New Coil-Over Conversion Suspension
- Thread starter Chris Bolander
- Start date
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racerjoe
Well-Known Member
Besides cars, I'm sure there were lots of cool things that came out in 1970. Just like cars and all those things, I'm sure they have improved in 55 years. People worked with what they had back then and even now. I have a hard time understanding why people think technology from 55 years ago is the best thing on earth.
How do you know his product will fail? Have you done an engineering analysis on it?
racerjoe
Well-Known Member
Why do you assume vintage trans am racing is the only form of racing people do with these cars? Plenty of us on the autocross and road course having fun with our car vs sitting a lawn chair behind it.
Scody21
Just send it
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I know it is not the only type of traveling at speed experience. The Hill-Billys pulling the lawn chair just want to have fun and not waste a **** ton of beer money on the front suspension of a beater A body they just pulled out the field. And the old farts sitting in lawn chairs, they are not driving anyways. Truly, reading all these coil over thread, I’ve not seen anyone post a major driving improvement from a coil over conversion compared to a well sorted stock style setup. To each their own…. With a lighter pocketbook…
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Ahem.....sometimes a lawn chair is in FRONT of it!
DionR
Well-Known Member
Racerjoe posted a thread about his setup before and after and with some work has done very well. Big long thread that turned into a bit of a turd slinger but I think it was a useful conversation. It is partly why I asked about some suspension plots from the OP as I would like to see some data instead of just “it’s improved”.
As far as I know, Joe is the only one that has ever sorted his TB suspension and then converted and sorted that one as well. Most go from a worn out stock suspension to an all new COC and marvel at how much better it is. No surprise there. But Joe actually put in the work. If memory serves, he went backwards with the COC but with his usual diligence and hard work, is now beyond what his TB setup was at. I think a TB setup could go beyond what Joe had before converting so I still don’t think a COC is the only way, and I am convinced that an out of the box COC is worse than a good TB setup.
I really don’t think this will get answered without 2 identical A-Bodies being built with both suspension types and being in the same place at the same time so the same driver can evaluate them back to back.
racerjoe
Well-Known Member
And I'll add that I really like my HDK setup. And yes, I did spend a lot of time adjusting it to optimize it to my liking. I'm currently running 8+ degrees of caster and around 2 degrees of camber. I have just under a degree of camber gain in the first inch of bump and right at 1" in the second inch of bump. The addition of the custom splined sway bar makes the car feel like it has never before. I can easily take 90 degree turns at 40mph and its completely controlled. The reason I'm asking questions to the OP about the geometry is because I'd like to see where it lands compared to what I have done. No answer so far and I expect we won't get one, which is disappointing. The only guys that pay attention to that statement are the ones that understand it and are likely into some form of cornering performance motorsport. Drag racers don't care about that stuff.
I don't remember Joe going backwards anytime, in fact, my memory had him up to speed right out of the gate. Of course, Joe being Joe, massaged it to HIS liking.
On a side note..... I bet it made his Gen III swap a whole lot easier.
DionR
Well-Known Member
That was my assessment based on some of the changes he made during the course of improving things. I don't remember exactly what it was or how, but my conclusion was that at one point in the middle he was about in the same place he was with his TB setup. Thus, my conclusion was the he went backwards handling wise at the start.
Another example would be when Joe had to swap in extra long UBJ's to get the roll center better, I would again argue that he went backwards until he corrected some things. Maybe those are standard now, but it's not what he started with.
I do think he is beyond his old TB setup now. But I'm not sure I would agree that a TB suspension couldn't be equal.
I know he was pretty happy with the swap. I'm pretty happy with my Holley swap parts, too.
Still comes down to what you want and how much you want to spend. And they all have their drawbacks.
DionR
Well-Known Member
I wonder if drag racers use the term "handling", but mean things like "it stays straight when the front tires touch back down". I could see bump steer being really important in that case while roll center and scrub radius are all non-issues.
fun fact....changing the ride height and / or tire diameter of your car changes roll center. In the world of car set-up, one size does not fit all. And to add a degree of difficulty to the set-up equation, what driver A likes in a set up, might not be even close to what driver B likes. Ever hear a racer get out of his teammates fast ride only to remark....I don't know how you drive that?
No secret, Joe could make a skate board fly, what car guys / racers like is adjustability and adaptability, which IMO, HDK affords both to the maximum.
I (we) get it, some just don't like rack and coil over conversions, regardless of any benefits.
There are guys on here with cars MUCH faster than my avatar (11.0's) but I would tell you that for me, leaving straight and staying straight is what handling is all about. After getting the correct caster in the car, it does this and no longer veers off to the left when the tire comes down.
What I DO wish is the toe didn't change so much throughout the suspension drop. I check/set it using the DC suspension manual guidelines but really just guess where the optimal lift point is to set it. I use 1" lift to set it as I assume that is closer to the amount of lift at the big end compared to the 4" or so at the line. But any unnecessary scrub is tire wear and thus wasted et.
tjpatte
Well-Known Member
Do you mean -2 degrees of camber?
racerjoe
Well-Known Member
Yes, sorry. Most people in the handling world will understand its negative camber. I see no application where you would want to run any amount of positive camber.
Lf of a left turning circle track car. lol
tjpatte
Well-Known Member
I couldn’t think of a reason why someone would run positive camber on a road car, but then again these are old cars and there might have been something I wasn’t understanding.
Just poking fun. Example of an application that uses positive camber from the handling world. What kind of car do you have?
Very cool!
My car. With positive LF camber. 
