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Removing swaybar on stock SW20

30K views 18 replies 11 participants last post by  venom00 
#1 ·
it is known that running no sway bars increases grip, but is this still applicable to stock 94' turbo? I was thinking of removing them and then stiffening up the stock shocks, stiffer in the front.
 
#2 · (Edited)
No, as someone who has done that as a test, it feels incredibly terrible. That said, ride quality improved tremendously also. But its not safe, the car is so slow to respond to inputs and very slow to take a set.

The no sway bar setup is a complete setup which consists of much more than just removing the swaybars. Spring rate, alignment, and ride height all play very large factors and all compliment each other. Furthermore, this setup is NOT a good street car setup, this is for racing only.

If you want more grip on a street car, get grippier tires. The latest top tier street tires have more grip and performance than you will ever need on the street.
 
#3 ·
+1 I've driven without front or rear swaybars in my 93 and I can tell you it doesn't feel nice. All the quick response and agility of the car goes down the drain and you feel like you're driving a bus. Having said that I now run no rear sway bar (still have the front) and it feels fine. Maybe it's because I got used to it but having just the front sway bar seems good enough? Someone correct me if I'm wrong.
 
#4 ·
e.widlingphoto said:
+1 I've driven without front or rear swaybars in my 93 and I can tell you it doesn't feel nice. All the quick response and agility of the car goes down the drain and you feel like you're driving a bus. Having said that I now run no rear sway bar (still have the front) and it feels fine. Maybe it's because I got used to it but having just the front sway bar seems good enough? Someone correct me if I'm wrong.
I really like how the car drives without a rear swaybar but I would do it with stiffer springs in the rear to compensate, otherwise the rear has too much body roll.
 
#5 ·
it will work if you have enough damping and stiff enough spring rate to keep body roll, camber and traction. KW's allows you that. Stock dampers will allow much body roll. You can minimize it with lowering, bumpsteer kit, spacers to widen track and stiffer springs. Sway bars are not that big of a role but just an aid to the overall suspension tuning. If you can work without it, the better as other components are more adjustable than the sway bars. I keep them compliant on mine to allow my struts and spring setup to do their part in a more predictable way.
 
#6 ·
This is incorrect.

Removing the front bar will increase front grip as it shifts mechanical balance onto the front axle by allowing the inside front tire to take on more normal force. The same is true for the rear bar, if you remove it you then shift the balance of the car to the rear.

Removing both bars is in absolutely no way increasing the total grip of the car.

Because the front and rear bar on most cars do not have the same torsional rigidity (stiffness), when both bars are removed there is a slight shift in mechanical balance onto the axle which had the stiffer bar. This could make the car handle better if that axle was slipping (front slipping = understeer, rear slipping = oversteer).

The other common instance where removing both bars would make the car handle better is if you had crap tires and the outside tires were being overloaded causing them to slip. In this case, disconnecting the bars would allow the inside tires to take an increased load thus decreasing the load on the outside tires and potentially preventing the outsides from slipping.

I absolutely would not recommend doing this for a car you are driving on the street with stock suspension. The car will be come pretty unpredictable and wandery? (not sure if that's even a word) when you hit a bump while cornering. I had to drive my 93 NA for a while with no bars when one of the links on the front and rear broke within 50 miles of each other, and it SUCKED!! I had to drive like a grandma around corners because there were a few instances where i hit a bump or pothole mid corner and the car would immediately dart and weave.

If you go with stiffer springs and/or higher damping rates and the car is more balanced without bars, then by all means go for it.

Hope this was hopeful!
 
#7 ·
I think removing a swaybar improves total grip on that axle given everything else stays the same (stiffer springs would be used so both options would have same body roll/wheel rate). The basic reason is a swaybar creates additional weight transfer compared to no swaybar and weight transfer is the enemy of grip.

There are alot of other benefits as well, a big one being the car has the same behavior on almost all surfaces/conditions. For some reason with swaybars my car could be loose on one surface and push on another. Or the rain/cold would change the balance of the car.
 
