Super-Cuda
MOPAR .. Move Over, Plymouth Approaching Rapidly!
Not a chance of that happening!
He's my brother and is very protective over his ride.
So am I LOL .!!
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DOES THE HDK SUSPENSION K-MEMBER HANDLE BETTER THAN A T-BAR SUSPENSION?
- Thread starter racerjoe
- Start date
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Not a chance of that happening!
He's my brother and is very protective over his ride.
So am I LOL .!!
Although I’ve never had chance to enjoy the HDK system, I would say that it undoubtably handles much better than a stock torsion bar setup, which was made for ride comfort over cornering. That’s my take on it anyway.
If you buy modern replacement parts for the stock front end, it'll work great. My car handles and steers like a new one. The aftermarket/coil-over stuff is the answer to lots of having to fab and create. It works well, as well.
MopaR&D
Nerd Member
It would be interesting to see some FEA on these systems. Looking at pics online I like the HDK setup the most since it uses a strut rod for the LCA like factory and the K-member looks beefier with more triangulation than QA1 or RMS and uses square instead of round-profile tubing. I doubt many guys are running from the cops through dry creek beds with COC front ends though lol.
Even though my preference is with torsion bars, if I had a Mopar with COC front suspension already it would be stupid to convert back. I don't think anyone in their right mind would do that.
My TB setup is similar to yours but with 1.14" Sway-a-way bars (quite stiff but not as harsh as some newer cars). I have the same tie rod sleeves and adjustable strut rods as you but the stock K-member is not welded (some day). Hellwig sway bars from @BergmanAutoCraft and Hotchkis leaf springs. Steering box is a Firm Feel Stage 2 PS box with minimal on-center play, maybe 1/8-turn at most. 12" OE Mopar-style front discs from Dr. Diff and stock 10" rear drums. Alignment specs are very close to yours but I got the caster with 'band-aid' offset UCA bushings, really want some SPC uppers and tall ball joint. The biggest deficiency is I'm running stock-replacement Sachs shocks which are far too soft for the spring rates, I think my next upgrade will be the Fox Monotube adjustable shocks from Peter. My tires aren't as grippy, Continental ExtremeContact DWS-06 all-seasons but I am running 255-wides in the front as opposed to 235s.
I was hoping to make it to an open lapping/HPDE event at a road course near me this year but with a wedding and honeymoon being planned I might not have the money lol. I'd try an auto-x event but with these soft shocks the stability in rapid direction changes kinda sucks. Hopefully in 2025 I'll be putting down the cash for shocks, UCAs and a DIY alignment setup and hitting the track as much as possible. Road Atlanta is on my bucket list.
The reason for that is obvious. We've preached and preached and preached about how GOOD the original factory suspension systems on these old cars are and it's true. All one has to do is look back at motorsports history and you'll see the stock style Chrysler suspensions were far superior to anything else offered at the time. These cars have won every major type of motorsports event right from the start.
Remember the article about the Movie Bullitt? They went on and on about how much modification the Mustang had to have regarding both power and handling for all of the stunts while the Charger required very little for either. It was essentially stock with a few reinforcements compared to the Mustang. The Charger still left the Mustang in the dust.
While our suspension systems can be improved upon, it's harder to do than just bolting on a few parts.
Yes, but it has to be more of a complete package approach. A piece of this and a piece of that has much less chance of improvement.
TT5.9mag
Two atmospheres are better than one
I think you (and a bunch of others) are missing the point here. This is not a discussion regarding stock torsion bar, as factory, set up VS a modern coil over conversion. Of course the coil overs would destroy that soft grandma goes to church set up. What @racerjoe has done is optimize (for the most part) BOTH systems and is now comparing them. He is one of the few people that have done an actual A to B changeover with each front end after they have been tuned/optimized to how he uses the car.
I'm convinced people can't comprehend what they are reading. Thanks for stepping in.
So now we're stupid, because we're not comprehending the way YOU want us to. Ok.
Seems the first half of your initial post was all about comparing a coil over suspension against a torsion bar suspension, exactly what I was speaking to. Just because you want to continue to the finer points of what YOU did by changing from torsion bars to coil overs is secondary to your title, and my opinion towards it. I’m not particularly interested in the finer points because I’m not running one, will probably never run one, because that’s not how I use my car, but I can certainly reap the benefits of this entire thread. Information is learning, and I like to learn. If you think I can’t comprehend your in-depth posts, you’re wrong. But go ahead and get huffy about it, because apparently your target audience is much more intelligent than I am.
Checking out, no need to interact any further.
TT5.9mag
Two atmospheres are better than one
No one is saying anyone is stupid or getting huffy. It just seems the responses are the same as every other FABO thread comparing a stock worn out torsion bar front end to a brand new “enter manufacturer here” coil over front end. And a true comparison cannot be made when that’s the case. The opinions generated by threads like that are not based in any way, shape, or form on fact because no data was acquired other than the owner saying “it drives much better”. Of course it does.
