Hi

Finally tried the autox thing and liked it a lot. The car oversteered like crazy everywhere on the track. Braking or on the gas, the rear end was always trying to get away from me.

Any ideas on reducing this problem? Thanks.

 

remove two spark plugs, that should reduce over steering

 

What (if any) suspension work have you done to the car?

 

yep, whats the suspension setup on that car?

you may have too stiff a shock on the back, or wrong sway bars

increase front bar size and/or decrease your rear sway bar size

 

List your set-up. It's hard to diagnose a problem without ever meeting the patient....lol.

 

I just thought there might be some general rules of thumb I could consider, but I'll be glad to get specific.

Polyurethane bushings everywhere and eibach springs. Monroe replacement shocks (i know, i know), tubular LCAs with poly in both ends (the 3 piece type bushings), and relocation brackets. Tubular panhard bar, for what thats worth, and SFCs welded in. Its got a factory wonderbar. Michelin PS2s up front and Eagle F-1 GSs out back. The tire combo is great fun goofing around on the street once in a while, but the Eagles might be a little hard for autox.

I think my rear roll couple might be a little tight because when it wasn't oversteering, I'd spin the inside tire coming out of corners and rear has a good posi in it.

I was running 45psi in the front tires and 36-37 in the back. If I'd have been thinking, I would have reduced the rear pressure a bit to effectivley reduce the rear couple, but it just didn't occur to me.

Next time out, I'm thinking about putting more gas in the car to increase downforce out back and starting with 30psi in the back tires. If that doesn't work, I'll probably change out the rear sway bar bushings and put rubber back in to see if that helps. If it does, I'll put the poly back and get a stiffer front bar or springs.

However, I'm really hesitant to buy bars and stuff until I change the dampers out. I might be able to adjust the oversteer out of it with yellow Konis. I dunno.

Looks like Konis and LS1 front brakes will be my spring project.

Anyway, what do you guys think?

 

yeah the mismatch in tire could possible have something to do with it. But mainly i'm thinking the monroe shocks are not helping. Get some good adjustables

 

Poly bushings in the lca's is contributingh to your problem. They bind and then snap loose causing oversteer. I don't see your swaybar size listed, that is important info to discuss.

Tires are the single biggest improvement you can make for autocross followed by shocks.

 

I've got the LCAs with the sperical poly bushings. I don't think they are capable of binding like you hear about. And the car never felt like it either. Breakaway was always smooth and predictable, just excessive. I think I need yellow shocks. Is that my wallet whimpering? My swaybars are the big oem ones. 36 and 24 or whatever they are.

 

The large rear bar is part of the problem. Try running a 19mm bar. That switch made a big difference for me.

 

[quote=redliterunner;3686134]

Next time out, I'm thinking about putting more gas in the car to increase downforce out back and starting with 30psi in the back tires. If that doesn't quote]

More weight (full tank) would hurt the handling more. Yes it would supply downforce which would only help in straight-line braking, but around a turn that momentum would work against you.

 

No such animal. You either have the poly bushings or spherical rod ends (aka - heim joints).

The rod ends will free up the axle and give it more movement. The poly bushings will cause the axle to bind and hurt handling.

You're on the right track with the new shocks. Adjustable shocks will let you dial the car in a little more. I'd also reduce the tire pressures some. And yes, Goodyear tends to make hard compound tires.

 

The LCAs he's talking about are offered by J&M and are fairly new. They are supposed to be good.
I'd say get some KONIs in the car, play with the air pressure (maybe a little less in the front), and drop to a smaller rear bar (21 might be what you need). You might want to put the Michelins in the rear...lol.
My car oversteers under throttle, but it's fairly nuetral when just hanging a turn. I have a 25.4 chromoly rear bar. I think the KONIs are why I don't have tons of oversteer when just turning.

 

Which eibach springs do you have? If you have the sportlines, it is very possible that you are hitting the bumpstop and causing snap oversteer. You may also want to look at how you LCA's are mounting, if the axle side is lower than the body side, that will cause roll-oversteer.

Without driving your car, its hard to know where to look. Is the oversteer on corner-enter? mid-corner? corner-exit? Are you trail braking, do you find you have to give a little less steering lock after you get the initial turn-in, causing you to saw the wheel mid turn? Is it progressive oversteer that you can feel coming on, or is it a snap oversteer condition?

Oversteer is a very generic term, that doesn't tell us much about what could be happening. Things you might do to cure snap oversteer coming out a corner, might be very diffrent than what you would do if the car wants to oversteer while trailbraking into a corner.

--John

 

tires helped me out a lot. 265/55/16 Kumho V710's are what I run now.
My street tires (Kumho 712 front, Nitto 555 rear) that I sometimes auto-x with cause me to understeer when turning hard which requires me to steer with the gas pedal.

I ran street tires at this past event since I thought the course would be wet from all the rain, and it still looked like it was going to rain some more.
I test fitted some 315/35/17 Sumitomos on the front of my car and they fit, so I ran with them up front and my Nitto 555's on the back.
With that setup I would oversteer since the 315's actually gripped.

I was kinda bummed since the course was totally dry and we only had a really light sprinkle, maybe 10 seconds. The V710's would have been perfect.

I would look around for a used set of race tires to try out, should be much much cheaper than buying new. I picked up my 8 V710's from a friend for $175 and borrowed a set of 16" 4th gen wheels from another friend.

 

The Pro kit

Thats what I'm thinking...better balance between the front and rear roll rates. I could get softer in the rear or get stiffer up front, either way. With the yellow shocks, I could dial in some extra stiffness up front, I guess. (never actually tried it) Then I could keep the larger bar in back. I'll probably try that first since I'm gonna get the yellows anyway.

Maybe so. It's just an experiment. Weight is bad no doubt, but more relative load on my rear suspension might, I said MIGHT, reduce the oversteer condition.

The rear tries to slide out during braking and turn in, at the apex and when powering out. I'm basically drifting through the turns. The rear gives way gently and predictably. I've dealt with a snap oversteer condition before, its not like that. It's actually fun, just not too fast a way to get through a course.

No doubt. I'll work on getting the handling of this camaro close to neutral this season, and get some experience, then go to a tire class next season.

Yep that's them. No indications of binding at all and they certainly had plenty of opportunity to do so.

Zepher, what class do they put you in? I ran Novice, but the car was F-stock, even though its not stock. I ran faster than any of the cars running in F-street prepared, so I'm gonna try to get into that class for the next event. Had one guy tell me I might have to run in G-stock though. Beats me. I haven't learned the autox vernacular yet.

 

If I were you, I'd get the KONIs and go from there. I have a larger rear bar than you, the same front, and the same springs. The only time I have issues with oversteer is when I'm throttling through the turns. If I just coast thru the turn, I have no problems. But that's not a very fast way to get through the course.

 

I think you're right. They'll have to wait until my wife cools off a bit, though. I drug home another old dirt bike Friday night and she's locked down my wallet for a while.

 

I am in ESP when I run the race rubber.
Actually, now that I think about it, I could probably run FSP since my race tires are 16x8, which are my stock wheel size. I was running 17x9.5 with race rubber so that is why I chose ESP, since I was running larger wheels.