Suspension Tuning: Avoiding Snap Oversteer?

[Rook]

Example: A Mustang oversteers way more than you want it to while coming into a turn, you correct and instead of stabilizing, it snaps into another bout of oversteer in the opposite direction, and continues to do so back and forth until you spin out.

 

Besides the obvious solution of becoming better at oversteer recovery, is there an element of suspension tuning or weight transfer that makes all this less likely to happen?

[Renntag]

I cant answer your question with any authority. What I can tell you is that any vehicle can be modified to do something better. Drag cars dont turn, road cars arent perfect for the drag strip, and so on.

 

As far as the condition you mention. I would ask you how many years have to been tracking a stick axle car or any for that matter? I drive a highly modified mustang, a tired stock one, and a brand new one. They all respond similarly and none of them display the condition you mention.

 

On the track, I WANT my car to oversteer. I make inputs necessary to achieve this.

 

Please share more specific info if you can.

[Driver]

Besides the obvious solution of becoming better at oversteer recovery, is there an element of suspension tuning or weight transfer that makes all this less likely to happen?

The only answer is to find some way to change the laws of physics, because snap oversteer is a driver thing....unless you have a Porsche, then it's standard equipment.

 

When your cars arse slips out, do you lift totally off the gas?

[Rook]

To answer both of your questions A) I've unfortunately never had the time to make it to the track. B) No I don't lift, I either feather on a bit more or hold where it's at to keep weight back.

 

I'm sure it was my own fault, but I was just curious as to if/how a car could be tuned to make that less likely.

[Renntag]

There is no cookie cutter answer as to how to avoid snap oversteer for every situation.

 

I like it when the back of my car is slipping. I dont want a big slide, but I want the car to slip enough that I can get to full throttle as soon as possible.

 

As to dealing with snap oversteer, I can say that 99% of the students I have helped used WAY WAY to much steering for most every need for wheel input. That being said it seems reasonable to assume that your problem can most likely be traced to steering input as it seems that you are conscious of throttle usage. The other major problem is your eyes. Where are you looking when you are having this problem.? You need to look as far ahead as possible.

 

I challenge students to try, on a daily basis, to use as little steering as possible. You will be amazed at what the car will do with less steering.

Try to focus on weight balancing. Once you initiate a right turn, try to keep the car consistently weighted on the left and then smoothly move the weight back to the middle.

 

I hope that makes sense and perhaps helps too.

 

Come out to the track. You'll love it for sure.

[Rook]

Yes, I have the feeling that the car did exactly what I told it to do...unfortunately I didn't know what language I was speaking. I really wish I could make a track day. Maybe I'll get lucky in the coming year.

[Renntag]

LOL.....yeah we all have to speak the same language for sure.

 

If I told my mother that I might come visit if I was lucky, she wouldn't expect me.

If I told her that I made plans to visit on a specific date and that all bases were covered, she would be prepared for my arrival.

 

Set a date. Make it happen.

[jimgood]

I was having a similiar problem in my FFR Roadster. It turned out to be me subconsciously snapping off the throttle the second I felt a hint of oversteer. That would generate a glorious tank slapper and send me off the track.

 

The example you gave was "coming into a turn". Does that literally mean when you're entering a turn, i.e. you are still braking, perhaps trailbraking?

 

If you enter a corner while braking and the car is understeering (i.e. plowing), coming off the brakes too quickly can cause snap oversteer. The reason is that you were maxing out the front tires by braking and turning at the same time. Snapping off the brake removes some of the work load and they suddenly bite and turn in. But it happens before there is significant weight transfer to the rear so the rear steps out.

 

Then the tank slapping begins and there's screaming and running...

[Rook]

I can tell you exactly what happened. I was just lifting off the throttle coming into a turn as I'd never been through that turn before. I was doing about 50 mph. Add the following factors: Car had sat for a week while I was in the field, rear tires were old and the compound was hard, and it was cold outside.

 

Like I said, the car did exactly what I told it to. Unfortunately, as I was correcting, I overcorrected....like 3 or 4 times. Sent me into a guardrail twice.

 

Check it out http://forums.sandhillsmustangs.com/showthread.php?t=134

 

Fortunately, noone was hurt, and I didn't hit anyone. I just can't help examining it from a performance driving standpoint. I always try to learn from a mistake like that.

 

...what a ride though, heh Fortunately, the beer I was taking to the cookout I was headed to, in the back seat, also survived (good thing something told me not to put it in the trunk!). It didn't survive the night though, I can tell you that. The cop asked if I was drinking, my response..."Not yet!"

[jimgood]

Ah, ouch, got it. Well, once the tank slapping begins it's all over but the shouting (and screaming and running). If you're late with the first correction...ppphhhhttt! It just gets harder and harder to catch up.

 

Sorry about your car.

[Rook]

It's just a car, brother. Even if it was two deployments worth of spending, they can be replaced. People can't, ya know? All in all, it ended well.

[Driver]

Wow, is it a total?....I want your front brake rotors...I'm serious. I can give you some rusted ones to toss on so that the insurance company doesn't notice.

 

I did think of something that may lead to braking oversteer: A screwy proportioning valve. I'm not sure what the cobra uses for OE proportioning, letting the car sit may do something negative. Having a short car with gobs of torque didn't help, either. Manual tranny?

