WardL,

Oh my! :eek::eek::eek:

My very first TTO resulted in a flip. Car nearly totaled, left arm ditto.

Guess exactly what tires were in the rear of the car?
Be very afraid! Unless Michelin has totally revised those tires, they have a very sudden breakaway. Be sure you have clear acreage to try them and don't make the mistake of thinking the tires might make you into a driver...

Sorry if this sounds harsh. I hope you can understand why it's a hot-button issue for me!

Tom

TTO in my experience is like grabbing the hand brake in mid corner (I learned this racing datsun 510's on ice in Edmonton).

If the rear tires are at their traction limit with cornering force, and then you ask them to do braking as well- (which is what you are doing when you let off the gas with the clutch engaged) - bingo, total loss of traction at the rear. Front tires are still fine, they have not been asked to do braking as well as cornering, so you pivot very quickly around the front tires!

That's why giving a small! amount of gas will work: you are removing the braking load from the rear tires and are letting them just do the cornering job like the fronts.

I wonder what effect the type of rear end has on TTO? Meaning open vs. limited slip vs locker vs Quaife/torsen style torque biasing. Anyone have experience or insight?

Very little, with any setup that allows some slip. Unless you're actually inducing longitudinal sliding, there's no change in the tire's coefficient of friction.

Tom, I must be easily understood. I'm in this thread because I don't want to do a TTO 180 or worse. You can probably tell I'm an engineer and want to know exactly what I do and don't understand. I do understand oversteer and understeer. I think I understand TTO but I have no sense of how or when it might happen to me. I have heard of the Michelin's unpredictability. I haven't experienced the unpredictability first hand and I really don't want to. I appreciate your concern and will certainly keep my eyes wide open!

WardL, hope you can open this video.....
 

Seems this guy made a slight turn and suffered the consequences. So is this the result of a TTO?

"This the kind of trouble that can happen in a heartbeat when you have really high grip tires on a Cobra where the driver has yet to learn how to master the car. Lesser grip tires would have never allowed this to happen and would have simply flat spun harmlessly into the grass."

Please play this over several times and then form your final opinions...

http://www.youtube.com/watch?v=sYRN70r7Zrc

Tom Wells, I am not sure who was driving, was this you?

Cheers, John, AKA, tin-man

oops, just re-read this post....one more question:
 

[quote=Barnsnake;1120496]
Lifting off the throttle or braking in an attempt to arrest the understeer might result in snap-oversteer and again, backing off the road.

so what happens when y'all gotta make an emergency stop, does all hell breaks loose?

Cheers, John, AKA, tin-man

tin-man,

Not me, although I know that person. My TTO was turn 3 at Summit Point in 2003.

As to braking, same rule as for acceleration applies: get all four tires pointed in the same direction!

WardL,

The Michelins I refer to are quite predictable: their loss of adhesion is sudden. There are other tires that give some warning through a more gradual loss of adhesion. Do some searches and you should find lots of alternatives.

Tom

Tto
 

A properly set up Cobra will not have excess TTO, shock valving, ride height, spring rates, rake angle, rear camber (assuming an independent rear) and even front to rear sway bar ratios can effect the tendency to come around on throttle lift.

You can use the this trait to get the car into a corner apex by alternately lifting and applying throttle (small amounts) until you get the proper angle. When you lift the nose comes in, when you apply throttle it moves out but not in an uncontrolled fashion. The cars that snap over steer under TTO usually have high ride height, too much rake, not enough rear camber and front to rear wheel rates that promote this problem. As pointed out many times within this thread though, the driver can be the major problem especially if he or she panics and brakes when the tail come out after a throttle lift. It is against everything you have ever been told but the throttle is your friend and will help control the car if you get back into it smoothly and slowly.

3170,

Would this be the correct rake angle?

http://floridagardener.com/misc/dvk_fg010.jpg

Curious!

Tom

After reading all of this all I can think of is....

Damn! I coulda had a Corvette! ;)

[/B

So how does this work exactly when I'm entering a 180 and there is a wall or gully rapidly approaching, what are the manoeuvres recommended, other than KYAGB? Granted it will take a great deal of concentration and quick reflexes but I am having difficulties visualizing getting back into it smoothly and slowly. or is it just too quick to take any action as in the video example I posted.

I'm thinking being a novice at that particular moment "panics on" and I am a true believer in prayer. :eek::eek::eek:

Decidedly a Bondurant Driver Training is an absolute must since it will give me some pointers, but just curious as to what is recommended on this site.

