Advanced Suspension Mods

[Ford Fester]

Score!

[Advancedynamix]

Well, I found a company that sells complete poly bushings for the festiva! Here are some control arm bushings ( only because I have blown out the stock rubber ones a couple of times and I have some otherwise perfect control arms to try these on.)

I'd like to visit Australia, if only to come back with luggage full of trick Festiva parts. I paid around 60usd for these, but they are cheap (35USD) in the kangaroo country.

[Christ]

He's saying that it doesn't actually change the arc, it just puts you in a more desirable part of the arc so that the up and down movement of the tire doesn't translate into as much in and out movement of the hub relative to the car body, but it doesn't work that way... The moment arc of a control arm is defined as the centerline between the mounting points and the center of the ball in the joint. Bending the control arm, while putting the control arm itself back into reasonable alignment, doesn't change the position of the centerline laterally from the ball joint back to the mounting point. That is determined by the strut length in a MacPherson strut setup.

However, if your bend moves the centerline of the ball joint closer to the mounting point, it will change the arc length negative, and obviously if it moves the centerline further from the mounting point, the arc length is changed positive. Positive increase in arc length means more travel to achieve the same degree change in the lateral centerline.

[Advancedynamix]

The two pivot points of the control arm are not located by the shape of the control arm, other than it's length. They are located by the wheel on the ground attached to the hub, captured by the knuckle which holds the ball joint on the outer end and the chassis mounting bolt on the inner end. the control arm could be shaped like a pretzel and it would have no effect on this until the ball joints were in a binding state, then it will lift the wheel off the ground (not good). To visualize this you have to put the wheel, hub and knuckle in the picture as well as the body mounting point (these are constants, not variables in this example.) To visualize camber gain you'll also need the upper strut mount in the picture(again, a constant.) The upper strut mounts relation to the length of the control arm and it's mounting point dictates the camber arc. without showing what the ends of that control arm are attached to, you cannot see that what effect (or lack thereof) bending the control arm will have. I'll draw a picture of this when I get back to Arizona. There will be a straight line from ball joint centerline to pivot centerline even if the control arm is bent, it will only lower the ball joint when the wheel is lowered, which would lift the car. In other words, the ball joint centerline will remain consistent with the axle centerline unless a spacer is used between the two. Bending the control arm will not have the same result as a spacer. Bending the control arm will only correct (or aggravate) an over articulated ball joint. The festive has plenty of ball joint articulation for 99% of us (check out movin's pictures for an example of the other 1%.)
Does this make sense or am i going crazy? I still can't see how bending the control arm changes the camber arc.

[Arnie]

I don't see how bending the control arm changes the ball joint location. In order to change the ball joint location the distance between the axle centerline and ball joint centerline would have to change. The shape of the control arm is irrelevant to roll center and camber curve, however the length of the control arm is relevant. Now, your caster adjustment is sensible, but would be difficult to duplicate on a festiva control arm due the the shape and material used. This is why I would make my own adjustable arms. Also, the festiva arm doesn't extend 90 degrees perpendicular from the body, it angles slightly forward, making the bend less effective.

Your drawing needs to display wheel centerline and shock length to show how bending the control arm does nothing except adjust the working angle of the ball joint. The Festiva has plenty of ball joint articulation for all but the most exotic setups ( yes Movin, your setup is very exotic and a special case where the factory ball joint falls short, lol).
One other factor that needs to be considered is the placement of the struts upper pivot. Since the strut top pivot is much further inward than the ball joint, negative camber will continue to increase as the shock travels through its stroke, even with the control arm far past it's tangenal parallel point. The increase in negative camber is actually quite aggressive for a street car that was not sold with the intentions of high performance.

Here's a nice diagram I found. One component of determining the instant center and roll center is by drawing a line through the center of the control arm pickup point and the rotational center of the ball joint, NOT through the center of the control arm. If you bend the arm to move the ball joint up or down from its original position, you will change the rotational center of the ball joint (and all the corresponding geometry) in relation to the center of the control arm pickup point. And this can raise or lower your roll center.

