DOES THE HDK SUSPENSION K-MEMBER HANDLE BETTER THAN A T-BAR SUSPENSION?

[HemiDenny]

Hey Denny, any idea if the below is a 1" extended ball joint, or a 2" one? Clipped it from the QA1 instructions.

View attachment 1716201740

Just curious.

It appears to have an extended stud but the ball joint is not the Qa1 over the counter 1" extended ball joint (#1210-238S) HDK has used since around 2012. BTW....long before Gerst or Qa1 even thought about building a Mopar suspension package.

QA1 1210-238S QA1 Ultimate Ball Joints | Summit Racing

just for you, once I pick them up from the machinist, I will post a picture of the 1" and 2" studs side by side

 

[HemiDenny]

I think you’ve answered this before, but how much can the track width be changed? The widest track is pretty close to the later 73+ disk track right? Is the narrow track similar to the SBP drum track?

The HDK can install from 1/2" narrower (per side) than a 67-72 drum brake model to slightly wider than the 73 and up disc brake model. The beauty of dealing with small Mopar only business, HDK can...and has built what is needed at the drop of the hat.

The 1/2" narrower track width is where the silver Duster is at with 5" wide rims / 2-1/2 backspacing.

Joes track width is the opposite, even substituting the 1" wider per side B/E body LCA's to accommodate his desired, wider track width along with the CPP spindles and the negative offset rims he already owned.

 

[racerjoe]

Any rim clearance issues?

Lots of space at the UBJ. Currently the limit of steering stops the tire about 1/2-3/4" away from contacting the frame rail. The next closest interference is the tie rod to the wheel. Once I have a wider wheel, the tie rod would likely contact the wheel, but the tire will contact the frame rail and pre-maturely limit steering before the limit of the rack. This would prevent the tie rod from ever contacting the wheel. Almost a happy coincidence. This has absolutely zero to do with the HDK, it's a result of my high offset wheels. Had I started with an HDK before purchasing wheels, I would have set it up with a narrower track width and sourced a set with less offset. It certainly would have opened up the available off the shelf wheels that would fit. As you know, finding +35 wheels with matching rears isn't easy.
Doesn't your tire contact the frame rail at full lock? I don't remember how close the tie rods were to the wheel on the t-bar setup.

 

[72bluNblu]

Lots of space at the UBJ. Currently the limit of steering stops the tire about 1/2-3/4" away from contacting the frame rail. The next closest interference is the tie rod to the wheel. Once I have a wider wheel, the tie rod would likely contact the wheel, but the tire will contact the frame rail and pre-maturely limit steering before the limit of the rack. This would prevent the tie rod from ever contacting the wheel. Almost a happy coincidence. This has absolutely zero to do with the HDK, it's a result of my high offset wheels. Had I started with an HDK before purchasing wheels, I would have set it up with a narrower track width and sourced a set with less offset. It certainly would have opened up the available off the shelf wheels that would fit. As you know, finding +35 wheels with matching rears isn't easy.
Doesn't your tire contact the frame rail at full lock? I don't remember how close the tie rods were to the wheel on the t-bar setup.

Ok, yeah I was curious about the clearance at the UBJ just because of the extended height. I know when I was running 2” drop spindles on my Challenger I definitely lost clearance to the outer tie rod, one of many reasons those aren’t a great idea with torsion bars.

My steering stops when the tire hits the frame, but I don’t have any proper steering stops. The QA1 LCA’s don’t have any and their narrow width means the lower ball joints never hit them like the factory set up. So I actually get more steering angle than factory.

The tie rod ends are fairly close to the rim, but with 18” wheels they actually fit inside the lip of the rim so with 18’s there’s really no backspace limit other than the frame rail/steering angle.

I don’t know that I’d narrow the track width if it meant shortening the control arms. Obviously it depends on how much, but that tighter the arc the wheel moves in the more potential you’ve got for bump steer, even if it increases camber gain. But even camber gain has its limits, if you’re gaining too much compared to the body angle you’re losing contact patch too. Ideally the camber gain would track with the lean angle of the car during cornering.

 

[racerjoe]

Ok, yeah I was curious about the clearance at the UBJ just because of the extended height. I know when I was running 2” drop spindles on my Challenger I definitely lost clearance to the outer tie rod, one of many reasons those aren’t a great idea with torsion bars.

