Why you should Kare about "K" (the truth about stall speed)
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Joined: Jul 2000
Posts: 88
From: PORT ARTHUR, TEXAS, US
rskrause, thankyou for your time.. but I still need more clarification.
Are you saying that if I had a transbrake on, the torque convertor would prevent me from revving the engine to red line? And what ever that RPM is, that is my stall speed?
Now, without a transbrake, it's impossible to know what the actual stall speed is?
How about when the car shifts gears? Say I'm going WOT down the 1/4 mile. When the car shifts, it's only going to go so low right? would that be the true stall speed?
Are you saying that if I had a transbrake on, the torque convertor would prevent me from revving the engine to red line? And what ever that RPM is, that is my stall speed?
Now, without a transbrake, it's impossible to know what the actual stall speed is?
How about when the car shifts gears? Say I'm going WOT down the 1/4 mile. When the car shifts, it's only going to go so low right? would that be the true stall speed?
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Joined: Dec 1969
Posts: 10,745
From: Buffalo, New York
rskrause, thankyou for your time.. but I still need more clarification.
You're welcome!
Are you saying that if I had a transbrake on, the torque convertor would prevent me from revving the engine to red line? And what ever that RPM is, that is my stall speed?
Yes.
Now, without a transbrake, it's impossible to know what the actual stall speed is?
Yes.
How about when the car shifts gears? Say I'm going WOT down the 1/4 mile. When the car shifts, it's only going to go so low right? would that be the true stall speed?
No, because by definition stall speed occurs with the output side of the converter at zero rpm. In the circumstance you describe, the engine rpm will be higher than the stall speed.
The stall speed per se doesn't mean much because the only time you see it is if you use a transbrake and even then most cars actually launch better below the stall speed. For example, on my race car 3,000-3,500 rpm works best. But it is useful as a way of comparing converters in terms of how loose or tight the converter is.
Rich
You're welcome!
Are you saying that if I had a transbrake on, the torque convertor would prevent me from revving the engine to red line? And what ever that RPM is, that is my stall speed?
Yes.
Now, without a transbrake, it's impossible to know what the actual stall speed is?
Yes.
How about when the car shifts gears? Say I'm going WOT down the 1/4 mile. When the car shifts, it's only going to go so low right? would that be the true stall speed?
No, because by definition stall speed occurs with the output side of the converter at zero rpm. In the circumstance you describe, the engine rpm will be higher than the stall speed.
The stall speed per se doesn't mean much because the only time you see it is if you use a transbrake and even then most cars actually launch better below the stall speed. For example, on my race car 3,000-3,500 rpm works best. But it is useful as a way of comparing converters in terms of how loose or tight the converter is.
Rich
Registered User
Joined: Jul 2000
Posts: 88
From: PORT ARTHUR, TEXAS, US
How about when the car shifts gears? Say I'm going WOT down the 1/4 mile. When the car shifts, it's only going to go so low right? would that be the true stall speed?
The stall speed per se doesn't mean much because the only time you see it is if you use a transbrake and even then most cars actually launch better below the stall speed. For example, on my race car 3,000-3,500 rpm works best. But it is useful as a way of comparing converters in terms of how loose or tight the converter is.
Rich
Rich
What should I be looking at?
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Joined: Dec 1969
Posts: 10,745
From: Buffalo, New York
Rich
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Joined: Jan 2015
Posts: 6
From: Cecil Co MD
Re: Why you should Kare about "K" (the truth about stall speed)
I posted in another thread about converter swapping between stock GM converters to get what I need....my cars LS1 stalls at 1500 with 350ft/lbs,.. I was told I could use the factory (hi stall unit for a Trailblazer) which is an 1900-2100 stall....so behind my LS1 your formula would give me almost 2300 with that "hi stall" factory unit...if I'm correctly using your way of figuring that would be perfect for my very mild early type LS6 factory cam...Am I barking up the right tree? and will that unit hold up in a mostly gently driven daily driver??
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