[Movin]

I LOVE ADVANCEDYNAMIX'S CAR! My wife gave me GREEN lights to go ahead to built our '93 Festiva like advancedynamix's car, 95% my wife WON'T let me spent money to built any cars I wanted in the past.. Now she's saving up money for our future Mini Rod Festiva, because it's not that expsensive plus she want to drive our future car... i have owned 48 vehicles in my life time, I think this is going to be my favorite car ever! I dream and cant keep it off my mind everyday since i drove his car about 6 months ago.... THANKS ADVANCEDYNAMIX FOR ALLOW US DRIVE AND YOUR CAR! YOU SURE MADE OUR WEEKEND TRIP WORTH!!! [/QUOTE]

:shock: Mini Rod ??

[DriverOne]

Welcome nastiva!!

Yes, welcome! And thank you, AD, for adding to the addiction!

[Advancedynamix]

My wife and I live in San Diego, Ca., We went to Mesa, Az, to visit Advancedynamix in person and his car, We are 50+ years old farts, when we saw his car, in my mind said "oh geezz low profile tires, hard bucket racing seats and low to the ground?' that gotta hurt my back and neck, plus wife hate hard ride car like my '06 GTO, So this guy let me drive his car, in my mind also said, "I have to drive like a race car that might be harder to drive and watch out for street roads, Sooo I drove his car.., My jaws dropped, everything I said in my mind is alll wrong! it's NOT a race car to me at all! This car is so DRIVE-ABLE!! This car ride so GREAT like a daily street car, this car is very quick probably little quicker than my 400hp GTO and ride better than GTO plus handle wayy better than my GTO! My wife also rode this car, She said she like this car better than my GTO, I LOVE ADVANCEDYNAMIX'S CAR! My wife gave me GREEN lights to go ahead to built our '93 Festiva like advancedynamix's car, 95% my wife WON'T let me spent money to built any cars I wanted in the past.. Now she's saving up money for our future Mini Rod Festiva, because it's not that expsensive plus she want to drive our future car... i have owned 48 vehicles in my life time, I think this is going to be my favorite car ever! I dream and cant keep it off my mind everyday since i drove his car about 6 months ago.... THANKS ADVANCEDYNAMIX FOR ALLOW US DRIVE AND YOUR CAR! YOU SURE MADE OUR WEEKEND TRIP WORTH!!!

Thanks Chris! And, you are very welcome! I had a lot of fun hanging out with you and your wife! I'm glad that my car helped to inspire and motivate the both of you. I'm looking forward to your B6t swap, your car is in such good condition!

[neanderpaul]

Where's the "LIKE" button?

Sent from my SGH-I727R using Tapatalk 2

X2! That was beautiful!!!

Welcome nastiva!!

[fastivaca]

Where's the "LIKE" button?

Sent from my SGH-I727R using Tapatalk 2

[Nastiva]

My wife and I live in San Diego, Ca., We went to Mesa, Az, to visit Advancedynamix in person and his car, We are 50+ years old farts, when we saw his car, in my mind said "oh geezz low profile tires, hard bucket racing seats and low to the ground?' that gotta hurt my back and neck, plus wife hate hard ride car like my '06 GTO, So this guy let me drive his car, in my mind also said, "I have to drive like a race car that might be harder to drive and watch out for street roads, Sooo I drove his car.., My jaws dropped, everything I said in my mind is alll wrong! it's NOT a race car to me at all! This car is so DRIVE-ABLE!! This car ride so GREAT like a daily street car, this car is very quick probably little quicker than my 400hp GTO and ride better than GTO plus handle wayy better than my GTO! My wife also rode this car, She said she like this car better than my GTO, I LOVE ADVANCEDYNAMIX'S CAR! My wife gave me GREEN lights to go ahead to built our '93 Festiva like advancedynamix's car, 95% my wife WON'T let me spent money to built any cars I wanted in the past.. Now she's saving up money for our future Mini Rod Festiva, because it's not that expsensive plus she want to drive our future car... i have owned 48 vehicles in my life time, I think this is going to be my favorite car ever! I dream and cant keep it off my mind everyday since i drove his car about 6 months ago.... THANKS ADVANCEDYNAMIX FOR ALLOW US DRIVE AND YOUR CAR! YOU SURE MADE OUR WEEKEND TRIP WORTH!!!

