DionR
Well-Known Member
I’ve said it in other threads, but I will say it again. If I were in the market for a kit, HDK is the only one I would look at. Invested in making his offerings better, and in my under informed opinion, the best design.
DOES THE HDK SUSPENSION K-MEMBER HANDLE BETTER THAN A T-BAR SUSPENSION?
- Thread starter racerjoe
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I’ve said it in other threads, but I will say it again. If I were in the market for a kit, HDK is the only one I would look at. Invested in making his offerings better, and in my under informed opinion, the best design.
junkyardhero
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question: have you ever driven or ridden in a car with a properly set up stock torsion bar suspension that would be comparable to a HDK or other COC?
I mapped it .....more than a decade ago and always have looked for an economical way to raise the upper control arm pivot point. As far as I knew, until very recently, there were no other affordable options.
I have always built the HDK with the best parts available at the time. I have incorporated QA1 1" extended ball joints, the longest extension they have, in the upper control arm since around 2012. Gerst got it from me around 2018 (?) when he started and Qa1 got it from Gerst. I have not seen them on the others. Doesn't mean they don't use them, I just have not seem them on any of their customers builds.
Yes, my first Hemi A-body, my 73 Duster was built with a OEM K, torsion bars and a pinto rack and pinion, very similar to the Mopar Pro-stock cars in the early to mid 70's. The rack actually moved a drag link in an attempt to get the inner tie rod in a better position to improve the steering curve and lessen the bump steer. I made custom steering arms to help with the ackerman but discovered using heim ends for tie rod ends made the steering feel harsh. Worse yet, the heims severely limited suspension travel and on the street didn't last very long without some type of dirt seal and lubrication. I tried Seals It dust seals on the heims but they fell apart after about 40 miles. I called Seals it and they laughed explaining they should be changed after every 2 or 3 races???? go figure?
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for me....the rack is what gives the newer car feel.
to review.....a torsion bar is simply a straight spring (vs a coiled spring) to hold the car up. I like torsion bars, especially the ease of ride height adjustment and the lower center of gravity they afford but unfortunately they no longer have a place to attach in the front with the required re-positioning of the LCAS.....plus they always seem to be in the way of the exhaust. One might get a better ride with the better quality shock used in coil over conversions (vs a pair of worn out Walmart gas-o-matics) but that can easily done with an OEM suspension.
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DionR
Well-Known Member
Gotcha. I guess I assumed from earlier discussions that you hadn’t mapped it. Thanks!
SixPaksRule
Well-Known Member
How much money did the OP spend on the suspension system?
It is unknown how low the car is, how low matters - roll center
I don't see where the car got any further chassis stiffening with either system
Without it there is large amount of twist in the unibody. With the proper stiffening and a welded k frame there is no dead spot in the middle of the steering -not conjecture just plain old experience. Unfortunately there was no time spent flogging the car on a road course - where the big dogs run. Lap times show results, i have no love for autocross but that is just me. I like driving, feeling, hearing the car bark at the moon under full power for long periods of time and running lap times that old stock looking mopars are not supposed to have. It's intoxicating.
It is unknown how low the car is, how low matters - roll center
I don't see where the car got any further chassis stiffening with either system
Without it there is large amount of twist in the unibody. With the proper stiffening and a welded k frame there is no dead spot in the middle of the steering -not conjecture just plain old experience. Unfortunately there was no time spent flogging the car on a road course - where the big dogs run. Lap times show results, i have no love for autocross but that is just me. I like driving, feeling, hearing the car bark at the moon under full power for long periods of time and running lap times that old stock looking mopars are not supposed to have. It's intoxicating.
The prices of Denny's kits are published on his website, moparsuspension.com. Spindles and brake kits are left up to the buyer.
The wheel opening of the front fender is 24.5" from the ground. This is an irrelevant point since different tire heights will change the position of the control arms.
I have welded subframe connectors in the car. Unibody twist is relevant with both CoC and torsion bars. While I have not added any additional stiffening to the front of the car, I may at some point. I have not seen any adverse affects from the HDK after 1000 street miles and nearly 50 autocross runs.
I'm sorry, but I have to disagree with you stating a welded K removes the dead spot in a steering box. My K-member was completely welded and both the steering box and idler arm mounting areas were stiffened with addition gussets. Guess what, the Borgenson box still had a dead spot in the center.
I understand you may think autocorss isn't real racing, plenty of people think the same way. I do challenge you to try it.
