New here and trying to solve understeer.

Hey guys wanted to drop by and say hello. I am a newb here. i spend most of my time autocrossing my 89 e30. One of the things i am currently battling with is understeer.

I was wondering if anyone here had much experience with e30s. I have been considering of adding a 22 mm front sway bar to see if that helps keep the front end together a little and keep the inside front tire form gaining positive camber due to body roll.

As far as current setup it is listed in my garage http://grassrootsmotorsports.com/reader-rides/5763/

Welcome and nice looking car!

I would do both front and rear sway bars. Reducing body roll will help front end grip, but (generally speaking) increasing front roll resistance relative to rear roll resistance will increase understeer...

To be sure, I've heard of cases where adding only a front bar reduced understeer by reducing body roll. But I think this car would like both. Especially given that you're running the 1.9l four and not as desperate to keep both rear wheels planted on corner exit (as with, say, an M52 swap), but at this point I'm perilously close to talking a bunch of smack I don't have experience to back up...

Your car would also love some camber plates. My E30 did, at any rate. You can get a little additional negative camber this way with your existing springs, though to really crank the camber up you'll need to swap out the front IE springs for coil overs due to clearance issues.

Just as an aside, reducing body roll will obviously improve the camber condition of both the inside and outside front tires (and the rears, too!), but I'd be more concerned about the outside than the inside, as that's where the bulk of the weight is mid-corner.

Okay a few things the car is a 6 cylinder. As far as camber plates, i am well aware of that. i am saving up fro ground controls and will be putting them in for next season. So I did not want to get Camber plates now and than having to buy new ones for the race spring ID.

Now as far as rear sway bar goes I am confused on that one. many e30 people I have spoke to recommend not running a rear sway at all and running stiff springs or running a stock bar to help with traction. The current springs I have the back seem to be a lot stiffer than front and that is why i was thinking of keeping stock rear bar for now.

decrease front tire pressure...

increase rear tire pressure...

Is the car running staggered wheels (more rear width?) try none staggered.

In reply to crazyb:

Oops... Must've misread your garage entry re: engine...

The only sway bar set up I ran actually came with my car when I got it (Eibachs, I think). So if you're getting that advice from people who've tried with and without and are recommending without, I'd listen to them before I'd listen to me

One more thing to keep in mind when looking at front bars (and again this is an area where I haven't tried multiple things) is that E30s can have their sway bar endlink mounts either on the control arm about 2/3 of the way outboard, or on tabs directly on the strut body (M3 style). That's a huge difference in leverage, so 22mm will behave very differently depending on how the linkage is arranged.

I'd ask around with people who are running whichever way you are. My car came with the M3-style tabs (possibly welded on after the fact) and that's what I used.

oldeskewltoy wrote: decrease front tire pressure... increase rear tire pressure... Is the car running staggered wheels (more rear width?) try none staggered.

No, no staggered stetup. Running 15x8 with rs-3 225/45/15 all around.

In generally, stiffening the rear will reduce understeer. How you do it, bar, springs, tire pressure are something you will have to experiment with.

Also depends on what class you are in. Stock class does not allow changes to the rear bar. When I was autocrossing my E46 I got lots of advice to put a heavy front bar on to stay in Stock. The improved camber situation more than offsets the understeer.

I am currently in DSP so I have a lot of options for suspension tuning.

Have you had someone else drive it and have they had an understeer problem?

Yeah my buddy drove it also the other person in the photo and had slight under-steer issue. Now I understand I am coming into the turns a little hot. But the car under-steers way easier than it over-steers at any sort of speed. So i figure I should be able to improve in this area a little.

A good rule of thumb is "the stiffer side slides."

Of course that's a generalization and not always true.

oldeskewltoy wrote: decrease front tire pressure... increase rear tire pressure...

this advice is backwards, unless the front tires are overinflated and losing grip because of it. typically, increasing inflation pressure will increase grip.

I think I am going to pick up a set of adjustable 22/19 sway bars thus should give me some options to play with for my set up.

On that E30 replace both bars and get yourself some camber plates. Understeer issues will be nonexistent.

yeah camber plates will have to wait until I get a set of Ground controls coil overs.

