Front Lower Control Arm Bushings

[DocB]

We would like to upgrade the FLCA bushings on an 08 Mustang GT FR500S from the soft squishy rubber ones to some nice hard ones.. The arms are the same found on an 07-09 GT500 Cobra. It is a dedicated track car with C/Os, big brakes and we are running GY Eagle RS 275/35ZR18s.
The present OEM arms have rubber in the front and a hydrogel-rubber bushing in the rear. Alignment and steering control are very important to me. In the past I have upgraded to hard bushings on other control arms and have been very happy with the results.
The only partially hard bushing upgrade kit I have found is the one from FRPP used on the new 302 Boss S. Although it will fit my control arms, only the front is a hard bushing while the rear is still a soft urethane in comparison..

Control arms:
http://www.fordracingparts.com/parts...tKeyField=9632

Intended bushing kit. Although deceiving, the rear bushings are in fact urethane.
http://www.fordracingparts.com/parts...KeyField=13110

My intention is to install hard bushings in both the front and rear attachment points.

I would like to know your thoughts on why this kit would have one bushing hard and one soft and if the rear bushing was hard would it negatively affect the movement of the control arm or the function of the suspension.

I am contemplating going through the effort of designing and fabricating a hard Delrin bushing for the rear unless someone knows of a good reason why this would not be a good idea. TIA.

 

[Roadracer350]

I have the same control arms on my FR. They are stock GT500 arms. Go with the Whiteline kit. 100x better than the stock bushings and it will have better turn in. Plus that Ford kit not only is more expensive it's not as good but thats my openion.

 

[DocB]

We have looked at the Whiteline kit also, but the bushings are still some sort of urethane, which equates to deflection.
I track my car, and track it hard. And hopefully even more so in the near future.
From what I have learned and understand, optimally it is the suspension components by design that should provide the movement, not the deflection of the components squishing around in rubber or urethane.

Two questions:

#1. WHY (in your opinion) do you say that the Ford kit is not as good as the Whiteline? If you could, please be specific as I am trying to learn.

And to keep this thread on track as a tech only thread,

#2. Why not a solid bushing at the rear attachment point of the FLCA? Does it need to move around?

Thanks in advance for your replies.

 

[Roadracer350]

From what I have learned is that the Whiteline bushings are a special blend that they don't let out. They look like urethane but are actually harder. The thing I like about them is the ease of installation and they are 100x better than stock. Better feel, turn in etc. most stuff I have seen tried and have tried from Ford Racing is usually overpriced and theirs other stuff that will work better. On solid Delrin bushings you will need to replace them from time to time plus I'm not sure if the added ridgidy from the solid bushings would help. It may cause more problems. The guy you need to talk to is Terry Fair from Vorshlage.

 

[Norm Peterson]

We have looked at the Whiteline kit also, but the bushings are still some sort of urethane, which equates to deflection.
I track my car, and track it hard. And hopefully even more so in the near future.
From what I have learned and understand, optimally it is the suspension components by design that should provide the movement, not the deflection of the components squishing around in rubber or urethane.

What you should really be looking at is the actual amount of this deflection (not "some" vs "nil"), and what it then means in terms of operating alignment.

Typically, poly is 10 or 20 times stiffer than OE rubber, which is good for something like 10,000 lb/in as an order-of-magnitude estimate. Every 0.01" of camber bushing compression amounts to something like . . . 0.03° camber. Bottom line, polyurethane deflection here does not seem to be at all significant.


Norm

 

[DILYSI Dave]

If you want zero deflection, I am developing a spherical bearing kit for OE arms. It isn't ready yet though.

 

[DocB]

Norm, thanks for the tech, including approximations on movement. I will try to actually measure the amount of possible movement of the rear bushing, and then make my decision from there.

Dave, when will it be ready? I would like to complete the upgrades before the racing season starts here in the NE.