ok, I read wikipedia and on howstuffworks.com to find out the inner workings of a tc. Very informative and well explained. I still can't quite visually get a hold of the changes in direction of fluid flow. Does anyone have any links with the fluid actually moving through maybe a model of a torque converter?
http://www.howstuffworks.com/engine.htm. This site has a moving model of the internal combustion engine. I'm looking for something like this, only showing fluid flow through the tc. Thanks!

 

This is not what your looking for, but up top in the Drivetrain section theres a sticky thread that rskrause started talking about lockup torque converters. Just another read if you want.

 

Yeah, I read the stickies here too. Not really looking for a text description. Hoping to find an illustrated, live action or animated simulation, if ya know what I mean. Thanks anyway.

 

http://www.drivesubaru.com/Fall02/Fa...rt/Diagram.gif

http://pcsl.mit.edu/2.000/z_archive/...erter/flow.jpg

http://www.aa1car.com/library/2002/elements/90222e.gif

http://www.dieseltrans.com/dodge/ima..._converter.jpg

hope those help

 

That's a little more along the lines of what I was talking about. Here's a follow up question:How does the torque converter engage the gears of the transmission. 1st gear, 2nd, ect..., and even reverse. I know it's like the clutch in a manual tranny, but how are the gears selected. This may not actually be a tc question, but in an m6, for example, you manually shift into 1st, 2nd, etc...What selects the gears in an auto? After the gear is selected, how does the tc engage them. You know, like the clutch mechanically engages the gears, one shifted into. How does the tc do this. Or does it?

 

The TC does not engage, or shift the gears. It is only meant to transfer power from the engine to the transmission. The trans shifts. There are bands, clutches, and solenoids in the trans that shift the gears. The PCM desides to shift depending on RPM, MPH, and other stuff like throttle position. When the PCM thinks it should shift it tells the trans and the trans shifts the gears. The torque converter does nothing for gears, only transfers power.

On a side note, the TC can do a lot more like increase torque, stall at different speeds and so on, but it transfers power.

One more thing, the reason the car can stop without stalling the engine is from the TC not spinning fast enough. The faster it spins (higher RPM) the more pressure it builds up. It eventually reaches a point where it can transfer power (stall speed). When it falls below the stall speed it cannot transfer power so the engine can spin without stalling.

 

Why does a manual tranny not have a tc?

 

Because it has a clutch instead! Seriously, your question gets into semantics. The term "automatic" transmission can have different meanings in different contexts. What do you call the type of transmission pioneered in F1 racing? It has a clutch and is normally shifted "manually" by means of paddles on the steering wheel. But it can be shifted by the on-board computer, which also controls the clutch in this "automatic" mode. What do you call an "automatic" with a "manual" valve body? The famous Lenco has a planetary gearset derived from the original "automatic" design - the Buick Dynaflow which was first produced in 1948. However, as usually installed is uses a clutch. The shifts may be "manual", but in many setups an rpm triggered electric solenoid or pneumatic piston does the shifting. The Lenco is also available as the "Lencodrive", which uses a torque converter (TC) instead of a clutch. This tranny can also be shifted manually or with an electric or air shifter. In my race car, I use a Powerglide with a manual valve body that is shifted with an air shifter. What should I call it?

The variations have proliferated, making the terminology even more fuzzy. The CVT (continuously variable transmission) used by Nissan, among others, has a very different design. There is no "clutch" in the traditional sense and no torque converter. While it's usually controlled by the computer, there have been variations with a shifter that can be controlled "manually". And as installed, traditional automatics can also be manually shifted.

As far as the advantages of a clutch vs. a TC. in general automotive use a manual with a clutch is generally a bit less expensive, is lighter, and has lower drivetrain power loss. It therefore has the potential for better economy and performance. However, the devil is in the details and there are examples where these generalizations do not hold.

Rich

 

An automatic in fbodies uses a torque converter which is used to transfer power (and not stall the engine at low speeds). A manual in fbodies uses a clutch that needs to be disengaged at low speeds so the engine does not get stalled/choked/killed or whatever you want to call it. That is why automatics have only a gas and brake pedal, while manuals have a gas, brake, and clutch pedal. Manuals you have to manually do all the shifting, and clutch engage/disengagement.