Spin Scenario With Auto Trans

[JMarsa]

If during the course of competition your car spins with a manual trans if you disengage the clutch you can prevent the engine from reversing right? What about an auto? Is there a mechanism built in the trans to prevent this? Can the torque converter spins backwards? Can it "grip" in reverse rotation and cause the engine harm?



--JMarsa

[69boo307]

How the heck could an engine that is running start turning in reverse, no matter what? If stuff is turning in reverse while the car is going forward, I'd think you have bigger problems to worry about

[Jagarang]

The only way I think this happens is if things go really bad somewhere in the drive train! Things gotta break. The weakest link in the system is the rubber to pavement friction coefficient; ergo tire smoke and flat spots. This friction coefficient only lasts as long as you’re on the pavement, since once you’re in the dirt, you better hope you don't have enough kinetic energy left over to reach the wall.

I have recurring dreams of cornering on the ragged edge of traction in a long sweeping turn and sloooowwllyyy my outboard tires creeping to the pavements edge as I desperately try to pedal some traction back into the turn while avoiding the brakes!! Of course as I feel the tires begin to slip off, even run along the knarly edge of asphalt, my heart skips a beat, jumps into my chest, and I get that empty, cold, helpless feeling in the pit of my stomach, as control begins to slip away! As the sweet bite of my last inch of tread departs entirely from the life giving concrete, I brace myself for the cruel painful wail of vintage metal as it bends and twists upon impact. Ohh the heartbreaking carnage I've inflicted on my pride and joy and underneath it all the adrenaline fueled, euphoric, speed induced intoxication caused by the relentless flood of endorphins into the bloodstream during the race! We’ll get em’ next time!!

Obviously my mind doesn't know what to do after a week of Spring break! Organic chemistry and Legal Aspects of Healthcare obviously have driven me COMPLETLY insane.... I’m going to have my medication now!

[myclone]

If during the course of competition your car spins with a manual trans if you disengage the clutch you can prevent the engine from reversing right? What about an auto? Is there a mechanism built in the trans to prevent this? Can the torque converter spins backwards? Can it "grip" in reverse rotation and cause the engine harm?

--JMarsa

Technically its somewhat possible if every thing happens just right and quick enough. On a later trans with a lock up converter if you change the direction that the tires are rotating quick enough that the torque converter clutch cant unlock from the pressure drop then yes it could spin the engine backwards for a short time (very short time). It would prolly only happen for a split second because the pump in the trans turning backwards will not supply fluid to keep the coverter locked which will cause the drive line to "let go" of the engine quickly with not enough rotation to cause the engine to complete more than one revolution or so (prolly not even that much).

Like I said its technically possible on paper but to get it to occur in the real world would be pretty hard to do.

[Kenova]

I have recurring dreams of cornering on the ragged edge of traction in a long sweeping turn and sloooowwllyyy my outboard tires creeping to the pavements edge as I desperately try to pedal some traction back into the turn while avoiding the brakes!! Of course as I feel the tires begin to slip off, even run along the knarly edge of asphalt, my heart skips a beat, jumps into my chest, and I get that empty, cold, helpless feeling in the pit of my stomach, as control begins to slip away! As the sweet bite of my last inch tread departs entirely from the life giving concrete, I brace myself for the cruel painful wail of vintage metal as it bends and twists upon impact. Ohh the heartbreaking carnage I've inflicted on my pride and joy and underneath it all the adrenaline fueled, euphoric, speed induced intoxication cause by the relentless flood of endorphins into the bloodstream during the race! We’ll get em’ next time!!

WHOOAAAA!!!! I wish I could dream like that!!!!!!
Ken

[Todds69]

You can get a full manual automatic with no engine brake. So when you get of the gas the engine/trans "free wheel" which doesn't decelerate the car unless you manually downshift the tranny.

[JMarsa]

I get the full manual part, how do you prevent the engine braking? I thought it was a product of the torque converter linking the engine to the drivetrain.

--JMarsa

[Todds69]

I figured you would ask me that. With a full manual auto the is no governor and vacuum operation it is 100% manual so it is the pressures inside the trans which creates this no engine braking. When you let of the throttle at 100mph you will coast and better be ready to use the brakes so you dont smack the person in front of you. I'm using one in my car I just haven't ran it yet, hopefully this summer....