How does a stall converter work?
12-10-2003, 07:53 PM
#1
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How does a stall converter work? Alright, i know this may be a stupid question
Lets say for example a 2400 stall speed.
How does this work, and even for a daily driver..
Does it engage to the transmission at 2400?
Someone please help me here!
Also when people mention on here about changing converters, is the a replacement for the stock converter? does it work better, or are they all stall converters?
Sorry, and Thanks
Lets say for example a 2400 stall speed.
How does this work, and even for a daily driver..
Does it engage to the transmission at 2400?
Someone please help me here!
Also when people mention on here about changing converters, is the a replacement for the stock converter? does it work better, or are they all stall converters?
Sorry, and Thanks
12-10-2003, 08:31 PM
#2
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This link contains a pretty good explanation of a torque converter. Link
Performance Torque converters are usually rated by stall speed.
Stall is the speed at which the converter will hold the engine speed and not allow further gain without moving the transmission/rear end.
Other features are stall torque ratio and lock up.
STR is EXACT OUTPUT TORQUE ÷ EXACT INPUT TORQUE
Lock up is a feature some torque converters have with a lockup clutch. When the two halves of the torque converter get up to speed, this clutch locks them together, eliminating the slippage and improving efficiency.
Having a higher stall ratio makes the torque converter looser at low rpms. It also allows a drag racer to hole engine spped higher before launching, having the engine in a better operating range. It also results in leter and firmer shifts in normal street driving.
Performance Torque converters are usually rated by stall speed.
Stall is the speed at which the converter will hold the engine speed and not allow further gain without moving the transmission/rear end.
Other features are stall torque ratio and lock up.
STR is EXACT OUTPUT TORQUE ÷ EXACT INPUT TORQUE
Lock up is a feature some torque converters have with a lockup clutch. When the two halves of the torque converter get up to speed, this clutch locks them together, eliminating the slippage and improving efficiency.
Having a higher stall ratio makes the torque converter looser at low rpms. It also allows a drag racer to hole engine spped higher before launching, having the engine in a better operating range. It also results in leter and firmer shifts in normal street driving.
12-10-2003, 08:33 PM
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Well...This is a big misconception,you do not have to rev the motor to the stall speed for the car to start moving...IMO a 2400 stall speed is way too low for an LS1, Correct me if im wrong but I think a torque converter works by two rotors(impellers) one is connected to the flywheel another connected to the input shaft of the tranny. The converter is locked at the desired stall speed with fluid. This is an explanation of a converter in a nutshell. Also it nets you et and mph by "slipping" your car into its power band, making the car more efficient and increasing the "brake stall" for hard launches. Traction will become a problem with an aftermarket TC. As I said earlier I wouldn't even think about going to a 2400 stall, I would atleast go 3500+. Good Luck
Wes
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12-10-2003, 10:21 PM
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Sorry, im trying to understand
So you can move before you actually hit the stall speed?
What happens at the stall speed?
And how does it keep engine at this speed?
I was under the impression that it engages to the back wheels when the engine hit that stall speed (2400 in this example), basically throwing you in your seat from a stop.. i can see the track use in this situation, but ive seen on the boards different members who use them for daily drivers
So you can move before you actually hit the stall speed?
What happens at the stall speed?
And how does it keep engine at this speed?
I was under the impression that it engages to the back wheels when the engine hit that stall speed (2400 in this example), basically throwing you in your seat from a stop.. i can see the track use in this situation, but ive seen on the boards different members who use them for daily drivers
12-10-2003, 10:37 PM
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No, it doesn't throw you back unless you want it to. 
It can move at speeds lower than the stall speed, but not as quickly as before. You will creep through traffic but will need to give it more gas to reach normal speeds than you had to with your stock converter. Those are the characteristics of a loose converer. A "tight" converter will act close to stock.
It can move at speeds lower than the stall speed, but not as quickly as before. You will creep through traffic but will need to give it more gas to reach normal speeds than you had to with your stock converter. Those are the characteristics of a loose converer. A "tight" converter will act close to stock.
12-10-2003, 10:50 PM
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To me all the stuff didn't really make sense till i got a TC of my own. It's hard for one to explain it and for you to fully understand what the person is saying. If you have an a4 just get a 3200+ TC and i promise you, you will thank me and all the others that told you to get one. Also make sure you get a tranny cooler along with the TC. What rearend gears do you have?
12-10-2003, 11:11 PM
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Stock gears...2.73s or 3.23s will make a larger converter seem more loose than the same converter with 3.73s as the rear end gear ratio. You want see a decrease in et if you have a tighter converter but you will notice it in your everyday driving routine. Like 2001 said you will need a tranny cooler, it would be a good idea to get a shift kit, this will make your converter seem much tighter than it would seem with the line pressure uped a little. Get it man trust me you want regret it. IMO I think my car is more driveable with my TCI SSF 3500.
Wes
Wes
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12-11-2003, 12:59 PM
#8
a 4400 stall is like evenly letting of the clutch of a 6 speed while at 4400 until it fully engages at 4400 but is much more efficient on a automatic because good clutches wont slip evenly like that. and if one does it will burn up quickly
imo the best killer mod on a a4 is gears and a 3800+stall. that will yeild huge gains in the quarter. (assuming you have some traction.)
imo the best killer mod on a a4 is gears and a 3800+stall. that will yeild huge gains in the quarter. (assuming you have some traction.)
12-11-2003, 08:21 PM
#12
Originally Posted by ULTIMATEORANGESS
i want a stall even more now.ill need a 12 bolt first though. 
12-12-2003, 03:54 PM
#13
Originally Posted by SMOKIN01TA
you dont need a 12 bolt yet. you not putting out enough hp on a a4 for a 12 bolt to be necessary yet. you should be safe with a good stall and some nittos for a while. get some headers and some low 12's then worry about the 12 bolt
i wish you were right.one rear broke already and when my cover was pulled recently it showed some excessive wear on this one with only a little more than 14k on this rebuild.it looks like its only a few launches away from breaking.
12-12-2003, 10:49 PM
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My 91 GTA broke the rear with a 2500 stall and street tires. The problem was to many trips to the track and hard launches for that car. But there is nothing better than a nicely setup a4 with a good stall. Sometimes I miss the auto, It was a lot of fun especially when people rode in that car for the first time.
12-13-2003, 05:40 PM
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Wheel hop is what kills most 10 bolts. A lot of poeple say get the HIGH Stall but they fail to understand that to do it properly and safegard your rearend, you also need to upgrate your suspension (Torque arm, LCA's) at least.Panhard and poly sway bushings a plus.
