EmperorOfChicken

you heard meh, i have my listening hat on, id like to know how a stall converter works and what it does for an auto car...please.

Soaring

Simply put, if yourMustang has an auto tranny, you have a torque converter already..they act kinda like a clutch, allowing the motor to spin without the vehicle moving. The stock converter is partially engaged at all times providing smooth take off and easy meneuvering in tight spots or with trailers. Stall converters are just torque converters that don't engage the tranny until a certain RPM at the motor. They are basically only for racing and not very streetable at the higher stalls. I would recommend only a light stall for your Mustang, around 1000RPM, that way you get the jump off the line at the track, but you can still drive comfortably around town. It takes a while to get used to a stall converter too, you'll likely think the tranny is slipping when you start out

my77stang

so if i have a 2800 stall (which i do) it shouldnt start rolling when in gear and i take my foot off the brake? i always kinda wondered this cause sometimes if i romp it from a stop it feels like it winds up a bit and then takes off quick and sometimes it just takes off.

THUMPIN455

Nah it will still move. The difference with the higher stalls, like 3500-6000 are they slip vastly more than a 1300-2400 stall does. For a daily driver a 2400 stall works really nice. You dont notice its there untill you stomp the gas pedal. They are tight enough to drive around normally and provided you dont have a 4200lb + car with a 500hp engine and 2.50 gears it will be just fine. Slippage creates heat, because you are shearing the fluid inside the converter rather than using the force of the fluid from the impeller to move the turbine. Excessive heat is bad.. lol.

I could explain how they work to you, but I dont feel like typing something you can read in a vo tech book.

If you have a lumpy cam that doest make much torque under 3000 rpm, a higher stall converter will allow your engine to reach a higher rpm before the car moves, provided you hold the brakes or flash the converter. It will also allow that same engine to idle in gear without stalling. A stock converter with an engine lacking torque down low will either push you through stoplights and make it very difficult to stop the car, or stall the engine whenever you are sitting still.

Stall speed is dependent on a variety of things. For instance, fin angle of the turbine or impeller, design of the stator, gear ratio, vehicle mass, engine size, available torque at different rpms, among others.

Stall is when the converter stops slipping so much and actually starts transfering power through the transmission. All of them stall, its the rpm at which that occurs, and the amount of slippage present inside the converter that make them different. All of them slip unless they have a lock up unit in them.

A modern overedrive trans like the AOD, AODE. A4LD, 4L60E etc, have a lock up converter. That means there is a clutch and pressure plate inside the converter, usually right behind the front cover closest to where the flex plate bolts up. Through electric or electronic controls the transmission will apply that clutch using hydrualic pressure. What that does is lock the input shaft to the engine so there is no slippage.

That means you can have your cake and eat it too so to speak. Lets say you have an AODE in your Mustang, you want a 4000 stall for an incredible launch. You can have that stall and have the converter lock up after you are moving fast enough that the converter doesnt need to slip anymore. So driving around at moderate throttle speeds, you will have the converter locked up with no slippage and very little heat build up. When you apply more throttle, it unlocks and now you have full stall speed available to you.

With no lock up, and a 4000 stall, you will excessively heat the fluid and burn the clutches (and other things) out of the trans, just by driving it around over 40 mph. it will be slipping the entire time, whereas a 2400 stall wont because you will be driving around closer to 2400 rpm than 4000.

Get it?

If not heres a article with pics and even more info..
http://www.carcraft.com/techarticles...rque_converter

Colorado_Mustang

I'll double that a 2400 rpm stall is good around town. That's the stock stall for my '93 Explorer. Who'd have thunk it?

groho

When i put the newconverter in with the tranny, while debating the stall speed, the builder specifically told me to avoid a stall speed that come close to matching your freeway RPM because the converter will over heat and shorten it's life. THUMPIN455, is this true? the theory makes since.

Colorado_Mustang

Avoid a stall speed that is higher than your typical cruising speed. Or, be lucky enough to have a tranny that supports a lock-up like the factory uses.

atomsk680

im putting a 2300 in my c4 soon

my77stang

sometimes when im idling in gear the car will want to die... but usually after it sits for a couple minutes like at a light or sitting in traffic.. could it just be loadin up on fuel? this is the only problem i really ever had with this motor and i always thought it was the carb or converter

fredjchavez

Does anyone know what convertor will provide approximately 2400 rpm stall speed on a mostly stock 289 with a reasonable performance cam? Can anyone speculate what the factory convertors in a 66 yield?

Fred