TTO: a force to be reckoned with.

[tin-man]

TTO: I have learned from this forum means: Trailing Throttle Oversteer. It is a phenomenon whereby the Cobra will do a 180 in a blink of an eye, caused by the sudden change in weight distribution due to the rear tires breaking loose effecting the rear end to slide in the direction the car is headed. This I am told can happen on any light weight car built like the Cobra having a short wheelbase coupled with a high performance engine and equally high torque.

On one of these threads recently a member, who shall remain anonymous stated, "The front and rear switched ends in a flash on a down-shift to pass a slow moving vehicle." his guardian angels where out in full force on that day since he survived from what could have been a nasty accident and lived to drive another day.

Understand guys, I am not endeavouring to create high drama here, just stating something that can happen and does with these cars if not driven correctly.

So, for the benefit of all new drivers, those still waiting for their Cobras to be completed, as I am, or those folks who are just contemplating getting a Cobra can we hear from members who have their Cobra how many have experienced TTO and a brief description of how it happened?

This type of shared knowledge may save a life.

Cheers, John, AKA, tin-man, Zhuhai, P.R.C.

[strictlypersonl]

To a large extent, TTO is a problem because it runs counter to our natural reflexes: Rear end swings out > back off the throttle!

Wrong.

If you are quick (and accurate), apply a small positive throttle. This will induce a small amount of understeer. This technique usually takes a lot of track experience to become reflexive.

The easier and slightly less effective method is to depress the clutch so that it separates all engine drag from the drivetrain.

[vettestr]

Said slightly different, TTO is first and foremost recognized by YAK and is displayed in the DPF. (YAK) Your Ass Knows instantly how bad you just screwed up and (DPF) Degree of Pucker Factor is a involuntary response. You will learn to associate YAK to DPF when sufficient seat time has been achieved.

YAK is a parameter that may in fact be hereditary,or total lack of. It guides you through many Cobra and non-Cobra decisions. It also has a small voice that whispers or in some cases shouts things like (YDMF) or other useful messages. YAK can only be heard by the YAK owner but I have had some claim they can hear me talking out of it? I can hear it now, I think it is saying delete this now. I should listen much more often.

LMAO
enjoy tinner .......... jeff

[Jerry Clayton]

TRAIL anything in a car related conservation is outta place------Trails are for donleys, mules, horses, goats,camels---

[crASH]

As an aspiring Cobra owner, I want to be sure I fully understand this phenomenon.

If a lack of driver experience prevents the YAK factor (as measured by the DPF) from averting a YDMF episode "at speed", is it safe to say that it's AMF because you are SOL? ...with credit to Vettestr, and thanks to Tinman

[crASH]

Originally Posted by Jerry Clayton

TRAIL anything in a car related conservation is outta place------Trails are for donleys, mules, horses, goats,camels---

I've blazed at least one "trail" that started on the asphalt, but ended up through the woods.... backwards.... where I was definitely "outta place", as a result of TTO.

[WardL]

Is TTO a cornering issue or acceleration issue? 1) Let's say you are doing burnouts (like a HS kid) and the rear end starts to drift sideways (at low speed); is this TTO? or 2) going into a corner and the rear breaks loose and slips sideways; TTO? Is TTO only when de-accelerating into corner or when accelerating out of a corner? Seems like it has to be associated with braking into a corner for TTO. Have I asked enough questions for one paragraph?

[Tom Wells]

WardL,

Before I start the lecture, all those with less than 100 horsepower may leave the room (unless it's raining LOL )

In simple terms TTO happens while turning:

TT = Trailing Throttle: the engine has been told to decelerate the car (the driver has let off the gas)
OVERSTEER: The rear of the car thinks it should pass the front as a result of TT

When you lift off the gas while the car is turning, the rear will try to pass the front. In a Cobra being driven spiritedly, it happens so fast it's almost below the level of human perception. I DO know this...

If the car is going slowly, that is, nowhere near its limit of adhesion, there is often time to correct the situation. All you may experience is a lurch.

