Teach me about fixing bodyroll

I recently started auto-crossing my latest purchase, a bone stock 95 Miata. I learned to autocross using my Mazdaspeed3, so this is a big adjustment for me. The Miata has been a ton of fun so far and I am enjoying learning the benefits of a light, balanced, rear wheel drive car. However, it does have a lot of body roll.

Exhibit A:

Exhibit B:

Now this isn't really a big problem in sweepers but it does cause problems in transitions (especially slaloms). I can really feel the weight crash from side to side. I know a suspension package like this (https://www.flyinmiata.com/index.php?deptid=5635&parentid=77&stocknumber=13-16750%20%201990-93%20NB) would fix the problem but I don't have an extra grand to spend on the car right now (the racing budget was more than used up in buying the car).

What i want to understand better is: what component(s) are the main contributor to the body roll? Is it mostly a spring rate thing? Do the shocks control this? Would just adding a big front anti roll bar fix the body roll? I'm sure they all make a difference but which one is the biggest factor?

Remove the suspension and make it lay rocker????

Can't roll with the body touching the ground.

Best, cheapest option is a set of sways. Heck, the hint is right in the name: anti-sway or anti-roll bars.

Only run the front one if you're restricted by the rules, or run both if you're allowed and you like the behavior. As a bonus, adjustable sways will let you tweak the handling balance between over- and under-steer.

Springs are also a contributor to roll stiffness (and CG height) but then you'd also need improved shocks, and you're going to start chewing through that budget.

You're rolling the wrong way.

From the letters on the side of your car you seem to be in a stock class. Good choice. It's a good place to learn skills and the rules restrictions will save you money. Keith is right, your best bet is a sway bar in front. I can't tell you exactly which one. Additionally, on your car you're almost certainly on other bump stops when you're leaned over that far. They're old, they might be good, they might not. They're worth checking. Shocks won't necessarily affect how far the car ultimately means, but they will affect it's behavior as it flops over and how composed it is when it gets to full lean.
I'd start with a bar and checking your bump stops and the rest of the bushings in the car. Even under the best of circumstances a stock class miata is a bit of a floppy beast. That's OK. They can still be fast and fun.
With the potential rule changes coming down the pipe for next year I'd be a little hesitant to do too much with the car until I learned what you'll be facing.

I'm with Keith and mazduce, I'd start with a good front sway bar, and update to a good set of shocks at the same time if money allows.

A bit of body roll is ok, but it's how fast the body rolls that can be the problem. If you think of everything the car does in terms of transfering weight, it's a bit easier to understand. You want the weight to move around in an easily controlled manner. The more control it has, the better the car will drive.

The best way to reduce body roll is to drive slower you scoff-law!!

What those guys said^^^^ (the ones who sounded halfway serious), though I would also echo racerdave600 and note that if your stock shocks are worn out, that will badly influence the manner in which the car rolls, if not the total lean in a sustained corner.

Springs and sway bars resist roll as travel occurs, in proportion to how far it has rolled. Dampers start resisting it the instant the body starts to move, in proportion to how quickly it is rolling. So in a slalom, dampers start resisting the next cone's roll as soon as you start unwinding this cone's steering lock...

Which is a long-winded way of saying that if your shocks are dead, I'd fix those before worrying about upgrades. If your shocks are in fine condition you can ignore my blithering...

Sway bars are the best way to cut down body roll specifically but springs (and shocks...and then strut bodies, top mounts etc etc, you basically have to upgrade everything between the frame and the upright AKA a coilover kit) make the biggest difference in handling overall - and cut down a lot of body roll too. They'll really harm your street comfort though, while hard sway bars will keep the body roll down without affecting the ride too much.

So I'd say that if keeping this a comfortable DD isn't a high priority and you want to get a big overall suspension improvement and lay a good foundation for future suspension mods, get a proper threaded coilover kit (classing issues aside). If you want a cheap mod that will give you a decent DD-friendly cornering improvement, get the sway bars. If you get the sway bars first and end up heavily modding the suspension later, you might have to change them again. In the grand scheme of suspension setup sway bars are a finishing touch to the system.

