Going to follow this, been looking at the same thing. I've had issues with the stock bar hitting my panhard bar, you get the same?? I had to do some light grinding on my swaybar and adjust it a bit to clear my panhard so I worry another stock style bar may have issues as well, the MM bar obviously will work fine.

 

The stock rear bar on a 94GT is 24mm... Maybe the Eibach bar is a solid bar and stiffer???

 

Well, that's an interesting development. I was under the impression that a stock bar is a 21mm on the 94 GT

Edit: Eibach website says that their bar is a 25mm Solid bar. What's stock? Is it hollow? Sure as hell does not feel like it.

 

I think the Bullitt and the 6cyl came with a 21mm bar. My 99 GT had a 23mm I think. The 25 was just right for me.

 

The 25mm Cobra bar is a solid replacement for the 27mm hollow bar that use to break at the ends. I bought the rear Roush bar from GEF Racing years back for less than $60 and it came with Ford part number F7ZZ5A772AA. Since then I added the 1-3/8 solid Roush front bar. The car is very neutral with 315 Kumho V710s all around but pushes like no tomorrow with the staggered street tires.

 

Ok, how about this for the 3rd option. Bumping rear spring rates 25 lbs. Right now I've got 350 front 250 rear combo. I've talked to a tech at Chicane23, and he said that I could do that but I would be better off with a stiffer bar, since the understeer is more evident on the corner exit.

 

FWIW, on my 86 I run the MM bar up front and their .75" solid adjustable in the rear; full MM suspension front/rear. With 300# C/Os in front and the light MM T/A conventional springs in the rear (380-440?), the car would push at corner entry and through mid corner; rear bar set on the softest setting. This setting is nearly the same as the 94/95 GT bar; middle setting is the 94/95 Cobra bar; finally the stiffest setting is 30% stiffer than the middle setting. I'm moved up to the middle setting and that nearly eliminated the push.

To be fair, at least one MM tech advised that I should move up to the stiffer T/A springs (440 - 520?) to balance front/rear rates, then use the bar to fine-tune. I chose not to do this because I want to maintain ride quality which is on the edge with the current spring/Bilstein package. Instead, I moved up the rear bar. With one more setting to go, I will experiment this weekend at a T&T A/X event.

Moreover, the MM piece is a "real" sta-bar as opposed to the Ford piece. The MM bar attaches to the axle with two arms reaching forward to adjustable end-links. Setting it up is easy to do, as well as changing the settings. Even if you need to go stiffer or softer with the initial bar, it is easy to do; MM sells the required pieces separately. I'd recommend the MM piece.

 

You could also experiment with a "smaller bar" on the front which would help alleviate understeer. What size bar is on the front now? Any SN95 cars run smaller OEM bars? V6 or Cobra maybe?

 

OEM Mustang Sway Bar Sizes

Sway bar stiffness is compared by taking the outer diameters to the 4th power. Thus, a 25mm solid bar is 17.7% stiffer than a 24mm solid bar. Hollow bars subtract the inner diameter to the 4th power and thus are not very stiff at all.

I'd start with a smaller front bar or more negative camber. Why remove grip from the rear instead of increasing grip at the front? I'd get some bars from a junkyard if you don't purchase the adjustable unit.

 

i should have read this before i made my post, my thoughts exactly
im running MM front bar and 98 GT rear bar, now i need wider front tires and more neg camber. shes glued to the street, cant imagine at the track with slicks

ill need stiffer springs

 

lke Curt C said, why not try the MM bar up front, if youre running coilovers all around with much stiffer spring rates, swap the massive front bar out for the smaller softer MM bar

 

I'm maxed out on camber, being somewhere between -3.0 and -3.5 I think. Also, adding rear bar is not going to simply take away rear traction, it shifts the grip balance towards the front. The front will gain grip, it will not remain the same with less rear grip. I've also been talking to a friend of mine who runs Global Time Attack (very successful at it too), and he is saying that I'm way undersprung. His suggestion was to bump the spring rates to 500 front and 400 rear just to support all the weight. The car is 3380 lbs. He is saying that rear sway bar method will lose me not only lateral grip but also longitudinal grip as well, which is a valid point.

 

Also, adding rear bar is not going to simply take away rear traction, it shifts the grip balance towards the front. The front will gain grip, it will not remain the same with less rear grip.

Can you further explain how this works? Interesting.

 

I was always under the impression that a car is kinda like a scale. Roll stiffness changes at either end don't just add or remove grip, but they effectively change the balance of grip. So for example, if you stiffen one side, the other side becomes relatively softer, and since both are attached to the same car, it all becomes relative towards each other. Softening the front bar would do the same as stiffening the rear bar in a sense of roll stiffness relative towards each other. The difference is that the car will roll more overall with softer bars, but all else being equal the balance of the car should be the same if the bar reduction or gain are equal. Maybe I’m misunderstanding something, but that’s the way I’ve understood the concept of roll stiffness. Otherwise what’s the point of getting the Torque Arm, if you will just eliminate that entire grip by stiffening up the rear?

 

No question. We are dealing with a dynamic mechanical issue here. I just never thought about sway bar changes affecting the "the other side" like a spring or geometry change (torque arm) would. For what it is worth I run -2.5 camber. I have a torque arm, no rear sway bar, Watts link, 475lb front springs, 250lb rear springs and the MM 1 1/8 bar up front. With the stock 1 5/16 bar it under steered. I find it to be fairly neutral on the road course with the M&M bar.

