Better ride quality for HEMI B body

I’ve put almost 10,000 miles on my 66’ Dodge Coronet convertable, (4,175lb.). I have aftermarket .960” torsion bars, Firm Feel 1.25” front sway bar, rear sway bar and “Firm Feel” Bilstien gas shocks, (which helped).
The car corners very flat, but has a “dump truck” ride. I am considering changing the torsion bars from .960, to .900 (440 B body).
The car is a cruiser, not a slalom racer. What do you think?

The Hemi bars (.920) in my Hemi RR gave a firm but compliant ride, Stock rear springs, too, and nothing special with the shocks, Monroes.
Put the same spec bars & springs & shocks on my current 383 RR, same deal.
I've no intent on pitching B-bodies around, though; I have another car better suited to that.

My 64 Sport Fury convertible has .920 torsion bars, QA 1 single adjustable shocks front and rear, tubular upper control arms, 15x6 205/70 front wheels and tires, hellwig front sway 1 1/8" and 7/8" rear and frame connectors and a 5 speed. I am amazed at the road handling for a Gen II Hemi (iron heads and a Lakewood scattershield) she has. I have refurbished (new foam and covers) stock seats and she is as comfortable as a living room sofa. Without side bolstering in the stock seats, there is a little missing for cornering but it works for me.

I think that would be a very good idea.

I have 1.12” t-bars (350 lbs/in wheel rate) in my 3209 lbs digital scaled 68 Barracuda Coupe. A-body t-bars are shorter. That stiffness is equal to a 1.22” B/E body t-bar.

BUT...

I run stock .87” t-bars in my 68 Dart conv. With front and rear sway bars, rubber bushings except front sway bar frame bushings. It’s a convertible. They do not have the body stiffness as a car with a roof. And the convertible top mechanism are rattle points, a piece of vinyl separates trunk noise from interior, etc, etc.

Yes frame connectors help. But they don’t replace a roof.

If you think it’s still too stiff, buy HD Monroe shocks

Play with tire pressure. Lower it some all around, just don't go too low.

I had the Bilstein's on my Challenger. 1" T-bars and 1.125" sway bar rode like a truck.
Changed to QA1 Shocks, now controlling 1.18 t-bars and 1.25 sway bar and the harshness is gone (although it corners much flatter)
My money is on the shocks that's making your ride unpleasant.

I'd like to see the actual calculations on that. The A body LCA is slightly longer than the B and E so that skews the numbers a bit.

I have 1.15" bars in my Charger, 1 1/4" front bar, 6 stage leafs with a 3/4" bar, Bilstein shocks and my car rides firm but in no way harsh...This is with 40 series tires up front and 45 series out back. Mine weighs just under 4000 lbs.

Agree with this!
A co worker with a miata was complaining about tire wear. The center of her tires were worn much more than the edges.
She said "i don't understand, I'm running 32lbs." I checked the pressure sticker on the car, recommended pressure for her car was 25!
Her other complaint was about the rough ride, gee I wonder why?

I also wonder if you're still on your original rear springs, If they've sagged much it can make for a brutal ride on big bumps.
They're forced to flex in the opposite direction.
I'd leave the torsion bars alone, the rear springs, and dampers are much more critical to a good ride.

From the MP chassis catalog

Depends on how much money you're willing to throw at it. If it was my car I'd put a pair of Koni shocks on the front and see if that helps. The Koni shocks are adjustable so you have several different valve settings to try. I've found that the Koni shocks provide the best ride with big torsion bars. The other thing to look at is your suspension bushings. If they aren't all new rubber bushings then maybe think about replacing them. Delrin or Poly bushings will ride harsher than OEM rubber bushings.

Wonder if the OP has installed any type of traction aid on the rear suspension, if that's binding, that could make the ride harsher.

Beautiful Charger!

I have Poly bushings all around, also use Caltrac mono leafs in the rear. (That vastly improved the ride).

Thank you. I USED to have a Gear Vendors overdrive in it......I wonder WHO has it now??
I recently swapped in a Tremec 5 speed.....What a HUGE difference in how the car feels at freeway speeds!

Yep, that is part of your problem. If you want a softer ride then you'll need to go back to rubber bushings. I have rubber bushings in my Duster with a split mono leaf Calvert setup out back. I use Calvert shocks in the rear and Koni shocks up front with a very big anti-sway bar. I use fairly soft torsion bars. The soft spring big bar approach was popular years ago and I still find it works on the street. My Duster is more of a Pro Street car than a road racer, but it rides nice and it goes around corners just fine. It won't hang with a Porsche around the corners but it will keep up with most daily drivers.