My responses were in no way comparing something worn out to something brand new. I never said or implied that. But again, since I'm obviously not responding the way yall want, I'm done. I was hoping to get something out of this, because I'm thinking of upgrading Vixen's suspension, but I can get information elsewhere. Maybe not as easily, but I can.
DionR
Well-Known Member
Far as I can tell, I don’t think you were included in the comment.
TT5.9mag
Two atmospheres are better than one
And I wasn’t speaking directly at you or anyone else. As far as I’m concerned this is the ONLY thread regarding a front end comparison where we might learn something.
DionR
Well-Known Member
Completely agree. We have some actual data, a roll center for a COC after some mods. We’ve never had anything like that before. And a back to back assessment.
Now we just need some more data points, both for a TB and other COC kits.
I would have had a roll center calculated for my car by now (I think), but I hurt myself pretty bad and am still 4-8 weeks from being cleared to even be in the garage.
It doesn't matter who you were addressing. Everyone has a viewpoint. I would have thought for the sake of a good conversation about something we can all learn from that everyones' views would be welcomed. I have an ignored thread list, too. That's where this is now.
TT5.9mag
Two atmospheres are better than one
That’s kinda the point, everyone’s views (opinions) are welcome. The problem with that is up until this thread, and maybe a few cars prior to it, (the green brick, hotchiss taxi etc) there really was no comprehensive comparative data to base logical opinions on. They were just opinions.
Super-Cuda
MOPAR .. Move Over, Plymouth Approaching Rapidly!
Thanks Steve!Looks beauty Al!
Doesn't Mosport have a rally course?
No autocross tracks in my area at all. Closest is in Nova Scotia.
For what it is worth, below is my reply to Tim on his heads up regarding posting this tread......
nailed it...and I wouldn't change a thing.
A often overlooked fact regarding the development of the HDK rack & pinion / coil over conversions is it was originally designed as only a rack and pinion conversion ....for room. However, it quickly became apparent to make a front steer rack and pinion work properly in our original rear steer Mopars, the lower control arm pivot point needed changed negating the torsion bars. I had no choice but to come up an economical and stealthy way to install coil shocks and springs. So....truth be told, coil overs were added not because (at least for me) we were seeking better handling / performance, we needed something other than the torsion bars to hold up the front of the car. The fact that they added even more room almost eliminating exhaust clearance issues was just another benefit.
Thank you for a well written article,
Denny
nailed it...and I wouldn't change a thing.
A often overlooked fact regarding the development of the HDK rack & pinion / coil over conversions is it was originally designed as only a rack and pinion conversion ....for room. However, it quickly became apparent to make a front steer rack and pinion work properly in our original rear steer Mopars, the lower control arm pivot point needed changed negating the torsion bars. I had no choice but to come up an economical and stealthy way to install coil shocks and springs. So....truth be told, coil overs were added not because (at least for me) we were seeking better handling / performance, we needed something other than the torsion bars to hold up the front of the car. The fact that they added even more room almost eliminating exhaust clearance issues was just another benefit.
Thank you for a well written article,
Denny
Like Tim, I had no idea either what to expect from my offer a few months ago but I knew I wanted to put my HDK in the hands of someone that would run it hard, put it away wet, and not sugarcoat the results. While the hard driving Auto X often tells the tale, I am also always interested in the street driving aspect too.
For me, the first step has been accomplished......get used to the suspension and rack and pinion. Fine tune the improvements / adjustments and at minimum be as fast as his somewhat flogged OEM set up. If he wasn't as fast or simply the HDK was not to his liking, all I asked was box it up and I would send a return tag for it.
I don't know about you guys on here, but I'm really looking forward to step 2. The competition??....probably not so much.
For me, the first step has been accomplished......get used to the suspension and rack and pinion. Fine tune the improvements / adjustments and at minimum be as fast as his somewhat flogged OEM set up. If he wasn't as fast or simply the HDK was not to his liking, all I asked was box it up and I would send a return tag for it.
I don't know about you guys on here, but I'm really looking forward to step 2. The competition??....probably not so much.
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TT5.9mag
Two atmospheres are better than one
@HemiDenny it’s awesome how impartial you are even when you are a manufacturer of one of these systems. You don’t make wild claims, and that is refreshing. I’m so glad your front end is on @racerjoe car and he is going to flog it. I’m excited for step 2. Thanks.
DionR
Well-Known Member
Interesting background, thanks for that. Makes better sense why you never mapped the geometry.
Just out of curiosity, was the ‘73 Duster in the late ‘90’s your first attempt at a rack swap? Such a sweet car, daydreamed about that one for years.
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