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Daytona Steering Knuckle Mods

Suspension 
6K views 25 replies 5 participants last post by  LaserDad 
#1 ·
I haven't found where anyone has done this project, but I think there is a definite need for it. My plan is to design new front steering knuckles, that will allow me to lower the front end, but retain some of the lower control arm angle.

As it is now, the front lower control arms sit at a slightly raised angle, which is not how you want your suspension to rest.

Right now, I'm only in the planning stage, so I'm not sure where this will end up. I do have a friend which a 3D scanner, so my intent is to at least get the 90's type knuckles scanned into CAD files. From there, it should be easy to re-position the hub/bearing assembly, to be higher, essentially dropping the ball joint and strut mounts.

Then, I can segment the knuckles into individual pieces that can be easily waterjetted and welded together. Because of liability issues, I don't plan to offer any parts for sale, but will release the drawings, at no charge, so that others can have them made.

It would be nice if others, who are knowledgeable, can add their input, as I plan to make this a modular design. I would even like to make it so that we can mount Willwood brake calipers, instead of having to use the old 90's, single piston, type. Of course, this leads to even more options, like using larger wheels, instead of the stock 15 inchers, and larger 6 piston calipers. Maybe even larger rotors. Who knows where it will end up?

The trick is to gather all of the requirements, before starting the design. That way, the different options won't require as many individual design changes.

On the negative aspect, I'm still way behind on my 3 project cars, and work out of town, so actual garage time is limited. The good news is that design work won't require much garage time.

Let the suggestions begin.
 
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#2 ·
um .. the 90's knuckles already have a lower balljoint position than your 86 lazer .. control arm angle solved right there

the only thing you need is to swap them in

personally the brake packages you mention .. if most of us could afford them we would not still be playin with 80's dodges

I know the brembo's for my 01 ford truck are 5-6K
 
#3 · (Edited)
Who's talking about Brembos? You can buy Willwood 4 piston calipers for $150 each, so with pads you are under $400.

https://www.summitracing.com/parts/wil-120-6818/overview/

I don't like where the 90 knuckles position the front tires. They are too close to the rear of the wheelwell, and, to lower the car, the lower control arms ride above parallel, which goes against convention.

I hope to make this an inexpensive project, under $1K total, with new calipers.
 
#4 ·
you have a set of 1990 knuckles ?
that might be the confusion - I believe it's the 92-3 knuckles that have the lower balljoint position and actually often move the wheel forwards
they actually modifyed the front of the wheel well openings on the 92/3 daytonas in that they extended the curve of the opening forward

the 92/3 knuckles should push the control arm down 'roundabout an inch

some do and some don't push the wheel forward it seems- depends on the drill location of the hole for the balljoint stud in the bottom of them

on a street car , 4 piston calipers raise the potential failure rate by a factor of 16 X
(just sayin" lol) but I think on the other site I saw a thread with the w-woods installed on an L body
sorry I don't have a link to that handy
 
#5 ·
91+ knuckles had the lower ball joint, it was like you said wrong placement of the ball joint in the LCA that moves the wheel around. With 2801 Eibachs, and Koni's the 89/90 11" brake, LCA, Kframe setup has my LCA's sitting perfectly level with the ground. The car is low enough already in my opinion. But it's a ShelbyZ so who knows.
 
#6 ·
quick way to get a shelby z an inch lower is a set of turbo z springs

I swaped my known good 87 shelby z front springs , struts and knuckles into my 86 when I put it on the road and the front end went up about an inch

same for the back - although I never got around to swaping in the shelby z rear springs I could see an inch more clearance above the rear shelby z tire compared to the same tire on the turbo z

edit
I'll add , I think there are two different spring sets for the turbo z

one for base , no options other than turbo z and one set for turbo z with base power group

I had a z with air and no other options , not even a rear wiper

my second z had the power mirrors and rear wiper (base power group)

the first one was much lighter feeling and definately a noteably more responsive car

the second one was very heavy slugish by comparison

I definately think checking off the base power group option gave you a set of springs ment for a car that was going to be much heavier
considering the 16 way driver's seat weighed 72 pounds on my bathroom scale ...

add some t tops , some power windows , a body kit etc and it's getting much heavier than the base model pretty quick
 
#8 ·
I wanted to post pics, when I started this thread, but was having problems with PhotoBucket. Now it seems to be working, so these should help explain what needs to be done. Hopefully, it will give viewers an idea of where I am starting from.

This pic shows how the outer ends, of the lower control arms, are higher than the inner pivots.


They should be lower, like on a stock setup, to allow a more correct arc, from low to high, as the suspension compresses.

These pics are 7 years old, but show how the car sat with full extension and compression.




These were the original coilovers.



I have converted to the adjustable coilovers, that Rich Bryant sells, and love them. They allow you to lower the car, but retain the normal travel. Shortening springs isn't the way to go.


This is just a pic of the Daytona's '92 K-frame setup. The Laser's is identical, but powdercoated with different colors.
 
#9 ·
Since starting this thread, one of my realizations is that there has to be room for the axle shaft boot to clear the bottom of the strut. This may jam up my plans, since I wanted to lower the ball joint and the lower strut mount.





I can still lower the ball joint, and achieve the lowered control arm, but there is probably an extended ball joint available, that would achieve the same effect, without the work and expense.
 
#10 ·
FYI, the 91+ spindles don't move the wheel like I stated above. there was a huge thread about it over on TM.com. They found that there are LCA's with different ball joint locations that move the wheel. Some LCA's had the ball joint in the right location and some didn't. Think the concensous was that it was bad machining tolerances. So you could use 91+ spindles on your 89/90 Kmember setup and not move the wheel just the LCA down. Or if you find a set that were machined in the right location you're ok too.

after seeing pics of your setup it's not just the LCA angle you need to worry about it's the CV and tie rod angle as well. I think your best bet to correct your geometry is to move the Kframe up like the guy on here that road races his did.
 
