Quote:
Originally Posted by oab_au
OK, I think you are placing a lot of your thinking around this statement, “Alex has stated that when he inserts the fuse, front wheel drive only is engaged. Therefore the signal now is correct for the system.”
This is right, but only when the fuse is inserted. This is the only time that the two TCU send the same signal for the same action. When the US fuse is inserted for FWD, the TCU sends a 95% signal to turn off the clutch. When the VTD fuse is in for DIFF LOCK, it sends a 95% signal, to turn on the clutch
The US trans has the clutch turned off, and the VTD has the clutch turned on. Its because the C solenoids are opposite to each other, that the US solenoid turns off the clutch. The VTD solenoid turns the clutch full on.
With Alex’s car, when the VTD TCU detects wheel spin, it will send a 95% signal to apply the clutch, but the US solenoid, being opposite, turns it into clutch off. 
When he is turning tight, the VTD TCU sends a 5% signal to turn the clutch off, the US solenoid turns the clutch on, to cause the binding. 
Changing the US solenoid for a VTD solenoid, will turn these signals back the right way, binding will not occur, and wheel spin will be prevented. 
Harvey. |
Harvey,
As usual you twist what is fact and what is true, in an attempt to prove a theory, which is wrong. Forget the percentage jargon. Confine actions to the binary. All else follows.
Inserting the fuse results in exactly the same control signal, in respect of the orientation of the pulses, as when normal control is functioning. The difference you describe is not in fact required. This is a figment of your imagination, alight as a means of justifying another fairy story.
The signals do not require turning back the right way. They are the right way. The signals are the same for both TCU. It is the final action which takes place, as a result of the signal, which is different in the two systems. The same signal achieves the same result due to the use of a different orientation of valve in each system.
!. A lengthening pulse energises the solenoid and extends the armature. 2. A shortening pulse allows the armature to retract.
1. Closes a N/O. valve. Opens a N/C valve.
2. Opens a N/O valve. Closes a N/C valve.
It is the relationship between the non electrical controls which requires “reversal” , and the difference in solenoid valve configuration achieves the required result. N.B. This relationship will mean a second “reversal” and therefore, no reversal, in the event that your theory is applied.
Normal VTD system. --- When increased front bias is required, (Or the fuse switch fitted to provide a locked up drive.) the pulse length will be increased, (Or a constant signal transmitted.) in order to close a N/O solenoid, thus increasing pressure, to close a LSD clutch. The TCU will be programmed to increase the pulse length.
With Alex' car. --- When increased front bias is required, (as when inserting the fuse switch), the same increased pulse length command, (or a constant signal) will open a N/C solenoid, thus reducing pressure, to open the centre clutch. The TCU will be programmed to increase the pulse length.
Think about it.
