Centre diff lock on AWD auto

[Andyjo]

Speaking of wear & such, what sort of 'side effects' could manually controling the DS c? you'd need to patch the original signal into something like ground... so the ECU doen't freak out, you can't just cut the wire....

 

Also, good PWM link above... sounds like a good idea, if we can get this sucker working, that would be amazing! i've actually started looking for spots in the car to add a switch & potentiometer

 

Also, how would we go about testing the split.. if it's 50/50 you can go out in the snow, and gun it to see if the front & back both spin, if it's 90/10 , or 100/0 then you can do the same, and the front spins, but how do we know if the modification is actually working? lift up the car and throw a torque wrench on all of the axle nuts and put it in drive? record the results?

hmmm....

[nipper]

Also, how would we go about testing the split.. if it's 50/50 you can go out in the snow, and gun it to see if the front & back both spin, if it's 90/10 , or 100/0 then you can do the same, and the front spins, but how do we know if the modification is actually working? lift up the car and throw a torque wrench on all of the axle nuts and put it in drive? record the results?

hmmm....

 

Thats where the oscilliscope would come in. One person will have to be the guimmy pig. Since we dont know how it owrks now, thats what we would have tofind out first. ice/snow/wet leaves on the front wheel, wet road ... read the scope and see what it does, then fiddle with it. First we need a baseline.

 

 

nipper

[Andyjo]

i nominate Skip

heh, i'll try it to if we can figure out which wires to tap into... i may need a larger inverter for the oscilliscope though.. or a long extension cord...

So what we need exactly is:

-The Stand Alone Signal (roughly what 100/0 would be)

-How the Pulse Width changes w/ conditions

 

To get the signal, we could perhaps throw in the FWD fuse, and check to see if that yields a high pulse width...

[NorthWet]

As I read this, we don't really give a rat's patoot what happens under various conditions, we just need to know what the solenoid's signal frequency is, and what the pulse width is for minimal and maximal conditions... and even the last we could guess that 50/50 is near-zero pulse width. All of the rest would be up to the nut behind the wheel as she/he turned the knob and/or flipped the switches.

[Andyjo]

I was just wondering what kind of things might happen.

anyhow, i was rolling through some of the FSM stuff i found

http://www.freebmw.net/Share/CarsBoatsBikes/Subaru/FSM/

i couldn't really find anything about the signal... or the center diff, but i didn't find anything... although i wasn't looking very hard either.

[nipper]

I was just wondering what kind of things might happen.

anyhow, i was rolling through some of the FSM stuff i found

http://www.freebmw.net/Share/CarsBoatsBikes/Subaru/FSM/

i couldn't really find anything about the signal... or the center diff, but i didn't find anything... although i wasn't looking very hard either.

 

does say something interesting about the transfer clutch pressure testing and throttle postions, which tells me the cycle is variable from 10% to 50%

 

nipper

[blitz]

As I read this, we don't really give a rat's patoot what happens under various conditions, we just need to know what the solenoid's signal frequency is, and what the pulse width is for minimal and maximal conditions... and even the last we could guess that 50/50 is near-zero pulse width. All of the rest would be up to the nut behind the wheel as she/he turned the knob and/or flipped the switches.

Any decent multimeter will have measurement for both frequency and duty-cycle percentage. I'd gladly grab my Fluke 87 and snag the measurements, except for the fact that:

 

1. It's currently 16 *F with 4" of snow and ice on the ground.

2. I have no reference for which is the DS C signal wire.

 

Much the same way that I don't understand why someone would put clothes in a dryer then select "Less Dry", I don't understand why anyone would want to set the clutch for anything less than full lockup in a slippery driving situation?

[nipper]

Any decent multimeter will have measurement for both frequency and duty-cycle percentage. I'd gladly grab my Fluke 87 and snag the measurements, except for the fact that:

 

1. It's currently 16 *F with 4" of snow and ice on the ground.

2. I have no reference for which is the DS C signal wire.

 

Much the same way that I don't understand why someone would put clothes in a dryer then select "Less Dry", I don't understand why anyone would want to set the clutch for anything less than full lockup in a slippery driving situation?