If the car is cornering at or near 100%, you will know what being inside of a blender is like

Try to experience this yourself only in a flat, open, level space.

This doesn't include places having other vehicles, curbs, berms, ditches, trees, light poles or other relatively immovable objects.

Public roads, freeway entrances or exits, exits from parking areas where a turn is made going in or out, entrances to subdivisions, well, you get the idea, are not real fine places to experience this physics demonstration unexpectedly.

It's fairly simple. It can have less than optimal results if you haven't practiced it.

A corollary to this is: make sure all four wheels are pointed in the same direction before applying any significant amount of throttle. Almost all y'all know how much throttle that is!

Tom

[WardL]

Tom, Thanks! I've always worried about too much throttle coming out of a corner which is probably what every novice protects against. You kid about needing more than 100 HP. But you don't need HP to decelerate, just compression and brakes? I understand oversteer and understeer, no problem. So this TT only happens when going into a corner near (or maybe over) the limit of you and the car, you are braking and do your down-shift and voila! your back tires break loose and you spin out before hitting the gas as you would coming out of the corner. Doesn't sound like you can get TT if in neutral or with the clutch in? I'm still getting use to 13.5" wide rear tires with 512 HP! Thanks again!

[tin-man]

[quote=vettestr;1120348]Said slightly different, TTO is first and foremost recognized by YAK and is displayed in the DPF. (YAK) Your Ass Knows instantly how bad you just screwed up and (DPF) Degree of Pucker Factor is a involuntary response. You will learn to associate YAK to DPF when sufficient seat time has been achieved...................

you're bad man, this is a serious discussion, ask DWRAT he accelerated and decelerated so fast on a curve his Cobra acted out accordingly and to DWRAT utter and complete amazement he S*** his pants big time and ruined his seat. Shortly thereafter he sold his Cobra, claims his wifey made him do it but you guys know differently, his gonads got sucked up so tight they are now an appendage under his chin and his anal retention abilities are now the stuff of legends that he must wear adult diapers.

While I certainly jest here, TTO can be a killer particularly if riding in busy traffic. Thus the request for actual experiences and causal effects, so a) if will help other members and b) it will save my sorry ass from disaster.

When, yeah, when I finally get my Cobra I want to have as much forewarned knowledge on this subject as I can retain, in addition to going to the Bondurant Driving Schools in Phoenix to get seat time and advice. One of my biggest concerns is what happens when the Bowler 4R70W auto tranny does a down shift and understanding the subsequent affect it will have while driving. If this causes a TTO, then I be F***** big time, thus my request for understanding.

Cheers, John, AKA, tin-man

[392cobra]

Originally Posted by WardL

I understand oversteer and understeer, no problem. So this TT only happens when going into a corner near (or maybe over) the limit of you and the car, you are braking and do your down-shift and voila! your back tires break loose and you spin out before hitting the gas as you would coming out of the corner. Thanks again!

Nope,you still don't get it.

It is about being at or near the limit in a corner/curve and releasing the throttle.

[tin-man]

Originally Posted by WardL

Tom, Thanks! I've always worried about too much throttle coming out of a corner which is probably what every novice protects against. You kid about needing more than 100 HP. But you don't need HP to decelerate, just compression and brakes? I understand oversteer and understeer, no problem. So this TT only happens when going into a corner near (or maybe over) the limit of you and the car, you are braking and do your down-shift and voila! your back tires break loose and you spin out before hitting the gas as you would coming out of the corner. Doesn't sound like you can get TT if in neutral or with the clutch in? I'm still getting use to 13.5" wide rear tires with 512 HP! Thanks again!

WardL, what tires would those be?

Cheers, John AKA, tin-man

[Barnsnake]

Here's another way to look at it:
Say you are taking a corner at, or near, the limits of adhesion. If you lift off the throtle, some weight transfers from the rear tires to the front tires (since your center of gravity is above your spindles). Cobras with drivers have a considerable rear axle weight bias. When the weight transfers to the front, the heavier rear loses its grip and you proceed off the road backwards.
911's and other short wheelbase, tail-heavy cars also have this tendency. Running larger tires on the rear helps a bit, but doesn't eliminate the possibility.

