Nice work Daze.

jkordzi wrote:

Is there any geometric change in the swing of the UCA and LCA in comparison to stock?

No, The LCAs are aftermarket units (before I modified them) correct for a 64.5-66 and the UCAs are factory length.  The UCA is mounted in the UCA drop position of 1" so the spindle arch and camber curve is the same as any other car with the UCA drop.

jkordzi wrote:

Does the upper mount get welded to the shock tower?

No, the upper mount is notched to fit into the spring seat so all the upward pressure is placed in the top of the shock tower as designed by Ford, and there are 3 holes drilled in the upper mount that match the shock tower cap mounts.  A plate than mounts to the top of the shock tower to cover the hole and help secure the mount in place.

jkordzi wrote:

How did you figure out how far to kick out the lower mounting point on the LCA to make up for the smaller spring of the coil over?

The mounts were not complicated at all.  For best handling the lower mount needs to be as close to the spindle as possible, but also in a place where it could easily be mounted.  The strut rod mounting holes are ideal for mounting the bottom mount.  The top mount started centered in the OEM spring pocket but than had to be adjusted slightly to get a spring angle that clears the UCA through full suspension motion.  Thats how I mocked it up originally but then I had to shorten the top mount because the front end was sitting to hi and then shorten it even more so I could lengthen the bottom mount to get sway bar clearance.

Basically this setup emulates the OEM suspension in general function, improves handling by making everything move freely, gives the improvement of a better lower spring mount, and will give me ride height adjustability on all 4 corners as the IRS uses QA1 coil overs as well.  I would like to say I invented something new but kits like this have been on the market for years.  I did this to save $$ and have the fun of making it myself.  Sounds like the same reason I retrofit the Jag IRS in my car 

Nice work as usual Day! But I think there was a misprint where it said you bought the upper control arm. That certainly can't be correct  

I've changed the design of my upper arms twice, and the lowers and sway bar links once since the original design. Keep up the good work.

Yeah I did Day, but it's quite similar to yours and others. I thought we talked about it at the Bash while driving in your rental Mustang. My latest version has the UCA ball joint back 1/2" and the LCA forward 1/2" which gives it 5* of caster with the arms 90* to the frame rail, and have -1 degree camber. I too am using QA1 coil overs, single adjustable, 502 model I think, and 350# springs, which is what Ron Morris told me he uses. I also lengthened the shock mount on the  LCA.

I don't know what causes pics to post sideways, or how to fix them   Some of my pics make it appear the UCA tubes aren't parallel and the sway bar link isn't vertical, but they are.

This first pic has my original disc brake spindle, LCA and strut rod, which are no longer used.





The UCA is made from 1-1/8" o.d. x .120 wall 4130, and use QA1 XM enduro rod ends with 5/8" thread and 1/2" hole. I bent them on a JD2 bender. The pivot bar which bolts to the rod ends and shock tower is made from 1-1/8" 4130 hex bar.



The upper mount to the shock tower uses 3 bolts where the original upper shock bracket mounted.



The LCA is made from 1-1/4" o.d. x .120 wall 4130 and use a Currie Johnny Joint at the pivot.



I attached the front of the strut rod with a rod end just forward of the original mount.



I did a 2" Arning drop as I read years ago the 69's could handle it. All I know is that it handles pretty dang well, very balanced, rides well, but I used to race karts, so...I've taken many hard fast turns w/o tire squeal, under or oversteer, yet.

Last edited by rpm (12/25/2018 4:32 AM)

I wasn't concerned about the strength of the clevis mount of the strut arm at LCA location, but since I was going to make a new arm with the offset BJ, I decided to steal the idea from Mike Maier's design. He uses a solid rod end sandwiched between the two plates.



This pic is my LCA with the solid rod end below the strut rod front QA1 rod end.



My belief is you want a solid mount at this location like the clevis and solid rod end provide, to keep the LCA from rotating during braking. I don't think you want or need the misalignment or movement the rod end allows.

Because my 69 is lower than stock by quite a bit, the stock sway bar links were too long. My current set up is my second attempt at it. I use 1/2" rod ends in a home made hex adjuster for the link which bolts to the rear side of the LCA. It bolts to the LCA thru a 3/4" o.d. x 1/2" i.d. tube that passes thru the LCA and is welded at front and back.  The top rod end is bolted to a home made bracket that bolts to the sway bar end with either a 5/8 or 7/8" bolt. The sway bar bracket is made from 1-1/4"x .095 wall 4130 round tube, with a shoulder nut welded to the bottom. The top horizontal tube is 3/4" o.d. x 1/2" i.d.



