reza

I want to get more information about Rear Swaybar between the different model and years.
The purpose is to determine whether to get aftermarket or just stock swaybar for my car. I compete in ASP. I think they allow swaybar swap, but I prefer to stay stock.
I have 93 Base, my goal is to have softer rear swaybar. I am trying to prevent too much oversteer. I have JIC FLTA2 12kg front and 9kg rear spring rates.

Which 94 or 95 swaybar should I get?

I know the following, but need more detail on hardness or softness:

93 All models has the same swaybar

94 All model has the same swaybar, but different than 93

95 has two different swaybar (hard/normal) One is same as 94.

Any recomendation?


Reza

neofreak

If you decide on 95, I've got a set taking up some room, let me know. (From base model)

adam c

iTrader: (2)

Hi Reza,

Mazda changed to a smaller rear bar in 94 to reduce the oversteer a little. The 94 is supposed to be a little more neutral. Since you have aftermarket springs, that will change how the sway bars work. I guess what I am saying is that I don't know anything except the 94 bar is smaller than the 93.

I'm a big help........

reza

Yes, I am looking for a softer swaybar. The spring that I have is too stiff for autocross, thus the tires break grip to easily on transition. I want to try tune it out a little by softer swaybar.
How much softer are the 94 or 95?

Neo, which 95 do you have? Do you have the part number on it? I saw two version in the parts book. Not sure if the base model the same as 94 swaybar.
Can I have it?

neofreak

If there is a part number on it, I'll look for it.. I'll trade you for something. =p

DamonB

What are your damper settings? They alone may cure your problem without swapping bars...

redrotorR1

Ditto. Try softening up the rear shocks. Also offset your front-rear tire pressures ... more, if they are already offset. This will naturally induce some understeer and possibly 're-neutralize' your setup. FWIW, I don't think your swaybar is the problem.

reza

Okay here is my setup for autocross:

JIC FLTA2 12front 9rear kg spring
Dampener Setup
Front: 14/16
Rear: 4/16

Kumho MX 225/50/16
Tire Pressure:
Front: 36-37psi
Rear: 33-34psi
I tried to keep 3 psi difference front to rear.

My car has always been loose in the rear, part of it is myself. I drove my friend 94, and it is understeering. So I am thinking the difference is the swaybar.
If I go softer swaybar, I can go higher rear dampener setting right?

neo: if you can get the part number that would be great. Let me know what you want for it.

redrotor: you have JIC as well right? What year is your FD?

damonb: what year is your car?

DamonB

I have a '93 with the stock rear bar, stock springs and Koni yellows. Your damper and tire settings reflect what I end normally end up with in my car: lots more damping in the front along with a few more pounds of tire pressure.

I still wouldn't jump to the rear sway bar yet. What is your alignment? Most specifically what is the front and rear toe? Where exactly in the corner does the car go loose?

How do the tires look front to rear?

KevinK2

stock springs ratio is 280/200 = 1.4 front/back. JIC is 670/503=1.33 with more rear bias.

stock rear bars are hollow, 17.3mm for 93, and about 15.9mm for later models. smaller bar is about 25% softer, worth a try. as said, try less rear shock rebound damping, and/or no rear bar.

reza

Alignment:
Camber Front 2.2 Rear 1.9
Toe front in 0.02 rear 0

Tire seems okay, the wear on sidewall is just before the mark, so I think I got the pressure right. I always play with higher pressure, but those 36/33 always seems right. On not so good surface I tried to lower rear to 30-32, while keeping the front 36.

The car go loose as you put in more throtle getting out of turn. Going into turn is fine, as you apply more throtle, it starts to swing more.
I have tendency to brake late or trail brake into turn, this only amplify the problem too. I usually have to wait for the car to start to settle a little bit, then hard on throtle. I learn that if I could start throtle earlier in the turn, I would be able to go faster.

The problem with dampener too soft in rear is the spring becoming more a factor here.
During transition left to right, the weight transfer can be so much amplify by the spring that the car can go into spin.
So hoping that with softer rear swaybar, will help me to get a little understeer then I can adjust the balance using the rear dampener. Meaning go higher than 4/14 to probably 8/14 or more

KevinK2: So the 94 and 95 is 15.9mm, how about the 95? it has two types of swaybar, normal and hard, would normal be the same as 94?

jimlab

My '95 PEP was often loose in the rear on corners with Eibach springs and Koni yellows. I upgraded to Racing Beat adjustable front and rear sway bars, but didn't like the feel of the front bar, so I dropped back to a stock R1 bar in the front. The RB rear bar was better than the stock bar and matched the R1 front bar pretty well, but wasn't perfect.

