Converter experts please teach me
02-05-2008, 05:15 PM
#1
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Converter experts please teach me okay
I am having a lot of trouble picking a stall for my V6
my first stall was a 3800 and 2.5 STR and second is 4600 and 2.5 STR
the 3800 was slow to spool and the 4600 is to loose up top
now i did some reading and it seems the STR can affect efficiency as well
problems
1. no trans brake for v6 cars (yet) (4L60E)
2. 3800 was slow off the line 4600 better spool but loose
2. on foot brake car rolls forward, no boost on foot brake (like on brake leg shaking with e brake on lol)
It seems I need to keep the stall as high as possible and lower the STR. this will allow the stall to flash to an rpm where the turbo can get right into boost, but it will not
my question
in a perfect world is i could keep the 4600 stall and lower the STR to like 1.8
what difference would i notice, on the street? on foot brake? from a roll for passing slow *** drivers?
It seem the lower STR should make the foot brake not so hard? i know it won't build 8 psi but even 2 psi would help a **** ton cause it would spool so fast !!
any proven information you have would be great
I am having a lot of trouble picking a stall for my V6
my first stall was a 3800 and 2.5 STR and second is 4600 and 2.5 STR
the 3800 was slow to spool and the 4600 is to loose up top
now i did some reading and it seems the STR can affect efficiency as well
problems
1. no trans brake for v6 cars (yet) (4L60E)
2. 3800 was slow off the line 4600 better spool but loose
2. on foot brake car rolls forward, no boost on foot brake (like on brake leg shaking with e brake on lol)
It seems I need to keep the stall as high as possible and lower the STR. this will allow the stall to flash to an rpm where the turbo can get right into boost, but it will not
my question
in a perfect world is i could keep the 4600 stall and lower the STR to like 1.8
what difference would i notice, on the street? on foot brake? from a roll for passing slow *** drivers?
It seem the lower STR should make the foot brake not so hard? i know it won't build 8 psi but even 2 psi would help a **** ton cause it would spool so fast !!
any proven information you have would be great
02-05-2008, 05:19 PM
#2
I found this from Yank the info may help some.
Stall Torque Ratio is one of the most misunderstood aspects of torque converter construction. Our competitors often call stall torque ratio: torque multiplier. The stall torque ratio is the amount of engine torque that the torque converter can multiply at a particular rpm level. By definition, stall torque ratio is when the turbine is at 0 RPMs and the converter is at maximum designed stall. This will produce a positive push on the turbine to increase the torque to the input shaft of the transmission, multiplied by the designed stall torque ratio of the torque converter. For example, a stall torque ratio of 2.0 would multiply 200 lb. ft. of engine torque to 400 lb. ft. of torque at the transmission input-shaft.
The misconception of stall torque ratio is that more must be better. This is not always the case. High stall torque ratio applications, typically are for industrial equipment or engines with limited low rpm engine torque. With high stall toque ratio converters, there are important trade-offs. What you take at one end you give up on the other. Typically, a torque converter with a very high stall torque ratio, such as 2.0-2.5, will be much less efficient above its rated stall speed. There is a sacrifice in higher rpm efficiency to achieve high stall torque ratios. That lower efficiency translates into less horsepower transmitted to the tires over an RPM range.
The problem with a high stall torque ratio converter is that it is only high while the car is not moving. Maximum stall torque ratio occurs at wide open throttle with no rotation of the transmission input shaft. As the input shaft starts to rotate with vehicle forward movement, the stall torque ratio will become non-existent much sooner than a converter of the same stall, with a lower stall torque ratio. A converter with a stall torque ratio of 2.2 for example, would display that at the starting line, but it would drop off much sooner than a converter with a lower stall torque ratio. See graph:
As you can see, the converter with the lower stall torque ratio will multiply torque for a longer period of time than the converter with a higher stall torque ratio. As most of you know, most racing occurs above 3,000 RPMs. That's why the lower stall torque ratio often wins the race:
*Lower stall torque ratio is gentler on the tires at the initial launch, but it will pull harder for the remaining 1,305 ft. of the 1/4 mile. Less races will be lost at the starting line from excessive wheelspin.
Lower stall torque ratio will be more efficient and transmit more torque and horsepower to the tires. This translates into lower ETs and higher trap speeds!
Stall Torque Ratio is one of the most misunderstood aspects of torque converter construction. Our competitors often call stall torque ratio: torque multiplier. The stall torque ratio is the amount of engine torque that the torque converter can multiply at a particular rpm level. By definition, stall torque ratio is when the turbine is at 0 RPMs and the converter is at maximum designed stall. This will produce a positive push on the turbine to increase the torque to the input shaft of the transmission, multiplied by the designed stall torque ratio of the torque converter. For example, a stall torque ratio of 2.0 would multiply 200 lb. ft. of engine torque to 400 lb. ft. of torque at the transmission input-shaft.