Echoing the comments above, a front sway bar will be the best bang for your budget. Then if budget allows, look at upgrading to an adjustable shock.

Upgrade to a bigger sway bar, get rid of the stock, soft sway bar bushings, and either go polyurethane or solid rod end links.

I'll be the dissenting voice after having a few E30s with "proper" suspensions (IE Ground Controls with properly spec'd rates and Koni Yellows valved to match those rates and motion ratio of the car) and now having a Miata with what I would definitely call a competent setup....but not ideal in terms of rates and non-adjustable damping for serious HPDE work.

I'd say save up and do a "good" suspension to begin.

You'll get good at driving the car with a crap suspension, you'll have more time to research what setups you should be looking at for your goals, and since you'll have more time to save, you won't end up with a compromise suspension.

That's my two cents.

Ah, the Miata.net answer. If you're not going to spend at least $2k on your suspension and make it all complicated, it's not worth even starting

How serious are you about autocrossing? My personal philosophy is that I'd rather build a fun car and autocross it wherever it ends up instead of limiting what I do to what the rules say I can do. My street Miata has an FM 2.5 suspension on it, which does all sorts of terrible things to the classing. But it's a fun, comfortable setup so I don't care - and I can still have a really good time with it on the autox course.

You don't need a multi-adjustable coilover setup. You can get away just fine with a good spring/shock setup. Similarly, you may find (like I do) that your car isn't any fun to drive with just a big front sway bar. Might be effective on the autocross course, but it may not be responsive enough for you in the real world.

Basically, figure out what you're looking to build in the long run and keep that in mind when modifying. If you want to rule CSP, you'll do different things than if you just want a fun car that is capable around the cones.

I didn't realize that was the Miata.net answer........I knew it was the MT.net answer.

But notice my last part where I said he needs to figure out what he wants to do with the car before he starts buying parts.

Like you, I couldn't care less about Auto-X so I'd just build it the way I wanted and go have fun. But others get very competitive about the parking lot stuff.

Replace everything that's worn out on the stock setup (shocks/bushings/etc.) and go back out. Repeat until the "nut behind the wheel" is tight.

If you've already done that, listen to Keith and get yourself some bars.

Doesn't just stiffening the front bar contribute to understeer? Would the worn suspension make it even worse?

Boy, those are some fantastic pictures. What a talented photographer!

Me

In addition to all the above, ditching the hard top on race day might help a little with body roll.

This sort of thing helps considerably

^This^
I put a RB front sway-bar and Bilstien Sport shocks on my 99 base edition on a budget and it greatly reduced the body roll and improved the drivability autocrossing.

Problem with that bar (besides the tendency for the bushings to bind) is that there are no adjustments. I much prefer adjustable bars.

If you don't change anything else and just add a front bar, the car will understeer more. Yes. Autocrossers seem to like understeer more than track guys do, as they're always in transition and running low gears. Chances are you'll have to adjust the rest of your setup to keep the understeer under control, such as alignment changes.

I have to say that I'm a bit disappointed somebody hasn't suggested an LSx swap into the blue couch in the second picture.

Thanks, Keith. That is what I thought.

From what I've seen, fast E Stock Miatas have more roll than some other cars. Do a front bar and see where that gets you. I know a lot of the fast E Stock Miatas are also using Fat Cat bump stops. That seems to be the hot set up. If that works the way I think it does, it relies on some amount of body roll. Not sure.

http://fatcatmotorsports.com/FCM_Suspension_Truth.pdf

The guy there seems to be the "go to" guy for E Stock Miatas.

Brett_Murphy wrote: I have to say that I'm a bit disappointed somebody hasn't suggested an LSx swap into the blue couch in the second picture.

Based on how it's parked, I assumed it already had one...

I had some complications when I was putting my suspension in my NC which has that goofy body roll too. The first day wrapped and all I had on were the sway bars on the front and rear, that drive home made a massive difference.

It was really complimented well by the struts and springs, but if nothing else sways are where it's at.