My steering stops when the tire hits the frame, but I don’t have any proper steering stops. The QA1 LCA’s don’t have any and their narrow width means the lower ball joints never hit them like the factory set up. So I actually get more steering angle than factory.

The tie rod ends are fairly close to the rim, but with 18” wheels they actually fit inside the lip of the rim so with 18’s there’s really no backspace limit other than the frame rail/steering angle.

View attachment 1716202628

I don’t know that I’d narrow the track width if it meant shortening the control arms. Obviously it depends on how much, but that tighter the arc the wheel moves in the more potential you’ve got for bump steer, even if it increases camber gain. But even camber gain has its limits, if you’re gaining too much compared to the body angle you’re losing contact patch too. Ideally the camber gain would track with the lean angle of the car during cornering.

I have no intentions of shortening the arms. While widening my front wheels isn't exactly cheap, it's much cheaper than buying another set of wheels.

 

[newguy]

I have an HDK setup I ordered two years ago and have still to install it (I work way too slow at my hobbies) and am wondering where to purchase this 2" upper balljoint? I don't need a canyon carver, but if this balljoint improves handling I rather intall it before I get too far into the install with the 1" balljoint.

 

[DionR]

I have an HDK setup I ordered two years ago and have still to install it (I work way too slow at my hobbies) and am wondering where to purchase this 2" upper balljoint? I don't need a canyon carver, but if this balljoint improves handling I rather intall it before I get too far into the install with the 1" balljoint.

Allstar Performance maybe?

Post #273

DOES THE HDK SUSPENSION K-MEMBER HANDLE BETTER THAN A T-BAR SUSPENSION?

That’s pretty cool how they welded that aluminum lower radiator support to the steel frame rails and sheet metal. You can actually see the welds in the pictures of the Cuda build. :rofl: Please share with us the quote of whoever made that claim

www.forabodiesonly.com

 

[racerjoe]

Sorry I missed your question. Yes it's an Allstar performance ball joint. Attached is their catalog page with all the available part numbers. Just google up the part number and you will find someone selling them.

 

[racerjoe]

I sure hope this thread doesn't get derailed again, like most of them do on this subject matter. For those actually interested in the content I'll provide an update on the car with real data, not speculative. I get it that most that disagree aren't educated on the physics required to actually make a car handle better. For the people wanting to talk $hit, please stay away. I don't care what you have to say.

The car now has a 5.7 hemi in it. The HDK made the swap super simple.

What makes a car "handle" well isn't necessarily how if feels compared to your worn out stock suspension. It's all about the geometry. In this photo you can see the front right wheel is nearly vertical and the body is rolling and I'm turning. Also note the front left is nearly completely flat on the ground. This is due to the camber gain and aggressive alignment.

Now take a look at this Charger - (nothing against Dylan here). Which tire do you think is applying more grip to the ground?

Lastly, I got 4th in the vintage class of grand champion autocross. I was less than 1 second away from 1st place. 1st place was a B-body with QA1 coil overs, 2nd was a B-Body with Hotchkiss, 3rd was an E-body with damn near all stock T/A stuff, which is amazing. 4th was me. I'll also add, everyone ahead of me was on a 275 or larger front tire. I have a 235 front tire. All things considered, I'd say all 4 of us are fairly equal drivers.

 

[Super-Cuda]

I sure hope this thread doesn't get derailed again, like most of them do on this subject matter. For those actually interested in the content I'll provide an update on the car with real data, not speculative. I get it that most that disagree aren't educated on the physics required to actually make a car handle better. For the people wanting to talk $hit, please stay away. I don't care what you have to say.

The car now has a 5.7 hemi in it. The HDK made the swap super simple.

What makes a car "handle" well isn't necessarily how if feels compared to your worn out stock suspension. It's all about the geometry. In this photo you can see the front right wheel is nearly vertical and the body is rolling and I'm turning. Also note the front left is nearly completely flat on the ground. This is due to the camber gain and aggressive alignment.

View attachment 1716305601


Now take a look at this Charger - (nothing against Dylan here). Which tire do you think is applying more grip to the ground?

