Sway bars : an update to John Hrinsine's table

[RonPorter]

There's also other variables that affect it. Rim width/tire selection/suspension bushings/struts/driving style. Keep everything constant, and it reacts a certain way. Change any of the mentioned, or add welded subframe connectors, the reactions to given bar sizes can change.

IMO, best is to tighten everything up with better components, and go to smaller bar sizes. Bars are a Band-Aid.

 

[GEN 3 SHO FAN]

All is stock on mine and I can't put 10 000 nor 5000$ in upgrades on this car. It cost me already some money just to restore it. It's the reason why I just want to put a rear bar to stiffen up the rear a little. But I understand your advice and the one of Mr. Newberg.

I tried a little harder yesterday on a long dry highway curve at 75 mph and I felt a little overteer (temp was 79 deg.). I'm wondering how it will be on a wet road... (worst for sure) I will probably begin to search a 23 mm to correct that.

 

[stephen newberg]

Sounds like you are making progress. The main thing to remember with oversteer, and particularly in a front wheel drive car, is do not feather the throttle as it comes on. Keep your foot in it, point the steering to where you want to go, and the rest of the car will straighten out and follow. Front wheel drive and all wheel drive cars are just great for leaving the corner faster than you came into it.

pax, smn

 

[GEN 3 SHO FAN]

After a few weeks of driving, I feel the car very well balanced. What I felt first week seems to be a little weight transfert (on the tires maybe). I added some km/h each time I pass the same curve and the rear end still gripped on road. I didn't try at extreme speeds (not my goal) but at 75 mph, no more understeer and body roll.

The bad side of this is a little more vibrations on the rear. Even with this, I don't understand why, my cd skip less often...

 

[GEN 3 SHO FAN]

Anyone have an advice on the influence of progressive springs on SARC suspension (oversteeer or understeer) ? Is progressive spings and SARC struts is a good idea ? When the 2 will be in stiff mode can it give too much stiffness and consequently, overteer ? I want to replace the rear spings which are bottoming out. OEM SARC parts will be difficult to find and I'm thinking to put the progressive rate Moog cargo coils which are stiffer too in "soft mode" (rear SHO=100lbs./in. Moog=137lbs./in.).

Thanks for the infos,

 

[stephen newberg]

Yes, if you stiffen the rear springs, there will be some increase in oversteer. Is it the rear springs that are causing your problem, though, or are the rear struts dead or dying? If they are the originals, and you have a lot of miles on them, it is very possible that the struts, rather than the springs, are the major contributors to your problem, as the struts and the springs work in combination to keep the car from hitting the bottom of its travel.

pax, smn

 

[GEN 3 SHO FAN]

I checked the rear height here and it is supposed to be 27.5 inches (ground to upper wheel well) and I have 26 inches on each sides with almost nothing in the trunk...

 

[stephen newberg]

And you are running stock wheels and tire size, right? If so, then there is definitely something wrong, and it becomes much more likely that it is springs.

pax, smn

 

[GEN 3 SHO FAN]

Yes stock wheels and tire size. Here take a look, I took this recently with almost nothing in the trunk.


What do you think ? Thanks again,

 

[stephen newberg]

I do think it looks low at the back. On mine the gap above the tire on the back seems just a bit higher.

pax, smn

 

[GEN 3 SHO FAN]

Ok, you're the second to say me that this week but which alternative I have ? The original ones seems very rare. It's why I ask if Moog cargo coils on the rear can be a good solution. It seems that some sport cars have progressive coils on the rear (don't know which one however).

 

[stephen newberg]

If you cannot find replacements, perhaps spring helpers? They are insets that prevent the spring from going to full depress position. Just a thought.

pax, smn

 

[GEN 3 SHO FAN]

I put spring helpers. That helped to eliminate some body roll, the car is more predictable. But it's a band aid. I will try to find something. I checked the stock spring rate for SHO. I was surprised to see that 96 had the stronger springs rate for this generation (front and rear). Front still good after all this time but rear...

Another guys in my area bought a 99 SHO last summer. The car is a very low mileage (40 000 miles) and in mint condition with no modification. Talking to him, I asked him if he have the SARC. After a check up, he said no and this was confirm by the built date (02/99). Talking about the 2 suspension setup, he said that his suspension is too soft on the rear too...

This guy have also a supercharged Marauder (with Ford parts and certificate). I'm considering he is knowing what he said. Sadly, he decided to sale his SHO recently...

 

[GEN 3 SHO FAN]

Since I put CC859 cargo coils to replace the 2 rear broken springs, I can say that a 25mm rear bar is a too stiff combinaison (probably good oversteer if I tryed). I put a rear 21mm with those and I had results after 2-3 months after the new springs take some softness. I take this no rust rear bar from a 95 auto SHO with only 69 k in a scrapyard... (what a shame). I was very lucky to find this in Canada but we can find rear 21mm bars elsewhere. (I found a '91 with a rusted rear 21mm which I put on my SLO.)

As the springs and bars are harder to find with time, I put here some results of my researches.

86-91 (2.5L manual) : 19mm?/21mm?
86-91 (3.0L) : 20.6mm/21mm
86-91 (3.8L) : 22mm/21mm
86-91 (3.8L police) : 22mm?/28mm (extremely rare, US west coast states only ?)
92-95 (3.0L) : 20.6mm/19mm
92-95 (3.8L) : 22mm/19mm
92-95 (3.8L police) : 22mm?/25mm
96-99 (3.0L) : 19mm/18mm
96-99 (3.4L) : 22mm/19mm
01/99 (3.4L) : 20.6mm/21mm (without SARC)

Notes :
For winter and spring daily drivers, I suggest to let a 19mm, it will be ok on rought road (less NHV) and little better grip on ice.

Watch it also for wear where the bushing are, they can lose diameter there and become to acting as a smaller one.

Good luck,

 

[stephen newberg]

Good data. Wear at the bushing point can also be a bar failure indicator, as they will break there during heavy use. I have done that twice over the years with used bars that had more than normal wear at the bushing location.

pax, smn

 

[GEN 3 SHO FAN]

Maybe putting a rear 21mm can help to balance the wear over time...

 

[stephen newberg]

Maybe, but simpler to either find one that is not worn or take your worn one to a good welding shop and have them add some material back on in the worn area. That way you know what you have for sure. Apparently it is not hard for a good welder to build back up the worn area on a bar without causing damage to the temper, or so I am told.

pax, smn