Best rear suspension for drag/street handling

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MOPARCODY

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I am in the process of making my car more street friendly. I am going to buy the hemi Denny k member kit with power rack sway bar etc.

My question is about the rear suspension. I don’t need it to handle like a spec Miata but I would like something that is on the tighter side with the ability to stick on a drag strip.
 
Depends entirely on your budget and plans for the car.

A set of 130 lb/in leaf springs with an adjustable rear sway bar is what some of the best handling mopars out there right now run.

Otherwise you’re just looking at various conversions- triangulated 4 links, true 4 links, 3 links, or the QA1 6 link. All have their issues and advantages.

Triangulated 4 link is probably the “easiest”, as in there are a few kits available. They retain most of the factory locations for stuff like the exhaust and fuel tank. But their adjustability isn’t actually a massive improvement, and they can limit travel a little depending on the layout.

A true 4 link would be more adjustable, but it would also mess with the factory location of things (like the entire back seat most likely). And you’d be building it yourself.

A 3 link is by far the most adjustable, and is favored by a lot of road racers. But again, this has issues with the factory locations of significant parts. There is a kit, XV Engineering makes it (one of the former people from XV motorsports). I don’t know much about the install beyond generalities, like usually the fuel tank location has to be moved. But yeah, probably the best from a handling and adjustability stand point. XV VTR REAR SUSPENSION A, B and E Body

And then there’s the QA1 6 link. It bolts in, uses all the factory locations for everything. Including the spring hangers, which limits tire width. And then there’s the suspension travel, which is significantly reduced.

Compared to what you’re getting for what you’re spending, unless you’re building an all out road racing car a set of good leaf springs and an adjustable sway bar will take you the furthest.

Nothing against HemiDenny either, but all you get from a coilover conversion is a rack and pinion and more header room. It does not improve handling compared to a well set up torsion bar suspension. Which costs a ton less. And you can have a very well handling car with a torsion bar suspension.
 
Depends entirely on your budget and plans for the car.

A set of 130 lb/in leaf springs with an adjustable rear sway bar is what some of the best handling mopars out there right now run.

Otherwise you’re just looking at various conversions- triangulated 4 links, true 4 links, 3 links, or the QA1 6 link. All have their issues and advantages.

Triangulated 4 link is probably the “easiest”, as in there are a few kits available. They retain most of the factory locations for stuff like the exhaust and fuel tank. But their adjustability isn’t actually a massive improvement, and they can limit travel a little depending on the layout.

A true 4 link would be more adjustable, but it would also mess with the factory location of things (like the entire back seat most likely). And you’d be building it yourself.

A 3 link is by far the most adjustable, and is favored by a lot of road racers. But again, this has issues with the factory locations of significant parts. There is a kit, XV Engineering makes it (one of the former people from XV motorsports). I don’t know much about the install beyond generalities, like usually the fuel tank location has to be moved. But yeah, probably the best from a handling and adjustability stand point. XV VTR REAR SUSPENSION A, B and E Body

And then there’s the QA1 6 link. It bolts in, uses all the factory locations for everything. Including the spring hangers, which limits tire width. And then there’s the suspension travel, which is significantly reduced.

Compared to what you’re getting for what you’re spending, unless you’re building an all out road racing car a set of good leaf springs and an adjustable sway bar will take you the furthest.

Nothing against HemiDenny either, but all you get from a coilover conversion is a rack and pinion and more header room. It does not improve handling compared to a well set up torsion bar suspension. Which costs a ton less. And you can have a very well handling car with a torsion bar suspension.


Wow, that was the most descriptive reply I think I’ve ever seen on here, thank you.
The only reason I am wanting rack and coilovers is for header clearance since I’m not running a mopar engine, and a tight steering ratio.

I want the car to drive like a new car that is what I’m after
 
Wow, that was the most descriptive reply I think I’ve ever seen on here, thank you.
The only reason I am wanting rack and coilovers is for header clearance since I’m not running a mopar engine, and a tight steering ratio.

I want the car to drive like a new car that is what I’m after

Well you can get a better steering ratio from a Borgeson steering box, they're 14:1. I run a 16:1 manual steering box on my Duster, and really it doesn't need to be any faster a ratio than that. Now, if you want to get rid of the on-center dead spot that every worm and ball steering box has, you have to go rack and pinion. But that's not a performance thing, that's a feel thing.

