Front Sway bar recommendation for FD
 

I'm looking for a little more rear stability when exiting corners, so I see the following options:

1) Bigger front sway + stock rear sway - Can anyone recommend a good front sway bar/size?

2) Stock front sway + smaller rear sway - I remember hearing that the 99 spec sway bar is smaller in the rear?

3) no rear sway bar (I don't really want to do this one)

Thanks!

suspension/tire specs if they matter:
Stance XR coils, 255 Hankook RS3

The 94 sway bar is ~1mm smaller in the rear.

What spring rates are you running?

I will be running 10/8 as soon as I get my Stance XR installed.

What kind of instability?

Please describe how you are exiting the corner and what is happening.

Suspension alignment can affect this as well. What are your toe and camber settings, front and rear? Rear toe out can make the back feel more unstable, but mroe responsive.

In general, use sway bars for fine tuning after you get your springs, shocks, tires, etc set up. The look at understeer / oversteer, in steady state and transitions. As you've noted, let are lots of choices and it looks like you have the right idea in your approaches. Some depends on budget. Personally, I have the Tri-Point front bar and a stock '93 rear bar, with Koni's and a sport spring. I had a heavier rear bar but went back to stock.

Without asking for any more info... I have a tanabe front bar + stock rear 93 bar. When the car has equal sized tires front/rear it transitions very well at autox.

Okay so, I have a square setup, 255 RS3 all around, 17x9 +44 wheels. I run about 270whp on the track.

So basically when I'm exiting a corner I can't put too much power down or else the rear can get a bit loose. I roll on the throttle but I feel like i can't really give it too much until the wheel is pretty straight. I mean it could just be a problem of driver skill, I don't doubt that at all. It's possible I just need more practice. But would a slightly bigger front bar (smaller rear) make the car easier to drive or less oversteer prone?

Yes, making the front bar bigger (or the rear smaller) would help this. Trying without the rear sway bar in an inexpensive way to see if this helps. Try it - you might be pleasantly surprised!

Adding a little rear toe in, or some more negative camber in the rear, can also help. What are your alignment settings? Adjustable sway bars, such as the Tri-Point bar, make this fine tuning easier.

I was running -1.2 all around, zero toe all around.

Tripoint Front Sway Bar. Middle size bar (.188) and it has 5 adjustments to fine tune your suspension system.

Stock Rear bar.

As others have said, alignment plays a large part. If you drive your car often on the street though, you may have to comprimise the alignment settings.

Great thanks. I'll be looking for a tripoint bar then!

the stock torsen is known to be a bit, scary, with its locking characteristics. One great upgrade you can do to get your rear end to stick is to buy a quality LSD; 1.5 way preferably. This is an expensive route, but also a rewarding one.

Os geiken and Carbonetics carbon lsd's are some of the best.

For suspension. I am running 12/10 spring rates with tanabe bar in the front and 93 bar rear. Car feels neutral even with 275's all around. make sure your shocks are a bit softer in the rear as with the tire pressure.

^ Why is a 1.5 way diff preferable over a 1 or 2 way?




John

I did a little report on this for a physics class I took over the summer. Figured I could make a boring class a bit fun. So here is my take on this,

it all depends on the type and specific clutch and it also depends on the driver. Generally though, 2 way is more desirable for drifting as the diff fully locks under breaking/throttle lift (deceleration). It can also cause under-steer issues ironically. If your off throttle going into a turn and the rear is locked, without applying a lot of throttle the rear may not way to rotate, but go straight...unless you break traction or perhaps go into a turn on throttle perhaps. A cool way to feel this is to sit in a fj cruiser or many other suv's which have manual diff lock options in 2wd mode. Lock the rear diff and drive around, do a u-turn a try to take turns smoothly. You will notice that the rear just wants to go straight and feels upset when turning. This is because the inner wheel during a turn will always rotate LESS distance than the outer wheel. (unless you are drifting) so the rear will want to continue going in the path of least resistance between both tires which is straight as that's the only direction where both wheels rotate evenly. For ppl who dont know, when the diff is locked, the two wheels are pretty much linked and forced to rotate together at the same velocity and torque.

