Firm Feel Suspension + Wilwood 6 Piston Disc Brake Project

[1970DCH]

Hey Everyone - I’m posting my most recent project on my 70’ Charger that included a full front suspension rip and replace, plus the addition of a 6 Piston Wilwood Disc Brake kit. Please note that my charger has the front spindles from a 1973 Challenger (larger diameter), which allows for the 6 Piston kit from Wilwood.

I decided to go mostly with items from Firm Feel to keep the existing suspension design after talking to some forum members (thank you @Kern Dog for the commentary). I must say, I am impressed with the parts from Firm Feel and I really like how all of the bushings are readily available for future replacement. Everything fit perfectly and was exceptional quality.

Parts list:

• Firm Feel Tubular Upper A-Arms
• Firm Feel 1-1/4 Front Sway Bar
• Firm Feel 3/4 Rear Sway Bar (not yet installed)
• Firm Feel HD Adjustable Strut Rods
• Firm Feel HD Adjustable Tie Rods
• Bilstein RCD Shocks (supplied by Firm Feel)
• Firm Feel Bump Stops
• Wilwood 6 Piston Brake kit includes hub, Calipers, 2-piece rotors, steel braided brake lines,etc.
• Refurbished and reinforced LCA
• Mevotech Greasable Lower Ball Joints
• Hotchkis 1.1 Torsion Bars
• Magnumforce Subframe Connectors

Other:

• Ride height (floor to fender lip) at 25 inches and yes, I know the fenders can be off so I confirmed equal leveling to the frame,
• I did the alignment myself and achieved +5.5 caster and set camber to -.5 degrees. Car drives straight as an arrow, wheel comes back to center, and everything looks on point.

After all was said and done, wow! I can genuinely say that I am surprised at how well the car handles. Even without the rear sway bar installed yet, the car feels incredibly planted and no noticeable body role during high speed on and off ramps/ higher speed turns. I took the car up to 110mph and it was very stable/ confidence inspiring. The subframe connectors also had a very noticeable impact as well; I went with Magnumforce because they bolt to the floor pan. The car no longer creaks when going over a speed bump off-center or when going in and out of slanted driveways. When I lift the car up, the door gaps also no longer change, indicating no noticeable body flex.

If anyone has any questions, let me know.

 

[Kern Dog]

That car has a bit of a circle track car vibe. The black wheels look cool.
I like the alignment numbers. I see many people quoting the Mopar Action “Skosh Chart” but to me, the caster numbers in it seem too low.
It sure would be great if we could motivate some of the guys in these western states to get involved in autocross events. I want to do it but have yet to make the leap.

 

[ckessel]

Speaking of spec's, what did you go with? My wagon will be getting that done soon.

 

[j-c-c-62]

Proper engineering methods normally require identifying a problem before seeking a solution. Since you already have a rear swaybar and seemed inclined to install it, this presents a useful learning opportunity. Many often just install everything and draw a conclusion. It also seems you will have put the car thru all its paces BEFORE installing the rear swaybar so you have a decent baseline and a few thoughts of what might improve the car. So, sharing your driving observations of installing a rear swaybar, after a well-designed full suspension upgrade should be informative.
No rush, but I am curious.

My gut feeling, with 1.1" TB and 1.25" SB and only .5 camber, you might be in the understeer area, before the rear bar install, I'd dial in a tad more negative camber first and get another baseline if that improves things . This a RB or a SB car?
Good looking car BTW.
IMO, your tires are now your weakest link.

 

[1970DCH]

That car has a bit of a circle track car vibe. The black wheels look cool.
I like the alignment numbers. I see many people quoting the Mopar Action “Skosh Chart” but to me, the caster numbers in it seem too low.
It sure would be great if we could motivate some of the guys in these western states to get involved in autocross events. I want to do it but have yet to make the leap.

Right, I’m definitely not trying to stay original; too many other nicer examples out there for that. Circle track car aligns, I’d say. We’ll see over time! Autocross interests me, but not at this stage of my life right now. In due time.

 

[1970DCH]

Speaking of spec's, what did you go with? My wagon will be getting that done soon.

Which specs?

 

[1970DCH]

Proper engineering methods normally require identifying a problem before seeking a solution. Since you already have a rear swaybar and seemed inclined to install it, this presents a useful learning opportunity. Many often just install everything and draw a conclusion. It also seems you will have put the car thru all its paces BEFORE installing the rear swaybar so you have a decent baseline and a few thoughts of what might improve the car. So, sharing your driving observations of installing a rear swaybar, after a well-designed full suspension upgrade should be informative.
No rush, but I am curious.

