Spragless TC - Good for a street/strip car?
09-24-2009, 06:37 PM
#1
Spragless TC - Good for a street/strip car? Or is it a race only type ?
I'm just about ready to order a TH350 TC and I see "Spragless" is available. I tried looking it up in Google and on P.I's site but these always result in links either just saying they have one or "you should get one". Never, "Why" or any conditionals like it's a race only or won't last on the street or too hard on parts, etc.
I'm just about ready to order a TH350 TC and I see "Spragless" is available. I tried looking it up in Google and on P.I's site but these always result in links either just saying they have one or "you should get one". Never, "Why" or any conditionals like it's a race only or won't last on the street or too hard on parts, etc.
09-24-2009, 10:46 PM
#4
Hey Tiago! Yeah, I have built (by Century there in Richmond,TX) TH350 on it's way to me here in Upstate NY. I just have to figure out which TC to get. So far, Looks like a 2400 Vigi. I'm just wanting someone to tell me if a Spragless is okay for a mostly street, some strip type car like mine. I found a link to tell me what it is, how it works but nothing on the suitability on the street.
How's your quest for a drivetrain that won't get murdered when you hit the boost ?
How's your quest for a drivetrain that won't get murdered when you hit the boost ?
09-25-2009, 11:16 AM
#7
12 Second Club
iTrader: (3)
Join Date: Jan 2006
Location: NEWARK OHIO
Posts: 439
Likes: 0
Received 0 Likes
on
0 Posts
To Sprag or Not To Sprag
The question of whether or not to consider a “spragless” torque converter, as well as the benefits and drawbacks of them is a topic of much recent discussion and bickering. Knowing a little more now (hopefully) about how a torque converter works, let’s think about it for a moment. Under hard acceleration, the stator should be locked stationary against the sprag or roller clutch for most of, if not the entire run down the drag strip. Every combination of converter elements will vary, but generally the stator will begin to rotate when the turbine reaches 80-90% of impeller (engine) speed. It is safe to say that the stator may only rotate on the sprag or roller clutch at the top of each gear (just before the gear change), and at or approaching the finish line. On the flip side, if the sprag or roller clutch fails to hold and the stator is allowed to rotate backward (counter engine rotation), the torque multiplication disappears, as does stall speed, and the performance suffers tremendously. If the sprag is eliminated and the stator is held stationary all the time, then obviously it can not break. Some have argued that excessive heat is generated by spragless torque converters. This could be true in some applications (such as street driven vehicles), but we have not experienced this in any of the cars we have tested spragless converters in. Another argument is that the torque converter will exhibit a loss of efficiency due to the converter’s inability to change to rotary flow. This argument could have some credibility in some vehicles, however many vehicles experience the opposite; an increase in efficiency due to the assisting effect of the like rotating oil exiting the locked stator.
Recent advances in technology, materials, and manufacturing techniques have resulted in the availability of stronger sprags and roller clutches. However, the horsepower and torque levels we subject these components to have also increased. Other factors such as burnout technique, transmission condition (particularly the converter charge circuit), etc. also play a role in sprag durability.
Although certainly not for street driven vehicles, there appears not to be a significant drawback to the spragless stator in most torque converters. It really comes down to personal preference.
the last paragraphseems like it doesnt much care for a spragless on a street car
The question of whether or not to consider a “spragless” torque converter, as well as the benefits and drawbacks of them is a topic of much recent discussion and bickering. Knowing a little more now (hopefully) about how a torque converter works, let’s think about it for a moment. Under hard acceleration, the stator should be locked stationary against the sprag or roller clutch for most of, if not the entire run down the drag strip. Every combination of converter elements will vary, but generally the stator will begin to rotate when the turbine reaches 80-90% of impeller (engine) speed. It is safe to say that the stator may only rotate on the sprag or roller clutch at the top of each gear (just before the gear change), and at or approaching the finish line. On the flip side, if the sprag or roller clutch fails to hold and the stator is allowed to rotate backward (counter engine rotation), the torque multiplication disappears, as does stall speed, and the performance suffers tremendously. If the sprag is eliminated and the stator is held stationary all the time, then obviously it can not break. Some have argued that excessive heat is generated by spragless torque converters. This could be true in some applications (such as street driven vehicles), but we have not experienced this in any of the cars we have tested spragless converters in. Another argument is that the torque converter will exhibit a loss of efficiency due to the converter’s inability to change to rotary flow. This argument could have some credibility in some vehicles, however many vehicles experience the opposite; an increase in efficiency due to the assisting effect of the like rotating oil exiting the locked stator.