I also saw mention of "all that suspension work". As you tighten a car, it becomes less forgiving. The better it grips, the more violently it will loose it.

[Rook]

Heh, that's actually a V-6 with a wishlist of handling mods and some 04 Cobra stuff, including the IRS. It was a rolling Maximum Motorsports catalog. Wasn't making bad power either.

 

It's funny you mention the proportioning valve, that car did tend to pull to either side under braking.

[Driver]

Ahh ya caught me.

[Rook]

Nah, lots of people used to mistake it for a Cobra...until they tried to corner with it. Man, that thing was so balanced. 350/650 Front/Rear spring rates on the coil-overs for oversteer. It was awesome...till it bit me when the tires weren't ready for it.

 

Gonna buy a 95 GT now...figure I'll put a 351 up front but...man I miss the balance of that sixer.

[Renntag]

You would definitely benefit from performance driving type training.

I try to make my car do these things on the street in the dry and LOVE it in the wet. Its tough since there arent many opportunities to slide the car on the street where its safe. Often there is traffic or parked cars or other hazards. Every once in a while there is a safe spot to play. Once there is snow on the ground....forget about it....its fun time.

 

It just sounds like you made a wrong choice and a bad recovery. Like you said fortunately no one was hurt. There are lots of cars out there to replace a bent one. People are a different story.

 

Best of luck with the next car. Hope to see you at VIR or CMP next year. You are in NC right?

[Rook]

Indeed I am! I'd love to make it to an HPDE next time they roll around. Here's hoping I'm stateside when they do. I'm also hoping I can do something to get the suspension and balance of a 95 GT to hold a candle to what I had that '00 v6 at. I really wish I was better at oversteer recovery.

[Driver]

Indeed I am! I'd love to make it to an HPDE next time they roll around. Here's hoping I'm stateside when they do. I'm also hoping I can do something to get the suspension and balance of a 95 GT to hold a candle to what I had that '00 v6 at. I really wish I was better at oversteer recovery.

Where are you stationed? Track days happen almost everywhere.

[Rook]

Fort Bragg, NC

[Driver]

I worded it wrong, doh! I meant where are you being deployed to?

[Sterling Doc]

I can tell you exactly what happened. I was just lifting off the throttle coming into a turn as I'd never been through that turn before. I was doing about 50 mph. Add the following factors: Car had sat for a week while I was in the field, rear tires were old and the compound was hard, and it was cold outside.

 

Like I said, the car did exactly what I told it to. Unfortunately, as I was correcting, I overcorrected....like 3 or 4 times. Sent me into a guardrail twice.

 

Check it out http://forums.sandhillsmustangs.com/showthread.php?t=134

 

Fortunately, noone was hurt, and I didn't hit anyone. I just can't help examining it from a performance driving standpoint. I always try to learn from a mistake like that.

 

...what a ride though, heh Fortunately, the beer I was taking to the cookout I was headed to, in the back seat, also survived (good thing something told me not to put it in the trunk!). It didn't survive the night though, I can tell you that. The cop asked if I was drinking, my response..."Not yet!"

 

Overcorrecting usually means late correcting. As Renntag mentioned, it's universal tendancy to saw at the wheel, and get off the gas. While you don't want the rears spinning, you do want to keep weight on the rears, and countersteer early - decisively , but still smooth. This is a skill best learned in a controlled environment without nearby gaurdrails.

 

Good luck with the yellow '95GT your looking at! Make sure you respect it's extra torque in the corners!

[Driver]

This is a skill best learned in a controlled environment without nearby gaurdrails.

Caution: If you practice sliding your car, you will begin to enjoy it.

[Rook]

This is a skill best learned in a controlled environment without nearby gaurdrails.

Caution: If you practice sliding your car, you will begin to enjoy it.

 

Man, tell me about it. I wish I could learn how to "drift" properly. If for no other reason, than to feel more comfortable in a slide. I wish I could find a 1 square mile parking lot with no poles or people in the way to just...screw around on until I got it.

[Driver]

This is a skill best learned in a controlled environment without nearby gaurdrails.

Caution: If you practice sliding your car, you will begin to enjoy it.

 

Man, tell me about it. I wish I could learn how to "drift" properly. If for no other reason, than to feel more comfortable in a slide. I wish I could find a 1 square mile parking lot with no poles or people in the way to just...screw around on until I got it.

Dude, one word:

Rallycross

It's one word!

 

You want to learn this at lower speeds, come north and play in the snow. 40-50mph in a parking lot isn't the place to get it wrong. I actually learned how to do it at Beaverun during my first HPDE (alsot the first HPDE held there). "Learned how" means "I was equipped with the knowlege to...", my instructor was showing me how to "rotate" my big car to make sharper turns at speed. From that I learned how to use the brakes to pitch the car into a slide and control it with throttle and brake.

[Renntag]

.... I wish I could learn how to "drift" properly. If for no other reason, than to feel more comfortable in a slide. ...

 

I am putting together one day classes at 495$ each that focus on these type of car control skills. This is Arrive And Drive. You need nothing. Helmets are provided as are fully caged vehicles with an instructor. Next class will be this month. Contact me for details and to sign up. This is held at Summit Point 15 minutes east of I81 at Winchester, Va.

 

at the end of this video you can see the "rallycross" courses that are used for this class.