[tin-man]

Originally Posted by 392cobra

Nope,you still don't get it.

It is about being at or near the limit in a corner/curve and releasing the throttle.

392 Cobra, so does that mean if I keep constant pressure on the accelerator while entering and completing a curve TTO is either greatly reduce or eliminated? So while this I guess is only the results of many hours of seat time how does one access how much is enough?

Cheers, John, AKA, tin-man

[392cobra]

TTO is only from releasing the throttle.

You can certainly go into oversteer from a number of other factors that involve exceeding the friction limit of you rear tires. So seat time and practice are the key to learning your cars limits.

[tin-man]

Originally Posted by Barnsnake

Here's another way to look at it:
Say you are taking a corner at, or near, the limits of adhesion. If you lift off the throtle, some weight transfers from the rear tires to the front tires (since your center of gravity is above your spindles). Cobras with drivers have a considerable rear axle weight bias. When the weight transfers to the front, the heavier rear loses its grip and you proceed off the road backwards.
911's and other short wheelbase, tail-heavy cars also have this tendency. Running larger tires on the rear helps a bit, but doesn't eliminate the possibility.

Barnsnake, here's one for you, if as an example I carry a significant amount of weight like 200# in the trunk coupled with my own weight 225#'s centered in the car, does this phenomenon still occur? In other words what is the empirical fix, if indeed there is one, or does in matter since the tires will still break loose?

Cheers, John, AKA, tin-man

[Barnsnake]

Interesting question, but not a simple one.
In the example, we were at the limits of adhesion and assuming somewhat neutral handling. Using the same parameters, with additional rearward weight bias from your "ballast" you would rotate off the road even faster due to a greater pendulum effect.
However:
Adding ballast to the rear would change the overall handling characteristics of the car. If you added enough grip to the rear (relative to the front) it might just try to understeer straight off the road long before you neared the limits of adhesion of the rear. Lifting off the throttle or braking in an attempt to arrest the understeer might result in snap-oversteer and again, backing off the road.

Weight (MASS, actually) is ALWAYS the enemy when trying to accelerate, stop, or turn. Increasing rear grip by increasing the coefficient of friction (big, sticky tires) is better than by increasing the force normal to the plane (ballast).

[tin-man]

Originally Posted by Barnsnake

Interesting question, but not a simple one.
In the example, we were at the limits of adhesion and assuming somewhat neutral handling. Using the same parameters, with additional rearward weight bias from your "ballast" you would rotate off the road even faster due to a greater pendulum effect.
However:
Adding ballast to the rear would change the overall handling characteristics of the car. If you added enough grip to the rear (relative to the front) it might just try to understeer straight off the road long before you neared the limits of adhesion of the rear. Lifting off the throttle or braking in an attempt to arrest the understeer might result in snap-oversteer and again, backing off the road.

Weight (MASS, actually) is ALWAYS the enemy when trying to accelerate, stop, or turn. Increasing rear grip by increasing the coefficient of friction (big, sticky tires) is better than by increasing the force normal to the plane (ballast).

Jim, so does this mean big sticky tires plus added weight in the trunk would help improve the traction thus decreasing the likelyhood of TTO?

John, AKA, tin-man

[Barnsnake]

Nope.
Weight is ALWAYS the enemy.

[WardL]

The tires are Michelin 335/35ZR17. Opps! Sorry, they are only 10.5 " wide. I think I got the HP right....

If you are driving to the limits you are off the gas before you get into a 90 Deg corner. Maybe a set of wide S curves getting tighter. Maybe you are down shifting and doing your heel-toe foot work. I can see screwing up the down-shift going into the corner and causing your rear to come around. Maybe we aren't talking a tight turn but a situation where you are taking a high speed turn and you down-shift instead of braking. There was a You-Tube video where the Cobra rolled after a very slight left at high speed and the rear end went around. Was that an example of TTO? Good night for now!