Recent advances in technology, materials, and manufacturing techniques have resulted in the availability of stronger sprags and roller clutches. However, the horsepower and torque levels we subject these components to have also increased. Other factors such as burnout technique, transmission condition (particularly the converter charge circuit), etc. also play a role in sprag durability.
Although certainly not for street driven vehicles, there appears not to be a significant drawback to the spragless stator in most torque converters. It really comes down to personal preference.
the last paragraphseems like it doesnt much care for a spragless on a street car
Trending Topics
09-25-2009, 11:40 AM
#8
Beautiful! Just the kind of succinct information I wanted. Thanks!
To Sprag or Not To Sprag
The question of whether or not to consider a “spragless” torque converter, as well as the benefits and drawbacks of them is a topic of much recent discussion and bickering. Knowing a little more now (hopefully) about how a torque converter works, let’s think about it for a moment. Under hard acceleration, the stator should be locked stationary against the sprag or roller clutch for most of, if not the entire run down the drag strip. Every combination of converter elements will vary, but generally the stator will begin to rotate when the turbine reaches 80-90% of impeller (engine) speed. It is safe to say that the stator may only rotate on the sprag or roller clutch at the top of each gear (just before the gear change), and at or approaching the finish line. On the flip side, if the sprag or roller clutch fails to hold and the stator is allowed to rotate backward (counter engine rotation), the torque multiplication disappears, as does stall speed, and the performance suffers tremendously. If the sprag is eliminated and the stator is held stationary all the time, then obviously it can not break. Some have argued that excessive heat is generated by spragless torque converters. This could be true in some applications (such as street driven vehicles), but we have not experienced this in any of the cars we have tested spragless converters in. Another argument is that the torque converter will exhibit a loss of efficiency due to the converter’s inability to change to rotary flow. This argument could have some credibility in some vehicles, however many vehicles experience the opposite; an increase in efficiency due to the assisting effect of the like rotating oil exiting the locked stator.
Recent advances in technology, materials, and manufacturing techniques have resulted in the availability of stronger sprags and roller clutches. However, the horsepower and torque levels we subject these components to have also increased. Other factors such as burnout technique, transmission condition (particularly the converter charge circuit), etc. also play a role in sprag durability.
Although certainly not for street driven vehicles, there appears not to be a significant drawback to the spragless stator in most torque converters. It really comes down to personal preference.
the last paragraphseems like it doesnt much care for a spragless on a street car
The question of whether or not to consider a “spragless” torque converter, as well as the benefits and drawbacks of them is a topic of much recent discussion and bickering. Knowing a little more now (hopefully) about how a torque converter works, let’s think about it for a moment. Under hard acceleration, the stator should be locked stationary against the sprag or roller clutch for most of, if not the entire run down the drag strip. Every combination of converter elements will vary, but generally the stator will begin to rotate when the turbine reaches 80-90% of impeller (engine) speed. It is safe to say that the stator may only rotate on the sprag or roller clutch at the top of each gear (just before the gear change), and at or approaching the finish line. On the flip side, if the sprag or roller clutch fails to hold and the stator is allowed to rotate backward (counter engine rotation), the torque multiplication disappears, as does stall speed, and the performance suffers tremendously. If the sprag is eliminated and the stator is held stationary all the time, then obviously it can not break. Some have argued that excessive heat is generated by spragless torque converters. This could be true in some applications (such as street driven vehicles), but we have not experienced this in any of the cars we have tested spragless converters in. Another argument is that the torque converter will exhibit a loss of efficiency due to the converter’s inability to change to rotary flow. This argument could have some credibility in some vehicles, however many vehicles experience the opposite; an increase in efficiency due to the assisting effect of the like rotating oil exiting the locked stator.