I like the guy's suspension. I like ANY aftermarket Mopar products. But these guys should be ready from constructive criticism. And so far from what I've seen of those coil over uprights, the critics are right. Look at the difference between his coil over system and this. There's no comparison. This INCORPORATES the already strong factory pieces.
mopowers
Well-Known Member
My only complaint with that setup would be the fact that the upper supports are bolted to the frame rails. If you're going that far, weld 'em in. Kinda like subframe connectors.
DionR
Well-Known Member
And yet the OEM’s are able to build cars that everyone says handle fantastic. Sorry, that’s a straw man argument.
Listing a tire size and ride height would make the data comparable between the two suspensions, even if the final setup wasn’t the same.
And the reality is, within the constrains of the stock sheet metal and frame rails, there really isn’t much variability if you are hunting maximum handling. It’s probably going to be a 25.6”-26” tire and like 5” of ground clearance. Those aren’t all over the place like you want to make it sound like.
No argument there.
Frankly, the only adjustability and adaptability I can think of that your kit offers (and I suspect the rest don’t) is changing your wheel base and track width. And I don’t see those as a game changer. Oh, and maybe you can custom build coils in 25# increments.
Add that there is a limit to what some car guys are capable of spending to get that adaptability and adjustablity.
So some car guys have to spend their money wisely and dropping a ton of cash on a part that maybe only gives a little bit more of those things doesn’t make the cut.
What I don’t like is people stating a COC is the only way to get there and magically fixes all the problems. Companies like to use marketing slang like “improved geometry” but without any data to back it up, making it “magic speak” to me because it must use magic. And then complete gloss over the compromises that are built into the system like they don’t matter. Every system has compromises, there isn’t one out there that doesn’t and some of those compromises do matter. Sometimes money can be thrown at it to make some of those compromises better or go away, which makes money a compromise of its own.
My T56 kit cost me less than your COC would cost me and frankly I see a much greater ROI on a 6 speed than I do on a suspension kit. And even if I spend the same amount upgrading my TB suspension, I can do it as fund allow instead of all at once. If I had to do both (the T56 is a non-negotiable), I probably couldn’t do it at all. And I’m still not convinced a COC is worth what it cost.
I have toyed with the idea of a max effort build which would include LT headers and would be easier with no torsion bars. But I would do some serious frame rail bracing if I did a COC and I might even try and come up with a spindle that isn’t so short. I don’t hate COC’s and have even pointed them out as options before (without even talking about the compromises). But I would have to come into some money to make it even an option. My point being that if the time was right, I would entertain a COC, but it would only be for header clearance and I would have to weight that benefit against the additional work on the frame rails. And I have to admit that part of me thinks custom LT headers would be cheaper than a COC and adding weight to the front of the car.
DionR
Well-Known Member
I would bet the very first COC for a Mopar was built to clear up room for headers and nothing beyond that. Makes complete sense in that regard and would flow very naturally into the street/strip and dedicated strip cars. And the focus on bump steer would follow that.
But I would guess that as the protouring segment got bigger, people started looking at the GM options and assumed that Mopars needed a coil over too, and probably without any investigation. So guys started grabbing them, adding stiffer springs and shocks and a sway bar and bam…”improved handling”.
The reality is GM suspensions like the early F-Body absolutely needed a COC as the required spring rate to get a decent wheel rate was huge. Note that no coil over will ever have the spring to wheel rate association that a torsion bar has. Add mediocre geometry and it makes complete sense that the GM products needed the kits. Now bring that same guy over to Mopars that doesn’t have the equipment or knowledge to figure it out and add some “old is bad” mindset and you have the perfect storm for companies selling kits just on the speculation that they are better.
Not saying a COC can’t have improved geometry and better handling, only that no one has given any hard data and until they do it is pure marketing hype.
And saying “improved geometry was never stated” and then being offended when someone say it doesn’t handle better is a smokescreen. If you expected it to handle better, it must have better geometry. Unless stiffer springs and better shocks are the source of the better handling, and those can be added to a TB suspension too so that can’t be the source of the improvement.
The COC companies need to be honest about their offerings. Frees up space for headers, offers a rack, but loads the rails differently than factory and uses a short MII spindle. And stop talking about handling and geometry unless you publish some data. And by data I don’t mean “the stock worn out suspension didn’t hold a candle to the new double adjustable shock coil over kit we swapped in”.
But I would guess that as the protouring segment got bigger, people started looking at the GM options and assumed that Mopars needed a coil over too, and probably without any investigation. So guys started grabbing them, adding stiffer springs and shocks and a sway bar and bam…”improved handling”.
The reality is GM suspensions like the early F-Body absolutely needed a COC as the required spring rate to get a decent wheel rate was huge. Note that no coil over will ever have the spring to wheel rate association that a torsion bar has. Add mediocre geometry and it makes complete sense that the GM products needed the kits. Now bring that same guy over to Mopars that doesn’t have the equipment or knowledge to figure it out and add some “old is bad” mindset and you have the perfect storm for companies selling kits just on the speculation that they are better.
Not saying a COC can’t have improved geometry and better handling, only that no one has given any hard data and until they do it is pure marketing hype.
And saying “improved geometry was never stated” and then being offended when someone say it doesn’t handle better is a smokescreen. If you expected it to handle better, it must have better geometry. Unless stiffer springs and better shocks are the source of the better handling, and those can be added to a TB suspension too so that can’t be the source of the improvement.
The COC companies need to be honest about their offerings. Frees up space for headers, offers a rack, but loads the rails differently than factory and uses a short MII spindle. And stop talking about handling and geometry unless you publish some data. And by data I don’t mean “the stock worn out suspension didn’t hold a candle to the new double adjustable shock coil over kit we swapped in”.
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