Not sure what to tell you about the headers with a non-mopar engine. The odds of something "off the shelf" fitting the swap probably increase with a coil over conversion, but that's a crapshoot as it's entirely possible nothing off the shelf will fit regardless. That's the downside to less common engine swaps, you're on your own for headers. A set of custom headers should set you back less than the difference between a coilover conversion and a well built torsion bar front end though. But suppose there's the engine mounts too, as Denny might be able to do that. What engine are you swapping in?

"Drive like a new car" isn't a fair comparison, IMO. There's a lot things that go into how it feels to drive a new car. Most new cars have independent rear suspension, first off. Not to mention traction control, ABS braking, and depending on the vehicle other computer driven handling improvements. Like "sport mode" that can do things like change the resistance on your electric power steering, or the shock damping for cars with magnetic shocks. Heck even raise and lower the ride height on some cars.

You're not going achieve most of those things with any aftermarket suspension, coil overs or otherwise, unless you're planning on grafting the body of your A-body onto a modern car's pan.

If you want your car to handle as well as a new car, that's achievable. Heck the Hotchkis Challenger pulled more G's on the skidpad than a modern challenger. And the Hotchkis Taxi lapped TireRack's test track faster than the 3 series Beemer's they normally use, with the same driver. The Hotchkis cars are still torsion bar/leaf spring cars, and quite frankly there are some parts out there now better than what Hotchkis offers. And not to brag, but my car handles as well as either of those Hotchkis cars. It's set up the same or better. But I can tell you right now, none of those cars feels like driving a new car. Performance wise they can compete, especially if you do something silly like turn off the traction control on your new car. But driving the old car to those performance numbers requires more effort and more skill to make up for all the computer driven goodies you won't have.
 
Well you can get a better steering ratio from a Borgeson steering box, they're 14:1. I run a 16:1 manual steering box on my Duster, and really it doesn't need to be any faster a ratio than that. Now, if you want to get rid of the on-center dead spot that every worm and ball steering box has, you have to go rack and pinion. But that's not a performance thing, that's a feel thing.

Not sure what to tell you about the headers with a non-mopar engine. The odds of something "off the shelf" fitting the swap probably increase with a coil over conversion, but that's a crapshoot as it's entirely possible nothing off the shelf will fit regardless. That's the downside to less common engine swaps, you're on your own for headers. A set of custom headers should set you back less than the difference between a coilover conversion and a well built torsion bar front end though. But suppose there's the engine mounts too, as Denny might be able to do that. What engine are you swapping in?

"Drive like a new car" isn't a fair comparison, IMO. There's a lot things that go into how it feels to drive a new car. Most new cars have independent rear suspension, first off. Not to mention traction control, ABS braking, and depending on the vehicle other computer driven handling improvements. Like "sport mode" that can do things like change the resistance on your electric power steering, or the shock damping for cars with magnetic shocks. Heck even raise and lower the ride height on some cars.

You're not going achieve most of those things with any aftermarket suspension, coil overs or otherwise, unless you're planning on grafting the body of your A-body onto a modern car's pan.

If you want your car to handle as well as a new car, that's achievable. Heck the Hotchkis Challenger pulled more G's on the skidpad than a modern challenger. And the Hotchkis Taxi lapped TireRack's test track faster than the 3 series Beemer's they normally use, with the same driver. The Hotchkis cars are still torsion bar/leaf spring cars, and quite frankly there are some parts out there now better than what Hotchkis offers. And not to brag, but my car handles as well as either of those Hotchkis cars. It's set up the same or better. But I can tell you right now, none of those cars feels like driving a new car. Performance wise they can compete, especially if you do something silly like turn off the traction control on your new car. But driving the old car to those performance numbers requires more effort and more skill to make up for all the computer driven goodies you won't have.


I’d love to ride in your car sometime. I am completely open to using different parts, I was under the assumption that coilovers and rack are a must, but I’m sure I can change my mind
 
Well you can get a better steering ratio from a Borgeson steering box, they're 14:1. I run a 16:1 manual steering box on my Duster, and really it doesn't need to be any faster a ratio than that. Now, if you want to get rid of the on-center dead spot that every worm and ball steering box has, you have to go rack and pinion. But that's not a performance thing, that's a feel thing.

I think that this is my biggest issue with my car. I don't like this "play on center" before the car actually start turning, for me it makes it hard to trust keeping it on center (especially at speeds). Is this play present on every steering box? Not too long ago I found that the three mounting bolts got a little loose...enough that there was play when i pulled at the wheels. Of course I tighten it back and re-aligned...now I am sensitive to this play at the steering wheel. Is this something that I just need to get use to?

