Dave Goerend knows his stuff....
06-04-2007, 11:11 PM
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Dave Goerend knows his stuff....
Ok sorry probably a pointless thread, but this just shows Dave Goerands drivetrain knowledge and customer service in a email reply to me.
Here is some information on our converters and valve bodies and how they work. It is probably more information than you need, but better more than not enough. If you have any questions, or if I failed to answer something, just let me know.
We like to start with a low stall triple disc converter that will keep the engine in its torque range of about 1700-2200 rpm, or put another way, the converter will have the engine working at about 500-800 rpm lower than a stock converter. The stock converter usually lets the engine rev to 2300-2800 rpm, this is past its peak power rpm. On the 24 valve engines and the Common Rail this torque range will be higher.
To explain how a torque converter works, let’s start with 2 wall fans facing each other, (a drive fan and a driven fan.) If we turn one fan on, the wind from this fan will make the other fan turn. In the case of a torque converter, the drive fan is bolted to the engine and the driven fan is connected to the input shaft of the transmission. When we are at a stop sign, with the trans in gear and the engine at idle, the drive fan is spinning so slow that it will not “blow” enough oil at the driven fan to make it turn. As we increase engine and drive fan rpm, it blows more oil at the driven fan and the driven fan starts to turn and moves the vehicle.
The drive fan ALWAYS goes a little faster than the driven fan, just like the wall fans. If you would stick a feather or straw into the driven fan blades it would slow the driven fan down but not the drive fan. This would be just like pulling a heavier trailer. (The straw in the driven fan would be just like adding a load. A heavier trailer is more load.) When we get up to speed, we have a lock up clutch that will “lock” the fans together. (It actually locks the driven fan to the front cover, which is bolted to the engine. The driven fan is now “locked” to the engine.)
When the drive and driven fan are not locked together, heat is generated in the converter. The greater the load and rpm difference, the greater the heat generated.
Let’s say, we have a converter that the drive fan (impeller) is going 2500 rpm and the driven fan (turbine) is going 1800 rpm, (efficiency would be 72%, 1800 divided by 2500, this efficiency is constantly varying depending on the rpm of the converter, the power input to the converter and the output load, or towed weight.) When the converter clutch locks the fans together, the engine rpm will drop 700 rpm. If we use a converter that is more efficient, like a “low stall” converter, say 88%, the impeller would be going 2500 rpm and the turbine 2200 rpm, then when the converter clutch locks the turbine to the front cover, the rpm will drop only 300 rpm. This is much easier on the converter clutch lining and will reduce glazing of the clutch lining, and because the fluid coupling of the converter is more efficient it will deliver more power to the wheels before the converter locks up and the converter will also run cooler before lock up.
To explain the “stall speed”, let’s start with the true full stall. If we put the Trans in drive and hold the brakes so the vehicle will not move, and then hold the throttle at wide open, the torque converter will “stall” the engine at a certain rpm, the engine will not be able to spin any faster unless the vehicle is allowed to move. This is true full stall.
WE DO NOT RECOMMEND TESTING TRUE STALL, AS IT CAN DAMAGE SHAFTS AND OVERHEAT THE TORQUE CONVERTER.
The next stall speed can be called “break away” stall speed. Let’s imagine we are stopped on a hill and rather than hold the vehicle stationary with the brakes, we do it by giving it enough throttle so we don’t move forward up the hill OR backwards down the hill. Let’s say, the engine rpm required to “hold” the truck is 1100 rpm. If we increase the rpm to 1125 and the truck starts to move up the hill, the “break away” stall speed was 1125 rpm.
“Flash stall” is when you floor the throttle from a standing start…The engine starts to accelerate quickly, then the engine rpm “pauses” and starts to pull the truck. Let’s say the engine gets from idle to 1500 rpm in l.5 seconds when you floor it, then it takes another 2 or 3 seconds to get from 1500 to 1700 rpm, this would mean the “flash stall” was 1500 rpm. When we lower the stall we want to lower the break away speed and the flash stall speed. This makes the engine work at a lower rpm for a given road speed and in most cases, will increase fuel mileage because the converter is more efficient.
Once we are up to speed, the computer will command the lock up clutch “on”, and the driven fan will lock to the front cover of the converter. Now the drive and driven fan will be going the same speed as the engine and all the engine power will be delivered to the trans and back to the wheels.
In a stock torque converter, the clutch has 1 clutch plate with about 37 square inches of clutch lining. We like to use 3 clutch surfaces that total about 105 square inches of lining and call this a triple disc converter. This 3 disc will hold much more torque than a single disc can.
The cost of this triple disc torque converter is Edit It has a lifetime warranty, even if the transmission fails or the input shaft breaks and the converter needs to be replaced. We will replace it for the cost of freight only. The warranty does not cover loss of use, time, towing, installation, freight or per diem damages.
Cost of a 100,000 mile warranty converter is Edit It would cost approximately ˝ to rebuild this converter if ruined by the trans or a broken input shaft.