How big is the front sway bar, Andy??

Factory rates were calculated with the factory control arms for a 1:1 ratio of torsion bar rate to wheel rate. Put an A body arm in a B body, then you will alter the rate slightly.



Poly bushings to transmit a considerable amount of Noise, Vibration, Harshness. If you prefer less NVH and a more factory like ride, then rubber will produce this.

Hemi Ragtop -- You didn't mention anything about your rear suspension. What setup (leafs?) do you have?

In my opinion, you've made a step in the correct direction by installing the .96 TBs, but, they are still relatively weak vs others. I would not reduce them in stiffness - only going to cause increased rise/lift and dive.

As others said, tune with adjustable shocks... as well as tire psi.

I have 1.24" TBs in my Challenger -- yes, intended primarily for autocross and track events -- but still completely OK on the street/highway -- just avoid the potholes and go slow over rail road crossings and speed bumps.

I have so much enjoyed the Gear vendor, how dow’se the wife like her new car?

I just finished the install of the .900 torsion bars. I now will adjust ride hieght and test drive,, I will report findings after the rain leaves!

Funny thing...I sold the GV to start the ball rolling to buy her the Challenger. Days after you sent the money, the A/C went out in her Honda so the Gear Vendors paid for the A/C !
I still put together $35,000 in about 16 months by selling a few cars and some parts. It was great to pay for the car in one lump sum!
Yeah, she loves the car!

That’s great! We both won! With the Gear Vendor, I can run in any lane of traffic that I choose, and stay below 3,000 rpm. (The cam likes 2,500 and above). I have tested the mileage runnning 70mph +. It averages 14.5 mpg; thats not bad with a 540 cu engine that made 670HP on an engine dyno!

I have Cal Track complete with composit springs. With the .900 bars, the ride is much better! Interesting enough, with the Firm Feel sway bars, I can’t tell any difference in the handeling!

1.25”

Great feedback

Just to clarify,

So you switched from .96” torsion bars to .90” torsion bars and nothing else?

And you felt a noticeable smoother ride with less harshness?

Yeah, it sounds like you're doing quite well. Good for you, friend!

I put my money on the shocks. I have one Charger with 1.04" torsions, and one with 1.06" torsions. both QA1 single adjustable shocks. The one with stiffer torsions, but softer shock setting, rides much softer than the other car, but both handle great. I need to soften the other car when I start driving it again.

Nobody calls them "torsions", sir.

https://www.ridetech.com/product/68-70-mopar-b-body-air-suspension-system/

Kevin

Do you happen to know the part # for the QA1 single adjustable shocks, I have a 67 coronet wagon that I put mopar performance torsion bars in to get less float and lean but it seems to have that harsh hit when going over potholes, sounds like a different shock would help.

Not a fan....

OEM shortfalls notwithstanding, I saw their 66 Chevelle go around a slalom course at a Goodguys show and make it look like he was just driving around. I realize the driver is a very large part of a good lap but a 66 Chevelle?

I had a 96 Town Car with rear air ride. It developed the same problem as the one in the picture but I found a reasonable priced source for new bags. It rode great and handled better than a barge should have, certainly better than the ride would have you believe.

Kevin

Yes it helped. the roads here, and in the mountains, can have lots of patches, I think I will change shocks next.
No racing for me, just long cruises with the top down.

My '69 Hemi Road Runner with stock suspension was the best driving of all the B-bodies I've owned. Maybe just duplicate the stock set-up and tweak it from there.

I didn't see it mentioned, but tires can make or break the ride quality, not to mention handling and traction.

OP post has picture of his car and looks to be 15” rims with tires with generous sidewalk that help cushion NVH from road. I’m guessing 235-245/60/15 in front and 275/60/15 in rear.

there are tires, then there are tires. An example of what I am talking about are the Mastercraft tires that were on my daughter's Explorer when she bought it, ill handling, rough riding, laughable traction. Replaced them with Michelin LTX's of the same size and the difference what so dramatic that even she noticed and commented upon it.

Not knowing what tire the OP has, I can't really comment on it's possible effect on the ride. Then there is the tire pressure to consider.