Spec_Ops2087

Ok, I just want to clarify what the "stall speed" really is as I always hear people (automatic domestics) talk about it.

This is what I think it is, correct me if I'm wrong please:

You brake your car (so it will not move), while locking the brakes you give it throttle so the rpms go up (but the car does not move) unitl the "stall speed" RPM. After that point the car will stall out.

The advantage is that you can "launch" an automatic car at a higher rpm giving a better start?


I'm just curious.

PedalFaster

You're mostly right; an automatic transmission's stall speed is the rpm the engine will settle at if you depress the gas and brake hard simultaneously. The car won't stall if this happens, though; the engine will just hit a certain rpm and stay there.

curiouz_G

its basically like a manual w/o the clutch when going from a dead stop.

PedalFaster

Huh?

Spec_Ops2087

Thanks for clearing it up

curiouz_G

nvm was thinking about something else.

nevert00fast

What you described is a trans-brake, except you use the tranny to brake instead of the brakes.

PedalFaster

Huh?

nevert00fast

People usually use transbrake to do a high rpm launch. Because even if you ran a 3200 stall the car probably won't rev to 3200 even though you hold the brakes.

With the transbrake you just floor the gas kind of like a 2-step.

"Activated by electrical solenoid control, a trans-brake simultaneously engages the first and reverse gears, locking the transmission and preventing the input shaft from turning. This allows the driver of the car to raise the engine rpm against the resistance of the torque converter, then launch the car by simply releasing the trans-brake switch."

PedalFaster

Sounds to me like he was describing a good old-fashioned brake stand -- depressing the gas and brake at the same time, without the use of any fancy electrical solenoid control-type gadgets.