Minimizing Oversteer

[ACHTUNG]

I took my S52 powered E30 to the track yesterday and found that it's tail happy. The rear wanted to come around in the corners a bit too much.

I'm running Koni Yellows with IE3 springs and stock swaybars.

What can I do to minimize the oversteer?

[nrubenstein]

More front sway is the first thing.

Where is the tail coming out? Is it coming out under power, or through loading? Oversteer under braking or mid corner is very different from oversteer at corner exit when your right foot is planted.

[jlevie]

Get a set of Bimmerworld 22/19mm sways for starters. More rear camber (3-3.5deg) will help a lot as will setting zero to 1/16" total rear toe. To get that you will have to install adjustable camber & toe plates. That much rear camber works great on a pure track car, but eats tires on a daily driver. Increasing the rear track width with spacers will help also. Be careful with the rebound adjustment on the shocks. You want just enough rebound damping to prevent wheel oscillation on rough surfaces. Too much rebound damping will increase oversteer on corner exit.

[ACHTUNG]

More front sway is the first thing.

Where is the tail coming out? Is it coming out under power, or through loading? Oversteer under braking or mid corner is very different from oversteer at corner exit when your right foot is planted.

It's coming out under power.

[Jaxx_]

It's coming out under power.

time to adjust your sways. big front and small(or no) little. It's a balancing act with what you actually want the car to handle like, but with enough front bar and no rear, you're probably going to be lifting the inner front wheel and rocketing out of corners.

[nrubenstein]

It's coming out under power.

How much rear tire?

You definitely want a bigger front sway. You should also be looking at your rear alignment. Have you checked where your rear is actually sitting? Jim's advice is very good on that front. Also, I've noticed E30s going toe out over time, which really screws up the handling.

[jlevie]

time to adjust your sways. big front and small(or no) little. It's a balancing act with what you actually want the car to handle like, but with enough front bar and no rear, you're probably going to be lifting the inner front wheel and rocketing out of corners.

The problem with trying to cure oversteer on corner exit with a big front bar and a small (or no) rear bar is that the car will understeer like crazy on corner entry. And to make matters worse the chassis will twist, even with a full cage in the car. The handling needs to be balanced between under steer and oversteer.

With the power available in this car some oversteer is just going to be a fact of life and that can be managed with throttle control. But getting everything else right comes first.

I didn't mention it, but the car needs to be put on a set a scales and the corner weights obtained. Fiddling with spring pads and addition/placement of ballast can be used to get the cross weights and front to rear balance better, which will help.

[nrubenstein]

The problem with trying to cure oversteer on corner exit with a big front bar and a small (or no) rear bar is that the car will understeer like crazy on corner entry. And to make matters worse the chassis will twist, even with a full cage in the car. The handling needs to be balanced between under steer and oversteer.

With the power available in this car some oversteer is just going to be a fact of life and that can be managed with throttle control. But getting everything else right comes first.

I didn't mention it, but the car needs to be put on a set a scales and the corner weights obtained. Fiddling with spring pads and addition/placement of ballast can be used to get the cross weights and front to rear balance better, which will help.

Well, you can solve a lot of the understeer on corner entry with trail braking - the other nice thing about a really stiff front end is that it lets you get through high speed transitions a LOT better. If you want a frightening example of this, the BMW Motorsport WTCC E46 front sway bar was 40mm.

Frankly, the thing that was particularly interesting to me running my 330is on track was just how incredibly sluggish the steering response was. Most of that came down to the soft 375lbs. front springs and 22mm front bar. You turn in and have to wait for the car to lean over. And wait. And wait some more. No doubt the extra weight of the S50 really hurt that too.

I would also suggest looking at the differential. I have a Z3 torsen in the car and it's annoying in a lot of ways, but it is MUCH smoother than any of the clutched diffs. I had no oversteer issues at all.

[ACHTUNG]

I was running brand new 225/45/15 Hankook RS-3 tires (which I thought did surprisingly well!)

I think I'll try a bigger front sway with the stock rear sway and see what that does.

I have a 3.07 torsen diff.

I also think that a lot of it was my in-experience with track driving as well. I think that I was over throttling on some of the corners. I need to get better with my throttle control. The car is so damn light and is putting down a lot of power with the S52 with Schrick cams. I just need to learn to control it better.

[TobyB]

I need to get better with my throttle control.

This will help, if the car is balanced otherwise. If you coax the throttle in, weight will transfer
more evenly, and you'll (probably) get more rear grip and less oversteer.

The exception would be if you have too much rear camber- it's not easy to do, but
if you're already very low, and the car squats more, you gain camber, and unload the
outside edge. And then the car oversteers.

Another thing to rule out- make sure your rear shocks aren't bottomed. That'll
give you a boatload of oversteer in a hurry.

I wish I had your problem...

heh

t

[Jaxx_]

The problem with trying to cure oversteer on corner exit with a big front bar and a small (or no) rear bar is that the car will understeer like crazy on corner entry. And to make matters worse the chassis will twist, even with a full cage in the car. The handling needs to be balanced between under steer and oversteer.

With the power available in this car some oversteer is just going to be a fact of life and that can be managed with throttle control. But getting everything else right comes first.

I didn't mention it, but the car needs to be put on a set a scales and the corner weights obtained. Fiddling with spring pads and addition/placement of ballast can be used to get the cross weights and front to rear balance better, which will help.

I agree 100%. I prefer to have the car neutral, off throttle, mid corner. All the rest can be managed with your right foot.

[Smelser]

Have to agree with the scales. Get em, borrow em, rent em. They are VERY indespensible, and the best part is, no matter WHAT you go to in the future, they will always be transferable from any car to any other thing you own, HELL, SCALE YOUR QUAD FOR MUD BOGGIN if you want,

Sometimes the best shop tools is the best thing you can get for your car!!