pascal

Sam, I understand what you mean and agree with you.
However, if I'm assuming that the OP is an average driver with a somewhat stock car, I'd worry more about the chronology of things to do to improve handling...
The Watts system isn't what I'd start with.

Of course everything is relative since there is more than one combo to do things and one driver will prefer one to another.
As far as racing rules, some overseas racing would allow mods to an extend on factory race cars.
I belong to a Belgian team and we're successful with a GT3 Mustang in endurance.
We've tried a bunch of different things (except IRS) on the rear suspension and ended up keeping things close to Factory specs.
An hand made aluminum duck tail was the best thing we did to the back end of the car.
Imagine that! LOL.

Norm Peterson

The Fays2 arrangement has also been used on GM's 1978 - 1987 intermediate chassis cars, which only use a 7.5"/7.625" axle. I have not heard of any problems there, but have heard some feedback about how while one such car felt slower to its (European, IIRC) driver it was actually running faster lap times. That has to say something good about predictability and driver confidence, since you don't tend to drive harder unless/until you're confident that the car isn't going to turn and bite.

I would not be afraid to run a chassis-mount like the Fays - you aren't going to be developing loads on the pedestals more than about 1200 lbs each unless you're sliding sideways into something solid. Since the clamps clamp around the full circumference of the axle tubes, they tend to locally stabilize the shape of the tubes right at the points where the bending loads are applied, meaning that they won't buckle as readily as simply applying the two point loads per clamp to the tubes a couple of inches apart would have you think.

There's another member here who apparently wasn't convinced on this WL vs PHB issue until he tried one. Search on 'F1Fan', with the knowledge that the Fays2 WL is adjustable for roll center height.

I suspect that the chassis-mounted football arrangement lets you get into the power a little more a little sooner on corner exit than the diff-mounted design. Most times, that's a good thing.

The video by Alexander a few posts back at least suggests that there is less axle "monkey-motion" going on with a WL as the suspension goes about its business. I'm looking at the width of the grey envelope of lateral PHB midpoint motion at close to design ride height vs the essentially straight line with the WL. The PHB would be better if it started out at a purely horizontal orientation at static ride height (preferably with the driver aboard). But OE PHBs are set up to be a sort of "best overall average" for the entire range of vehicle loading, which puts the chassis-side pivot up higher than it should be for the driver-only max-performance condition.


A WL will probably find its way onto my '08, eventually. I can't describe what I haven't yet experienced, but I can tell you that you don't have to be driving at or above 75% of the car's capability to "feel" some of the various differences in handling "feel" or other behavior. It probably depends at least as much on how sensitive you are to that sort of thing.


Norm

Norm Peterson

I just went out and threw some outside calipers on some axle tubes - the 8.8" tubes on the '08 Mustang are clearly bigger than the 7.5/7.625 tubes on the '79 Malibu. Probably by 1/4" or so.

I do know that the GM installations have combined the WL with the two converging upper links, which can serve to increase the load on the WL and UCA fasteners above what the lateral force at the rear roll center actually is. That's not the way I'd ever run a WL, but knowing that there's at least that much margin is nice.


Norm

FastDEW

Other than Price - What is the advantage/disadvantage of each of these?:

Steeda

Fays2

How difficult is it to setup if you have to work on setting the roll center?

Sleeper_08

The FAYS2 has rod ends and the Steeda is poly bushed.

The Steeda may have less NVH but for as my car already had only 1 rubber bushing left in the rear end that was not a factor for me and the cost savings was.

Changing the roll center height requires undoing the center bolt and moving it up or down. Mine is still the center.

FastDEW

So in other words, the Steeda is for street applications and the Fays2 is for track only. Most people would not want rod ends on a daily driver.

How much NVH increase is there with the Steeda vs the stock PHB on the street?

jsnyng

The only noticeable NVH I get from my Fays 2 is above 60MPH and under hard acceleration above those speeds. Even then, it is minor. Just cruising around town, I don't hear any NVH from the Fays2.

JIM5.0

You nailed it on the head about me. I am exactly what you described: an average driver with a relatively stock car.
But with aspirations to get into track racing, autocross, like what Sam does even. Of course, getting to Sam's level of driving will take a whole lot more time and practice, but learning the aspects of handling and what gear is used to improve each is one of the first steps I am researching at the moment.

Watt's link is just one piece of gear I am looking into, and no, I too would not begin with a Panhard or Watt's as my first suspension mod. I would actually first address the wheel hop with upper & lower control arm upgrades. That is the simplest thing to start with.
I would then move on to springs and struts.
Camber plates would be my next choice. And something to address caster too (but if caster adjustability requires a whole different K-member, I would address that last).
Then I would attack the lateral movements: sway bars
The Watt's link would come afterwards.
Then I would choose something to address Ackerman adjustability (this is probably an aftermarket K-member).

Rear axle geometry is actually only one of my many handling questions, and of course, Panhard/Watts Link only addresses one aspect of the rear axle handling.

And skill? Yes, no amount of gear and upgrades will make me win a race.
So things pertaining to skill are not in my question set because the only way to address skill is to go out to a track and practice.
I might have some questions about technique in the future though. These would be a whole different question set.

The gold pot of my handling questions is this: For track racing (not oval, not straight line drag strip), what suspension settings are ideal? Camber angles, Caster angles, Ackerman?
Of course, there will be way too many answers for this because of the usual answers
"It depends, are you autocross racing?"
"It all depends on your driving style"
"It depends on your gear, each piece is affected by the other pieces you have on your car"
etc.

FastDEW

I am not calling into question your individual perception of NVH. However, I cannot imagine having rod ends on the Watts for a daily driver!

I have LCA's that use rod end on one side and poly on the other. I noticed a substantial increase in NVH, even to the point of being able to hear the gears when at low speed. A Watts with all Rod Ends would be way to much for me on the street. Plus, I imagine that the polys are plenty.

Is that the only difference between the Steeda and Fays2?

Thanks!

FastDEW

Thanks for letting me interlace your thread with some additional questions, mainly targeted at street......