My gut feeling, with 1.1" TB and 1.25" SB and only .5 camber, you might be in the understeer area, before the rear bar install, I'd dial in a tad more negative camber first and get another baseline if that improves things . This a RB or a SB car?
Good looking car BTW.
IMO, your tires are now your weakest link.

Interesting that you brought this up as I discussed this subject with Firm Feel. For a tight course auto-cross, it is apparently advantageous not to have a rear sway bar. My motivations on the rear sway bar are partly that conversation and party my experience with stiffer rear sway bars on my previous cars. For the kind of driving I like, I do prefer what the rear sway bar adds. This car did have a front sway bar originally. With everything being shot and needing replacing, I wanted to improve where I could.

I’ll try more aggressive camber and see what’s that’s like. I’ll chime back here when I get the rear bar on later and let you know my thoughts.

I 100% agree in the tires now being the weakest link with the tall sidewall; lots of flex.

 

[68 Sport Satellite]

Interesting that you brought this up as I discussed this subject with Firm Feel. For a tight course auto-cross, it is apparently advantageous not to have a rear sway bar. My motivations on the rear sway bar are partly that conversation and party my experience with stiffer rear sway bars on my previous cars. For the kind of driving I like, I do prefer what the rear sway bar adds. This car did have a front sway bar originally. With everything being shot and needing replacing, I wanted to improve where I could.

I’ll try more aggressive camber and see what’s that’s like. I’ll chime back here when I get the rear bar on later and let you know my thoughts.

I 100% agree in the tires now being the weakest link with the tall sidewall; lots of flex.

Love the report, thanks for sharing. Even if you stay with 15" tires, there are better grippier options out there to replace those BFG's
What leaf springs are on the car?
I also have a FF rear sway bar and very much appreciate that their design allows the installation to be bolted ABOVE the rear end instead of below it like most other brands. I had a local suspension shop install the rear bar for me while I watched. It was VERY tricky to install it with the leaf springs and axle in the way, but after some trial and error they were able to snake it up and over and get it bolted in.

 

[1970DCH]

Love the report, thanks for sharing. Even if you stay with 15" tires, there are better grippier options out there to replace those BFG's
What leaf springs are on the car?
I also have a FF rear sway bar and very much appreciate that their design allows the installation to be bolted ABOVE the rear end instead of below it like most other brands. I had a local suspension shop install the rear bar for me while I watched. It was VERY tricky to install it with the leaf springs and axle in the way, but after some trial and error they were able to snake it up and over and get it bolted in.

At the time when I bought the car. It needed tires and had mismatched wheels; this was a decently priced option while I mull over another set in due time.

I bought a set from ESPO, with +2 in height. Currently have a 1 inch lowering spacer as it was tough to gauge how high the car would actually sit.

Yes, the placement is the same reason I went with FF for the rear sway bar. Thanks for the input on the trickiness to install it; I had been looking at what might need to be done to do it.

 

[ckessel]

Camber, caster and toe. According to my old handling book, it said go for 1* -camber, 4+* positive caster. Toe varied depending on usage. Anywhere from 1/8" in to 3/32" out. The wagon is getting the FF arms, like yours, that I bought for my 65 plus the 1.06 bars and Bilsteins. Front sway bar courtesy of KernDog engineering. AKA modified Chevy C30 truck unit from a wrecking yard.

 

[j-c-c-62]

Bravo

 

[Kern Dog]

Interesting that you brought this up as I discussed this subject with Firm Feel. For a tight course auto-cross, it is apparently advantageous not to have a rear sway bar. My motivations on the rear sway bar are partly that conversation and party my experience with stiffer rear sway bars on my previous cars. For the kind of driving I like, I do prefer what the rear sway bar adds. This car did have a front sway bar originally. With everything being shot and needing replacing, I wanted to improve where I could.

I’ll try more aggressive camber and see what’s that’s like. I’ll chime back here when I get the rear bar on later and let you know my thoughts.

I 100% agree in the tires now being the weakest link with the tall sidewall; lots of flex.

