Losing control on a turn - What to do?

[Royalty]

Stupid question, but bear w/ me....

Let's say I am taking a turn a little to fast on a turn and my tires start to lose grip. My car is skidding towards the outside of the turn. What do I do?

The reason I ask is that I've actually heard some conflicting advice here around the forum. I think the reason is that what you do in a FWD car is not the same in a RWD car. So AWD seems to be even more confusing. Here are some things I've heard:

1) You should let off the gas and give slight pressure on the brakes.
2) You should add some gas to gain some grip on the tires.
3) You should downshift.
4) You should NOT downshift because you may break the tires even more.


I found this on another forum and thought this would apply to us as well.

 

[UCSLugRacerX]

Read Carroll Smith Tune to Win. (As well as his other 2 books.) While you're at it, read Race Car Engineering and Mechanics by Paul Valkenburg.

The question you raised is enormously complex.
In general though:

FWD: understeer, front tires will lose traction first, and plow wide
RWD: oversteer, rear tires lose traction first
AWD: depending on center diff, will be more balanced, but with 65R/35F, it will oversteer. A 50/50 will understeer.

There are MANY variables, i.e., staggered tire sizes, heat saturation, tire slip angles, camber, toe, and so on.
The VFAQ page should help. Also, Jtmcinder wrote a very good article about handling characteristics of our DSM's. Hit Search.

That is all I will say.

 

[Defiant]

After over twenty years of only-RWD driving, and a hideous, xenophobic hatred for FWD and all it represents (easier and cheaper construction for manufacturers at the cost of repairs, complexity and tire wear for the consumer, along with downright dangerous handling quirks [don't bother me about it, I'm a bigot]), I found AWD on my 93 astounding.

Then I slightly-overcooked a simple 110°, off-camber city intersection turn, nice greasy paving along with thick crosswalk paint on a hot day.

Well, it was quite enlightening. My over-experienced reflex of giving it more gas and a quick flick to toss the back end around the front did nothing but make both ends slide more. Thankfully, it was only at about 40 mph, and I did have some room before the looming curb was a hazard, and I found that letting off of the throttle made it start to just track the curve.

After a couple of months of getting used to DSM's (proper, 50/50) version of AWD, I had occasion to fiddle with it and the ABS on a nice wide stretch of SR88 some miles outside Jackson on about four inches of snow on a hard-packed base. It took very little time to conclude that you'd have to try really hard to get the car to do anything stupid.... and that once it started to, you may not be able to ever reign it in.

As for "Losing control on a turn - What to do?" well, you should have gone before we left. Now, mop up the seat. And roll down the window, for crying out loud.

 

[Royalty]

damn homie. i was just asking a general question. Ihavent lost control of my vechile. gracious.

 

[99gst_racer]

Let's say I am taking a turn a little to fast on a turn and my tires start to lose grip. My car is skidding towards the outside of the turn. What do I do?

1) You should let off the gas and give slight pressure on the brakes.
2) You should add some gas to gain some grip on the tires.
3) You should downshift.
4) You should NOT downshift because you may break the tires even more.

The best thing that has ever worked for me was #1. Giving more gas will cause you to futher slide to the outside. And you cant always downshift. One thing that make a big difference is your differential. A stock (open) diff will not help in a slide around a corner, but an LSD will tranfer power more efficiently around a corner allowing a quicker regain in handling.

 

[jtmcinder]

There's no one answer because there's more than one way to be sliding.

If you are plowing (understeering), then lift or add some LFB to move some weight forward.

If you are loosing the tail (oversteering) - which on most DSMs means that you already hit the brakes for some reason - then gently add power (or delete braking) to shift weight rearwards.

If you are in a four-wheel drift, don't do anything.

The one constant is to avoid abrupt inputs, especially those with your feet.

- Jtoby

 

[Defiant]

damn homie. i was just asking a general question. Ihavent lost control of my vechile. gracious.

Well, I was just explaining what happened, officer...

 

[leet]

There's no one answer because there's more than one way to be sliding.

If you are plowing (understeering), then lift or add some LFB to move some weight forward.

If you are loosing the tail (oversteering) - which on most DSMs means that you already hit the brakes for some reason - then gently add power (or delete braking) to shift weight rearwards.

If you are in a four-wheel drift, don't do anything.

The one constant is to avoid abrupt inputs, especially those with your feet.

- Jtoby

This is what I do as well. Has saved me a couple of times.

