late model design.

[RIDELIKEHELL]

I'm running the QA1 LEVEL 3 Set up out front, key really is beefing up the foundation  I have US CAR TOOL front & rear torque boxes welded in,XV Motorsports inner fender support braces & frame connectors. Running  HOTCHKIS Torsion bars,leaf springs & rear sway bar. I also plated my front frame rails & cross member and added a gusset from cross member to inner frame rail. It's tight! The 2 way adjustable QA1 shocks on all 4 corners allow you to select your ride comfort. I LOVE IT! Also went with the Borgeson box and bigger adjuster sleeves & tie rods ends. I had the Control Freak IFS but it ruined my frame rails. Oh ya I am also running MAGNUM FORCE 2 " Drop spindles..LOW & TIGHT like a GO-KART NOW 

[Lennard]

  Do you also have the QA1 subframe? I thought about buying it but I've read about them not being rigid. There is no strong triangular shape in it and to pay $600 for 4 pounds of weight savings compared to the factory K frame is not worth it to me.

Same with the QA1 lower control arms. They look flimsy compared to my braced factory ones. So paying $350 to save 3 pounds... nope.

I do have their tubular upper control arms,  aluminum dynamic strut bars and aluminum single adjustable shocks.

[RIDELIKEHELL]

Do you also have the QA1 subframe? I thought about buying it but I've read about them not being rigid. There is no strong triangular shape in it and to pay $600 for 4 pounds of weight savings compared to the factory K frame is not worth it to me.

Same with the QA1 lower control arms. They look flimsy compared to my braced factory ones. So paying $350 to save 3 pounds... nope.

I do have their tubular upper control arms,  aluminum dynamic strut bars and aluminum single adjustable shocks.

It's not about weight savings for me..I didn't have my K anymore....The level 3 is https://www.speedwaymotors.com/QA1-HK03-CRB1-1966-70-Mopar-B-Body-Handling-Suspension-Kit-Level-3,257996.html?sku=721HK03CRB1&utm_medium=CSEGoogle&utm_source=CSE&utm_campaign=CSEGOOGLE&gclid=EAIaIQobChMIo7aTiPLL2gIVUweGCh1qyA1MEAQYBCABEgJW5PD_BwE I think the LCA ARE beefy..have u seen in person?

[RIDELIKEHELL]

I would of beefed up my K & lower arms if they were still around A little welding goes a long way 

[Lennard]

When you don't have the original parts I understand your decision.  I have not seen the QA1 lower control arms in person. Just pictures and videos. I bought the K frame stiffening kit and lower control arm braces from Firm Feel ($75) for my '69 and copied them for my '68.

[Mike DC]

   
I don't think the factory left much room to improve on their K-frame and LCAs.  Not while you are keeping the torsion bars and stuff.  Just plate & weld up the weak areas on the stock parts and run them.   

-------

You could build a copy of the K-frame in aluminum.  You might manage to lose 15 lbs off it for a lot of fab work.

It would take a very good item to convince me for durability issues though.  We are welding up weak spots on the stock steel ones these days.  The tubular steel ones don't look strong (or rigid) enough to my eyes.  If some aftermarket company just whips up a tubular aluminum stand-in for the original, without showing any familiarity with the pros & cons of the original, I wouldn't trust it. 


The UCAs could be done in Aluminum.  Does somebody already do that?  XV motorsports was making some (and had a failure or two IIRC) but that was for their Corvette-based front suspension.   

The LCAs, I wouldn't bother. They still need the steel castings at both ends and the steel adjusting bolt setup in the middle.  There is hardly any weight to lose just from replacing the sheetmetal parts with aluminum.

[Lennard]

I don't think any company makes aluminum control arms for classic Mopars. I wouldn't buy them for a street driven car anyway, with the crater size potholes in the roads nowadays.

[1974dodgecharger]

seems people who favor the stock setup or stockish setup are the ones who have not experienced the coil over setups on our old mopars and then the folks who have the coil overs setup aren't talking, lol......

both have valid points from each side errr...I mean kinda both sides, but a coil over setup has many benefits with the mustang rack and pinion vs a stock will never have.  If you plan to drive your car on weekends that's great stock is awesome nothing wrong its proven for 50 plus years what a torsion bar can do, but if you drive daily, which is rare with these old mopars, then a coil over is benefited greatly over stock stuff by far. 

A lot of guys don't like modern stuff in cars because these old cars reminds them of when they were younger and the feel and nostalgia is all there when they turn that key and smell the fumes that's great, but some folks who buy these cars want more than what stock offered and Im glad the aftermarket has stepped up to the plate for us mopar folks to enjoy these new modern toys with old cars.

I remember when EFI hit the scene people said the same thing they hated it this tech is stupid and unreliable, but now EFI is scene and sold almost every where and are now reliable.  I don't think I could go back to a carb setup knowing EFI kits are out there for same price and I don't need to worry about adjusting my carb weekly. 