Unrelated but an interesting story....
In the 90s, either Hot Rod or Car Craft magazine did a 4 way test of the 4 most popular suspension kits available for the 1970-81 Camaro and Firebird. I recall two of the manufacturers were Herb Adams and Rancho suspension. All four had different approaches to improve the handling.
Herb Adams was the one that favored soft springs with huge sway bars. Their thinking was that you'd have a nice ride that would corner well when needed.
Rancho liked stiff springs with small sway bars. The ride would be harsher but the front suspension would have less spring rate transfer when cornering which in their mind, meant that the independent suspension remained independent.
The other two were sort of a mix between Rancho and Herb Adams.
I had a Camaro at the time that article came out so it interested me. Nowadays, I'm back into the Mopars and since we are a smaller market than the GM F bodies, our choices are fewer. Hotchkis had a system, I believe called TVS for Total Vehicle System, I think.
Would you mind telling us the wheel brand and sizes along with the tires?

 

[icetech]

Camber, caster and toe. According to my old handling book, it said go for 1* -camber, 4+* positive caster. Toe varied depending on usage. Anywhere from 1/8" in to 3/32" out. The wagon is getting the FF arms, like yours, that I bought for my 65 plus the 1.06 bars and Bilsteins. Front sway bar courtesy of KernDog engineering. AKA modified Chevy C30 truck unit from a wrecking yard.

Toe out? not toe in?

 

[Kern Dog]

Toe out can be beneficial for greater response during turn in. The drawback is increased tire wear!

 

[icetech]

Toe out can be beneficial for greater response during turn in. The drawback is increased tire wear!

ah.. didn't know that..

 

[j-c-c-62]

It is, but also why increased negative camber is the first adjustment suggested for improving turn in, with fewer downsides like dartiness.

 

[1970DCH]

Unrelated but an interesting story....
In the 90s, either Hot Rod or Car Craft magazine did a 4 way test of the 4 most popular suspension kits available for the 1970-81 Camaro and Firebird. I recall two of the manufacturers were Herb Adams and Rancho suspension. All four had different approaches to improve the handling.
Herb Adams was the one that favored soft springs with huge sway bars. Their thinking was that you'd have a nice ride that would corner well when needed.
Rancho liked stiff springs with small sway bars. The ride would be harsher but the front suspension would have less spring rate transfer when cornering which in their mind, meant that the independent suspension remained independent.
The other two were sort of a mix between Rancho and Herb Adams.
I had a Camaro at the time that article came out so it interested me. Nowadays, I'm back into the Mopars and since we are a smaller market than the GM F bodies, our choices are fewer. Hotchkis had a system, I believe called TVS for Total Vehicle System, I think.
Would you mind telling us the wheel brand and sizes along with the tires?

I had never considered the combo of soft springs and stiffer sway bar. Logically that makes sense. Yes, Hotchkis does have the TVS system but I wasn’t a fan of their upper A-Arms.

The wheel brand is Bassett, D-hole style and the sizes are:
Front -> 15x7 with 3.75” back spacing
Rear - > 15x10 with 5” back spacing

Tires are BF Goodrich, sizes are:
Front -> 235/60-15
Rear -> 295/50-15

 

[Kern Dog]

In theory, the soft spring/big sway bar principle seems smart but.....
I had stock torsion bars and leaf springs in Jigsaw....

With 1 1/4" front sway bar and a 3/4" rear bar. It corners okay but I didn't like the brake dive or the overall "floaty" feel. I put in 1.03" torsion bars I got in a collection of parts I got last year. What a huge improvement. It feels more solid and stable with the bigger bars.
This car has 1.15" bars...

It feels as rock solid as any car that I have driven. I shake my head at the people that would say You'll rattle your fillings out with bars that stiff.

 

[1970DCH]

In theory, the soft spring/big sway bar principle seems smart but.....
I had stock torsion bars and leaf springs in Jigsaw....

View attachment 1920360

With 1 1/4" front sway bar and a 3/4" rear bar. It corners okay but I didn't like the brake dive or the overall "floaty" feel. I put in 1.03" torsion bars I got in a collection of parts I got last year. What a huge improvement. It feels more solid and stable with the bigger bars.
This car has 1.15" bars...

View attachment 1920361

It feels as rock solid as any car that I have driven. I shake my head at the people that would say You'll rattle your fillings out with bars that stiff.

Good to know from practical experience! I too do not like the floaty feel and after taking my car out for another spin, I’m loving the setup. I’ve read your TKX post a few times…potentially pulling the trigger on that next.

 

[Kern Dog]

My Tremec swap was one of the last TKO transmissions that Silver Sport had. I got the whole kit with drive shaft for under $6000.
The improved TKX model was brought in to replace it.
The manual transmission swap was responsible for making the car so much more fun to drive.
For drag racing, the automatic is the way to go. It was faster with the automatic but more fun with the manual.