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Got to know my E46 a little better. (Autocross)

17K views 83 replies 31 participants last post by  Mango 
#1 ·
So I autocrossed for the first time. Had a lot of fun and really got to learn my car more. Very humbling experience. I was very very happy with the way my car behaved on the course except I did have to deal with some understeer at times.

I'm sure I can thank the staggered stock setup for that! I kept coolant temps in check consistently throughout the day, all went perfect. Highest I went was 96c while sitting in line w/ the a/c on. pretty much stayed at 90-93c the whole time. I was also very happy with the brakes.

Went on back to back to back runs and everything went very nicely. I think next time I want to have a little less body roll (rear convertible swaybar) and light wheels w/ RS-3s. These street tires aren't so grippy out here but I learned a lot from sliding around..

Here are a few pics:
























 
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#40 ·
Technically, tires have one "perfect" pressure that produces maximum grip, and any pressure below or above that will generate less grip on that axle. In practice, increasing rear tire pressure WILL increase oversteer....and it has little to nothing to do with the diameter of the tires, lol. You'll never get an e46 on street tires to not understeer, in my experience...and a wimpy OE sway bar is a waste of time. More front camber from camber plates, and/or bigger aftermarket sways like UUC or the like.

I think 40psi all around is probably too much. It's hard to tell from the pics, but it looks like OP isn't scrubbing the tires all the way to the sidewall; there are usually arrows or indicator marks on the tire to aim for.
 
#42 ·
I'm confused then. I have eliminated my understeer by keeping my front tires at the maximum door jamb pressure (32) and the rears in the towards the low/middle side of pressure.

I don't have understeer...mine it pretty neutral right now. When I apply gas lightly through turns, I push out the rear end and definitely notice throttle steering.

You might increase the throttle steering response with higher pressure, but a little more pressure does make the tire diameter greater, and thus the same angle of steering causes more turning.

This is what I've read in many places and have direct experience with...just saying.

Mango, I agree, though, that I bet a lot of time has to do with contact patch and that using door jamb, even at autoX might be better than 40 all around (though that might be closer to your recommended pressures than mine). I'm 29-32 in front and 33-41 in rear (I think).
 
#44 ·
doug i'm going to have to complete disagree with you here. you haven't eliminated your understeer. tire pressure alone will not eliminate understeer. you will need to dial in several other modifications to get your car neutral. it's very hard to do.
also the pressures on the door jambs are NOT recommended for autocross. when you're cornering under extreme conditions your tire gets much more force than under street driving. you cannot drive as hard on the street as you do in autocross. i don't care who you are and where you drive you just can't do it.
in his original pictures you can see the tire tread patch. then you can see slight wear on the outsides of that. that is a sign the tire did not have enough pressure to deal with the force it had on it and needs to be increased. the tire will flatten the more weight you put on it and the sides will start to "roll over"
he should be running at least 40 psi. at my autocross yesterday i ran about 41 all around and still had slight rubbing outside of the tread patch. anywhere outside of that tread patch is considered to have zero grip.
 
#48 ·
I really like that you put your car to the test, mango. It gives me faith to push my further to it's limits, and I kinda' did that today. I know I have repairs to do, but you know us and our constant need for an adrenaline rush. Today, I decided to push the car a bit harder. They're were a couple of bends and curves, and I pulled out of em' with the rear sliding just a tad bit. It felt good! Only because I've never experienced the amazing control the 330 offers when it's pushed hard. Then I saw your post and smiled, haha. I'll be buying front/rear strut bars and front/rear h&r sway bars to improve the handling. I love the way the power train puts it's power down, but I don't think BMW's are street brawlers-in the drag racer sense. I think these cars shine in the track/autocross.
 
#49 ·
good advice, nick, although i know the basics of understeer, oversteer, lift throttle oversteer, weight transfer, etc. i do plan on knocking my pins next time before my next alignment. and yes im positive its my wheel bearings.

i did let my car idle after runs for about a minute. still great tips.

and dmax, afaik, raising front tire pressure relative to the rear will introduce even more understeer. it wasnt that bad.

Sent from my SGH-T989 using Bimmer App
 
#83 · (Edited)
I demand gopro footage of future mango autocross action (MAA).
I agree man. I wanted one bad that day. I would do 5D Mark II footage but need a sturdy mount first :evil:
If you get a mount I have a sony 3D 1080p video cam
:pimpin:

Actually I think I'll make that my next homebuilt project after I finish the seventeen I'm currently working on. :rofl:
 
#69 ·
NAW, BMAparts.com is by far the best and cheapest and highest quality. Do not get from Autozone.
 
#68 ·
May the force be with you. My last one (driver's side front) is coming in today, but not sure the dust caps are. So I will most likely be doing this tomorrow. Wish me luck!

P.S. If you have any issues with the rears, PM me if during normal weekday hours and I'd be glad to help out. Did you get all the HF tools you need? remember what I posted in my wa wa wa thread about the Edz Garage video not really being perfect in terms of removing the rear hub. If I had to do this all over again, I would without a doubt, 100% invest in two new brake dust shields because they get mangled from removing the hub. Hope your E-brake shoes and rear rotors are not that old either because it's an absolute btch dealing with that after replacing the bearings. I need all new springs, shoes and rotors very soon, but I just want the wa wa wa to go away first, then I'll be happy!
 
#71 · (Edited)
Autozone sells front OEM bearings rebadged as Timken. I'll pick them up today and post pictures. I got everything else from BMA. Here's the master parts list you'll need:

Front:

TWO FRONT WHEEL BEARINGS: 31226757024

TWO FRONT HUB NUTS: 31211128336

TWO FRONT INNER DUST COLLARS: 31206777788

TWO FRONT OUTER BEARING DUST CAPS: 31206777789

Rear:

TWO REAR WHEEL BEARINGS 33411090505

TWO REAR AXLE NUTS: 33411133785

TWO REAR LOCK RINGS: 33411138648
 
#75 ·
Autozone sells front OEM bearings rebadged as Timken. I'll pick them up today and post pictures. I got everything else from BMA. Here's the master parts list you'll need:

TWO FRONT WHEEL BEARINGS: 31226757024

TWO REAR WHEEL BEARINGS 33411090505

TWO REAR AXLE NUTS: 33411133785

TWO FRONT HUB NUTS: 31211128336

TWO FRONT INNER DUST COLLARS: 31206777788

TWO FRONT OUTER BEARING DUST CAPS: 31206777789

TWO REAR LOCK RINGS: 33411138648

Not 100% true. Flashtwosix bought them from autozone online and she was shipped Koyo bearings which are apparantly no-name brands. She did this two different ways and got the same thing each time.
 
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