Spinning out Front Wheels - What to do ?

Between 2003 and 2004, it changed significantly. Since then, I don't think it has. Description you're looking for is on pages TH-46, TH-47 of the 2004 New Car Features Manual (pages from dead-tree version), I copied part of it here. Any changes in later generations will be covered in their respective NCF manuals.

In general, any question of the form "interesting to have an overview on how it works, the benefits" is a question for which the answers are in the New Car Features Manual.

-Chap

 

Traction Control (TRAC)
By reading data from the ABS wheel-speed sensors, TRAC can tell if a drive wheel is turning faster than the wheel on the opposite side, which can indicate a loss of traction. When TRAC detects slippage, the system can automatically reduce engine power until the wheel that is slipping slows and regains traction. If reducing engine power isn't enough, the braking system will slow that wheel by pulsing the brake of that wheel.

 

Vehicle Stability Control (VSC)
VSC 7 helps prevent wheelslip and loss of traction by reducing engine power and applying brake force to wheels that need it. The system reads data from a steering wheel sensor and the ABS wheel-speed sensors to determine if the vehicle is following the driver’s steering inputs. If the vehicle is deviating from the direction in which the driver is steering, VSC is designed to reduce engine power and pulse the left- or right-side brakes to help correct the situation.

 

I'd still like to know what caused the loud bang I heard when my front wheels spun.
I don't see anything in the description of TRAC and VSC that would create a loud noise.

 

With any wheel spin, there's usually a moment the wheel spin stops. During the spin, traction has been lost. As the wheels slow, a point comes where traction returns. Usually that isn't gradual, and the wheels/axles are 40-50 pounds or so of mass with plenty of angular momentum, suddenly turning into a pull on the pavement.

I've never had that happen in my car in a way I would describe as a boldfaced bang, but with even a little more looseness in any suspension bushing, etc., it could end up sounding that way.

There is no purpose-built banging device built into the drivetrain.

-Chap

 

I've had the same BANG! when spinning occur only once I nearly pooped my pants. With all the wet leaves lately I've been having quite a bit of spin but no bang.

What I think it was that made the bang was the spin and a small drop in the pavement where tires suddenly caught an edge and traction and the gas engine kicking in all at the same time. BANG!

 

Have you got that rear suspension bolt bulletin checked out? Could be.

 

If the car was 10 or 15 years old, I wouldn't mind so much. But I shouldn't be hearing any boldfaced bangs after I had the car for only 6 months.

Oh well, that's what warranties are for. I wonder how long the wheels have to spin before the "engine power is reduced", and/or the "brakes start pulsing." (I only spun for 2 seconds.... One thousand one... One thousand Two... Bang! ) I bet that sure scared the mice outa there!

 

Thanks for the reminder. I'm going to do that at the next oil change... Get my new nuts installed.

In the meantime, everything is good! She's running like a well-oiled machine! There is not one rattle, shake, shimmy, noise, or vibration anywhere that I can tell. Inside or out. I went up hills, down hills, over bumps, into dips, took a couple fast corners, did some quick "S" turns, stomped on the brakes, accelerated briskly, drove on the freeway at 75... Flawless performance.

I'm now ready for Formula One. (Hybrid style. )

 

...don't let that meek-looking little white car fool ya.

It's the White Knight!"

 

You may find it to be pretty awesome. Why?

Because the electric drive not only gives you traction-breaking torque when you're not being careful, it also gives you totally finessable torque all the way down to nearly zero, when you are being careful. (It would be all the way to zero, if they hadn't felt the need to build in imitation auto transmission creep.)

That's feather control of your torque to the wheels, without trying to feather a clutch (or wonder how long you get away with it before smelling clutch fumes), wishing your engine idled lower, etc.

So you can do things like this.

Ice, now ice is always a wild card. And your tires always determine how much traction you have to play with. But nothing gives you more control over what you do with the traction you've got.

-Chap

 

Maybe the loud bang is not your car and is instead the safe So Cal surroundings reminding you to install a safe beneath your seat and put something there besides an In-N-Out burger.

 

Really? I'm going to need to get mine looked at. At 9,200 miles the hatch rattles a little on mine and I swear I can here a high pitched electric "whine" from the battery area when the battery is at a high load or being recharged by retardation. I don't notice it when the ICE is running and my wife can't hear it but I swear it's there.

 

The whine's not unusual—the inverter does pass current in high (audible) frequency sips. I find how noticeable it is in my Gen 3 kind of depends on what I'm carrying in back (and when I made a couple of trips with the rear deck board removed, it was extra annoying).

I don't usually mind it; it sort of reminds me of the Detroit People Mover, or BART, two of the earliest electric-powered conveyances I remember riding in.

-Chap

 

I might have made it sound too exotic. There's really nothing that has changed about the technique since I was in driver training (which was a long time before there was ever a Prius). If you are on a surface that can accept no more than X torque to the wheels without the tires breaking free and spinning, your job as the driver is to deliver no more than about X torque. Otherwise you just turn your tires into snow and ice polishers, like this guy, which is counterproductive:

All the Prius changes is how easy it is, because you can just begin pushing the go pedal down slowly, a millimeter at a time, and have almost complete control of your torque to the wheels from near zero, ramping up gradually until something happens. In a conventional car, you could be stuck with too much torque unless you're really attentive to feathering the clutch and not killing the engine, and so on. No such fussing in a Prius, it's all just how far you press the go pedal.

So instead of looking like the ice polisher above, you want to look like one of these guys:

You can see in both those cases that they don't completely avoid breaking traction; they are powering right to the edge of the tires' grip, so there are little breaks in traction here and there, but none of the sustained polishing you see novices doing.

And in fact, keeping the torque right at that limit and correcting those brief slips is something you can trust the Prius traction control to do for you. Both of those drivers are probably just holding the go pedal at a constant, moderate position, and letting the traction control find the limit for them and do the fussy work.

The exact condition of your tires and the surface is what's going to determine your destiny. You'll end up moving exactly as fast as those conditions allow. How fast that is, you just have to find out in each situation.

There can be some situations where you simply don't have the traction you need. Those are the situations where no matter how gingerly you push down the go pedal, you never find any middle ground between nothing-happening and surface-polishing. When you find yourself in that situation, you just stop right away (before you've polished yourself into place until Spring thaw) and think about how to change the game. Dig some, or spread some sand, throw the floor mats down as Doug did, find somebody to push, etc.

But if you've got decent tires and control of your right foot, you should really rarely find yourself there.

In a Prius, no, not really. I was in reverse in my out-of-mud story, but that was just a consequence of the way I had parked. A quirk of the Prius is that only battery power is available in reverse, so if you have much distance to cover, you'll be better off forward ... or you might find yourself making intermediate stops while the engine tops up the battery again.

-Chap