Recent advances in technology, materials, and manufacturing techniques have resulted in the availability of stronger sprags and roller clutches. However, the horsepower and torque levels we subject these components to have also increased. Other factors such as burnout technique, transmission condition (particularly the converter charge circuit), etc. also play a role in sprag durability.
Although certainly not for street driven vehicles, there appears not to be a significant drawback to the spragless stator in most torque converters. It really comes down to personal preference.
the last paragraphseems like it doesnt much care for a spragless on a street car
09-25-2009, 12:37 PM
#9
You guys are on the right track. "THEBRAD" response is right on the money. Each converter can very of when it couples so the sprag is locked through most of the run. So in an all out race setup, a spragless is a good idea for dependability and durability. But in a street car it will not free wheel, thus creating more heat.
What are you power levels and weight? There are also different versions of sprags for the TH350. There is a 10 element mechanical diode that will hold 2000+HP.
Give me a call and I can give you some details on converter options.
713-895-8834
Chris
What are you power levels and weight? There are also different versions of sprags for the TH350. There is a 10 element mechanical diode that will hold 2000+HP.
Give me a call and I can give you some details on converter options.
713-895-8834
Chris
09-25-2009, 01:05 PM
#10
Before adding the T76, my car with me was 3,650. I suppose it's like 3,700 now. I went 108mph in the 1/8th mile last week so I guess by some of the calculators out there,
724.33 flywheel HP and 651.897 rear wheel HP
Calling now
Thanks for the responses...
724.33 flywheel HP and 651.897 rear wheel HP
Calling now
Thanks for the responses...
You guys are on the right track. "THEBRAD" response is right on the money. Each converter can very of when it couples so the sprag is locked through most of the run. So in an all out race setup, a spragless is a good idea for dependability and durability. But in a street car it will not free wheel, thus creating more heat.
What are you power levels and weight? There are also different versions of sprags for the TH350. There is a 10 element mechanical diode that will hold 2000+HP.
Give me a call and I can give you some details on converter options.
713-895-8834
Chris
What are you power levels and weight? There are also different versions of sprags for the TH350. There is a 10 element mechanical diode that will hold 2000+HP.
Give me a call and I can give you some details on converter options.
713-895-8834
Chris
09-26-2009, 10:27 PM
#13
We are currently running a Circle D 230mm spragless converter in our quicker car. It doesn't see much street time anymore, but we hit the track with it 2-3 weekends out of the month.
We don't have to worry about the sprag breaking and it will run the same 60ft all day long. It just doesn't get anymore consistent than this and we are still running pump gas which is known for not being the most consistent burning fuel.
I managed to win the last 2 bracket races we competed in and I contribute a large part of our success to the consistency of the car. Some rounds were won by mere a
.001 -.004.
I'm a believer in the spragless
We don't have to worry about the sprag breaking and it will run the same 60ft all day long. It just doesn't get anymore consistent than this and we are still running pump gas which is known for not being the most consistent burning fuel.
I managed to win the last 2 bracket races we competed in and I contribute a large part of our success to the consistency of the car. Some rounds were won by mere a
.001 -.004.
I'm a believer in the spragless
09-30-2009, 02:46 PM
#15
Do not run a spragless on the street. Very well explained. We build fulll competition converters as well and most are spragless including the one that just set the world record on 295 drag radials!!!!
Greg
Greg
__________________
FTI COMPETITION CONVERTERS AND TRANSMISSIONS
"IT'S NOT CHEATING, IT'S THE COMPETITIVE EDGE."
1-866-726-8358
info@ftiperformance.com
FTIPerformance.com
FTI Converter build sheet
FTI COMPETITION CONVERTERS AND TRANSMISSIONS
"IT'S NOT CHEATING, IT'S THE COMPETITIVE EDGE."
1-866-726-8358
info@ftiperformance.com
FTIPerformance.com
FTI Converter build sheet