1.5way is more common for racing because you have more stability during breaking and lift off. the ".5" is just saying that the forward and reverse limiting torque is not the same, but also not 0. Basically, there is more lock for accel vs decel. This allows for smoother transition between on/off throttle or accel/decel as the is more gap between the amount of rotation of one tire to the other. You can have more difference in torque applied to each tire before it locks. I personally think this is best.

Keep in mind that when it comes to traction, you dont really want the diff to lock up too quickly. This is good for drifting because obviously you want to break traction to drift, but for racing you want distribute torque between the two wheel as much as possible before lock up to gain the fastest corner exit speed possible.

I like the stock diff characteristics and prefer it to many other options available out there. I do know several AutoXers using the Kaaz and OS Giken. Most of them I've talked to have used it to get rid of an understeer problem they had.

My SSM FD has a 1.5 Carbonetics.

Definitely easier to use the power through corners than with the stock torsen.

Hey Jared, I don't doubt for a minute that a well tuned aftermarket diff is better than the stock unit. I just don't think it's anywhere near as bad as most people make it out to be. Of all the cars I've had the opportunity to drive on track, I personally think it works better than most of the other sports cars out there.

Look forward to hearing how your time trial goes. I have a feeling you'll be at the top of the sheet ;)

so I'm close to the same boat as the OP ,

I have a little bit over oversteer on my car. but if I up the stiffness on the front shocks 8 way adjustable Gabs i get under steer , so I want a swaybar to bridge the gap .

I preferably would like adjustable But the tripoint is pretty expensive . is this my only real option? or are there any other adjustable front sway's out there for a bit better price?

I would say looking to the front of the car (front swaybar) is the wrong direction when trying to gain corner exit traction as the weight transfer is to the rear of the car at this point.

A stiffer front bar WILL provide more understeer on corner exit by unloading the inside tire more (to the point it lifts), but I see this as limiting traction to find a desired balance whereas I would focus on maximizing rear traction.

Stiffer front bar WILL affect corner entry and steady state vehicle balance as well. If you are happy with your corner entry balance and steady state, don't mess with the front bar. If you would like more understeer/less oversteer on turn in/corner entry/steady state as well a larger front bar may indeed be your solution.

The low speed compression damping on the Stance XR may be stiffer than optimal to allow weight transfer to the rear. Less low speed damping will increase rear traction on corner exit by allowing more weight transfer.

Watch as you have someone drive your car off low speed corners or have someone take pictures of you driving off corners. Is there visible rear squat? If not, try to get some.

Setting your static negative rear camber to correct for the dynamic camber scenario of corner exit will also aid corner exit rear traction. (Note, fix camber after you get some weight transfer happening as above).

Toe in on the rear can help corner exit stability.

A differential limiting inside wheel spin will also increase traction on corner exit.

Having well trained throttle application is also critical and cannot be ignored. It is possible you are getting very good weight transfer to the rear already and just need to learn exactly how much of the available torque the rear tires can transfer to the ground.

My view is a heavier front swaybar to correct corner exit traction alone would be a bit of a bodge.

I'm getting the car loose on corner entry the front will bite but the rear will slide a bit then i have to wait for it to settle to put power down again . or drifto happens

i'm running -2 rear camber , and minimal very minimal toe in at the rear. I dont have the alignment sheet on me and cant remember where I put it , but its a very minimal ammount .

ofcourse if I smack the throttle mid corner I will kick the rear end out .

I have stock sways at the moment

and yes I do have rear end squat . not a great deal but its there . rear shocks are on softest settings . short of unhooking the rear sway cant do much for softening the rear .

I am running high spring rates , 650f / 500R

Make sure to lubricate the front sway bar bushings regularly with a grease (like prothane). When unbolted, the bar should rotate on the bushings effortlessly. A stuck bar will limit weight transfer and increase the spring rates.