understeer how do I minimize it?

[hendrik]

What will minimize understeer in an e30? I currently have h&R cup kit and stock sways. I am sure that a modification of the sways will change things, just not sure how they will on the e30. Any help is greatly appreciated. Thank you.

[DSP74]

First off to eliminate understeer the RIGHT way leave the rear of the car alone....This applies to almost everyone here with a few exceptions....

Sticky tires, the correct camber setting, and correct suspension components to take advantage of your camber setting will all ADD GRIP to the FRONT.

Right off I'd say you either need camber plates, a bigger front bar or both.

[DSP74]

Most importantly slow in fast out.... Stop inducing it.

[Hick]

easiest thing to do its to play with the tire pressures, before spending any money.


lower front, or higher rear will help understeer.

lower rear, or higher front will help oversteer.

[iflytii]

Typically understeer is corrected by reducing the front bar or increasing the rear bar. I'm not trying to say the OP doesn't need new sway bars, just saying throwing a larger front sway bar on a car that already pushes isn't the answer.

As stated previously, the cheapest route is to play with tire pressures. To reduce understeer or induce oversteer, you can increase tire pressure in front and reduce tire pressure in the rear.

Alignment will also help. Something free to try would be simply adding a little toe out in front. I run around 1/8" total toe out (1/16" per side) Additionally (equipment permitting) you can add more front negative camber and positive caster.

Spring rates can make a big difference. To help with understeer, you can either soften the fronts or increase the rears or both. I noticed in another thread you were looking at coilovers. That will give you the opportunity to tune to your taste by choosing spring rates of your choice. Of course you will also be able to corner balance the car as well. For stock diameter springs, you can play with spring pads to lower/raise the car.

[DSP74]

Typically understeer is corrected by reducing the front bar or increasing the rear bar. I'm not trying to say the OP doesn't need new sway bars, just saying throwing a larger front sway bar on a car that already pushes isn't the answer..

According to the books people read....

The car right now, needs a bigger front bar.

[joshh]

Most importantly slow in fast out.... Stop inducing it.

Took the words out of my mouth.

If you're autocrossing, do not break too hard too late.

[Borat]

According to the books people read....

The car right now, needs a bigger front bar.

pretty sure you've got that wrong, generally a bigger front will increase understeer, and a bigger rear bar will increase oversteer

[DSP74]

pretty sure you've got that wrong, generally a bigger front will increase understeer, and a bigger rear bar will increase oversteer

Nope:D

[iflytii]

According to the books people read....

The car right now, needs a bigger front bar.

So your suggesting that a basic understanding of suspension dynamics isn't a prerequisite for giving good suspension advice?

Suspension tuning isn't as simple as "stiffer" here and "softer" there. It requires some understanding, i.e. reading, and a lot of experience tinkering. I'm sure just about everyone here with a good amount of seat time has eventually fallen into the prescribed formula for what works best for our cars. At that point it's easy to simply suggest Y component will fix X problem. My post was an attempt to give some insight to the OP rather than blindly suggesting bolting parts onto his car. Not knowing the usage of the car, the drivers experience level and nothing more than the springs installed there are a lot of solutions possible - many of them are free.

Sway bar settings in relation to understeer/oversteer are heavily dependent on other suspension variables. Camber, tire pressure, spring-rate, rebound all play a major role in how different sway bar settings will affect which end looses traction first.

As I said previously, stiffer swaybars up front will result in less movement of the suspension under cornering load, resulting in understeer. However, combine a stiff swaybar and a lot of negative camber and the result under suspension load is the front outside tire ends up being "square" to the ground creating the maximum contact patch in an optimal setup (i.e. lot's negative camber up front and relatively soft front springs). The key is here is determining the "optimal setup".

Anyway, getting back to the original problem. Assuming the understeer problem is not mostly driver induced then you have to start somewhere with fixing the issue I suppose. DSP74's method is certainly valid - throw a bunch of parts at the problem and eventually the car WILL outperform the driver. Personally my checkbook has taught me to be a little more educated in my decisions.

[Hallen]

DSP74, How do you figure that? An increased roll bar stiffness will act the same as stiffer springs for the purposes of under/over steer.

Stiffer roll bar in the front will increase understeer and decrease oversteer. It will help to reduce body roll so the car will be more responsive, but it will still increase understeer.

Just one reference in the chart on this page

[DSP74]

Camber control

[whiltebeitel]

iflytii has the right idea. Sways will increase traction to a point, then it will become counterproductive when it prevents all the wheels from contacting the ground. Generally, a bigger bar from stock, coupled with the sticky tires you SHOULD have is quicker.

[nando]

Camber control

you are right in that respect, but you have to be *really* low in order to get to that point in the camber curve where you start loosing camber (basically where the angle between the control arm and strut is greater than 90*).

And if you are that low, chances are your car is stiff enough that your suspension isn't compressing appreciably to notice much difference in the camber curve, even if you are passing that point. Essentially, you could simply go with stiffer springs and have the same effect.

[AlarmedBread]

Trail brake, feint, handbrake. In order of preference.