What's Stall speed?

[Mactruck]

Can someone explain to what stall speed is in relation to torque converters. As some of you know I've been researching (to death) transmission Mods. Although I'm sure that I'll be going with DTT, I don't understand what stall speed is.

This is just a question, No Brand Wars please.

Thanx.

Kevin M.

 

[redneckdr]

stall speed

don't mind me... ... ... . i just want to listen in. still tryin' to learn, you know

 

[rogerblind]

Stall speed definition

See following website for more than you want to know about stall speed. http://autorepair. about.com/gi/dynamic/offsite.htm?site=http://www.converter.com/faqs.htm

 

[Bob Wagner]

just fixin the link

Originally posted by rogerblind

See following website for more than you want to know about stall speed. www.converter.com/faqs.htm

 

[redneckdr]

stall speed

went to the link and read. i guess i'm just a thick headed old man--i still don't fully understand what the heck stall speed is... .....

 

[Mopar-muscle]

its basicly the rpm where the TC is transferring power most efficently . though on a gasser its different than a diesel , in a gasser the engine will want to stall when you reach stall speed while foot braking or over power the brakes if its a high power engine , the motor will nose over if you will ... on a diesel , at least my experience with a cummins , the engine doesn't stall or nose over , it takes off and breaks parts inside the transmission



also the torque peak of the cummins is at such a lo RPM and so broad that if you took their recommendation and placed it 500 -700 below peak torque , the stall would be at idle , as the cummins peak starts at 1300 rpm ... you wouldn't be able to put the truck in gear , never mind hold it with the brake pedal . gas more torque peak is at a higher RPM and maybe the peak is a 200 -300 rpm wide , where the cummins is 1000 rpm plus ...

 

[Stefan Kondolay]

Stall speed is playing with fire. Testing stall speed on a turned up dodge diesel will break parts.



Stall speed is when the engine rpm's will no longer climb any higher. On our personal truck we make 42psi of boost and my dad tests the stall speed at 34-36psi of boost. Lets just say that bad things happen when he does stupid things like that. The way he looks at it is that it cost $50 in parts and 2 hours of his labour. it will cost you alot more.



The following picture will show the results.



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[Mopar-muscle]

well , wheres the pic , i never saw what mine looked like

 

[Stefan Kondolay]

Mopar,



You blind or what. It shows up nice and clear on my screen.

 

[Bill Kondolay]

I guess i must be moving up in the world if my own son calls me stupid.



First of all SON, when i do stuff like this is called research and development when you guys do stuff like that it is stupid.



The Dodge ram is basically 2 different engines.

One with boost and one without boost.



Stall speed is very challenging to measure on a Dodge ram , especially one that has been cranked up.

Measuring true stall speed usually will result in broken transmission parts before you reach your true stall speed.



Stall speed is when your engine rpms no longer increase under full boost.



Guys that are measuring stall speed feel they know where their stall speed is at as soon as their tires break loose.

However that is not correct. All that means is that your tires broke loose.



I have done enough stalls tests on various brand tc's to tell you this , you will reach fuel cut off before you reach your true stall speed as these Cummins have a tremendous amount of torque.



One of the reasons stall speed is not used a lot in this industry anymore as a way of promoting converters is because the stall speed is mechanically provable and can conflict with low stall advertisment claims.

 

[Devildog]

R&D

Bill, looks like Stepan could use a trip to "behind the wood shed"