AutoX terrible understeer

e30gentry

Private
May 24, 2019
45
23
0
Ride
2008 135i 2008 CLS63 AMG 335D
Attended my first SCCA autocross event with the 135
While setting relatively good times there was terrible understeer on sharp corner entry.
2008 135i auto MHD XHP3 PSP goodies
Sport Alignment settings
Stock wheels and brakes
Steering and suspension is in well working order
225F 255F Firestone Firehawks.

I started my run at 38PSI square
Reset to 40F and 38R
This is where my fastest and consistent times were but I feel there is still a second or so with the terrible understeer.

Any suggestions on alignment or tire pressures for those autoXer's out there.
 

chris_flies

New Member
Nov 1, 2019
5
3
0
Woodbridge, VA, USA
Ride
2009 BMW 128i
Try disconnecting or removing the front sway bar. It's at least worth a shot; takes 10 minutes to do, and another 10 to undo. I did it in my 128i, and it CLEARLY doesn't have any understeer, unless I drive like an idiot...
 
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e30gentry

Private
May 24, 2019
45
23
0
Ride
2008 135i 2008 CLS63 AMG 335D
Try disconnecting or removing the front sway bar. It's at least worth a shot; takes 10 minutes to do, and another 10 to undo. I did it in my 128i, and it CLEARLY doesn't have any understeer, unless I drive like an idiot...
I'll give that a shot tomorrow. I'll go through the garage and look for my ground down thin wrenches tonight.
 
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chris_flies

New Member
Nov 1, 2019
5
3
0
Woodbridge, VA, USA
Ride
2009 BMW 128i
I'll give that a shot tomorrow. I'll go through the garage and look for my ground down thin wrenches tonight.

Also, keep in mind that the 1-series is infamous for its built-in understeer characteristic. I'd also try to dial out a lot of camber in the rear. My car is wonderfully neutral, sitting at -2.3 degrees of camber up front, and -0.5 in the rear. You won't be able to get that front number without camber plates, but you can get the rear setting.
 
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Bnks334

Lieutenant
Dec 1, 2016
524
340
0
New York
Good suggestions so far. Removing a front endlink is a quick and cheap way to make a big suspension change. You can even do it in-between heats.

Are you trying to stay in street class? That will help steer further suggestions...