#8 ·
That defies physics.

Disregarding normal force created by aerodynamic devices (since most MR2's don't really have any), the maximum amount of grip a car produces is determined by its mass X coefficient of friction of the tires. That is the total amount of force (grip) allowing a car to corner. You may be right in the fact that a tire has a different coefficient of friction depending on tire pressure, normal force, camber, temperature, slip angle, etc. (Here's a link if you want to get your toes wet with tire data http://www.calspan.com/transportation/tire-research) So it it absolutely possible that removing a bar can create a scenario where both tires on that axle would then be in a situation where they would be operating at a slightly higher coefficient of friction, and would therefore be creating more total grip for the car. But it doesn't seem logical to me to think that removing the bars would create a significant difference in total grip.

Also, the bar does not change the amount of weight across the car. The bar changes the amount of normal force carried by the inside tires. If you disconnect the front bar, you are taking load away from the inside rear tire and moving it to the inside front tire thus giving the front end more grip compared to the compared to the rear.

Total weight transfer is not changed by spring rates. It is THE RATE OF WEIGHT TRANSFER that is changed by the changed by the spring.

Weight transfer is calculated by, W=((a*h*m)/l)
Where:
W = total weight transfer
a = acceleration
h = the height of the center of mass
m = mass
l = wheelbase for longitudinal acceleration or trackwidth for lateral acceleration.

You have to account for the most basic physics F=m*a (force=mass*acceleration)
As the car is rolling (when the car initiates a turn) or pitching (under braking) the body of the car is accelerating... That means there are forces lost from weight transfer to accelerate the body of the car in pitch or roll. This time duration in which the car pitches or rolls is determined by the spring rates. The higher the spring rate, the more quickly the springs will balance out the acceleration of the body. Imagine driving down the road on super soft springs and you slam the brakes, the nose immediately dives and after some time period stops diving. You do the same thing on a much stiffer spring and the time from when initially hit the brakes to the time when the nose stops diving is significantly less. That means on the stiffer springs, there is a shorter time period when force was being lost accelerating the nose of the car down. In both scenarios, once the nose gets all the way down and is no longer accelerating or diving down, then TOTAL WEIGHT TRANSFER from rear to front axle is absolutely the same (as long as the height of the CG isn't changed by the length of the springs once compressed in front/extended in the rear).

You are absolutely right that the balance of the car can vary from surface to surface. I could go into my own story of car balance changing on different surfaces, but I'll spare you the details. But basically whats happening, is that a different surface will lead the tires to operating under a different set of parameters of friction and slip.Now the balance of the car has to be adjusted to get the tires back to their best operating conditions.

Hope some of this makes sense, it's late and my brain doesn't want to work anymore tonight, so I started short-cutting some explanations. :smile:
 
#10 · (Edited)
Its explained much better here:
http://farnorthracing.com/autocross_secrets24.html

Farnorth said:
Ideally, you want no bars at all - while they don't create any extra weight transfer (the total amount of weight transfer is a function of track, CG height, and roll centre location) they can only add a larger proportion of roll resistance at that end of the car, which means increasing that end's share of the roll resistance, which in turn means "unsticking" that end of the car.
Regardless of the theory, I have done alot of actual testing, both on the street and autoxing on swaybars vs non and it busted alot of myths for me. Especially the one that swaybars don't affect ride quality, they do in a huge way.

No bars really only works on very light cars IMO, as the spring rate required to keep body roll in check for cars over 2500 lbs gets very extreme. But I think the point stands that sways should be kept to as little contribution to body roll as possible.
 
#11 ·
For a street car, yes, I'd run at least the front bar to keep spring rate (read ride quality) in check. For a dedicated race car the game is very different. I think no sway bar setup works VERY well given proper setup. Shocks and alignment play a big role here.
 