Even at the drags these days you see some of the racers now so many electrics I was shocked with EFI setups.

[HPP]

I disagree entirely.  There is simply no parallel of a coil over to suspension like EFI to induction. EFI is electronically control based on a multitude of monitored parameters being feed into a processor to make real time adjustments. A coil over suspension does not monitor anything to improve its range of motion. Please explain to me how exactly a coil spring is more sophisticated than a torsion bar and what its many benefits are.

As I said above, shock technology is the greatest modern advancement in suspension. Shocks do not care if they are control a coil, leaf, torsion, or air spring. Now, as we get into electronically controlled shocks that use road sensing and feedback to adjust their motion, like some modern supercars are using, then we will figure out how to adapt that to our old cars too. But, they still won't care what spring they control.

I will admit stock steering boxes are the biggest weak link in an other decent system. The new Borgeson box conversions are a big step up. While not as precise as a R&P set up, they are still a modern box equivelent. But, the steering box does not determine the operating range nor performance of the suspension. It also doesn't care if it directs a coil or torsion bar systems.

Leaf springs are probably the oldest spring design out there, but they actually have a fair amount of technology  built into them that many are unaware of. The early 70s mopar leaf was probably the pinnacle of leaf design. Even now, the only changes to improve them have been to make them in composites. Now, I will admit there are some very distinct advantages to ditching leaf suspension for a coil or torsion suspension, but those advantage have very little to do with daily driving  and the improvements they provide are typically are only beneficial in competition environments.

[1974dodgecharger]

I disagree entirely.  There is simply no parallel of a coil over to suspension like EFI to induction. EFI is electronically control based on a multitude of monitored parameters being feed into a processor to make real time adjustments. A coil over suspension does not monitor anything to improve its range of motion. Please explain to me how exactly a coil spring is more sophisticated than a torsion bar and what its many benefits are.

As I said above, shock technology is the greatest modern advancement in suspension. Shocks do not care if they are control a coil, leaf, torsion, or air spring. Now, as we get into electronically controlled shocks that use road sensing and feedback to adjust their motion, like some modern supercars are using, then we will figure out how to adapt that to our old cars too. But, they still won't care what spring they control.

I will admit stock steering boxes are the biggest weak link in an other decent system. The new Borgeson box conversions are a big step up. While not as precise as a R&P set up, they are still a modern box equivelent. But, the steering box does not determine the operating range nor performance of the suspension. It also doesn't care if it directs a coil or torsion bar systems.

Leaf springs are probably the oldest spring design out there, but they actually have a fair amount of technology  built into them that many are unaware of. The early 70s mopar leaf was probably the pinnacle of leaf design. Even now, the only changes to improve them have been to make them in composites. Now, I will admit there are some very distinct advantages to ditching leaf suspension for a coil or torsion suspension, but those advantage have very little to do with daily driving  and the improvements they provide are typically are only beneficial in competition environments.

I can adjust my rebound, height, etc they have double adjustable coil overs these days.  Like I said not dogging the torsion bar setup its great proven 50 plus years, but there are others who want to do other things with their cars and coil over fits that market of what they want to do with it.  One of the fasest cars is run off leaf springs, but if you know the guy and ask what he has done to those leaf springs I can tell you the average mopar guy will not go that far to do what he did to make his car run that hard on the drags his leaf spring setup costs more than coil over kits.  I enjoyed my leaf springs and torsion bar setup with the hotchkis setup and before that all stock setup, but once I started to improve the ride I knew there was room for improvements on our old cars that a torsion bar with leaf spring could not provide me personally.

[myk]

Is it true that turning radius is decreased with any of the new front suspension setups outside of the t-bar setup?

[1974dodgecharger]

Is it true that turning radius is decreased with any of the new front suspension setups outside of the t-bar setup?

with the mustang 2 rack and pinion YES the turning radius is decreased a downfall to it also the wheel width is pushed out more than stock....which I hate.

[myk]

To me that's a deal breaker.  The turning radius of the stock suspension is severely lacking, IMO.  I guess if a car is tracked only, then turning radius isn't a problem but for the idiots like me who drive Chargers around town and like getting rear ended,  I need all the turning radius I can get...

[garner7555]

To me that's a deal breaker.  The turning radius of the stock suspension is severely lacking, IMO.  I guess if a car is tracked only, then turning radius isn't a problem but for the idiots like me who drive Chargers around town and like getting rear ended,  I need all the turning radius I can get...

Hahahaha    At least you are able to find humor in the situation MYK.    In my opinion a street car is more fun than a track car anyway.  A track car is awesome, but only when you can go to the track.

[myk]

Humor is the only thing keeping me sane at this point.   In any case, the world has become too crowded for cars that don't have a good turning radius; I can't afford to lose one degree...

[Fitz73Chrgr]

Is it true that turning radius is decreased with any of the new front suspension setups outside of the t-bar setup?