BTW, @72bluNblu , how did you lower your rear suspension? I have a 9" rear end but don't know the rear leaf spring rate and I want to lower the back end and add rear sway bar.
 
Wow, that was the most descriptive reply I think I’ve ever seen on here, thank you.
W/72bluNblu, that’s what you get. Straight to the point no B.S. and long winded posts that contain pork fat crap.
Always da’Man!
I want the car to drive like a new car that is what I’m after
For what I know …. Not much…. That’s a tall order.
I myself, have not had the need to upgrade more over a good new spring and gas shock set up though a good sway bar is an excellent addition when you don’t have one.

Reading with interest. Because you never know!
 
I think that this is my biggest issue with my car. I don't like this "play on center" before the car actually start turning, for me it makes it hard to trust keeping it on center (especially at speeds). Is this play present on every steering box? Not too long ago I found that the three mounting bolts got a little loose...enough that there was play when i pulled at the wheels. Of course I tighten it back and re-aligned...now I am sensitive to this play at the steering wheel. Is this something that I just need to get use to?

BTW, @72bluNblu , how did you lower your rear suspension? I have a 9" rear end but don't know the rear leaf spring rate and I want to lower the back end and add rear sway bar.

All "worm and ball" style steering boxes will have a small, on-center dead spot. Just part of how they work. Now, that said, it should be pretty small. As steering boxes wear it increases, and worn steering components- tie rod ends, pitman and idler arms, even worn suspension bushings and ball joints can make that feeling worse. Loose steering box bolts would definitely make that feeling worse, as will any cracks in the K frame at the steering box mount. Those cracks are not uncommon.

So, before I say it's something that you should get used to, it's worth making sure you don't have any worn or damaged parts first. But even with all brand new parts and a solid K frame that play on center will not be zero.

I haven't done much of anything to lower the rear of my car. Most of it is just the AFCO leaf springs I'm running. They're 121 lb/in, "zero arch" springs. Factory mopar springs for these cars are pretty close to flat when loaded, they sat pretty low in the back already. I did replace my leaf spring hangers with a set of leaf spring sliders, and my bracket to do that lowered the rear of my car about 3/8". Not much in the grand scheme of things.

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Other than running springs that don't raise the back of your car (like the super stock springs do), your best bet for lowering is just a set of lowering blocks between the spring and spring perch. Cheap, easy, and if they're 1" or shorter no real dramatic changes in suspension geometry.
 
All "worm and ball" style steering boxes will have a small, on-center dead spot. Just part of how they work. Now, that said, it should be pretty small. As steering boxes wear it increases, and worn steering components- tie rod ends, pitman and idler arms, even worn suspension bushings and ball joints can make that feeling worse. Loose steering box bolts would definitely make that feeling worse, as will any cracks in the K frame at the steering box mount. Those cracks are not uncommon.

So, before I say it's something that you should get used to, it's worth making sure you don't have any worn or damaged parts first. But even with all brand new parts and a solid K frame that play on center will not be zero.

I haven't done much of anything to lower the rear of my car. Most of it is just the AFCO leaf springs I'm running. They're 121 lb/in, "zero arch" springs. Factory mopar springs for these cars are pretty close to flat when loaded, they sat pretty low in the back already. I did replace my leaf spring hangers with a set of leaf spring sliders, and my bracket to do that lowered the rear of my car about 3/8". Not much in the grand scheme of things.

View attachment 1715781413

View attachment 1715781414

Other than running springs that don't raise the back of your car (like the super stock springs do), your best bet for lowering is just a set of lowering blocks between the spring and spring perch. Cheap, easy, and if they're 1" or shorter no real dramatic changes in suspension geometry.

Thank you! I really could use your help setting up and determining my suspension....How can I tell which rear leaf spring I have? the car has a slight forward rake because the top of the wheel arches (measured from the ground) Front: 26.75" ....Rear 29.25" ...........my wheels are Front: 26" dia (215/65R15) and the Rears: 28" (275/60R15).... So I know that if i change the rears to something that matches more closely to the fronts I will be more leveled... I am looking at a front suspension rebuild kit from POL to help with the loose steering feel
 
26.75 is a little higher than what I run, 26.125". This is with a 26" tall tire. Lowering the rear would help quite a bit to achieve some balance. The Borgeson steering kits offer zero play on center, unlike the factory pieces. There are several ways to tighten up the steering linkage and suspension to improve the feel and safety. For instance, I have a Stage 1 suspension kit to improve the precision of the lower control arm and improve alignment. PM with any questions. Bergmanautocraft.com
 
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