Replace both bars (preferably with adjustables) and run camber plates up front. Worked perfectly for me, I've got my car dialed in to be neutral, with just a hint of oversteer when you lose adhesion.

AngryCorvair wrote:

oldeskewltoy wrote: decrease front tire pressure... increase rear tire pressure...

this advice is backwards, unless the front tires are overinflated and losing grip because of it. typically, increasing inflation pressure will increase grip.

I won't get in a shouting match...

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=58

http://www.timskelton.com/lightning/race_prep/suspension/corrections.htm

http://www.google.com/search?q=oversteer+and+tire+pressure&sourceid=ie7&rls=com.microsoft:en-us:IE-SearchBox&ie=&oe=

if youre getting fully adjustable camber/caster plates, not fixed, i'd set caster as high as you can which will probably end up around 6 degrees (actually, you have offset bushings so it may be higher maxed out... ) and camber depending on its autox dedication i suppose. and if its independantly adjustable you could check tire temps at the event and make small camber adjustments even.

our gutted challenge e30 runs about -3.2 degrees up front, 450# front and 600# rear springs (on the softer side, but also much lighter than yours likely), the larger of the two stock rear bars (only because it was a challenge car, otherwise it'd have ST bars), and the rear toe is just about zero, and if i recall rear camber is around -2.5 degrees. you cant adjust your rear camber or toe unless you make your rear trailing arm mounts adjustable, which i definitely recommended, budget allowing. the car turns in great, dances around with throttle input, and is just a joy to drive especially given the budget. we usually have to fine tune a bit of oversteer out of it by lowering rear pressures.

on my similar to your car's weight e30 M3 i'm running bilsteins and eibach springs, 22/19 ST bars, and fixed camber plates that make it around -2.5 degrees. my rear toe is way off, toeing out right now, but the combination of rear toe and front camber makes it surprisingly neutral. when i make my rear subframe adjustable i'll likely stiffen up the rear bar to counteract the toeing in from where it is now.

Maroon92 wrote: A good rule of thumb is "the stiffer side slides." Of course that's a generalization and not always true.

that's only a generalization if you don't have camber control issues.

Looking at the picture, it's pretty close to showing the front tire leaning out. So fixing that by putting in more front roll stiffness should help. Or by dialing in front camber.

Alfas and Golfs have this problem in spades. To the point that even with an adjustament in the front camber, it still has to be stiffer. Modern tires are amazing vs. what was available 30 years ago.

Once you reach the limit of the front grip, then I would address the rear for balance.

My rule of thumb is always- first address the end you want to fix, if that is not enough, then do the other end. Which is what I mean by the above sentance.

In reply to oldeskewltoy:

neither will i. OP is trying to reduce understeer (which is directionally the same thing as increasing oversteer). here's a quote from your first link. i had to add the --- marks to align the entries:

Guide To High Performance Handling

Adjustments-------- Decrease Understeer---------- Decrease Oversteer

Front Tire Pressure ----------Higher-------------------------- Lower

Rear Tire Pressure ----------Lower---------------------------Higher

and here's a quote from your second link (again, i added ---- marks to help with alignment):

understeer corrections-------------------------------- oversteer corrections.

Push, plowing, front tires slide out first.------------ Loose, rear tires slide out first.

Usually slight understeer is safer.-------------------Oversteer can be dangerous, especially at high speeds.

Raise front tire pressure.------------------------------Lower front tire pressure.

Lower rear tire pressure.------------------------------Raise rear tire pressure.

see? no need for shouting from either one of us. i think you know what you are saying and just said it backwards. because the links you provided support my correction of what you originally said.

Yeah i think i am going to get this setup and see how it works at the next event. I will start off with max setting on front sway and medium on back and go from there.

http://store.nexternal.com/ireland/sway-bar-set-for-e30---22mm19mm-p597.aspx

Left foot brake as you turn in. The hrader you rake the more the rear will come out.

Funny you suggest that, i have been trying to work on my left foot breaking for a few weeks now but not having much luck. I have no sensitivity in my left foot as far as pedal modulation so I end up slamming the breaks.

But it is getting a little better.