Along with the converter, I would also install a stronger 1-2 band apply lever when you have the trans out, because if the stock one breaks the trans must come out to replace it. The cost of the lever is Edit There is also a stronger apply strap and anchor for the band. The cost for that is Edit for the pair.
You may want to replace the front clutch seals with the updated seals as long as the trans is out.
A lot of times, on a good working low mileage trans, replacing the front drum seals with the updated seals is all you need to do in the front section of the trans, along with the stronger band lever, strap and anchor and the band apply piston cover.
If it is a high mileage trans you may want to replace the input shaft and hub with new, it is not uncommon for a stock shaft with a lot of miles to break. Cost of a new shaft and hub from Dodge is Edit
There are also stronger input shafts available if needed for Edit
The valve body we build will fill the torque converter in all gears, including park so the front bushing of the trans will get oil while the engine is idling. The lube circuit is modified so there is always line pressure feeding the lube circuit. With the factory valve body, if the trans fluid gets hot, you may lose oil to the lube circuit while decelerating downhill while the engine is at low rpm or idle and the trans pump can’t keep up due to the hot thin fluid. With our valve body, this will not happen.
Our valve body will have pressures starting at 60-90 psi at idle and will go to 150-190 psi at wide open throttle depending on the application. (The factory valve body has pressures of about 50-60 psi at idle and 85-95 psi at wide open throttle.) While our pressure is much higher than stock, our trans still retains a smooth shift. We do not like a firm bang shift.
This valve body is also ported so if the shift linkage ever gets loose, it will not cross-feed and damage the forward clutch while in reverse or park.
This valve body is capable of lockup in 2nd, 3rd, and 4th, or all forward gears. 1st, 2nd, 3rd, and 4th if desired, via a toggle switch. This is for use with an exhaust brake or to keep the transmission temperature down while towing uphill. If the valve body is built to lock up in 2nd, 3rd, and 4th, it will not kill the engine if you forget to turn off the toggle switch when you come to a stop; like it would if capable of lockup in all forward gears. We do not recommend letting the trans shift from one gear to the next while the converter is locked.
This valve body comes complete with solenoids. The governor pressure solenoid and governor pressure sensor are New Dodge parts. The cost of this valve body is Edit
A stronger 1-2 shift lever, apply strap and anchor is also recommended when using this valve body. The higher pressures may break the stock lever. Cost of this set is Edit
Thanks.
Dave Goerend
Edit
Here is some information on our converters and valve bodies and how they work. It is probably more information than you need, but better more than not enough. If you have any questions, or if I failed to answer something, just let me know.
We like to start with a low stall triple disc converter that will keep the engine in its torque range of about 1700-2200 rpm, or put another way, the converter will have the engine working at about 500-800 rpm lower than a stock converter. The stock converter usually lets the engine rev to 2300-2800 rpm, this is past its peak power rpm. On the 24 valve engines and the Common Rail this torque range will be higher.
To explain how a torque converter works, let’s start with 2 wall fans facing each other, (a drive fan and a driven fan.) If we turn one fan on, the wind from this fan will make the other fan turn. In the case of a torque converter, the drive fan is bolted to the engine and the driven fan is connected to the input shaft of the transmission. When we are at a stop sign, with the trans in gear and the engine at idle, the drive fan is spinning so slow that it will not “blow” enough oil at the driven fan to make it turn. As we increase engine and drive fan rpm, it blows more oil at the driven fan and the driven fan starts to turn and moves the vehicle.
The drive fan ALWAYS goes a little faster than the driven fan, just like the wall fans. If you would stick a feather or straw into the driven fan blades it would slow the driven fan down but not the drive fan. This would be just like pulling a heavier trailer. (The straw in the driven fan would be just like adding a load. A heavier trailer is more load.) When we get up to speed, we have a lock up clutch that will “lock” the fans together. (It actually locks the driven fan to the front cover, which is bolted to the engine. The driven fan is now “locked” to the engine.)
When the drive and driven fan are not locked together, heat is generated in the converter. The greater the load and rpm difference, the greater the heat generated.
Let’s say, we have a converter that the drive fan (impeller) is going 2500 rpm and the driven fan (turbine) is going 1800 rpm, (efficiency would be 72%, 1800 divided by 2500, this efficiency is constantly varying depending on the rpm of the converter, the power input to the converter and the output load, or towed weight.) When the converter clutch locks the fans together, the engine rpm will drop 700 rpm. If we use a converter that is more efficient, like a “low stall” converter, say 88%, the impeller would be going 2500 rpm and the turbine 2200 rpm, then when the converter clutch locks the turbine to the front cover, the rpm will drop only 300 rpm. This is much easier on the converter clutch lining and will reduce glazing of the clutch lining, and because the fluid coupling of the converter is more efficient it will deliver more power to the wheels before the converter locks up and the converter will also run cooler before lock up.
To explain the “stall speed”, let’s start with the true full stall. If we put the Trans in drive and hold the brakes so the vehicle will not move, and then hold the throttle at wide open, the torque converter will “stall” the engine at a certain rpm, the engine will not be able to spin any faster unless the vehicle is allowed to move. This is true full stall.
