Franko6
Vendor , w/Business number
Since first working on the PD motors, we found the setting of the torsion value a bit of a mystery. The torsion value is located in VCDS/Engine Module/ block 4/ torsion value. We tended to figure that 0.0 was a good figure and originally let it go at that.
However, early on, we had a Passat Wagon that lost 4 mpg when we set the torsion value to 0.0. The customer had us return the value to it's original setting of -.5 and the mileage came right back.
Now we find that the value can be positive or negative a much greater degree. Most recently, we checked the value on a car that was in for an oil change. The torsion value was set at -5.7 and the owner says her manual transmission car averages 45mpg and on a trip will get over 52mpg!
This is what we think is happening:
The only way to set the engine for TDC is by using a crank lock, such as that sold by Metalnerd. We have been providing their timing tools for several years. However well the tools are made, we find that the hole in the flange that is used to pin the crank sprocket into position has a movement of about 1-2 degrees. There is also a question about the accuracy of the location of the front flange location hole that the crank lock uses. I think the hole location in the flange could allow another 1-2 degrees of error.
The total deviation, given these two variables, could allow the crank setting to be off as much as 4 degrees, +/-. Since the cam position is relative to the crank timing, that can create a wide variation for each engine's correct torsion value. That would account for the reason one engine works well with a +2.5 reading, while another is working very well with a reading that is nearly -6.0.
There is no TDC mark on the flywheel,nor is there any other positioning reference besides the crank lock to locate TDC. That takes away any scientific method of relating the crank position to the cam position.
The only way I know to accurately locate the true TDC mark is to remove the #1 injector and with a dial indicator and find the piston rolling through TDC. I have noticed that in the Passat, there is a hole that is on the side of the block where a mark could be made. This may also be true of the other PD motors. I will look.
But unless there is a method by which you can determine accurately where the TDC actually is, the setting of the cam's torsion value will be experimentation.
Those wanting to optimize their fuel ecomony/ power should move the cam sprocket in relation to the cam shaft. Moving the cam shaft in the direction of rotation moves the cam torsion value in the positive direction. Just like the injection pumps for the ALH engine, the setting is very precise and a small adjustment makes a lot of difference. Movements of a few points and then either taking performance runs or recording mileage should give you an idea if there can be an improvement over the existing torsion value setting.
However, early on, we had a Passat Wagon that lost 4 mpg when we set the torsion value to 0.0. The customer had us return the value to it's original setting of -.5 and the mileage came right back.
Now we find that the value can be positive or negative a much greater degree. Most recently, we checked the value on a car that was in for an oil change. The torsion value was set at -5.7 and the owner says her manual transmission car averages 45mpg and on a trip will get over 52mpg!
This is what we think is happening:
The only way to set the engine for TDC is by using a crank lock, such as that sold by Metalnerd. We have been providing their timing tools for several years. However well the tools are made, we find that the hole in the flange that is used to pin the crank sprocket into position has a movement of about 1-2 degrees. There is also a question about the accuracy of the location of the front flange location hole that the crank lock uses. I think the hole location in the flange could allow another 1-2 degrees of error.
The total deviation, given these two variables, could allow the crank setting to be off as much as 4 degrees, +/-. Since the cam position is relative to the crank timing, that can create a wide variation for each engine's correct torsion value. That would account for the reason one engine works well with a +2.5 reading, while another is working very well with a reading that is nearly -6.0.
There is no TDC mark on the flywheel,nor is there any other positioning reference besides the crank lock to locate TDC. That takes away any scientific method of relating the crank position to the cam position.
The only way I know to accurately locate the true TDC mark is to remove the #1 injector and with a dial indicator and find the piston rolling through TDC. I have noticed that in the Passat, there is a hole that is on the side of the block where a mark could be made. This may also be true of the other PD motors. I will look.
But unless there is a method by which you can determine accurately where the TDC actually is, the setting of the cam's torsion value will be experimentation.
Those wanting to optimize their fuel ecomony/ power should move the cam sprocket in relation to the cam shaft. Moving the cam shaft in the direction of rotation moves the cam torsion value in the positive direction. Just like the injection pumps for the ALH engine, the setting is very precise and a small adjustment makes a lot of difference. Movements of a few points and then either taking performance runs or recording mileage should give you an idea if there can be an improvement over the existing torsion value setting.