 

[bigfoot]

Scream real high like a little girl. Relieving your bladder works good too.

 

[Thomas91169]

let off the gas. and play gran turismo more.

 

[RipperXX]

There's no one answer because there's more than one way to be sliding.

If you are plowing (understeering), then lift or add some LFB to move some weight forward.

If you are loosing the tail (oversteering) - which on most DSMs means that you already hit the brakes for some reason - then gently add power (or delete braking) to shift weight rearwards.

If you are in a four-wheel drift, don't do anything.

The one constant is to avoid abrupt inputs, especially those with your feet.

- Jtoby

I did something very VERY stupid one night, this was back when I plum hated AWD because i couldn't get it to oversteer except on rare instance's that were extreamly hard to duplicate.

So I though hmm awd, already tried slideing around turns downhill, maybe uphill will work better since it will have more grip Theres a road not far from me that's pretty steap and has long but sharp turns.


Sooo 75mph into the sharpest one I yank on the ol e-break, next thing I know the whole car is slideing completely side ways twords a really big tree. I downshifted out of 5th (duno wtf I was thinking being in 5th anyway) down into 4th and mashed on the gas, the car oversteered very slightly but was pulling out of it. Pulled out and had some horrid snap back. almost lost it again, kept it stedy though, when I got to the top of the hill/moutan, which was one turn away I just thought to myself "I am NOT doing that again anytime soon"

however I still fly up this road from time to time, I encounter some understeer sometimes but seems like as long as I mash the gas more, and turn in a little I dont lose my line, but it's still understeering just I guess you could say controled?

 

[sonicnofadz]

Like what was said above, a 50/50 awd differential split will most likely have the car understeering like fwd (although traction through the turn with awd will be greater because fwd is definitely inferior). This means the front of the car will start to slip towards the outer edge of the turn. This is how most awd dsms behave during corners, unless you have restributed more weight to the rear end, in which case the car might have some slight oversteer to it. With understeer you LET of the gas to regain traction. Hitting the gas will only make things worse, unless you slam on the brakes and hit the gas simultaneously to try to pull the rear out, but that is a very risky move. Wish I had awd argh! Still saving up for my 2g awd (transplanting my six bolt from my gst)

 

[nutshot]

Scream real high like a little girl. Relieving your bladder works good too.

I want to ride with you!

I try to load the front suspension when it understeers by lifting the throttle, then when I feel the tail lightening up, I apply lots'o' throttle.

Squealing seems to help too. :laugh:

 

[HokieDSM]

Weight distribution is the key to figuring out how to handle a given turn. The question you want to ask - is, where can I put the weight of the car to give me the most grip to go where I want to go? It seems like a complicated question, and it probably should. In the end though, finding the answer is more something you need to figure out by the way the car "feels".

Entering a supremely tight turn, hitting the brakes hard seems the way to enter the turn - but this will shift weight to the front wheels, which will give you grip - to a point. Overload them, and you'll find that you're pushing the front wheels out of grip, and you have understeer. So, if you feel the weight shifting too far forward, ease off the brake, and add gas - this will give more equal distribution, and you'll be able to steer around the turn.

The basic rules for keeping decent control are (or should be) taught in every drivers ed class- the big one being, not to brake when you're turning - this is always a good policy for beginners - but people do it anyway, and it always seem that they're ill equipped to deal with the result. AWD cars like ours have the advantage that you can use the brake and throttle while in a turn, but we still can't be stupid about how we do it. Too much brake, we either overload the front wheels and push out, or we lose so much grip that the rears become light and slip out from behind us. (Depends on your suspension setup really)

 

[ldstang50]

damn cinder, i did a quick browse in here to see if anyone mentioned left foot braking, applications for understeer and oversteer. but you said everything i wanted to say.
To get the front end to bite more in a turn you have to load the tires somehow, and like you said, left foot braking. As with rear tire bite, apply a little more gas to have the weight trasfer to the rear.

 

[x camaro owner]

its called trail brakeing and if you need to use that on the street most likely you are screwed anyways

 

[jtmcinder]

Trail braking is a question of when.

Left-foot braking is a question of how.

They are rather different.

Sometimes I trail brake with my left foot (as in when the turn does not require a down-shift) and sometimes I trail brake with my right (when it does).

Sometimes I am LFBing at corner entry and sometimes I am LFBing while going straight.

Separate issues. Try to avoid confusing them.

- Jtoby