Single or Multi Disk?
11-06-2013, 10:02 AM
#31
As I understand it, true stall is the engine RPM when you go WOT with the driveshaft locked in place, like with a transbrake. Flash stall is initial jump in RPM above true stall when launching.
11-06-2013, 10:35 AM
#32
Torque converters care about a rotational speed difference between the input (engine) and output (transmission). As the speed difference increases the force transfer between the two increases exponentially.
11-06-2013, 10:59 AM
#33
Some questions I still have...
1) Is it safe to lock in 2nd at WOT with this much power? (I rarely see myself going fast enough to be able lock in 3rd, and never in 4th).
2) Are there any other benefits to a multi disk other than being able to lock at WOT or while towing? Reliability? Longevity?
3) In a turbo application, wouldn't the stall RPM only really matter while launching, or when at sub-stall RPM in 1st? I figure if you're moving fast enough, at WOT the trans will downshift and the RPM will jump up higher than the stall speed anyways (I know there's more to it than this, but is basics of this thinking correct?).
*Sorry for all of the noob questions, but this is all helpful info!
1) Is it safe to lock in 2nd at WOT with this much power? (I rarely see myself going fast enough to be able lock in 3rd, and never in 4th).
2) Are there any other benefits to a multi disk other than being able to lock at WOT or while towing? Reliability? Longevity?
3) In a turbo application, wouldn't the stall RPM only really matter while launching, or when at sub-stall RPM in 1st? I figure if you're moving fast enough, at WOT the trans will downshift and the RPM will jump up higher than the stall speed anyways (I know there's more to it than this, but is basics of this thinking correct?).
*Sorry for all of the noob questions, but this is all helpful info!
11-06-2013, 11:43 AM
#34
1. I dont think its very smart to lock in 2nd, especially with big power. You will be through that gear before the converter really has a chance to lock depending how you have it set. In other words, I dont think you will gain anything by it and it will just be hard on the trans.
2. More reliable when locked, less chance of burning up the clutch.
3. With a turbo, you need the stall speed loose enough so you can spool the turbo adequately, but not so loose you are already above the engines main power range. Stall speed is based on the speed difference between the engine and trans. This is most obvious when stopped when the engine is turning but the trans speed is zero. I like to think of it more in terms of converter slip rpm (engine rpm-trans rpm). This number will decrease as engine rpm increases as the converter couples harder.
For instance, when I launch I leave on 3400rpm converter slip, by the time I am at the top of 3rd my converter slip is down to 310rpm because the converter is coupling hard. With a stock converter it would probably be something like 3000rpm difference, which means all that extra power thats not going to the wheels is going into the converter fluid making **** tons of heat.
2. More reliable when locked, less chance of burning up the clutch.
3. With a turbo, you need the stall speed loose enough so you can spool the turbo adequately, but not so loose you are already above the engines main power range. Stall speed is based on the speed difference between the engine and trans. This is most obvious when stopped when the engine is turning but the trans speed is zero. I like to think of it more in terms of converter slip rpm (engine rpm-trans rpm). This number will decrease as engine rpm increases as the converter couples harder.
For instance, when I launch I leave on 3400rpm converter slip, by the time I am at the top of 3rd my converter slip is down to 310rpm because the converter is coupling hard. With a stock converter it would probably be something like 3000rpm difference, which means all that extra power thats not going to the wheels is going into the converter fluid making **** tons of heat.
11-06-2013, 07:11 PM
#35
X2 on all of what Atomic said. I will add this though:
1. If the 80E had a better lockup circuit, I would lockup in 2nd, but it doesn't (too slow to react), so leave it unlocked here at WOT.
2. Roots blowers and Turbos can create ungodly amounts of torque at a low throttle angle, like 30% TPS at lower rpm. So if you have a single disk, you have to have it tuned VERY carefully here.
3. Torque converters literally convert torque. The more torque you make (or the higher the load), the higher the stall speed. This is why a "3600" stall can cruise around town at 2000rpms, but as soon as you floor it (aka increase torque input), its stall speed goes up. If you are boosted, it will also go up. If it stalls at 3600 N/A, when you make boost it will go up.
1. If the 80E had a better lockup circuit, I would lockup in 2nd, but it doesn't (too slow to react), so leave it unlocked here at WOT.
2. Roots blowers and Turbos can create ungodly amounts of torque at a low throttle angle, like 30% TPS at lower rpm. So if you have a single disk, you have to have it tuned VERY carefully here.
3. Torque converters literally convert torque. The more torque you make (or the higher the load), the higher the stall speed. This is why a "3600" stall can cruise around town at 2000rpms, but as soon as you floor it (aka increase torque input), its stall speed goes up. If you are boosted, it will also go up. If it stalls at 3600 N/A, when you make boost it will go up.
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