 

minor details ..weather .. always an excuse i'm having back surgery in two weks im not complaing

 

You seems to forget one point. AWD is working ALL the time, not just slippery conditions. Its nice to be able to dial in the amount of torque split for more balanced driving like in the twisties.

One of the benafits of AWD is handling . If you treat all four wheels the same, handling is vastly improved as well as performance.

 

i do remeber in one panick manuver at 65mph (women and cell phone) i had to do an extreem lane chang and recover. Very odd feeling when your on dry pavement and you can feel the split change to 50/50. It was the car trying to save its own rump roast, if it was a 2wd car i think i would have been in the bushes or worse. That required an extreem manuver. in the twisties i would like to dial it in like the high end wrx for proper balance.

 

 

nipper

[Storydude1]

You people are overthinking the problem.

 

The Duty C goes from open, to closed. The rate at which it does that, determines the amount of power going to the rear.

 

Now, a PCM controler is Not needed if all you want is a semblance of 4wd.

 

Take Multimeter, and measure resistance of Duty Cycle c. Splice wire from Duty C, and allow the circuit to be cut. This will lock Duty C. Run wire from SPDT switch to interupt Duty c, and send that signal into a resistor of the same value as the Duty C.

 

TCM should not freak out, you get 4wd, and no complex stuff is needed.

[blitz]

minor details ..weather .. always an excuse i'm having back surgery in two weks im not complaing

I'll make you a deal; spot me a half dozen of them Vicodin, and I'll do a headstand in the snow while I take take measurements ...no complaints.

 

You seems to forget one point. AWD is working ALL the time, not just slippery conditions. Its nice to be able to dial in the amount of torque split for more balanced driving like in the twisties.

One of the benafits of AWD is handling . If you treat all four wheels the same, handling is vastly improved as well as performance.

I don't believe that I'm forgetting anything. I own a both 5-speed manual and a 4EAT so I'm well aware of the differences between the two. I can tell you that my 4EAT car is FWD except for three conditions:

 

1. Front slippage.

2. "1" gearshift selection.

3. WOT

 

i do remeber in one panick manuver at 65mph (women and cell phone) i had to do an extreem lane chang and recover. Very odd feeling when your on dry pavement and you can feel the split change to 50/50. It was the car trying to save its own rump roast, if it was a 2wd car i think i would have been in the bushes or worse. That required an extreem manuver. in the twisties i would like to dial it in like the high end wrx for proper balance.

Your statements are contradictory. Either the Subaru system is brilliant, advanced, and highly sophistocated - or it's deficient in some way and needs to be modified. Which is it?

[nipper]

I'll make you a deal; spot me a half dozen of them Vicodin, and I'll do a headstand in the snow while I take take measurements ...no complaints.

 

I don't believe that I'm forgetting anything. I own a both 5-speed manual and a 4EAT so I'm well aware of the differences between the two. I can tell you that my 4EAT car is FWD except for three conditions:

 

1. Front slippage.

2. "1" gearshift selection.

3. WOT

 

Your statements are contradictory. Either the Subaru system is brilliant, advanced, and highly sophistocated - or it's deficient in some way and needs to be modified. Which is it?

 

Actually i just got a refill of Vicodin ... now have someone record the headstands in the snow and we got a deal...

 

The subaru system is very sophisticated for the cost of the car. The mechanics are fairly straight forward, but the logarythem they use is very sophistacted to vary it from 10-50% and everything inbetween. They als use a G sensor to help determine how much to split the awd.

 

i dont know how you got deficient out of something that saved my rump roast But that was a extreem manuver, id ont know how it works on more subtle manuvers...

And besides there are those of us that want to do it just because we can. not because it makes an sense. We like our gadgets.

And i was thinking instead of interupting the signal to the solenoid, just out in a diode so our black box cant back feed to the computer, but the computer can step in if it feels it needs to do its job.

 

nipper

[Andyjo]

And besides there are those of us that want to do it just because we can. not because it makes an sense. We like our gadgets.

And i was thinking instead of interupting the signal to the solenoid, just out in a diode so our black box cant back feed to the computer, but the computer can step in if it feels it needs to do its job.

 

nipper

 

Diodes scare me.... and i thought this thread needed another bump!

And i dunno.. i sort of like having complete control, so the computer doesn't get fussy w/ me playing with it... but good idea! has anyone figured out the signal yet? or even where this mystery wire is?