#12 ·
I removed my rear bar and did my first track day of the year and loved the change. I added adjustable tension rods in the front removed the hard poly bushings and set caster to 6deg. The total change was teriffic. easy to correct, more predictable, and faster.

setup is: Tein HA's 4k front/8k rear with the stock front bar. RCA's, and adjustable tie rods up front. 91 rear crossmember . 225/45-15 245/45-16 Toyo R888's
 
#13 ·
On paper, it definitely sounds like you made the right choice losing the rear bar. Having rear spring rates double the front rates, AND a rear bar, just too much of your roll rate was coming from the rear. Oversteer city = hard to drive fast.

I haven't been running sway bars for several years now, and overall really like it. I wouldn't say I am 100% anti sway bar, they do serve a purpose especially for a street car, but I would say I am anti REAR sway bar. All that a rear bar does is force you to run a front bar that is that much bigger.
 
#14 ·
I have a 94 turbo with a 3rd gen swap and bolt ons and looking to upgrade my suspension.. The car is mainly a street car with maybe occasionally some track use but I doubt much. As of now the car is on KYB AGX adjustable shocks and Eibach Sportline springs with 17's. I was planning on buying a poly urthethane bushing kit and replacing all of the bushings and a set of sway bars but after reading through some threads most of you guys only run the front sway bar especially for a street car.. I want the car to be fun in the streets while having a somewhat comfortable ride which is why I chose not to go coilovers. I wanted some feedback on what you guys think?
 
#15 ·
I wouldn't say most people only run a front bar. In fact, I would say that setup is still quite rare on the MKII. Stock class autocrossers have historically upgraded the front bar only, but that was because that is all they were allowed to do by class rules.

I think a front bar only with appropriate spring rates would make for a great street car setup, but I don't think most "lowering springs" will be stiff enough to pull it off. Coilovers of some flavor (and with custom spring rates compared to what "off the shelf" coilovers come with) are pretty much required for a no sway bar setup, and probably for a single sway bar setup as well.
 
#16 ·
Thanks for chiming in.. So considering what upgrades I mentioned I would like to do and the type of driving I do, what would you recommend? Running both upgraded sway bars or just upgrading the front? I'm new to all this mr2/ mid engined world.. Lol I just would like a well balanced fun car to drive.
 
#17 ·
Be careful, especially with suspension, not to just throw parts at the car. Suspension is one area where it's best to have a specific problem you want to address before you change anything.

That said, how does the car feel currently with regards to ballance? (oversteer/understeer). When driven hard does it wear tires evenly, or does it wear the outside edge?

With comfort in mind, you may want to consider upgrading to some Koni inserts. Those KYB's are known to ride very harshly, and the Koni's will both ride and handle better.

The other thing is, the Sportlines are a fairly agressive drop, especially considering how soft they are. You may want to consider some stiffer springs that don't lower as much, for two reasons. One, lower has negative effects on the suspension geometry, and two being too low and too soft will cause you to bottom out, making the ride harsher.
 
#18 ·
Thanks for the feedback. Let me give you a run down on the situation.. I bought the car as a project.. I have not registered or driven it yet besides from in and out of the shop. When I purchased the car it needed shocks and springs, tie rods and sway bars.. So before I put her on the road I wanted to buy the parts needed.. Rather than buying oem stuff, if I can or should upgrade certain parts i rather do it one time to save myself time and money. I work at a shop so I'll be doing the work myself but I rather do the job once rather than keep taking it apart.. Hope that makes sense.. :smile:
 
#19 ·
Back from the dead post.

Reading this I believe I will remove my rear sway bar at this weekends autox.

I am currently running

93 MR2 W/Gen3
BC BR Coilovers w/ 4k-F 8k-R
Dropped 1.75"
0* camber all 4 corners, i will get this to ~(-3*) sometime to help out alot.
215/40 17x7 +40 front
255/40 17x9 +35 rear

Continental DW (Terrible tire, but came with the wheels just wearing them out.)



 
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