What I like about autocross is as follows:
- The course changes every month. I have about 30 minutes to learn the course (by walking it) and decide on the fastest route. It's not only a driver skill, there's mental skill. Anyone can pull up a youtube video of a particular road course and learn the fast line.
- Autocross doesn't beat up my street car as much as a road course would.
- For autocross, I don't have to have a full cage, containment seat, hans device, etc. in my street car.
- I don't have to worry about some other fool on the course running into my street car when I'm on the autocross.
- I pay $45 for a day of autocross. For a single open track day, it's $400+. So basically I can autocross all year for the cost of one open track day.
If you aren't familiar with the Optima series, you should look it up. There's plenty of "big dogs" out there destroying an autocross track.
DionR
Well-Known Member
I really like the Borgeson box I put in my car, but I can’t remember now if it has a dead spot. I know it felt a lot more precise and a much better ratio than the manual box it replaced. I don’t remember it feeling any worse than my 2015 Challenger R/T either, but there were several years between when I sold the R/T and when the Borgenson box went in my Duster.
for clarity
the HDK includes Mustang II spindles....standard or 2" drop. The optional 2" taller ball joints?...no extra charge.
Having done a complete change-out of stock style suspension and steering box, I can tell you that my particular setup feels and behaves like a new car. I like the results achieved by buying this and that. The only thing I might do, is change to a smaller diameter torsion-bar. I also did this stuff to an E-body. The K-frame, idler, Pittman, and center-link are the only original factory replacement pieces.
When driving straight down the road, rock the steering wheel. There will be a dead spot where the car doesn't react. That spot doesn't exist with a rack.
DionR
Well-Known Member
I am familiar with what it is, I’ve had way too many old Mopars to miss it. Just didn’t pay any attention to that aspect after swapping the box in.
nice looking ride!!!
Super-Cuda
MOPAR .. Move Over, Plymouth Approaching Rapidly!
my upper control arm angle is likely closer than you think to Tim's improved set-up.
built (around 2010) with.....
Wilwood Pro spindles............................adds 1/2"
Qa1 1" extended ball joints...................adds 1"
27" tall tire with same ride height..........adds 1/2" (plus)
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the above combination adds close to ...if not more 2" (plus) of upper ball joint height to improve the upper ball joint angle
The HDK Hemi version package that I used drops everything 1/2" strictly to get the Hemi under the flat hood....the main goal. I do have a slight 5% LCA angle downward from the outside....as close as I could get with the pieces available at that time.
Not all bad.
..................and that's his Moms car.
All my cars have a properly set up torsion bar suspension. My preference in this hobby is to enjoy the cars the way they came. I like old cars because I like old cars. I like the way they feel on the road, and all of their eccentricities. I can drive any of our daily driven rack and pinion vehicles, but I prefer to drive my Roadrunner. It is a 6bbl, 4 speed, Dana, manual steering, and manual drum brakes. That to me is heaven, just like it was in 1970, and it makes me happy to be able to enjoy it just the way it came.
I came to this thread to read about the HDK front end, and the coil over front systems that are available. I like engineering and figuring things out, not necessarily to apply to my cars, because in my world it takes the feel out of the car. But I don’t bash anybody that wants to enjoy their car in any way they see fit. It’s when someone bashed me for not jumping both feet into their vision for their car that I take offense to. I’m not a road and track racer, but I can certainly appreciate the setup that makes that possible in an old car. It’s just not for me, and I don’t appreciate being dogged about “not reading” the entire post. I don’t need to, I simply answered to the title of the thread.
And, as a matter of reference, when Denny wanted to build his front suspension for early A bodies, I gave him a shell of a car to do his mock up on, because I had it and he needed it. He offered me one of his HDK kits at a really good price, but I declined, because it’s not the way I drive my cars. I just wanted to help him bring his product to the early A guys that do want to drive that way.
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True that.
DionR
Well-Known Member
Not bashing you, just a comment. There is way more to a thread than the title, any thread.
DionR
Well-Known Member
That’s true, but I also think a more specific description of what the thread is actually about would’ve maybe been in order. I answered directly to the thread title, but had the thread been titled something like “how to set up the HDK for road racing in 100 easy steps”, I may not have even read it. But, then again, many more people might that want to set up their car that way. And not only here, I see that the whole world can see these threads by just doing a google search with a couple key words.
It’s all good tho, I’m done here anyway, as the content doesn’t speak to my use of my cars. Although throwing an HDK on my 66 does sound like fun.
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