Questions for Reducing Body Roll
 

Hi All!

I have recently upgraded to a set of Hankook V12's (cost effective for the time being) and I am now experiencing a good amount of body roll that was never there before.

This is my first performance driven car and I have no experience with adjusting suspension to dial everything back in. I have heard of using upgraded sway bars as a tool to reduce the roll but have also heard that it's useless without upgraded springs. I am still trying to keep costs down for the time being and have been considering getting the Eibach Pro or Sport line Anti-Roll kit, which comes with the lowering springs and front and rear sway bars to boot. Does anyone have any feedback or suggestions? Any advice would be GREATLY appreciated. Thanks! :)

Contrary to what some may think, some body roll is a good thing...

It's allowing your tires to grip & actually improving handling performance. Being a new performance car driver, trying to dial it out may do more harm than good for your car.

Once you get really comfortable w/ the handling, maybe you can then look for some ways of reducing it--but don't go too crazy, or you'll give up grip!

Enjoy!

On this car, stock, body roll is most assuredly reducing grip. Sure, if you go too stiff you can lose mechanical grip, but stock is a long way from that point. The car doesn't have much camber, and excessive body roll will further reduce camber relative to the road. Limiting body roll will improve tire grip.

That said, I have to wonder if the OP is *really* experiencing more body roll or squishier/softer tire sidewalls. The car should not be rolling more at the same cornering speeds.

You might try just sways first. Lowering springs would also help a lot by further increasing stiffness and giving some much needed negative camber (lower c.g., too, but this is offset by lowered roll centers), but stiffer springs should be matched with stiffer dampers. Have to be *very careful* with aftermarket dampers, as most are crap. Eibach Pro kit w/ Konis might be OK.

The car is definitely rolling more at same cornerning speeds. The steering response is like a sponge now, which disheartens me a lot... I miss the tighter, crisper feeling I got with the stock tires. Granted, I do understand that you give up steering feel/response with stickier tires. That is why I have come to you all. Looks like sway bars might be a good first step. Would springs to go with it be too much?

??? Who told you that?! Most serious performance tires have stiff sidewalls and give much better feel and responsiveness. Unfortunately you picked a tire that doesn't.
http://www.tirerack.com/tires/tests/...y.jsp?ttid=149
What We Liked: Adequate road manners and traction
What We'd Improve: Handling precision at the limit

Go to tirerack.com and check out Extreme and Max Performance category tires, and pick one that's rated highly for cornering stability and responsiveness. Michelin Pilot SuperSport is probably your best bet in Max Performance. Dunlop Direzza ZII in Extreme Performance (if you're willing to give up some hydroplaning resistance), or AD08R, or RE11A.

I wouldn't address the suspension until I tried truly responsive tires first.

I put sway bars on first on mine. After I did that my tires were in need of extra grip, steering was a lot better, a lot less body roll.

Instead of changing sway bars, by changing stiffer spring will Get the job done too right(reduce body roll)

If you're getting more roll at the same speeds, it's not the chassis or suspension, it's the tires. If you find the response is mushy, also the tires. My response/feel was MUCH better on ZII's than on the stock tires, so was the grip.

Different tires won't generate different forces at the same speeds (assuming both are still gripping not sliding at that speed), so how the suspension is loaded (and therefore what kind of body roll you're getting) won't be any different at all.

If the worry with body roll is keeping the front camber in check, you're far better off to just get camber bolts up front to dial in ~1.5* of negative camber than to swap both sway bars out.

This is mine on ZII's, 100% stock suspension and alignment. You can see the front contact patch isn't perfect, but it's also not terrible.

https://fbcdn-sphotos-g-a.akamaihd.n...7828704bd05d86

I was going to say the same thing.
Changing tires isnt going to magically change the way the suspension responds (decreasing roll resistance).

One thing the OP didnt mention: Did you notice this on the street or on the track?
Most of the things you are commenting about are nearly impossible to experiment with on the street.
Or maybe the butt dyno is telling you your suspension is not setup correctly :bellyroll:

ANd as for the "mushiness" what tire pressures have you experimented with.

Apparently Eibach ruined progressive handling on local SC'd development car. Standard suspension is good in my opinion. A bit more grip will make it evil - in a good way! :)

Everything's a compromise.
Don't forget that sway bars link both front wheels and both rear wheels. I have stiffer springs than stock plus stiffer front and rear sway bars and I can feel the cross talk at the front. (Not so much at the rear.)
On the plus side sways are a relatively inexpensive mod.

Body roll results from cornering force. Unless you change the spring rate body roll is proportional to cornering speed, not tires. Body roll results from the momentum of the sprung weight (basically the "car") acting on the springs, compressing the outside springs and unloading the inside springs. At the same speed and by definition body roll remains the same.

You must be experiencing roll effects in the tires, which are air springs from the suspension perspective. Stiffness of the tire carcass affects the feel of the tire a lot. Try raising your tire pressures, if the roll feeling diminishes then it's the tires you selected. Wear them out and get better ones next time. BTW the stock Michelins are a very good tire, just not as good as they could have been.

Missed this thought before... but have you checked the pressure in the tires to make sure they aren't way too low? Tires rolling and mushy response sounds a lot like way too little pressure.