I've been running with the Mugen 31mm bar for awhile now and have some mixed feelings about it.

I initially installed the bar to prevent snap-oversteer at the track. I've never experienced dangerous oversteer with the S2K, but thought this would help me run at the limit a little better. I've yet to have a track day since I installed the bar, but I have participated in an autox with it. At the autox the turn in seemed a better and maybe my times improved a bit, overall it worked fine with no problems.

My real issue with the Mugen bar is on the street. In everyday driving, I've found the car will push like a pig (understeer), if one is not careful. The 31mm bar forces me to use much smoother and lessened steering input at the risk of scrubbing the front tires into understeer. I don't find it to be a dangerous condition, it's just slow and not as much fun.

Maybe it's just me, I'm a RWD guy and have only owned RWD cars over the last 2 decades. I suspect those more accustomed to FWD cars might find the S2K oversteers a bit more than I do. I'm very comfortable with the level of oversteer on the street and track with the stock setup. I've had a few bobbles but never anything serious, even at the limit.

I'm going to keep the bar on until my next track day and test it there. But if it doesn't add anything to the experience, I'll be going back to stock, at least for the street.

 

This is just my 2 cents and I know 100 people will shoot me down on this.....again but........ I believe that this car needs a stiffer rear bar and front bar. going to a stiffer front bar only masks the situation. Also my experience with track tires (I am runnning BFG's wiht the fiberglass sidewalls) that the car is neutral to slight oversteer after the apex. This is associated with roll, not becasue the rear end is too stiff. But what do I know those 2 national championships dont really mean that much anyway!
But still to each his own. I will be putting on bigger bars front and rear. I think that when going up just on the front bar thicness, it moves the ratio of the roll between the front and rear too much. Just putting a bigger front bar is more of a crutch than a fix. always look at why its oversteering.

 

With this car's quick steering, it is very easy to turn the steering wheel too fast when starting a turn. Once the tires are past the optimum slip angle, they just plow straight ahead. The other thing that can affect the car is if you get on or off the brakes suddenly when you start the turn. I'm working on being smoother at turn-in because I also have seen the car understeer with a stiffened front sway bar.

 

Wouldn't a good set-up be to add a larger front bar and a SMALLER rear bar?? This would allow the rear roll more and not break loose as fast.

 

Alot really depends on what tires you are running on. A car might handle horribly with street tires and then work a lot better with track tires. Most all of the tech in track tires for sedan/ street cars has gone into the sidewalls to get out as much of the roll as possible. I am just saying from my experience that I think the car needs something other tan a bigger front sway bar. The biugger front sway bar does not fix the problem....... everyone that puts it on says the same thing.....it now has a push..... Hmmmmmmm Exactly. Plus so many people here have so many differnt taste of what a proper setup is. But the thing to look at is exactly what is the problem with the car and why is it doing what you dont want it to do. The Bfg's do require at least 2 degree's of neg camber. Right now I am running -2 in front and -2.5 in the rear. I would much rather put an adjustable bar on front and rear and have the abillity to change bump, rebound and spring rate.
Ride height has alot to do with the handling also. to just throw a bigger front bar on will not cure the cars mid to late corner oversteer.

 

Mikey,

You really hit the nail on the head. There have been a lot of threads on changing the front rollbar right out of the box. After Neal Sapp mentioned the oversteer on his S2000 everyone jumped on the bandwagon. Your tires, suspension, and driving style dictate the balance, and you cannot over estimate an individuals driving style. I have the same suspicion that you do, in that many of the people are FWD converts and are more accustom to understeer. I personally like mild oversteer and think the solution for a little better rear control would be to change to coilovers and slightly soften the rear (rebound dampening). This might take the

 

[QUOTE]Originally posted by wea
[B]I personally like mild oversteer and think the solution for a little better rear control would be to change to coilovers and slightly soften the rear (rebound dampening).

 

Hmm-

Interesting.

I've never had a problem with the S2000 understeering at any time, unlike some of my other cars. I've driven FWD, RWD, AWD cars extensively in all sorts of engine/chassis configurations. In fact, for me, the front end is so planted anything that helps tuck the rear end in for a longer duration is good. The general concensus in this thread is not what is generally accepted- it may be one of the reasons why autocrossers go with significantly bigger front swaybars than the Mugen 31.8mm bar, because the rear end tends to get out from underneath you before the front end even hints at it...

I don't advocate a larger rear bar- that will make the tail wagging even worse. For me, the goal is to get more grip in the rear, not less grip in the front.

If your S2000 is understeering, I would suggest checking the alignment. It's just not a trait of this car when driven correctly.

 

I think that many of the items touched upon in this thread have a ring of truth to them, its just the context that needs to be examined.

1. Stock car understeering - it can happen, but it is largely driver dependent. The car will understeer coming out of a corner if you aren't in a low enough gear (weight transfer to the rear and off the front). If you work hard to load the fronts coming into a corner you can get understeer too, but at the risk of a quick transition to oversteer.

2. Need for a bar in autocrossing - I think the big issue here is tires. Many autocrossers (those on Kumhos at least) have been forced to run a 225/245 front/rear combo. As we know, the rear tires on the stock S2K are already near the 245 mark in actual width, which means the grip ratio front to back has been changed. With more front grip, the rear end will be the first to go away under full load cornering. Hence the front bar is needed. I've autocrossed my car a couple of times on the stock street tires and had no problem coming out of corners and no lifting of the inside rear tire. No problems with excessive oversteer either. I'm pretty sure I was pushing it too as I ran second fastest TOD behind only a B-stock Miata on Kumhos. I'm going again on Saturday and maybe I'll have my buddy bring along his video camera for a closer inspection. Had similar performance at the road course on the stock tires. But in my experience a bigger front bar along isn't really necessary on street tires.

3. Bigger rear bar. I wouldn't do this by itself, but in conjunction with a bigger front bar it might improve handling. The key is to make sure the roll rates are properly matched. You don't want it to feel like a new Mustang GT where the front and the rear roll at vastly different rates.

UL

 

While it may not be a consensus you agree with, it's certainly the shared opinion of more than one of us. I've just been rereading some magazine reviews of the S2000s handling. Most of their pro's describe it as very neutral. As such it only makes sense that a stiffer front bar could cause understeer.

But as Bill says above, "you cannot over estimate an individuals driving style". And with most of the cars on the road now being FWD, it's easy for me to see how many people have become used to understeer.