Engine dies after car spins

[Shaun]

on a manual car you're supposed to clutch in AND brake to lock the wheels so the engine is not stalled or tries to reverse rotatate while the car is going backwards in a forward gear. If you clutch in and brake hard it will not stall.

on an auto it is common to stall it when spinning if the brakes have not been locked. it is not good for the car when reverse rotation happens.

 

[Tanzy]

Shaun,

Why does the car reverse rotate after the spin?
So to prevent this I assume that in an auto car, during the spin I should lock up the brakes.

 

[Racebred]

yes, i have experienced it several times, in other makes too.

 

[TripleM]

Re: Engine dies after car spins

Is it normal for the engine to cut off after a spin?

Have you been practising donuts bro?

 

[Shaun]

Shaun,

Why does the car reverse rotate after the spin?
So to prevent this I assume that in an auto car, during the spin I should lock up the brakes.

yes, definitely lock the brakes.

When you are moving forward in a forward gear, the crankshaft is rotating one way. When you spin the car and the car is now trying to move backwards in a forward gear, forces are fed through the drivetrain, through the gearbox, and to the crankshaft to try and reverse its motion.

 

[Tanzy]

Shaun,

OK. Pull hand brake during a spin. Roger that.


TripleM,

Donuts not really possible without an LSD fitted. Big donuts can, but small donut no way. What I have been very good at is leaving black spiral marks on the roads when i spin out.

 

[Racebred]

no more donuts practice in singapore liao lah... i took part in an autocross remember? after a spin, the car died. hahahah. have to restart car in front of 500 people. a bit malu.

 

[Shaun]

Shaun,

OK. Pull hand brake during a spin. Roger that.

No, use the proper brakes - esp on track where other people are using the track and predictable direction of travel of a spinning car is important. The only way to guarantee a car will hold a straight line even in a spin is if all 4 wheels are locked.

Even if you are alone and messing around, using the handbrake will only wear it out, and the rear tires, quickly. Also the brake force of the handbrake may not be enough to lock the rear wheels at speed.

aiyoh you ah! everything also must fancy. fancy brake pad break in, fancy braking procedures.. can dun fancy anot?!

 

[Tanzy]

Shaun,

Won't ABS kick in and prevent lock up?

Fancy? Me? what did I do? :verysad:

 

[Racebred]

when you're spinning, it doesnt matter if your ABS is on or not. hahahhaha

 

[Shaun]

Shaun,

Won't ABS kick in and prevent lock up?

No, when you have lost it in a turn, you have already overwhelmed the grip of the tires. your car is probably oriented close to 90 deg to direction of travel (sliding) there is no force trying to turn the wheels at a perfect 90 and quite litte at angles around 90. the braking is to keep vector as predicatable as possible till the car has come to a complete stop. it is predictable safe for the person following you.

when you tires line up with your line of travel, ABS may allow the wheels to rotate slightly and vector may change slightly depending on where the steering is pointed, but the movement is still small and ALOT better than a totally free wheel. in newer cars with lateral G sensors and more advanced CUs, the slight freeing up of the wheel by ABS can be eliminated. not sure what cars are like that, but the rule still stands.. BRAKE

 

[Tanzy]

:singsing: So it is official. When cars begin to spin out of control on Sepang, drivers must stand on the brakes!

Another things is that the DSC and DTC from BMW is darn good! I couldn't provoke the car into a spin with it enabled but usually received violent understeer. I tried really hard. As long as the tires and brakes are still working, I doubt any cars will be go crazy on the track.

 

[Azrielsc]

no more donuts practice in singapore liao lah... i took part in an autocross remember? after a spin, the car died. hahahah. have to restart car in front of 500 people. a bit malu.

MALU!

 

[Racebred]

go crazy in the sense of power oversteer. but all the electronics in the car cannot help momentum oversteer, if the force is big enough. usually people get into trouble with momentum, not power since our bmws are weak and heavy.

In contrast when i track with LC's 4200GT with traction off, slight prods at turns like 2, 4 and 9 send the car into an immediate power oversteer. doubt that will happen in our cars.

 

[Tanzy]

Racebred,

Ya, I suppose I was concentrating on power over.
Scandinavian flick, any one?

 

[Shaun]

our bmws are weak and heavy.

Now you will be banned from the forum!

 

[Racebred]

let me try to explain why a car may reverse after a spin by logic. momentum is foward moving. If a car spins between 90 to 270 degrees, it will still follow the foward direction of the momentum, meaning the car will move in reverse.

any spin less than 90 deg can be caught back, so we dont normally see this example on the track. in this case the car is still moving forward.

any spin between 270 and 360, usually the momentum would have been killed by then and you'll stop still facing the forward direction.

any spin above 360, the cycle begins again.

Now, most scenarios on the track, we're doing the right things. sometimes, the entry speed is only a little bit too fast, or the braking is a little too late. so spins of more than 360 are seldom, thats why most of the time the car will reverse after spinning.

 

[Tanzy]

My friend recommended shifting to neutral gear during a spin for automatic cars. Just pushing the stick forward without depressing the shifter lock.

 

[Shaun]

yeah you can do that too if you are quick enough. the stunt drivers do that on the momentum 360 spins but they have the advantage of planning what they're doing. when you slip at the track, you're not really expecting it to the same degree

 

[Tanzy]

Shaun,

Do you have something about guys behind red face masks? Rocking spidey now and guy with red nomex fire proof mask previously.