people are saying a 32/21mm setup is not ideal but a 32/19 mm setup.

Think a 32/21 mm woudl be better balanced, and less body roll?

 

Alot of people feel that a 21 rear bar is too much, which is why the stock 19mm is somewhat popular with a bigger front bar.

While we dont have an IRS, many cars with independant rears will keep a small rear bar, or completely remove it, either making up for it with more spring or not, the feeling that this is a better setup seems somewhat unanimous. I almost wonder if doing so on a solid axle rear car would provide more benefit than on an IRS car, but I really dont know, or maybe it would be better in some aspects and not others, like better for road racing and probably worse for straight line.

 

I think this is also a prefrence question too based on driving style. For autocrossing it seems that the Pros (Strano) tend to use the 19mm. For road racing (Gigliotti), the 21mm. This is the trend that I noticed. If I were to explain it, I would guess that where most people autocross, its usually a bit rougher than the track, more bumps etc and the smaller bar would help keep the rear wheels a little more independent, where the track tends to be smoother and perhaps a bit more perdictable.

Dont look at this as an answer or a valid reason though Kev's best guess...

--Kevin

 

Good points, preference, springs that are used, even your alignment/front-rear grip, and speed of driving play a role HOWEVER Gigliotti sells the 32/21, so I would imagine he would run what he sells and build the rest around the car.

I know several RR guys that all seem to prefer the 19mm rear, unless they drag. I've spoken with a guy that runs a 4th gen, ran several 3rd gens, and his son has a Mustang that ran small rear bars, the Mustang also ran very light rear springs and was a VERY competitive car and was nearly unbeatable in thier series. This was road race not AutoX.

 

I currently still run both stock bars and I like the feel of the car with my setup. However, to lessen body roll and maintain the current feel I will be upgrading to the 32/21 setup.

 

I don't mean to be obnoxious (honest) but there's a lot I don't understand here. In particular I think people are understating the importance of springs.

"many cars with independant rears will keep a small rear bar, or completely remove it, either making up for it with more spring or not"

While I knew this was true for race cars with downforce and very stiff springs (I believe this is the reason they do it, not IRS v. lve axle), I didn't know it was true for street cars. What street car runs no or a very small rear bar?

"springs that are used, even your alignment/front-rear grip, and speed of driving play a role"

Springs play a bigger role than the other things, since they affect understeer/oversteer balance exactly the same way bars do.

"For autocrossing it seems that the Pros (Strano) tend to use the 19mm. For road racing (Gigliotti), the 21mm"

I think that this is because the road racers tend to use stiffer front springs.

"to lessen body roll and maintain the current feel I will be upgrading to the 32/21 setup"

You're increasing the stiffness of the front bar by 29% and the rear bar stiffness by 49%. That will definitely make the car feel different.

Eric - What springs are you running? No one can comment sensibly on bars without knowing that.

 

My 73 240Z, no rear bar, indipendant rear. Most V8 Zs likewise remove a bar if they had one before, and make adjustments with springs.

There were many cars in the 60s that likewise had no rear bar, my dad's old 76 Dodge van also had no rear bar.

Exactly the same way? I dont agree with that. Remember bars reduce independance of the suspension, so there has to be a balance. Obviously too much spring is not a good thing either.

 

This may be true, but they are generally combo'ed together. I won't know the true effect until after I make the cange.

 

Strictly from a w2w roadrace point of view: I try to use springs as the "coarse" adjustment, and use the bars as a fine tuning device. GM blessed us with a wide range of rear stabilizer bars to play with, so I carry several with me to the track. I try to run the lightest rear bar possible to keep the inside tire planted.

 

Very similar to again what I heard from a racer and his 3rd/4th gen racers (CMC) and his son's Mustang setup (CMC racer) as well, anything to keep the solid axle as stuck to the road as possible.

If your going slow its probably not such a big deal, but if your doing 100-130+ in corners then it becomes more an issue.

 

"If your going slow its probably not such a big deal, but if your doing 100-130+ in corners then it becomes more an issue."

I disagree (hopefully not disagreeably ).

In order to go fast, you have to accelerate off the corner early and hard. In slow corners in a low gear you need _more_ rear traction (smaller rear bar/more understeer) to get the power down. It's a reason why a big rear bar is absolutely not good for autocross, and why some very successful autocrossers like 35/19 with V8 springs.

In a fast corner in a high gear you have less rear wheel torque to deal with and the optimum setup has less understeer/bigger rear bar.

 

I switched to the 32/21. On higher speed turns is were I found the most improvement,lots less waggle/dance with steering adjusments mid-turn.Lot more planted,stable,hooked.But the slower/sharper turns coming in hot took some getting used too,as to not cook the inside tire on the exit. Very happy w/the set-up for larger road coarses.But if I was to be constantly throwing the weight around tight turns(like autoX)Stock rear would be replaced,keep the 32 front.
T.

 

Most of my thinking is on "paper", but this is a guy who has alot of experience. His son was spanking everyone in CMC with his Mustang, through once again, thier experience, with small rear bars and often lightweight springs in the rear as well (V6 stuff usually). They laughed at how the car "was going to flip any moment" in particular turns but they turned better lap times with it setup that way, same with thier 3rd gen Camaros.

As for the 4th gen, the springs were setup when they did a day or two of track testing, with a rep from Global West, so spring rates are "unknown" except by calling.

 

"Most of my thinking is on "paper"

We have a lot in common there. My SCCA racing days were 20 years ago, now I just read a lot and race computer simulations.

"but this is a guy who has alot of experience. His son was spanking everyone in CMC with his Mustang, through once again, thier experience, with small rear bars and often lightweight springs in the rear as well (V6 stuff usually). "

I don't disagree with that, only with your comment about how a softer rear would matter less in slower corners. It matters more.

In NASCAR2002 (computer sim), on a short track, you need a lot of understeer or you lose the back end when you try to accelerate off the corner. On a high speed oval you stiffen the rear until you're just about to lose it, or the understeer drag makes you slow. I'd be amazed if that wasn't true for the real deal. It also works that way in road racing. Yu need understeer to accelerate off the low speed corners, but too much makes you slow through the high speed sweepers. The balance of a good setup is a compromise that depends on the track.

 

Suprisingly some of those games are very true to life. To the extent that younger drivers like Dale Earnhardt Jr. and Harvick use them to practice and learn courses.