View attachment 1716305607



Lastly, I got 4th in the vintage class of grand champion autocross. I was less than 1 second away from 1st place. 1st place was a B-body with QA1 coil overs, 2nd was a B-Body with Hotchkiss, 3rd was an E-body with damn near all stock T/A stuff, which is amazing. 4th was me. I'll also add, everyone ahead of me was on a 275 or larger front tire. I have a 235 front tire. All things considered, I'd say all 4 of us are fairly equal drivers.

A couple of quick questions .

Does the 5.7 hemi sit in the factory location with the HDK system or is it moved further forward or back from the original v-8 engine position ?

Did you have to modify the lower front fenders for tire clearance using 235's ?

Thanks.

 

[racerjoe]

A couple of quick questions .

Does the 5.7 hemi sit in the factory location with the HDK system or is it moved further forward or back from the original v-8 engine position ?

Did you have to modify the lower front fenders for tire clearance using 235's ?

Thanks.

Denny's mounts allow for adjustment, I don't recall how much. Maybe an inch. I initially had them on the engine so it would be as far back as possible. That proved to be too far back for me. I have my main engine harness connector on the firewall and it was just too close to work. It also put the valve cover very close to my already trimmed steering column tube. I'm sure other applications, the rear most position would work fine. I feel like I have it very close to where the small block was. I didn't take any of those measurements to confirm.

The front of the inside of the fender is trimmed. It's the part that folds under near the rod that goes to the bumper bracket. I just cut it on a 45. Hardly even noticeable. I also rolled the fender lips slightly. Keep in mind, with the HDK, track width has a ton of adjustment. I'll be widening my wheels and switching to either 265s or 275s soon.

I did "adjust" the K slightly to move the lower control arm forward. I did this to keep the tire off the rear side of the fender due to the amount of caster I'm running.

 

[autoxcuda]

[cut] 3rd was an E-body with damn near all stock T/A stuff, which is amazing.[cut]

Was the 3rd place E-body Mitch Lelito from Chicago?

1.24 T-bars, 12.7:1 T/A steering arms, 1 1/4"? front and custom rear sway bar, fiberglass leaf springs, Viking Shocks, 295 wide tires.

https://www.holley.com/blog/post/holley_moparty_2021_mitch_lelito_s_1972_dodge_challenger_t_a_clone/

 

[racerjoe]

Was the 3rd place E-body Mitch Lelito from Chicago?

1.24 T-bars, 12.7:1 T/A steering arms, 1 1/4"? front and custom rear sway bar, fiberglass leaf springs, Viking Shocks, 295 wide tires.

https://www.holley.com/blog/post/holley_moparty_2021_mitch_lelito_s_1972_dodge_challenger_t_a_clone/

That's him. I never looked at his setup super close, but I peaked under it this time and saw stock stamped steel UCAs! Factory style Chrysler steering box, not a borgenson. I realize some of this stuff can have modifications, but dang it's unassuming! Great car, great guy.

 

[HPP]

Mitch's Challenger is about as dialed in for autocross as you can get a stock suspension mopar. It was built for national level SCCA stock class competition.

Once upon a time , a t-bar mopar set-up was very desirable and could be set up to run very well, as demonstrated by Mitch's Challenger. It always had a compromise with the caster/camber relationship, but that could be aided with spacers on the lower ball joint, shorter strut rods and offset control arm bushings. Now days, the limited choice of t-bar selection has made stock performance set-ups even more challenging to achieve.

The aftermarket coil over suspension do have a huge advantage in spring selections can be changed in 50# increments, and you can find these springs in swap meets in a range of rates for about $50 a pair. They have geometry that is more dialed in, out of the box, than most average guys will ever achieve with stock stuff. They are lighter than a stock system. Also, a R&P system provides precision a recirculating box can only dream of. I won't say they have an advantage in brake access because ARE and Dr Diff have plenty of kits to access big brakes. They also lake the millions of rough road miles that a stock system is capable of achieving. Will some get there, I'm sure some day, but these also aren't daily driver cars anymore either.

 

[72bluNblu]

Mitch's Challenger is about as dialed in for autocross as you can get a stock suspension mopar. It was built for national level SCCA stock class competition.

