Autocross help

[JesseW.]

I ran my first autocross event this weekend and my car has massive oversteer on and off throttle. for right now the car has eibach pro springs, stock shocks, -2.5 degrees camber in the front wheels running nitto 555's 255/45front 285/40rear, and stock sway bars. the back end was stepping out on almost all the corners and looking like a drift car. i spun once going through a slalom just as i barely pressed the throttle.

what can i do to to make this better for the next event without killing my wallet? i want to buy some tokico d-spec struts and shocks, but dont have the money for it right now. i'm thinking lca relocators might help as the diff end of the lca are higher than the body mount end and reversing/evening this might give me more rear traction. i played around with tire pressure and anything lower than 36 psi or higher than 40psi in the rear made it slide worse.

 

[Vapour Trails]

Given that it was your first time, I'd say that your driving was the cause of your oversteer problems. There is nothing about your setup that would make your car especially tail happy, except misapplied throttle/brake/steering or simply asking too much of your tires. You are likely upsetting the car with your inputs, the key is being smooth.

Go out an get some more experience under your belt before you make any changes. Levelling your LCAs is generally not a concern for auto X or track performance. Upgrading struts/shocks is a very good idea with aftermarket lowering springs, but at this point that is not a limiting factor.

I recall my first few autox events - it wasn't pretty. All the "problems" I later discovered were the result of bad driving, not a bad car.

 

[Sam Strano]

LCA brackets won't help. Your rear air pressure is too high. And no offense, but folks usually drive directly cone to cone in slaloms making very abrupt turns at each. If you do that, and slap the throttle on a car with high rear pressures and not very sticky tires and good power you will go for a ride.

Better dampers will help as they change how the car generates roll speed and changes direction. But in all honesty you just need seat time. Parts help, and make for a better driving car on or off the autox course. But the car still has to be driven, and autox is probably the hardest thing to do, it's a very learned thing. Things come at you so quickly, you have an abundance of torque, the course is not as apparent as a race track with it's asphalt then grass (and fewer turns over say 2 miles).

 

[JesseW.]

ok, that makes me feel better, i'll put the money from lca relocators and get koni's instead when i can afford them!!

i'm sure i need more seat time being my first event, i came in telling everyone i was new and was gonna be the slowest guy out there(i wasn't, but i wasnt near being fast either). the rear sliding around off throttle confused me as i thought i would be having a lot of understeer.

sam- do you have a tire pressure range you would recommend, or i'm guessing its mostly trial and error?

 

[Sam Strano]

Tire pressures are really hard to pin down.. So much involved and the driving style too. Too little or too much air will make things bad. Within a range, generally more air makes the tire slide more, less makes it's a little slower to respond and more likely to get beaten up on the shoulders (mostly by newbie drivers--no offense).

I can give you a best guess. That would be 36-42 front, 28-35 rear based on your size tires (but not knowing the rim size). And that could change with different brand/construction tires too. That's a good a guess I can make given what I have read and not being able to see your setup and how the tires fit the wheels and how you drive. Generally a 5 psi split front to rear (high in the front) is about right but again that can vary. I've run as much as 12 psi split and on certain days in certain cars run with higher *rear* pressures (that's not normal of something I'd recommend to you at this point).

 

[Cone Sweeper]

^^^^ Thats good information there Sam for Tires..

 

[Vapour Trails]

For reference, I use 37 psi front and 33 psi rear most of the time (275/40/17 V710s)

 

[JesseW.]

ok, sounds like i was in the ball park on the last run 36f-32r. it felt a lot looser than 40 all around though, but then again i ran 2 seconds faster... the place where we run is almost all concrete except one small asphalt patch and a lot of people (me included) kept losing it on the asphalt.

they run once a month so i want to do one upgrade a month to the car. hopefully shocks for november, sway bars for december, then run that way for a while and finally get a set of wheels and r-compound tires.

