Increase torque split in auto??

[TomsSVX]

Just a quick idea... would one be able to fit a resistor inline to increase the torque split but not induce binding?? I understand its a signal not a voltage reading but what do ya think??

Tom

[Manarius]

Originally Posted by TomsSVX

Just a quick idea... would one be able to fit a resistor inline to increase the torque split but not induce binding?? I understand its a signal not a voltage reading but what do ya think??

Tom

As in set the solenoid C from 0% duty to 100% duty? I know of guys that have done it with a switch, but not with some sort of resistor.

You're going to get binding if you try to put in too much torque without enough slip.

[Nomake Wan]

No... removing power from the solenoid causes it to go to 0% duty, which fully engages the clutch, causing 50/50 split.

Full signal (not power... signal) causes the solenoid to go to 95% duty (there is no 100%) and thus give you 100/0. This is when you put in the FWD fuse.

What Tom is suggesting is a way to make the car start off with something other than 90/10 (if that is indeed what the base split is; I intend to dig deeper about that). For instance, starting with 70/30.

To answer your question... since it is a signal, I'd think you'd need a way to create your own signal instead by creating a circuit designed specifically to translate the signal based upon a ramp. So that you still get 50/50 when need be, but that any signal which goes past a certain duty level is sent as the duty level for your specified rating instead. I understand the concept at hand, but don't look it me when it comes to designing the actual circuit. I don't know anything about that sort of thing. Someone with more experience will have to chime in and tell you what would be required.

Of course we'd also have to know exactly how Solenoid C and the TCU operate together before messing with it...

[Trevor]

Originally Posted by TomsSVX

Just a quick idea... would one be able to fit a resistor inline to increase the torque split but not induce binding?? I understand its a signal not a voltage reading but what do ya think??

Tom

Tom, I do not have data on the US system incorporating a clutch and have read confusing comments. Is the clutch engaged or is it released, when fluid pressure is applied.

When I can be absolutely sure in this regard, I will comment further.

Thanks, Trevor.

[Nomake Wan]

95% duty cycle of Solenoid C results in the clutch being 100% disengaged. Though I don't know what that means, perhaps you do.

[crazyhorse]

Couldn't a variable pulse wave generator make this happen?

If so, I think I can lay hands on one in an industrial relay form.

[Trevor]

Originally Posted by Nomake Wan

95% duty cycle of Solenoid C results in the clutch being 100% disengaged. Though I don't know what that means, perhaps you do.

The "C" solenoid valve in 4AUT transmissions is normally closed. The valve is shut when the solenoid is not energised and opens to a drain when energised, thus reducing the fluid pressure delivered to the clutch.

Therefore if a 95% duty cycle of Solenoid C results in the clutch being 100% disengaged, the solenoid is open and there is low pressure delivered to the clutch when it is open and pressure would close the clutch.

However this must be absolutely confirmed before any suggestions can be examined. I hope Tom has hands on knowledge of the mechanics involved.

P.S. If the above is correct, Tom's idea of a resistor would appear feasible and worthy of experiment.

[Crazy_pilot]

So the idea is to have the car operating at a standard torque split with more rear bias than it does now, right? Obviously we can't exceed 50:50, but more rear than I have now would be awesome. After the first few winter days in the SVX, I can say that it definitely doesn't swing the tail as easily as the Foresters when I step on it in a turn. It also doesn't do donuts as tightly.

[b3lha]

I don't think a resistor will do the trick. The solenoid will still pulse open and closed at the same rate.

I think you need a circuit like this to generate your own duty cycle. Then you need a switch to select whether the transmission uses the TCU's duty cycle or the one from your circuit.

http://www.doctronics.co.uk/555.htm#more%20astables

You could replace R1 and R2 with a single potentiometer which you would turn to vary the duty cycle.

(Please check this with an electronics expert before you try it out. I've repeatedly proved in my memory dump thread that I don't know much about electronics.)

The ultimate solution is to reprogram the TCU. But there is a lot of reverse-engineering to be done before that becomes possible.

[longassname]

Trevor,

trust me you don't even want to waste your time with this one as the people providing you information are providing you even worse information than usual/average.

There are a several things of importance which are well beyond their reckoning. First of all as is typical of most automotive transmission fluid circuits what you are actually dealing with is a play of pilot pressure versus line pressure not simply the control of one fluid pressure. Secondly the friction materials in an automatic transmission have a coeficient of friction which varies wildly according to the torque applied. Thirdly the atf used has a friction profile (on a side note many of the problems with heat/performance complained about on the 4eat are a result of users using a fluid with an inapropriate friction profile) which is far from linear.