Now I have JIC coilovers and a stock front bar sitting in the corner of the garage, and it's time to figure out what to do about a rear bar again. I plan to run the R1 stock bar in front.

My RB adjustable rear bar was bent when I pulled it off the car, so I junked it. Doesn't say much for the quality of the bar, since my car has never been wrecked. It also started squeaking unless you kept the bushings well used, and wanted to "walk" to the right, even with the clamps that are supposed to keep it centered installed. In other words, I don't want another RB rear bar.

Sounds like I'm in the same situation as Reza, but I don't want a stock bar in the back. Other than stock bars, what's a good match for a stock R1 front swaybar?

KevinK2

reza ... don't think 2 diif rear bars were used in 95.

jimlab, mazdaspeed has a solid version of stock 17.3mm 93 rear bar, with 2 holes per end (like RB). But this is to go with a solid version of the stock 28.6mm front bar. I'd think stock bars would be best match with stock front, unless you run more front spring rate bias, vs rear.

redrotorR1

I don't think that the right way to approach it. For slaloms, almost all the tweaking you want done is through your shocks. Swaybars will have some effect, but not as much bang for the effort. Worst case scenario ... you can just run without the rear swaybar. I know a lot of CP guys that do this ... apparently it just works out better.


I have a '93 R1. It's setup with Koni Yellows, Tri-Point Front swaybar, and I run race rubber (Victoracers). Typically, I'll run the fronts at full stiff and the rears at 1/2-1 turn from full soft. I also run in 245/45 16 sizes ... which I highly recommend for you, reza. 245's give you more lateral grip and your stiffer spring rates necessitate more rubber.


For street tires, I'd say that your air pressures are fine. For any real change in performance, you'll need to either increase or decrease by 3-4 psi for any noticeable difference. And as far as applying the throttle earlier, well ... turn earlier ... especially in slaloms. If you get good at this, you never have to lift on constant radius slaloms. You end up using your left foot as a modulator for speed.

Aristo

iTrader: (8)

To avoid playing any guessing games about the relative stifness of the bars from various years, why not just swap the rear springs to 8 kg/mm?

reza

left foot? hmmm...are you talking about left foot braking? Another guy in my region kept suggesting that I do this. I tried this on the road, it is very hard to control my left foot, it kept thinking the brake is clutch, so push all the way huh

According to parts book, there are two version of bar in the 95 FDs.

Looks like I have to run without rear bar, and see what it does? How to run without it? just disconnect it on one side, or should I remove the whole thing?

Aristo: I don't want having to buy another spring. It is easier to replace the swaybar. I am sure JIC must have thought out the spring rate before selling the kit...

DamonB

I think your driving style is most of your issue, but even so I would add some toe in at the rear since you don't have trouble until after mid corner when you get into the power.

You'd be suprised how far adding 1/8"-1/4" of rear toe in will go towards solving your exact problem.

If you are certain the alignment is sound, you can easily add the rear toe in yourself. With the car at rest on the ground (very important!) Grab a tape measure and measure across the back of the tire tread from one tire to the other (I find it easier to measure the rear tires from the back) being certain to measure to the same spot of the tread on both sides. Since we are adding toe in and measuring from the back, we wish to increase whatever dimension you measured by 1/8" to add 1/8" of rear toe in; that means we will in fact incease each side by 1/16" to add 1/8" total. Again we are assuming your rear toe was in fact zero to begin with.

Break the locknuts loose on the rear toe links (also easily done while lying under the rear bumper).

Measure across the treads one more time. For 1/8" of total toe in we wish to move each side out (remember we are measuring from the back of the tire!) 1/16". With the tape measure held in place crank one side until it moves 1/16". Then lock that side. Now go to the other side and crank it out 1/16" and lock it.

Congrats! You just added 1/8" of rear toe and it's actually pretty easy! If 1/8" helps but you still have some of the same problem, I would try a 1/4" of rear toe. Anything over that I think is best approached through tuning other parts of the suspension; the rear sway bar for one thing.

The rear toe in will help the exact problem you are having: the rear end wanting to come around when you power out of the corner. Changing the rear toe is easy and free, so I would try that first. I honestly think you'll cure your problem.

adam c

iTrader: (2)

My 82 GSL had stiff springs. I found that removing the rear bar helped quite a bit. You should try it. It won't cost anything, and you can always put it back. I would remove it completely. Don't just disconnect it.

redrotorR1

Kinda what I was poking at earlier. Although, with a basically zero toe alignment all around, you shouldn't be having THAT much tail-happy tendencies. But, definitely try it out ... it might be the quick fix that you're looking for.