A decreased turning radius would be a good thing...

[myk]

Is it true that turning radius is decreased with any of the new front suspension setups outside of the t-bar setup?

A decreased turning radius would be a good thing...

You know what I mean...

[RIDELIKEHELL]

I have a huge turning radius now with the QA1 /Borgeson set up

[HPP]

I can adjust my rebound, height, etc they have double adjustable coil overs these days.  Like I said not dogging the torsion bar setup its great proven 50 plus years, but there are others who want to do other things with their cars and coil over fits that market of what they want to do with it.  One of the fasest cars is run off leaf springs, but if you know the guy and ask what he has done to those leaf springs I can tell you the average mopar guy will not go that far to do what he did to make his car run that hard on the drags his leaf spring setup costs more than coil over kits.  I enjoyed my leaf springs and torsion bar setup with the hotchkis setup and before that all stock setup, but once I started to improve the ride I knew there was room for improvements on our old cars that a torsion bar with leaf spring could not provide me personally.

Adjusting rebound and compression is a shock function. Install a similar mono-tube, double adjustable shock into a t-bar suspension and you will have all the same benefits. Coil over = coil spring over a shock with adjustable mounts.  A hallmark of the torsion bar system is that it can also adjust ride height, and actually do it easier than  setting the upper and lower mounts with a spanner wrench that a coil over takes. All it takes is a socket to adjust torsion bar height.  T-bars also have an advantage over coil overs be putting the mass of the weight lower and further back towards the center of the car. This improves the moment of inertia over a coil suspension. T bars are compact and because the load paths are are run through the lower sub-frame system, it requires less chassis stiffening higher up in the car to allow even further reductions in center of gravity height. These benefits is why a number of later model cars and trucks still use or have switched over to incorporated torsion bar suspension systems in to them.

Leaf springs, as I said, there are some advantages to replacing them, but there are also tweaks that can improve them quite a bit as well. I can adjust ride height, roll center, roll steer, instant center, bias control and spring rate with my leaf springs. Actually, most of us on here can as well, but it is not easily done, cheaply done, nor are they light weight when your doing it. in this regard, a coil over system can make all these changes much simpler and easier to do.

If you are happy with your coil over conversion, that is great. My point is simply ditching the stock system for a coil over system because you want something "modern" can actually be minor to no improvement and in the case of turning radius, a step backwards, compared to careful selection and application of key parts in the stock system.

[1974dodgecharger]

I can adjust my rebound, height, etc they have double adjustable coil overs these days.  Like I said not dogging the torsion bar setup its great proven 50 plus years, but there are others who want to do other things with their cars and coil over fits that market of what they want to do with it.  One of the fasest cars is run off leaf springs, but if you know the guy and ask what he has done to those leaf springs I can tell you the average mopar guy will not go that far to do what he did to make his car run that hard on the drags his leaf spring setup costs more than coil over kits.  I enjoyed my leaf springs and torsion bar setup with the hotchkis setup and before that all stock setup, but once I started to improve the ride I knew there was room for improvements on our old cars that a torsion bar with leaf spring could not provide me personally.

Adjusting rebound and compression is a shock function. Install a similar mono-tube, double adjustable shock into a t-bar suspension and you will have all the same benefits. Coil over = coil spring over a shock with adjustable mounts.  A hallmark of the torsion bar system is that it can also adjust ride height, and actually do it easier than  setting the upper and lower mounts with a spanner wrench that a coil over takes. All it takes is a socket to adjust torsion bar height.  T-bars also have an advantage over coil overs be putting the mass of the weight lower and further back towards the center of the car. This improves the moment of inertia over a coil suspension. T bars are compact and because the load paths are are run through the lower sub-frame system, it requires less chassis stiffening higher up in the car to allow even further reductions in center of gravity height. These benefits is why a number of later model cars and trucks still use or have switched over to incorporated torsion bar suspension systems in to them.

Leaf springs, as I said, there are some advantages to replacing them, but there are also tweaks that can improve them quite a bit as well. I can adjust ride height, roll center, roll steer, instant center, bias control and spring rate with my leaf springs. Actually, most of us on here can as well, but it is not easily done, cheaply done, nor are they light weight when your doing it. in this regard, a coil over system can make all these changes much simpler and easier to do.

If you are happy with your coil over conversion, that is great. My point is simply ditching the stock system for a coil over system because you want something "modern" can actually be minor to no improvement and in the case of turning radius, a step backwards, compared to careful selection and application of key parts in the stock system.

again, minor improvement didn't say it was a major improvement    my coilover setup I found more advantage than my leaf springs and stock front end.  that's just me again though I do drive or did drive more than the average person who has a old car driving 12k miles a year is more than normal for these cars and chugging it in 115 degree heat in Arizona with no air I done did it, lol.......if we kept all our leaf springs and stock setups it be one boring place.....plus I just love making purists mad anyways