The misconception of stall torque ratio is that more must be better. This is not always the case. High stall torque ratio applications, typically are for industrial equipment or engines with limited low rpm engine torque. With high stall toque ratio converters, there are important trade-offs. What you take at one end you give up on the other. Typically, a torque converter with a very high stall torque ratio, such as 2.0-2.5, will be much less efficient above its rated stall speed. There is a sacrifice in higher rpm efficiency to achieve high stall torque ratios. That lower efficiency translates into less horsepower transmitted to the tires over an RPM range.
The problem with a high stall torque ratio converter is that it is only high while the car is not moving. Maximum stall torque ratio occurs at wide open throttle with no rotation of the transmission input shaft. As the input shaft starts to rotate with vehicle forward movement, the stall torque ratio will become non-existent much sooner than a converter of the same stall, with a lower stall torque ratio. A converter with a stall torque ratio of 2.2 for example, would display that at the starting line, but it would drop off much sooner than a converter with a lower stall torque ratio. See graph:
For example: A competitor's converter with a claimed stall torque ratio of 2.5 (red graph line) would typically have an efficiency of around 90% at high RPMs (5,000 plus). That means 300 flywheel horsepower would translate to 270 horsepower at the transmission input-shaft. A Super Yank Converter with a stall torque ratio of 1.6 (green graph line) has efficiency in the 97% range. That means a 300 horsepower engine would transmit 291 horsepower to the transmission input-shaft: A gain of 21 horsepower!
As you can see, the converter with the lower stall torque ratio will multiply torque for a longer period of time than the converter with a higher stall torque ratio. As most of you know, most racing occurs above 3,000 RPMs. That's why the lower stall torque ratio often wins the race:
*Lower stall torque ratio is gentler on the tires at the initial launch, but it will pull harder for the remaining 1,305 ft. of the 1/4 mile. Less races will be lost at the starting line from excessive wheelspin.
Lower stall torque ratio will be more efficient and transmit more torque and horsepower to the tires. This translates into lower ETs and higher trap speeds!
__________________
02-05-2008, 05:25 PM
#3
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I found this from Yank the info may help some.
Stall Torque Ratio is one of the most misunderstood aspects of torque converter construction. Our competitors often call stall torque ratio: torque multiplier. The stall torque ratio is the amount of engine torque that the torque converter can multiply at a particular rpm level. By definition, stall torque ratio is when the turbine is at 0 RPMs and the converter is at maximum designed stall. This will produce a positive push on the turbine to increase the torque to the input shaft of the transmission, multiplied by the designed stall torque ratio of the torque converter. For example, a stall torque ratio of 2.0 would multiply 200 lb. ft. of engine torque to 400 lb. ft. of torque at the transmission input-shaft.
The misconception of stall torque ratio is that more must be better. This is not always the case. High stall torque ratio applications, typically are for industrial equipment or engines with limited low rpm engine torque. With high stall toque ratio converters, there are important trade-offs. What you take at one end you give up on the other. Typically, a torque converter with a very high stall torque ratio, such as 2.0-2.5, will be much less efficient above its rated stall speed. There is a sacrifice in higher rpm efficiency to achieve high stall torque ratios. That lower efficiency translates into less horsepower transmitted to the tires over an RPM range.
The problem with a high stall torque ratio converter is that it is only high while the car is not moving. Maximum stall torque ratio occurs at wide open throttle with no rotation of the transmission input shaft. As the input shaft starts to rotate with vehicle forward movement, the stall torque ratio will become non-existent much sooner than a converter of the same stall, with a lower stall torque ratio. A converter with a stall torque ratio of 2.2 for example, would display that at the starting line, but it would drop off much sooner than a converter with a lower stall torque ratio. See graph:
As you can see, the converter with the lower stall torque ratio will multiply torque for a longer period of time than the converter with a higher stall torque ratio. As most of you know, most racing occurs above 3,000 RPMs. That's why the lower stall torque ratio often wins the race:
*Lower stall torque ratio is gentler on the tires at the initial launch, but it will pull harder for the remaining 1,305 ft. of the 1/4 mile. Less races will be lost at the starting line from excessive wheelspin.
Lower stall torque ratio will be more efficient and transmit more torque and horsepower to the tires. This translates into lower ETs and higher trap speeds!
Stall Torque Ratio is one of the most misunderstood aspects of torque converter construction. Our competitors often call stall torque ratio: torque multiplier. The stall torque ratio is the amount of engine torque that the torque converter can multiply at a particular rpm level. By definition, stall torque ratio is when the turbine is at 0 RPMs and the converter is at maximum designed stall. This will produce a positive push on the turbine to increase the torque to the input shaft of the transmission, multiplied by the designed stall torque ratio of the torque converter. For example, a stall torque ratio of 2.0 would multiply 200 lb. ft. of engine torque to 400 lb. ft. of torque at the transmission input-shaft.