[Advancedynamix]

A lot of people are interested in the way I've modified my rear shocks, well, here is an example of the versatility of the setup.

There is an entire BP engine in the back, with other spare parts, tools and a pallet and a couple of tires. I just turned my rear spring adjusters three turns to accommodate all the weight. No rubbing.

[Advancedynamix]

I don't see how bending the control arm changes the ball joint location. In order to change the ball joint location the distance between the axle centerline and ball joint centerline would have to change. The shape of the control arm is irrelevant to roll center and camber curve, however the length of the control arm is relevant. Now, your caster adjustment is sensible, but would be difficult to duplicate on a festiva control arm due the the shape and material used. This is why I would make my own adjustable arms. Also, the festiva arm doesn't extend 90 degrees perpendicular from the body, it angles slightly forward, making the bend less effective.

Your drawing needs to display wheel centerline and shock length to show how bending the control arm does nothing except adjust the working angle of the ball joint. The Festiva has plenty of ball joint articulation for all but the most exotic setups ( yes Movin, your setup is very exotic and a special case where the factory ball joint falls short, lol).
One other factor that needs to be considered is the placement of the struts upper pivot. Since the strut top pivot is much further inward than the ball joint, negative camber will continue to increase as the shock travels through its stroke, even with the control arm far past it's tangenal parallel point. The increase in negative camber is actually quite aggressive for a street car that was not sold with the intentions of high performance.

[Arnie]

Wouldn't I have to bend them upward to do that? (raising the ball joint in relation to the control arm fulcrum point) The festiva control arms are very stout in that area and not only would they be hard to bend consistently, but it would most definitely weaken them. They look to be forged steel, not just cast steel and the section your talking about bending is very short, cold bending them would be difficult and heating them would ruin the ball joint. For me it would be easier to make my own control arms. Other members have built control arms for their Festivas, it's a very simple part. In the future I will most definitely make control arms, but I want to see how far I can take the stock parts first.
Bending the ball joint end downward would result an a more exaggerated angle on the control arm. Bending it upward would allow the control arm to rest more level with the ground.

No, you'd bend the arm end downward. Basically relocating the ball joint closer to its original position before a car is lowered. Look at this rough diagram I made illustrating the relative position of the ball joint and the knuckle interface in 3 options: normal, ball joint/control arm end raised, and ball joint/control arm end lowered. You can see that by lowering/bending the control arm end it locates the ball joint/knuckle at a more optimum position, i.e. closer to OEM.




You made great diagrams, BTW. Your diagram explains exactly what would happen if you bend the arm end lower to locate the ball joint lower. Bending the arm down takes the place of a ball joint extension you have pictured. There should be enough articulation in the ball joint for things to still function properly, i.e. slot into the knuckle, go through the complete range of suspension motion without binding. We're only talking a few mm's here. I use Whiteline ball joint extension kits on lowered WRX/STi's and Evos.

As an aside, the whole "horizontal control arm" thing is just a very, very rough guide for people to get a ride height in the ball park of keeping things "good". The actual item that determines the geometry is the ball joint and its interface with the knuckle. Some cars actually have this in a lower position than the arm or even higher. For example, on the Festiva, you can see that the ball joint is actually located a few degrees above the centerline of the control arm. So having the Festiva arms parallel to the ground on one's static ride height already has you in the "bad" portion of the camber curve.

I like the idea of taking stock or stock fitting as far as they can go as well. Which makes a simple mod of bending the OEM control arm so nice. I did the same to my Peugeot to gain more caster. Bent the control arm end forward to relocate the ball joint. Here's a pic of the difference it made:





Pic of wheel position in wheel well before and after:

[Advancedynamix]

After watching a full race Yaris run, it was decided that the Festiva might
make the ultimate closed wheel racecar

I couldn't agree more!