Correcting Understeering Problem

[scole]

Hey guys..

I've been doing some autocross lately, and I've noticed that when pushing my car really hard it tends to understeer pretty bad. It's got the stock 25mm sway bar up front, and i think 15mm in the rear. It's got KYB AGX's with rsr race springs; the rates are 5kg/4.5kg front/rear.

What are you guys running as far as alignment goes? I have about 2° camber up front and 0 toe, and about 1° camber and 0 toe in the back. Would some toe out in the front help against understeer? What about sway bars?

[Onizuka]

I run even more camber than that up front for autocross, like 3 degrees negative(I use camber plates with marks so I can set it back for street use). I tried putting some toe out on the front wheels for a couple of sessions and didn't notice much difference. You might want to try playing with tire pressures. Have you been to a test and tune day before? I highly recommend it if your region offers it.

Honestly it just sounds like your coming into corners too hot (sorry if I'm wrong in assuming your relatively new to autocross). Try getting your braking done earlier so you dont overload your front tires mid-turn. Better to adapt your driving style I say, then you don't have to spend your hard earned cash on suspension equipment that probably wont alleviate any traction woes anyway. And you get to improve as a driver to boot.

[jsilva]

The car seems fine... should be fairly balanced. What kind of car are we talking about by the way? What tire pressures are your running? Its good to play around with that aswell. A firm pressure up front to keep your tire from rolling onto the sidewall. In the rear, you usually want to run a bit lower, to gain traction out of the turn. Lower pressures in the rear will gain bite, higher will allow you to rotate better. Basically, just play around till you find something that works well for your style.

Like the previous post... slow in, fast out is the key! you'll loose far less time that way as opposed to pushing thru the turn and plowing cones.

[onosqv]

Fix the driver, then fix the car.

Have a veteran run your car a couple laps, then you'll see what I'm talking about.

A lil toe out in front & toe in in rear will help (depending on driving style)... but if you are driving the way it seems you are currently driving, you will still be pushing everywhere.

[scole]

I guess ill definitely try coming into corners slower then i am now before i change anything on my car.

I should say that i am not a complete n00b, but i am pretty new to autocross. I feel like i'm improving every time i run, so i'm sure ill figure it out with more run time.

[onosqv]

dont' worry about it. we're all noobs. I still go too hot into a lot of corners, that's why I know what your problem is... knowing is half the battle.

[nissanman04]

The setup sounds pretty good. I agree with more seat time, that's what makes the biggest difference. Another thing that improved my times a lot is that you can usually start braking a bit later than you would think.

You coming to Xerox on the 26th? I'll be in the honda.

[scole]

Yeah, i think im gonna go out there. Cya there.

[Type X(J)]

you probably are going a bit hot in the turn. look ahead and anticipate the next turn. brake early and throttle steer accordingly. try softening the rear suspension a little more and feel the cars' weight move from front to back, side to side.

[Bubba1]

Hey guys..

I've been doing some autocross lately, and I've noticed that when pushing my car really hard it tends to understeer pretty bad. It's got the stock 25mm sway bar up front, and i think 15mm in the rear. It's got KYB AGX's with rsr race springs; the rates are 5kg/4.5kg front/rear.

What are you guys running as far as alignment goes? I have about 2° camber up front and 0 toe, and about 1° camber and 0 toe in the back. Would some toe out in the front help against understeer? What about sway bars?

240sx is a naturally understeering car, so you have to adjust your driving style (plus the line you drive) to compensate. I firmly believe in working with the hand that your dealt, and improving your line/inputs is by far the biggest improvement you can do to minimize understeer. Before dropping a bunch of money on suspension upgrades, you might try dropping a couple psi out of your rear tires. That might help.

[nismoautoxr]

This may not work for everyone.I personally (with my car at -3.0 camber front/ -2.0 camber in rear and 0 toe front and rear)have found that the less air pressure in the rear I run, the more the car rotates and the less it understeers so I just adjust tires to get what I want .I run Toyo RA1 tires with a 100 treadwear so your tire choice may be optimal with differant pressures than mine ..I run 38psi front and start there with the rear and let em down till I get what I want .I drive the car fast and hard and adjust to that .Late turn in seems to help it also for my car and then I just ride the oversteer.Ill take oversteer anyday over understeer.

[Free Motion Tail]

4 words-bigger rear sway bar.

[a_ahmed]

what i did as i can not afford swaybars or better springs+shocks at the moment plus i plan to park the car for winter is run lower tire pressures in rear and higher in front... its a patch fix but alas.

I am running 3/4 front and 7/8 rear on the agx with stech springs... it does not understeer.. as it used to... almost every other setting understeered...

I want new swaybars.. and coilovers, but before i go that route the car will sleep for the winer (very soon )... I'm in canada ey lol..

Oh yeah installing rear strut bar helped me get rid of understeer too is what i noticed.. but once i installed front strutbar and nismo power brace i introduced understeer again (although the car did have better turn in and was much more tight in feel).

i have all whiteline bushings... except that the subframe inserts SNAPPED (gay), but its too much work for the time being to get spl solid aluminum ones....

i have spl pro outer + z32 inner tie rods and tc rod are on the way, wont get rid of understeer but im sure itll improve feel and turn in... and well i kind of want to get that c pillar bar to tighten rear some more... i will see what that does, hopefully itll have an effect on eliminating understeer as the strut bar did (i could notice a big difference).

My next purchase is a custom coilover setup and sways... that wont happen until next spring/summer...

Overall though what i have now is a descent setup... needs more grip and less understeer, and i want more response/turn in...

Unfortunately I won't be able to run more autox as the season is pretty much over... it will probably start snowing here anyways haha... I miss the summer already

[scole]

I like the way my car feels now, its real tight and pretty responsive. It still does understeer if you come in a corner too hot, but i think ive figured out how fast i can go and not understeer. I just wish i had some more power for accelerating out of corners. I think before i was coming into corners too fast to conserve as much speed as possible because i cant really accelerate out of them.