WE DO NOT RECOMMEND TESTING TRUE STALL, AS IT CAN DAMAGE SHAFTS AND OVERHEAT THE TORQUE CONVERTER.
The next stall speed can be called “break away” stall speed. Let’s imagine we are stopped on a hill and rather than hold the vehicle stationary with the brakes, we do it by giving it enough throttle so we don’t move forward up the hill OR backwards down the hill. Let’s say, the engine rpm required to “hold” the truck is 1100 rpm. If we increase the rpm to 1125 and the truck starts to move up the hill, the “break away” stall speed was 1125 rpm.
“Flash stall” is when you floor the throttle from a standing start…The engine starts to accelerate quickly, then the engine rpm “pauses” and starts to pull the truck. Let’s say the engine gets from idle to 1500 rpm in l.5 seconds when you floor it, then it takes another 2 or 3 seconds to get from 1500 to 1700 rpm, this would mean the “flash stall” was 1500 rpm. When we lower the stall we want to lower the break away speed and the flash stall speed. This makes the engine work at a lower rpm for a given road speed and in most cases, will increase fuel mileage because the converter is more efficient.
Once we are up to speed, the computer will command the lock up clutch “on”, and the driven fan will lock to the front cover of the converter. Now the drive and driven fan will be going the same speed as the engine and all the engine power will be delivered to the trans and back to the wheels.
In a stock torque converter, the clutch has 1 clutch plate with about 37 square inches of clutch lining. We like to use 3 clutch surfaces that total about 105 square inches of lining and call this a triple disc converter. This 3 disc will hold much more torque than a single disc can.
The cost of this triple disc torque converter is Edit It has a lifetime warranty, even if the transmission fails or the input shaft breaks and the converter needs to be replaced. We will replace it for the cost of freight only. The warranty does not cover loss of use, time, towing, installation, freight or per diem damages.
Cost of a 100,000 mile warranty converter is Edit It would cost approximately ˝ to rebuild this converter if ruined by the trans or a broken input shaft.
Along with the converter, I would also install a stronger 1-2 band apply lever when you have the trans out, because if the stock one breaks the trans must come out to replace it. The cost of the lever is Edit There is also a stronger apply strap and anchor for the band. The cost for that is Edit for the pair.
You may want to replace the front clutch seals with the updated seals as long as the trans is out.
A lot of times, on a good working low mileage trans, replacing the front drum seals with the updated seals is all you need to do in the front section of the trans, along with the stronger band lever, strap and anchor and the band apply piston cover.
If it is a high mileage trans you may want to replace the input shaft and hub with new, it is not uncommon for a stock shaft with a lot of miles to break. Cost of a new shaft and hub from Dodge is Edit
There are also stronger input shafts available if needed for Edit
The valve body we build will fill the torque converter in all gears, including park so the front bushing of the trans will get oil while the engine is idling. The lube circuit is modified so there is always line pressure feeding the lube circuit. With the factory valve body, if the trans fluid gets hot, you may lose oil to the lube circuit while decelerating downhill while the engine is at low rpm or idle and the trans pump can’t keep up due to the hot thin fluid. With our valve body, this will not happen.
Our valve body will have pressures starting at 60-90 psi at idle and will go to 150-190 psi at wide open throttle depending on the application. (The factory valve body has pressures of about 50-60 psi at idle and 85-95 psi at wide open throttle.) While our pressure is much higher than stock, our trans still retains a smooth shift. We do not like a firm bang shift.
This valve body is also ported so if the shift linkage ever gets loose, it will not cross-feed and damage the forward clutch while in reverse or park.
This valve body is capable of lockup in 2nd, 3rd, and 4th, or all forward gears. 1st, 2nd, 3rd, and 4th if desired, via a toggle switch. This is for use with an exhaust brake or to keep the transmission temperature down while towing uphill. If the valve body is built to lock up in 2nd, 3rd, and 4th, it will not kill the engine if you forget to turn off the toggle switch when you come to a stop; like it would if capable of lockup in all forward gears. We do not recommend letting the trans shift from one gear to the next while the converter is locked.
This valve body comes complete with solenoids. The governor pressure solenoid and governor pressure sensor are New Dodge parts. The cost of this valve body is Edit
A stronger 1-2 shift lever, apply strap and anchor is also recommended when using this valve body. The higher pressures may break the stock lever. Cost of this set is Edit
Thanks.
Dave Goerend
Edit
06-05-2007, 05:39 AM
#7
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Is this 1-2 band apply lever or strap the same thing i have been hearing other transmission guys tell me I should replace with a Kevlar band? Just curious if it's different terminology for the same thing?
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06-05-2007, 12:15 PM
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That is a great explanation - the same one that has been on his website for a while:
http://www.goerend.com/torqueconvertertech.php
http://www.goerend.com/torqueconvertertech.php
06-05-2007, 01:49 PM
#14
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They are different, but----The band holds the drum, the apply lever is what is used to apply the band.
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