 

[Corpo]

Be careful with the r-comps, if you still don't have driving down by then. They tend to have great traction, but once they break loose they really break loose. However, i have seen the s197 perform very well in stock trim with just a set of r-comps. The guy was 2seconds faster then my modded stang. My tire setup is crap though. Just goes to show how good driving can take you alot further then mods

 

[Sleeper_08]

Be careful with the r-comps, if you still don't have driving down by then. They tend to have great traction, but once they break loose they really break loose. However, i have seen the s197 perform very well in stock trim with just a set of r-comps. The guy was 2 seconds faster then my modded stang. My tire setup is crap though. Just goes to show how good driving can take you a lot further then mods

This is good advise but there are differences between R-comps. In my case I ran street high performance BFG KDW2 for two seasons of lapping track days as I was a newbie and the advice from most people is to learn first on street tires before going to R-comps. For my third season, this one, I moved to Nitto NT01s. These are not as fast as Hoosier R6 or A6s but I chose the Nittos for 2 reasons;
1) they last longer than the Hoosier's and so I can afford them
2) they give more warning before they let go

I'm still learning to push the R-comps to the absolute limit but as you can hear from this video they do squeal when you are getting close and my data logger says they are pulling .95 to 1 G on a lot of these corners

http://www.youtube.com/user/frederickmith#p/a/u/0/rhyOKkh6B0c

This was the 8th track day for these tires and they still have about 1/3 of the tread left.

The biggest benefit I immediately found from the Nittos was being able to get on the power sooner and faster when coming out of the corners and with my SC this is important.

 

[Ken04]

I've seen alot of people using the chalk trick for tire pressure. Draw a line from the tread down an inch or so onto the sidewall. Increase tire pressure until it stops scrubbing the chalk line off the corners of the tread. Worked for me.

ok, sounds like i was in the ball park on the last run 36f-32r. it felt a lot looser than 40 all around though, but then again i ran 2 seconds faster... the place where we run is almost all concrete except one small asphalt patch and a lot of people (me included) kept losing it on the asphalt.

they run once a month so i want to do one upgrade a month to the car. hopefully shocks for november, sway bars for december, then run that way for a while and finally get a set of wheels and r-compound tires.

 

[jayel579]

For reference, I use 37 psi front and 33 psi rear most of the time (275/40/17 V710s)

Really you run them that high? I ran mine at 31 psi coming back into the paddock

 

[Sam Strano]

I've seen alot of people using the chalk trick for tire pressure. Draw a line from the tread down an inch or so onto the sidewall. Increase tire pressure until it stops scrubbing the chalk line off the corners of the tread. Worked for me.

Don't bother. Doesn't work with the sidewall stiffness of most tires now, and the more performance oriented the less that gimmick tells you anything. It might work on some econobox tire, like $50 Kumho's you see on a Hyundai Accent, but that's about it. Left over remnant of crappy tire days gone by. You will learn as much by looking at, and feeling the tires with you hand.

 

[RedMosesSC]

I had a lot of understeer my first few runs out as well, no need to change your set up as you will have to re-learn the cars manners again, seat time will make you better and you learn how to drive YOUR car in THIS config.

One thing that helped me is NOT braking while turning into the gate, make sure you do you braking before the turn allowing your car to get back to balance before the gate.

 

[JesseW.]

i went out for my second autox day yesterday and did MUCH better. the course was a lot easier to memorize and i think that had a little to do with it and i ended up being faster than many of the people who beat me last time.

I figured out the car does indeed understeer as i got better and picked up my pace. I haven't had the funds to do any suspension upgrades yet so i am still running eibach pro's with stock everything else, and nitto 555's in 255/45-18 and 285/40-18. the last three runs i was a lot calmer and things started coming together as i started braking before the turns instead of in them and that helped with understeer a lot .i was being a lot lighter on the throttle but staying on it longer. I seemed to be getting into the ABS a lot...

I rode with a guy in an ST prepped S2000 that set the fastest time of the day and it helped me out with my lines a lot. ended up 6.9 seconds slower than ftd on a 61 second course. last month i was 13 seconds out on a 82 second course. I also finished second out of 6 in the Street Mod class to a heavily modded awd VW GTI(all parts from an R32!!) that was .9 seconds faster.

I have a feeling i'm gonna send a lot of money to Sam in the next couple of months...

 

[Sam Strano]

Well, I'm here to sell parts.... but I think you'll end up sending me less in the long run then you'd send to other shops that don't really have any idea about autocrossing or suspension in general.

In fact it's not unheard of for me to back people down from their initial lists!

I think you'll be happy with my work, and I know I'd love to have your business--and think that aside from competitive pricing, you'll get a good education too.