Once upon a time , a t-bar mopar set-up was very desirable and could be set up to run very well, as demonstrated by Mitch's Challenger. It always had a compromise with the caster/camber relationship, but that could be aided with spacers on the lower ball joint, shorter strut rods and offset control arm bushings. Now days, the limited choice of t-bar selection has made stock performance set-ups even more challenging to achieve.

The aftermarket coil over suspension do have a huge advantage in spring selections can be changed in 50# increments, and you can find these springs in swap meets in a range of rates for about $50 a pair. They have geometry that is more dialed in, out of the box, than most average guys will ever achieve with stock stuff. They are lighter than a stock system. Also, a R&P system provides precision a recirculating box can only dream of. I won't say they have an advantage in brake access because ARE and Dr Diff have plenty of kits to access big brakes. They also lake the millions of rough road miles that a stock system is capable of achieving. Will some get there, I'm sure some day, but these also aren't daily driver cars anymore either.

Agree to disagree on some of your points. Torsion bars are available in ~50 lb increments if you look at sizes between Firm Feel and Sway Away. Now they're more like $400-$500 a pair, but, we're still driving Mopars right? I have A-body bars in 1.06, 1.12, 1.14, 1.18 and 1.24 for my Duster. There's less than a 50lb change between all of those except the 1.18 to 1.24's, but Sway Away offers a 1.2" bar. Firm Feel still advertises custom bars too, although I'm sure those would be very spendy.

Caster/Camber has been solved with adjustable control arms, you can do darn near anything with the SPC adjustable UCA's I have on my car. I'm sure those are a still a no go for a lot of SCCA classes, but for the CAM stuff they're fine.

This whole "coil over set ups are lighter" thing. Not that much. Like, if you compare a manual rack HDK set up to an OE set up with manual steering it's less than 30 lbs different. If you compare a power rack HDK to mopar suspension with a Borgeson box the HDK is about 35 lbs lighter. And that's without aluminum strut rods and tie rod adjusters, tubular LCA's, etc on the Mopar suspension. So yes, technically the coil over set ups are lighter. But it's not such a massive difference that other choices can't make a bigger difference, like say adding AC to your car, or choosing a heavy set of wheels vs a light set, having a big block vs a small block vs Gen III hemi, etc.

 

[HPP]

Fair enough. I forget Sway Away is still making torsion bars. At $400-500 a pair, they are a bit spendy to have a whole mess of them to swap around, but even a few pairs of t-bars are less expensive than a whole new system. I'd also guess that most of us aren't racing these cars in a manner that necessitates those types of change over, t-bar or coil over.

I did point out the caster/camber relationship isn't a show stopper, but it does require some effort or parts to overcome.

I certainly wouldn't go to a coil over suspension as my first choice for losing weight. There are plenty of other ways that provide a much greater bang for the buck by comparison.

I'm still a fan of the stock set up and am working on a few tricks to push it further out on the envelope. The are ways to alter the geometry for improvements, but they aren't always easy and it will always have the lower control arm pivot/torsion bar interference issue that will require adjustments to improve bump steer curves.

 

[72bluNblu]

Fair enough. I forget Sway Away is still making torsion bars. At $400-500 a pair, they are a bit spendy to have a whole mess of them to swap around, but even a few pairs of t-bars are less expensive than a whole new system. I'd also guess that most of us aren't racing these cars in a manner that necessitates those types of change over, t-bar or coil over.

I did point out the caster/camber relationship isn't a show stopper, but it does require some effort or parts to overcome.

I certainly wouldn't go to a coil over suspension as my first choice for losing weight. There are plenty of other ways that provide a much greater bang for the buck by comparison.

I'm still a fan of the stock set up and am working on a few tricks to push it further out on the envelope. The are ways to alter the geometry for improvements, but they aren't always easy and it will always have the lower control arm pivot/torsion bar interference issue that will require adjustments to improve bump steer curves.

Yeah I don't think most people, even those being fairly aggressive in their racing participation, would really need more than a couple sets of torsion bars. With AutoX it would be down to tire compounds, so really I think you'd only need 1 set of bars unless you were doing different classes that had dramatically different tire compound rules. And if you were doing road racing it would depend on your tracks. But really, even the most prolific racers probably would have it covered with 2 or 3 wheel rate options.

