[Trevor]

Originally Posted by TomsSVX

Trevor, everything I have said about this is based on an assumption. I have never stated anything more than that. Unlike you down unders I am OK with being wrong. So please, pretty please prove that the duty cycles are not reversed and that the Sol. C change would not fix his binding issues. I never said it would do more, but it would make it driveable. Until you do, you are pointing fingers.

Once these figures are posted, and I am indeed wrong I will admit my assumptions were incorrect. But you are nit-picking to try and find fault rather than trying to find a solution

Tom

Tom,

Please be sure that I am not nit picking and trying to find fault when none exists. My object is to ensure that members are provided with correct information. In particular, that Alex is/was not persuaded to spend time and money on a wild goose chase.

E.G. If you were arguing about a flat earth and I pointed out -- That tall objects at a distance were visible but not short objects at the same distance. That a vehicle could travel in the same direction and end up at the starting point. That the shadow on the moon was indicative.

In the event that you did not understand these concepts, this would not show factual evidence as being unproved.

This argument is costing me a great deal of time. However as I have always had respect for you, I am sure that you are simply confused, rather than dodging the issue, as is common in respect of another member opposing me.

You demonstrate considerable mechanical knowledge. However in this instance, I am at advantage, having trodden this same road for many years. My bread was buttered by designing electrical/electronic control systems. A design error in respect of any large contract, would have sent my company bankrupt, with all my employees out of a job. This has forced me into a habit of accuracy.

In current argument no set of figures is involved or required and nothing of this order can be, or is required to be posted.

If there was a difference in the duty cycles, (i.e. That they are reversed.) there would NOT be a need for different solenoids in the VTD and US transmissions. This very fact proves that the duty cycles are NOT reversed. What is more there is additional solid evidence.

I again present the statements of proof, that I have already posted in the threads. -----

Thread, jdm svx trans, will it work?

#87 Trevor. If the normally closed C solenoid in the USDM transmission, *Alex now has fitted, is changed for a normally open C solenoid from a VTD transmission, the function of a signal from his current VTD TCU, will be reversed. e.g. An instruction to reduce clutch pressure, will result in an increase in pressure and vice versa. This is so, no matter which TCU is used. (The basic signals from the VTD and US being similar)

#90 Trevor. With the VTD TCU fitted in Alex’ SVX, when pressure is intended to be increased, a signal with an increased pulse length will be sent from the TCU, with the expectation of closing a normally open solenoid bleed valve. This would normally result in increased pressure and close the centre differential clutch to lock the centre differential.

The same increased pulse length (or a continuous) signal, when sent to the normally closed solenoid valve, now fitted in the US transmission in Alex’ car, will open the valve and reduce the pressure, opening the centre transfer clutch and provide only front wheel drive.

Fitting the special fuse, will have this same effect. N.B. This fact was confirmed by alex in post #40 as follows.---
“when i insert the fuse in Diff Lock then the rear diff is not in use and the car could spin on the front weal.”

#92 Trevor. This is the guts of the situation. ---

#1 Normal VTD system. --- When increased front bias is required, the pulse length will be increased, 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.

#1 With Alex' car. --- When increased front bias is required, the same increased pulse length command, will open a N/C solenoid, thus reducing pressure, to open the centre clutch. The TCU will be programmed to increase the pulse length.

#2 Normal VTD system. --- When increased rear bias is required, the pulse length will be reduce, in order to open a N/O solenoid, thus reducing pressure, to open a LSD clutch. The TCU will be programmed to reduce the pulse length.

#2 With Alex' car. --- When increased rear bias is required, the same reduced pulse length command, will close a N/C solenoid, thus increasing pressure, to close the centre clutch. The TCU will be programmed to reduce the pulse length.

The above shows that at present the sequence is as required and does not require the change in solenoid. (Both systems have the same sequence in respect of a signal.)

#114 Trevor. The VDT TCU will provide the same instruction, to a now N/C solenoid, as when the complete VDT LSD system was in use,to enable the same result. There is no change of solenoid required.

If a US type TCU is fitted, the same sequence will apply and the same N/C solenoid must be used. A simple reversal of the action of the command is required. (There is no change of solenoid required.)

This reversal is taken care of as a result of the changed transmission, with its existing normally closed C solenoid. A change to a normally open C solenoid, as has been wrongly suggested, will result in no change, and no reversed action as is required.

#122 Trevor. The same signal in respect of pulse length, is transmitted by both types of TCU. In both a lengthened pulse operates the solenoid. A shortening pulse disengages the solenoid towards its normal non-operated position when not energised.

The difference in solenoids provides the required reverse action for the associated valve. The US tranny has a solenoid valve which when energised opens to take pressure off the clutch i.e. a N/C. The VTD has a solenoid which when energised applies pressure and locks up the clutch. "It is that plain and simple"

#124 Trevor. I have in several instances, including the above, proven that the signal is the same in respect of the application of pulse length. Both use a lengthened pulse to increase the effect/movement of the SOLENOID, but not operation of the VALVE which is opposite in the respect of a normally open and normally closed solenoid valve.

A normally open (N/O) solenoid valve, rests with the valve open. A normally closed (N/C), with the valve closed. A very good reason why I often use the full wording "solenoid valve" in preference to simply "solenoid".

Thread, US over European.

#12 Trevor. It has been done in Europe, but THE C SOLENOID WAS NOT CHANGED and the ORIGINAL N/C SOLENOID RETAINED. A US TCU was installed. All exactly as I have been stating, over and over.

#13 Trevor. The solenoid MUST match the transmission in use, NOT the TCU. The same increasing/decreasing pulse length signal, is applied by both TCU. The "phasing" is NOT reversed.

This IS the very REASON for the different solenoids in respect of the two transmissions. Reversing the action of the solenoids corrects an otherwise incorrect signal, thus preventing the need for any mechanical alteration.

#26 Trevor. By changing the C solenoid, as you keep suggesting, the proper duty cycle signal will be reversed when applied to the transmission. An off period will register as an on period and an on period as an off period.

#29 Trevor. The duty rates have nothing to do with the argument. The overall duty rates and duty signal would be reversed if the C solenoid is changed, thus completely upsetting the proper operation of the clutch.


Pleas read and assimilate the above data carefully.

All the very best, Trevor.