#12 ·
I did some further investigating and realize that the steering knuckle/ball joint mod is not going to work.

The wheel is actually centered OK, so I don't know why I thought that was an issue.


The main issue, with the tire, is that there is an inner wheel well bump, which limits the amount of tire clearance.


It's not bad, with stock width tires, but limits going to anything wider, unless I get some wheels with different spacing.

The ball joint extension won't work, because it already sits close to the inner wheel.


Therefore, I guess the K-frame mod would be the best option. Of course that will create a whole new set of issues. Maybe creating a tubular K-frame, which I know has been done, will be the best option.
 
#13 ·
If I understand correctly, you're wanting the lower control arm to be lower on the outside (ball joint) than the inside (K-member). If that's the case, why? If the control arm is close to level at ride height and the suspension is compressed, the arm moves up bringing the ball joint inward. The strut is compressed and since it's mounted at angle, the upper portion of the knuckle moves inboard as well. This would maintain most of the camber that was set at ride height. If the control arm is low at the ball joint end at ride height, then your ball joint would move out and the top of the knuckle would move in, going negative with the camber. I suspect it would help cornering to some degree but could have some other bad effects. Are you looking for that much of a camber change when loaded? Just trying to understand your thinking. I've changed knuckles on another vehicle with similar effects and it left me with some questions. Maybe your ideas can help me understand the relationship of the parts better.
 
#15 ·
If I understand correctly, you're wanting the lower control arm to be lower on the outside (ball joint) than the inside (K-member). If that's the case, why?
To gain camber as you corner.

If the control arm is close to level at ride height and the suspension is compressed, the arm moves up bringing the ball joint inward. The strut is compressed and since it's mounted at angle, the upper portion of the knuckle moves inboard as well.
Correct.

This would maintain most of the camber that was set at ride height.
Incorrect. When you turn the cornering forces force the contact patch into positive camber. So you want to ADD camber when the suspension compresses.

If the control arm is low at the ball joint end at ride height, then your ball joint would move out and the top of the knuckle would move in, going negative with the camber. I suspect it would help cornering to some degree but could have some other bad effects.
Correct and exactly what you want to happen. There are no other bad effects.


Are you looking for that much of a camber change when loaded?
Yes because you're trying to oppose the forces that are going into the tire and the suspension bushings and body flex that is happening.

Just trying to understand your thinking. I've changed knuckles on another vehicle with similar effects and it left me with some questions. Maybe your ideas can help me understand the relationship of the parts better.
Also By having the LCA's point upwards at the ends the roll center goes to hell. Google roll center. There's pages out there that explain it with diagrams much better than I can. But the worse the roll center the more the car will lean. So by over lowering the car like in the pics you either need to make up for it with super stiff springs or huge sway bars. A lowered car might look cool to some but a properly set up car will out-handle it any day of the week.
 
#17 ·
The reason for my interest, was that my son and I used 93 Sundance knuckles on his 81 Omni to convert to 5 lug wheels. Using the Sundance knuckles and 90 L-body arms did seem to increase the LC angle somewhat from horizontal (down>out). Frankly, I think it handles great for what it is. I just noticed that straight line steering seemed to suffer a little and the need for more correction over changes in road surface. I've gotten used to it and have come to enjoy it somewhat. It feels "racier" if that's a word and makes me want to drive too fast. After reading up on RC, I see where the real benefit would come from and now you've got me interested. That said, if knuckle mods aren't going to happen, what about the K-member? I would think it would be easier to work with (cut/weld) vs. making a knuckle.
 
#18 ·
OK, maybe this isn't a dead idea. I had though about going to a larger wheel, because 15" performance tires are getting harder to find. It would also allow for larger calipers, as the stock wheels are way too thick.

I still think that the K-frame is going to need modding, but I am going to keep the knuckle mod on my bucket list. I just don't know when I am going to find time to work on it. I haven't even developed the reverse cooling setup yet.

That's another problem with our cars. They aren't popular enough to generate trick parts, like Mustangs and Camaros.
 
#19 ·
I am late to this party but you are finding out all the things that everyone else has over the years. We need a workable extended ball joint which noone has so far ever produced proof of finding, and even then you are limited by wheel clearance and most in this community are still running small diameter wheels.

The one consolation i can offer is that the more lowered your car is, the closer you are to having no up-travel for other reasons than just strut limitations. If you care enough to lower the car that much you probably have fairly large wheels, and if you care about handling that much you probably have fairly large tires mounted. The net effect is that people who lower the car and still want it to handle end up with relatively little up-travel before they start rubbing, so you add/modify front bumpstops to prevent that rubbing, and at that point your spring rate is very high and your camber curve and roll center cease to make anything any worse. It comes down to the old saying "any suspension will work if you don't let it". The front suspension of my lowered minivan certainly works this way and it handles surprisingly well, all things considered.

https://youtu.be/31Ewc9_DP-0?t=117
 
#25 ·
According to the P-body thread, there was interference with the axles. But, they also raised the control arm pivot 2 inches. I was thinking more subtle, like 1/2 inch. Maybe it wouldn't gain much in cornering, I don't know. I guess it really depends on how low the car is from stock. Even a partial improvement would be better than nothing but is it worth the trouble?
 
#26 ·
This is an old thread, but if someone wants to see where this has led, here is an updated link:

I had spent a lot of time getting the front suspension to its maximum limits, with 17" tires. It's not a practical conversion, but might give someone enough info to go in a different direction ending up with something that is practical.
 
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