I've been aware of Mitch's car for quite some time now, and as far as I know he's had the same 1.24" torsion bars for well over a decade now and he participates in a lot of events.

As far as geometry optimization, I really don't think there's an issue with the torsion bar suspension. Honestly, I think this thread shows pretty well that out of the box the coil over conversions aren't overall better for geometry than the torsion bar suspension is. Sure, there are differences, but really neither one is dramatically better than the other, both have pros and cons. And there are now just as many ways to optimize the torsion bars set up as there are ways to optimize the coil over conversions. So if you're going to tune and optimize you can get into the same ballpark with either suspension. And keeping the torsion bar suspension definitely has advantages when it comes to chassis loading, namely, its in a chassis that was designed for its loading points.

 

[autoxcuda]

Mitch’s car ran in SCCA E-Street Prepared class that rules don’t allow geometry changes and is limited to spring, sway bar, and shock changes.

 

[racerjoe]

Mitch’s car ran in SCCA E-Street Prepared class that rules don’t allow geometry changes and is limited to spring, sway bar, and shock changes.

Would the offset UCA bushing be allowed in that class?

 

[72bluNblu]

Mitch’s car ran in SCCA E-Street Prepared class that rules don’t allow geometry changes and is limited to spring, sway bar, and shock changes.

I thought I recalled that the class he ran was pretty darn strict. Although that's a two way street, all the competition is stuck with their factory suspensions' shortcomings too, and Mopar's definitely weren't the worst from a geometry standpoint.

It's very impressive though that he can place third against cars that aren't set up that strictly. I know he's running 18x11's all the way around now with 295/30/18's with a 200 tread wear compound tire, which is pretty impressive. But unless he's changed his engine it's still just a 340 set up to T/A specs, and last I'd heard he was running a 727 for a transmission. He has to be down horsepower by quite a bit compared to some of the pro-touring set ups.

 

[autoxcuda]

I thought I recalled that the class he ran was pretty darn strict. Although that's a two way street, all the competition is stuck with their factory suspensions' shortcomings too, and Mopar's definitely weren't the worst from a geometry standpoint.

It's very impressive though that he can place third against cars that aren't set up that strictly. I know he's running 18x11's all the way around now with 295/30/18's with a 200 tread wear compound tire, which is pretty impressive. But unless he's changed his engine it's still just a 340 set up to T/A specs, and last I'd heard he was running a 727 for a transmission. He has to be down horsepower by quite a bit compared to some of the pro-touring set ups.

Yes, that is true competition with class rules.

He upgraded to a 4" stroker motor and ported steel heads recently. With the idea of track days. Still automatic.

I don't think on this tiny course the HP is that much of a difference maker. Article says he runs them in 1st gear. Torque multiplication is big.

 

[racerjoe]

I thought I recalled that the class he ran was pretty darn strict. Although that's a two way street, all the competition is stuck with their factory suspensions' shortcomings too, and Mopar's definitely weren't the worst from a geometry standpoint.

It's very impressive though that he can place third against cars that aren't set up that strictly. I know he's running 18x11's all the way around now with 295/30/18's with a 200 tread wear compound tire, which is pretty impressive. But unless he's changed his engine it's still just a 340 set up to T/A specs, and last I'd heard he was running a 727 for a transmission. He has to be down horsepower by quite a bit compared to some of the pro-touring set ups.

I was .089 seconds behind him in autocross. I'm still on 235 front tires.

 

[75slant6]

I was .089 seconds behind him in autocross. I'm still on 235 front tires.

Dang. I think I need more hp. And A LOT more seat time! Justin Sykes outran me in his crew cab Dart and Doug outran me in his 48 panel van on the stock Dakota chassis! Planning to upgrade power as well as add the 2” balljoints before next MoParty.

Something else I’ve noticed, I turned my shocks all the way stiff for MoParty and I haven’t turned them back down since. And while the ride is definitely more firm, it’s not harsh. The front actually feels real similar to how the back has been since I installed the Mopar circle track springs. So I’m planning to swap out my 400# springs with 450’s, then readjust the stiffness of my shocks accordingly.