[nipper]

Diodes scare me.... and i thought this thread needed another bump!

And i dunno.. i sort of like having complete control, so the computer doesn't get fussy w/ me playing with it... but good idea! has anyone figured out the signal yet? or even where this mystery wire is?

 

Have a vicodin ... then diodes wil be your freind. Diodes are simple so are resistors .... now the evil of the transistor ... devils work.

 

nipper

[Gnuman]

Diodes scare me.... and i thought this thread needed another bump!

And i dunno.. i sort of like having complete control, so the computer doesn't get fussy w/ me playing with it... but good idea! has anyone figured out the signal yet? or even where this mystery wire is?

 

The wire in question is inside the extension housing. I believe the signal to it is through pin 12 of the connector that is for the control signals (one connector is for the selector position, and the other one gives transmission info to the TCU, and sends control signals back to the tranny from the TCU. The connector we are looking for is the one whose harness goes into the left side of the tranny). Is that of any help?

[e4620]

Diodes scary? Nah, think of them as a one way street, it just lets the electricity go one way. Well...and drops the voltage a little tiny bit, but forget about that for now. And transistors? Basicly think of them as a switched diode......now...large scale integrated circuits:drunk:thats the fun one:banghead:

 

Anyway, if anyone decides to make a circuit to control this thing lemme know, I can probly provide some assistance. If I drove an auto I'd be out there right now working on it.

[nipper]

SOMEONE LOAN THIS MAN AN AUTO SUBARU !!!!!!!!!!!

 

 

nipper

[Andyjo]

dude, you're on long island, he's in northern NJ... loan him your suby! i'd be there but it's sort of a long drive for me

[nipper]

dude, you're on long island, he's in northern NJ... loan him your suby! i'd be there but it's sort of a long drive for me

 

well in 17 days its parked for 6 weeks .. if he wants to come and play. My driving is limited to 2 miles, and with the transit strike, hes prbbly alot closer to you then to me right now :-p

 

nipper

[idosubaru]

i leave for a week and look where this thread goes.....

 

not sure i see the benefits of all this control of the solenoid.

this has already been done in a 4EAT. a guy built what he called a "paddleshifter" for his 4EAT. includes the ability to manually shift and dial in the DS C exactly like you're talking about.

[nipper]

i leave for a week and look where this thread goes.....

 

not sure i see the benefits of all this control of the solenoid.

this has already been done in a 4EAT. a guy built what he called a "paddleshifter" for his 4EAT. includes the ability to manually shift and dial in the DS C exactly like you're talking about.

 

You know the more you mention things, the more trouble your going to cause

 

*drool*

 

paddle shifter

 

where is said "guy"

 

 

nipper

[idosubaru]

where is said "guy"

 

unfortunately he doesn't talk (figuratively speaking).

[WoodsWagon]

The circuitry doesn't need to be complicated at all. The single pole switch would either let the computer controll the solenoid, giving what we can all rate as adequate AWD, or cut it off, letting full hyd. pressure to the clutch pack and splitting the tq. 50/50. You won't be able to bias the power rearward because the clutch pack just takes power from the front and equalizes it with the rear. But with a 50/50 lock, it's the same as a lever shift 4wd car. You no longer have to wait for slipping to begin to engage the rear wheels. A diode isn't neccecary because you are cutting power to the solenoid, so there will be nothing to feed back to the computer. Cut the wire leading to the tranny, splice in a couple of longer lengths, and put a switch in the dash. Now you have selectable AWD to 4wd. The computer most probably won't freak out either, because it will never detect slippage front to rear, therefore never having a reason to change the state of the solenoid. It will be giving the switch a 12v signal, but that is where it will stop. It will never know that the solenoid isn't working. Once someone finds a FSM that tells which wire controlls the C solenoid, it's a 20minute job to put a switch in.

[tunered]

the way i understand this is with your switch you are doing the same as putting the fuse in,not 4 wd.

[idosubaru]

the way i understand this is with your switch you are doing the same as putting the fuse in,not 4 wd.

 

wrong, i've done it and explained it already at the very beginning of this post.

[tunered]

wrong, i've done it and explained it already at the very beginning of this post.

so you DONT know if it will work on the newer cars.