Cheers, John, AKA, tin-man

John, I am a true believer that the best education you will ever get is seat time. I am lucky enough to have a few different areas in which I can push the car to the point of loosing control, so I know what my car is capable of and how to bring her back to control. If you ever get in a situation where you do loose control, there is not usually enough time to think about what you need to do, your instincts have to kick in. So any word on when you will be back in AZ?

Hi Mark, thanks for this, your are correct the only way to experience this is thru seat time and I intend to do just that extensively when I get my Cobra. I also will get some professional driving instructions from Bondurant. That said I am very much interested in hearing from the members what they have experienced, such intel is priceless.

Regarding your AZ comment, I'll be back in Phoenix sometime in June to get the Cobra registered and I plan on retiring at the end of this year. I am finally coming home. Yeah.

Cheers, John

Tom, as I go over this movie again and again I can't hep but realize this guy may have lost his life given the way the car finally wound up. Can you help us all and let us know, did he survive and if so, did he ever recount the cause of the spin out and flip?


Please play this over several times and then form your final opinions...

http://www.youtube.com/watch?v=sYRN70r7Zrc

John, AKA, tin-man

While you are waiting, read some good race car driving books.
Drive to Win by Carroll Smith
A Twist of the Wrist by Keith Code (motorcycle racing, but great info anyway)

They will really help you understand the fundamentals and give you a head start in driving school.

Thanks,
 

dallas, I appreciate the heads up and will check out these books.

Cheers, John, AKA, tin-man

What do you do.
 

The Cobra in the video had way too much ride height for driving on a race track. The narrow track and good grip helped flip the car, if the car were
lower (2"-3") it probably would not have flipped but just spun out. It looks like the driver lifted abruptly but who knows, without data it is difficult to say.
A little aid you can use is to set the idle speed way up so that you reduce engine braking when the throttle is closed quickly. This will also increase braking distance so it is not a cure all just a slight tuning aid. The best thing you can do is go to a good driving school especially one that uses formula cars. That will teach you very quickly how to modulate the throttle to adjust corner entry and exit lines. Developing the proper reflex action takes lots of seat time as stated here in many replies. It is about as difficult as learning to left foot brake in a competition situation so it won't come easily because it needs to be a subconscious action. If you need to think about it it is already too late. You might consider buying a Gokart, that would give you lots of experience in a short time for minimal investment.
Karts are very fast and very difficult to drive and there are kart tracks everywhere.
I heard from a second hand source that the Cobra driver at VIR was unhurt and that it was a woman driving another persons car. I can't vouch for this but that is what I heard.

John,
Maybe this will help until you can read up on some of the books previously mentioned. A rolling tire will travel in the direction it is pointed. A skidding tire will travel in whatever direction the car was moving (notice I said the direction it was moving, not the direction it was pointed) when it started to skid. If, while in a turn near the limits of tire traction, the demand for traction on the rear tires exceeds their physical capability, they will skid in the direction the car was headed at that moment (i.e., tangent to the radius of the turn). One reason this might happen is a sudden increase in rear wheel braking caused by TTO. As the front tires are still turning, the rear end of the car will quickly move to the outisde of the turn. If it happens quickly enough, the angular momentum (i.e., the spinning motion of the car) will carry the rear end all the way around. If the driver is quick enough in recognizing and reacting to the loss of traction and skidding of the rear wheels, he should try to get them to begin rolling again at about the same speed the car is traveling while he uses the front wheels to point the car in the direction it is traveling. With the rear wheels now pointed in the direction they are traveling and with the same speed, the rear tires will resume rolling rather than skidding. At that point, the driver can resume the turn. ... Adding a little power when the skid begins is how the driver brings the rear wheel speed back up to match the car speed.

My car was originally built as a dedicated SCCA racer and I've spun it at least twenty times on various tracks. I made it a practice to not press the limits unless there was a safe runoff area, and I never felt in danger. I do not press the limits on public streets. TTO should not be a problem unless you are pressing the car's limits and you shouldn't be doing that unless you are on a track where it is safe to do, IMHO.

tin-man,

Driver unhurt. TTO/overcorrection caused spin, followed by rollover.

My case was hitting an 18" berm at the Summit Point track while spinning causing a rollover. Hindsight: no berm, no problem :eek: As my wife says, you can't what-if backwards...

Tom