Again, sorry for the sideways pics.

Last edited by rpm (12/26/2018 1:28 AM)

Daze wrote:

I do like the modular design of the strut arm, mounting bracket to lower arm, and lower shock mount. I thought of using a bolt on lower shock mount but never got around to doing anything about it.
 

jkordzi wrote:

Do you believe that the benefit is mainly in adjustability and perhaps a reduction in sprung weight, or more?

First let me start by saying that the OEM Mustang suspension is really very good.  The basic concepts are there to have excellent handling.  I have heard from more than one autocross driver that are quite fond of the OEM mustang design even over more modern suspensions like the Mustang II.  This is not to say that you can take a bone stock Mustang and turn in fantastic times on the autocross course.  The design is good but the OEM equipment is a little lacking.  I have found that the formula to having an excellent handling Mustang using the OEM design is:

medium rate front spring performance but not harsh 400# range
performance shocks
1" sway bar
adjustable strut rods
roller perches
1" UCA drop 
performance alignment.

 I have run this setup for years and am very happy with it.  This combination will handle extremely well and the rid is not bad but the ride is still not a smooth as a modern car.   With that said there is room for improvement.  and that is where the full coil over front suspension comes in.  (full coilover where the coil mounts to the LCA not to be confused with the less expensive kits where the coilover mounts to the UCA)

The simplest way to explain it is to picture a modern strut.  The strut attaches directly to the spindle so all road changes are transmitted immediately from the spindle to the spring shock combo with out any other movement of any other parts.  Road vibrations are more effectively transferred directly into the spring and shock, where it is absorbed improving ride quality.  A coil over or modern strut type front suspension also has better leverage from the spindle to the spring compared to the OEM Mustang setup.  This is because the location of a stock Mustang spring perch is approximately centered between the pivot shaft of the upper control arm and the ball joint. In its simplest terms the spring is acting on a 6" lever (the UCA) The result of this is adequate but minimal leverage between the arm and spring.   By relocating the lower coil-over mount closer to the spindle on the LCA,  the length (of the "lever") increase to about 12" which is a vast improvement over the UCA mounting location.  This allows for more consistent tire to road contact and allows you to run a softer springs without sacrificing tire to road contact which, in turn, again improves ride quality.   A classic Mustang with one of these kits will respond in the front more like a new car due to improve control of wheel movement over changes in the road without increasing the stiffness of the front suspension, which in turn maintains the excellent handling potential of the OEM design but improves ride quality over a stock suspension. 

Many Coil over kits also provide complete adjustability in aligning the car and most coil over shocks can be adjusted in both stiffness and spring location, resulting in adjustable ride quality and ride height.

This is not to be confused with a coil over kit that attaches to the UCA in place of the spring perch.  IMHO other than ride height adjustability there is no advantage of this over an OEM type spring and shock combo sitting on a roller spring perch, especially given the cost.
 

jkordzi wrote:

Thanks Day.  And then they're the "fabrication satisfaction" factor, which can't be overemphasized.

 
There's that, but it can be a double edged sword. If Day is like a few guys here, they've been known to remake a part that is not visible to onlookers because it wasn't up to their standards, and it would eat at them if not fixed.

Heh, safety wire everything and say that picture is from a helicopter rotor assembly and I doubt anyone wouldn't believe you.  Might have to go to a braided stainless brake line too, but other than that it looks downright aerospace.  That's one tricky endlink!

lowercasesteve wrote:

How much distance is there between the fabbed end link and the frame rail?  I wonder if it might hit on a hard turn.

That's a bad pic, and doesn't give a good perspective of the pieces in relationship to each other. The pic even had me questioning the clearances. There is no interference, and I moved the arms and sway bar thru its range of motion several times w/o the spring during the fabrication.
 
I'm loving these sideways pics.

Wow! With all the pictures and discussion I just want to go out and buy all the tools and equipment to build my own. How cool is that. Suspension by Day, or Suspension by RPM. 

Good work guys. Keep up the discussion.

True74yamaha wrote:

What length and spring rate coil spring did yall use Daze? That is if you don't mind me asking

Sorry it took me a couple days to answer this. I couldn’t remember the spring rate so I had to put the spring in my shop press on a bathroom scale. It’s 300 pounds per inch and 12” long.