 

Honestly I'd try dialing back the camber to under 3 degrees. What's your toe at when camber is set for the track?

 

I don't change it around, since the car does not get driven much, but I think I had it around 1/8 out.

 

Get it down to zero toe and maybe 2.5 camber and i bet the front end tightens up nicely.

 

I can try it, but last time I was at the autoX, I ran the car with the alignment that was already in it, somewhere around 2.3 degrees, and then I slammed the plates just for the hell of it, to see what happens. Took a full second off on a 35 second lap (small course). Best way to do it is would be to actually probe the tire temps after a sessions, but I didn't have a chance to do it this time, and I was really focussing on learning the track.

 

Autox =/= Buttonwillow

 

I am aware of that. I was mostly learning the track, so I didn't have a whole lot of time (will) to play with setup. Next time I'll bring a pyrometer, and do some checking of the temps, see if I'm getting the most out of the contact patch.

 

I would use either the Steeda or MM tubular front bar. They are much lighter than factory and should dial out the understeer. You could try a V6 bar, but I like the added benefit of a lighter and stronger bar.

FWIW I would also run -3 camber with 1/16" toe out.

 

ReplicaR,

You need more rear swaybar stiffness or less front. When you make this change, the rear tire pair will lose some amount of overall traction, the front tire pair will gain some overall tire traction, and the combination of all four will gain some tire traction.

Your understanding in post #15 is essentially correct. The percentage of the total roll stiffness at each end of the car directly determines the percentage of lateral sprung weight transfer at each end of the car. The end of the car that transfers a greater percentage of its weight when cornering loses more grip than the opposite end of the car. When the roll stiffness distribution is set up to give the car neutral handling, the car will have the most total cornering grip.

-3 degrees of front camber is fine for Buttonwillow.

On a perfectly smooth track it doesn't really matter if your roll stiffness comes from swaybars or springs. It won't affect the cornering grip if the roll stiffness is the same. Softer springs/stiffer swaybars will increase brake dive and squat on acceleration. In the real world with bumps, if the swaybars have relatively low friction, the softer springs and stiffer swaybars combination results in more cornering grip since the tire hop (unsprung mass) frequency is further from the corner (sprung mass) frequency.

Going from a 24mm to a 25mm swaybar is going to be too small of a change. You need a bigger change than that. Unfortunately there are virtually no bolt on rear swaybars larger than 25mm available for the rear of the car.

You could install a smaller front swaybar. That will increase body roll. If your spring rates are high enough that may not be a problem. Almost all of the SN95 front swaybars are hollow.

The MM tubular front bar is for a Fox chassis. It will not fit on your car. There are a number of OEM Ford bars of various sizes you could install.

Your GTA friend is wrong about the physics involved. A 500lbs/in front spring rate would be a good place to start on a serious track car that weighs 3,380lbs.

 

Hope I’m not hijacking the thread but I’ve been following this and it looks like there is some good discussion on F/R balance, body roll etc. Below is a pic of my car at an auto-x this past season. To me there appears to be an excessive amount of body roll; I also have what I’d describe as steady state understeer. I’m thinking a better combination of swaybars is needed but I’m not sure where to go with it. I’ve have a pretty good selection of OEM and aftermarket front bars to choose from. Current car set up is as follows:

Front:
MM kmember, std. offset fox length arms, 425# coilovers, mm race 2 struts, 15/16” swaybar, 16x11.5x23.5 hoosier slicks, -2.25* camber, 1/16" toe out per side.
The control arms are set in the bottom holes.

Rear:
MM TA/phb, MM 7/8”x.125 rear bar (set 1 notch from full soft), 325# coilovers, mm race 2 shocks, road race lower arms, 16x11.5x23.5 hoosier slicks, T-lok w/ carbon fiber clutches, 3.55 gears

The engine is a mild HCI (about 275/310 to the wheels). My minimum weight per CP rules is 3,020 and I usually come in right there; F/R weight distribution is 56/44.

I’d also like to know the merits of going to sn95 std. offset or forward offset A-arms relative to front end grip.

 

Your current setup has about 57% of the roll stiffness coming from the front suspension. This is low considering your front weight bias is 56%. Normally this would make the car loose, but since your car doesn't have enough overall roll stiffness for the grip, you are loosing quite a bit of front tire grip from poor camber angles up front.

I ran some simulations on your car. I think the best thing to do would be to install the stock 1.30" front swaybar with a 1.25" x 0.120 wall rear bar. This will increase the overall roll stiffness by 55%. The front roll stiffness percentage will be adjustable from 62.9% to 67.3%. With the improved front camber angles this will make the car more neutral.

We don't sell a 1.25" x 0.120" rear bar, but I made one for a customer a while ago. I think they are no longer using it. If you are interested in it, PM me. You would still need to purchase the arm kit for the 1.25" bar. MMRSB-95

I would change the swaybars before doing the FCAs. You will get a much bigger improvement for the dollar.

 

Thanks Jack, sent you a PM.

Also, could you clarify your statement below. Is the range in front adjustability due to the rear bar being adjustable?

The front roll stiffness percentage will be adjustable from 62.9% to 67.3%.

Thanks again!

 

John,

Yes, the adjustment is all going to be in the stiffness of the rear swaybar (4 hole positions). When the rear roll stiffness is changed, it affects the PERCENTAGE of the roll stiffness in the front suspension.

 

lot of great info here... thanks guys

do the SN95 front & rear bars drop right into fox bodies?

is 2000 the newest car we can use?