The misconception of stall torque ratio is that more must be better. This is not always the case. High stall torque ratio applications, typically are for industrial equipment or engines with limited low rpm engine torque. With high stall toque ratio converters, there are important trade-offs. What you take at one end you give up on the other. Typically, a torque converter with a very high stall torque ratio, such as 2.0-2.5, will be much less efficient above its rated stall speed. There is a sacrifice in higher rpm efficiency to achieve high stall torque ratios. That lower efficiency translates into less horsepower transmitted to the tires over an RPM range.
The problem with a high stall torque ratio converter is that it is only high while the car is not moving. Maximum stall torque ratio occurs at wide open throttle with no rotation of the transmission input shaft. As the input shaft starts to rotate with vehicle forward movement, the stall torque ratio will become non-existent much sooner than a converter of the same stall, with a lower stall torque ratio. A converter with a stall torque ratio of 2.2 for example, would display that at the starting line, but it would drop off much sooner than a converter with a lower stall torque ratio. See graph:
For example: A competitor's converter with a claimed stall torque ratio of 2.5 (red graph line) would typically have an efficiency of around 90% at high RPMs (5,000 plus). That means 300 flywheel horsepower would translate to 270 horsepower at the transmission input-shaft. A Super Yank Converter with a stall torque ratio of 1.6 (green graph line) has efficiency in the 97% range. That means a 300 horsepower engine would transmit 291 horsepower to the transmission input-shaft: A gain of 21 horsepower!
As you can see, the converter with the lower stall torque ratio will multiply torque for a longer period of time than the converter with a higher stall torque ratio. As most of you know, most racing occurs above 3,000 RPMs. That's why the lower stall torque ratio often wins the race:
*Lower stall torque ratio is gentler on the tires at the initial launch, but it will pull harder for the remaining 1,305 ft. of the 1/4 mile. Less races will be lost at the starting line from excessive wheelspin.
Lower stall torque ratio will be more efficient and transmit more torque and horsepower to the tires. This translates into lower ETs and higher trap speeds!
this sucks to low and its still slow to high and top end suffers
02-07-2008, 05:18 PM
#6
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anyone else?
here is some more info to look at
http://www2.turbov6camaro.com:443/11.htm (scan from run below)
http://www.fquick.com/videos/viewvideo.php?id=1534
here is some more info to look at
http://www2.turbov6camaro.com:443/11.htm (scan from run below)
http://www.fquick.com/videos/viewvideo.php?id=1534
02-09-2008, 08:34 AM
#7
I have done quite a few turbo setups and they are very tricky because of how the torque comes on. You have to get just enough to spool, but to much and loose efficiency in the top end. Give me a call, I have a lot of questions for you. 713-895-8834
Chris
Chris
okay
I am having a lot of trouble picking a stall for my V6
my first stall was a 3800 and 2.5 STR and second is 4600 and 2.5 STR
the 3800 was slow to spool and the 4600 is to loose up top
now i did some reading and it seems the STR can affect efficiency as well
problems
1. no trans brake for v6 cars (yet) (4L60E)
2. 3800 was slow off the line 4600 better spool but loose
2. on foot brake car rolls forward, no boost on foot brake (like on brake leg shaking with e brake on lol)
It seems I need to keep the stall as high as possible and lower the STR. this will allow the stall to flash to an rpm where the turbo can get right into boost, but it will not
my question
in a perfect world is i could keep the 4600 stall and lower the STR to like 1.8
what difference would i notice, on the street? on foot brake? from a roll for passing slow *** drivers?
It seem the lower STR should make the foot brake not so hard? i know it won't build 8 psi but even 2 psi would help a **** ton cause it would spool so fast !!
any proven information you have would be great
I am having a lot of trouble picking a stall for my V6
my first stall was a 3800 and 2.5 STR and second is 4600 and 2.5 STR
the 3800 was slow to spool and the 4600 is to loose up top
now i did some reading and it seems the STR can affect efficiency as well
problems
1. no trans brake for v6 cars (yet) (4L60E)
2. 3800 was slow off the line 4600 better spool but loose
2. on foot brake car rolls forward, no boost on foot brake (like on brake leg shaking with e brake on lol)
It seems I need to keep the stall as high as possible and lower the STR. this will allow the stall to flash to an rpm where the turbo can get right into boost, but it will not
my question
in a perfect world is i could keep the 4600 stall and lower the STR to like 1.8
what difference would i notice, on the street? on foot brake? from a roll for passing slow *** drivers?
It seem the lower STR should make the foot brake not so hard? i know it won't build 8 psi but even 2 psi would help a **** ton cause it would spool so fast !!
any proven information you have would be great