Originally Posted by Trevor

Tom, I do not have data on the US system incorporating a clutch and have read confusing comments. Is the clutch engaged or is it released, when fluid pressure is applied.

When I can be absolutely sure in this regard, I will comment further.

Thanks, Trevor.

[NiftySVX]

WOW that's not very nice. I don't see the need to make assumptions about facts that are beyond other people's reckoning. All of that is true, and it is not hard to see that the pressure is actually pilot pressure. I mean, there is a pilot valve... and there is a transfer control valve... but those don't appear relevant when discussing a resistor to the duty solenoid c...

This reminds me of what is wrong with this board

People calling other people stupid, making statements like "There are a several things of importance which are well beyond their reckoning"

If you would like to explain, in detail, including all of these things that are beyond reckoning, that modification to the control circuit in this fashion is a bad idea, then be my guest. Maybe you think it's a good idea? I look forward to you explaining, in full detail, exactly what the effect of this might be, such a wealth of knowledge should not be lost to the world.

Don't forget to include:

The pilot pressure and why it is important to consider that in this context.

The coefficient (that's 2 f's, mind you) of friction which varies wildly according to the torque applied. (keep in mind coefficient means number so an equation would be relevant, since you brought it up)

Oh, and the friction profile of the fluid. This one may need a graph. Oh, and don't forget to include the equation.

Gee, seems like that would take an awful lot of writing to say that increasing transfer pressure could cause clutch wear and modifying the solenoid could cause, among other things, its failure?

[longassname]

Nifty,

My appologies. I wasn't trying to insult you in fact my comments were not directed towarards anything you said.

I was simply addressing the "reservations" which Trevor was rightfully reserving. Any condescendeing tone was my bad and just an admission of frequency in which the information given to Trevor as rock solid fact is in fact wrong, wrong, wrong, wrong.

I really wouldn't like to explain in detail the play of pilot pressure vs line pressure, or the coefficient of friction vs torque, or the friction profile of the fluid. That was the whole point of my comment. Trying to apply a linear modification to a circuit with two non linear inputs and a non linear control..........well, you get the picture.

Originally Posted by NiftySVX

WOW that's not very nice. I don't see the need to make assumptions about facts that are beyond other people's reckoning. All of that is true, and it is not hard to see that the pressure is actually pilot pressure. I mean, there is a pilot valve... and there is a transfer control valve... but those don't appear relevant when discussing a resistor to the duty solenoid c...

This reminds me of what is wrong with this board

People calling other people stupid, making statements like "There are a several things of importance which are well beyond their reckoning"

If you would like to explain, in detail, including all of these things that are beyond reckoning, that modification to the control circuit in this fashion is a bad idea, then be my guest. Maybe you think it's a good idea? I look forward to you explaining, in full detail, exactly what the effect of this might be, such a wealth of knowledge should not be lost to the world.

Don't forget to include:

The pilot pressure and why it is important to consider that in this context.

The coefficient (that's 2 f's, mind you) of friction which varies wildly according to the torque applied. (keep in mind coefficient means number so an equation would be relevant, since you brought it up)

Oh, and the friction profile of the fluid. This one may need a graph. Oh, and don't forget to include the equation.

Gee, seems like that would take an awful lot of writing to say that increasing transfer pressure could cause clutch wear and modifying the solenoid could cause, among other things, its failure?

[longassname]

I also admit my spelling has gotten really bad as of late

[Trevor]

Originally Posted by longassname

Trevor,

trust me you don't even want to waste your time with this one as the people providing you information are providing you even worse information than usual/average.

There are a several things of importance which are well beyond their reckoning. First of all as is typical of most automotive transmission fluid circuits what you are actually dealing with is a play of pilot pressure versus line pressure not simply the control of one fluid pressure. Secondly the friction materials in an automatic transmission have a coeficient of friction which varies wildly according to the torque applied. Thirdly the atf used has a friction profile (on a side note many of the problems with heat/performance complained about on the 4eat are a result of users using a fluid with an inapropriate friction profile) which is far from linear.

Rest assured I am well able to analyse information which has been provided to me and it is my prerogative should I seek additional confirmation.

I require no instruction in regard to fluid mechanics or associated control systems. I can find nothing within your text which makes any form of logical statement in regard to the topic at issue.

[longassname]

Ok, my bad. You go about adding resistors to solenoid c then.

Originally Posted by Trevor

Rest assured I am well able to analyse information which has been provided to me and it is my prerogative should I seek additional confirmation.

I require no instruction in regard to fluid mechanics or associated control systems. I can find nothing within your text which makes any form of logical statement in regard to the topic at issue.