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yet one MORE idea... for lsd/traction control...


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16 replies to this topic

#1 scrap487

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Posted 02 March 2006 - 05:17 AM

this may or may not have been talked about before, but I forgot which newer vehicle it was coming on, I think it was the toyota FJ cruiser thats supposed to come out sometime this year. I read about how they have some sort of brake system setup, so when its engaged it regulates fluid pressure between all 4 wheels to keep them all moving the same speed. I dont know how it works, but I imagine its gotta involve a computer of some sort... anyone wanna take a wild guess at what it would take to develop and adapt a comperable system to a subaru? such a system seems like it would be extremely effective and beneficial for most situations, not as good as front and rear locking differantials, but much better than LSDs... this make sense to anyone? what it is designed to do is increase the brake fluid pressure in the line going to the wheel that is slipping, causing more power/torque to the wheel that is turning slower with more traction. I have no idea how this system operates, but I'm guessing its something electrical?

#2 scrap487

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Posted 02 March 2006 - 06:13 AM

ok did some more reading... guess this kinda thing is pretty comon, i just didn't know about it.. :-p

so I guess any who are wondering, i dont know how ABS works exactly, but traction control is pretty the opposite of ABS... with abs, speed sensor detects when a wheel starts to slow down, so the system lessens the braking force on that wheel untill its closer to the speed of the other wheels, and then repeats. it can cycle up to 15 times a second. traction control will increase the braking force on a wheel when a speed sensors detects a wheel going faster than the others.

so now my question is, what vehicles that are easily found at a junkyard came with traction control, how could we addapt it to work with our subaru, how hard/safe would the plumbing/fitting be, and what would it take to fit the proper hardware to the wheels... all on an ea81 wagon

and I assume, that with traction control ABS comes with it?

#3 stinky

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Posted 02 March 2006 - 06:15 AM

I guess you could use ABS gear controlled by a custom controller to tell it when and where to apply brakes.

#4 scrap487

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Posted 02 March 2006 - 06:22 AM

I guess you could use ABS gear controlled by a custom controller to tell it when and where to apply brakes.


I dont know anything about abs... so i have no idea what that means lol

:confused: :confused: :confused:

#5 Dylan86GL10

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Posted 02 March 2006 - 08:18 AM

Anti-Lock Brake System? :banana:

Anyway you could mount ABS and just make it think you are always braking, then it will modulate the brake pressure to whatever wheel is turning fastest (less traction). The kicker here is that you need brake pressure generated so unless you press the pedal, you'd need some sort of high pressure pump. The other caveat is that most systems use common lines up to each wheel. So every wheel is going to receive braking and the "slipping" wheel less braking. You'd basically need to reverse the normal ABS operation. I don't know the duty cycle of normal ABS solenoids but I guess you could wire in a reversing circuit so that the valves are normally closed and ABS opens them to send pressure to the fastest wheels. You would then need to wire the system to "deactivate" when you press the brake pedal OR a circuit to "reverse" the reverse circuit.

Not sure I kept any of that straight.

#6 chazmataz

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Posted 02 March 2006 - 11:01 AM

If you want this type of system, you would be better off buying an Outback or Forester.

you would need the computer or computers, axles with toner rings and wheel speed sensors and a way to mount them, lots of wire or wiring harness(whole car), lots of brake line( each wheel needs its own separate brake line ( single circuit)not connected to another wheel like your car has now, I.E. frt-rr, side-side), and what ever control module or modules, depending on the system you went with, plus the drivetrain of what ever donor car you use.

Lots of work, time, headaches galore and $$$$$$$$$. so basically if you want this just buy a car with it, its more practical.

my .02 cents worth, if it means anything.

#7 Numbchux

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Posted 02 March 2006 - 02:16 PM

I think a better/easier application would be the dual ebrake. Just mount 2 handles, one for each front wheel. if one starts to slip, pull up on that handle.

#8 scrap487

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Posted 02 March 2006 - 04:03 PM

I think a better/easier application would be the dual ebrake. Just mount 2 handles, one for each front wheel. if one starts to slip, pull up on that handle.


yeah, thats what I was going to do cause I dont have any money... its just not as effective that way.

#9 BlackBoot

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Posted 06 November 2012 - 04:43 PM

I was exploring an option like this, using racing brake line lockers.
Search forums for" solenoid brake lock traction control"

#10 WoodsWagon

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Posted 06 November 2012 - 11:53 PM

The 2nd gen legacy's with FWD only came with traction control. It uses a modified ABS unit to actuate the front brakes as well as providing the normal ABS functions to all 4 wheels. The 3rd gen VDC cars use brake force distribution to control handling as well as traction control. That's why the came with open rear diffs while the non-VDC cars came with the viscous limited slip rears.

Toyota's A-trac system that you were thinking of provides traction control to all 4 wheels and can do it without reducing engine power. Most traction control systems also incorporate engine power reduction to stop the slippage, to the point that the wheels won't even spin on ice. The assumption is that the driver is clueless and standing on the throttle, so it's better for the car to not move at all than to spin madly and go nowhere. It works great for the majority of the driving public because they are clueless.

There are plenty of ABS pumps out there in junkyards capable of doing what you want. Plumbing them in is pretty straightforward too. The problem is the computer and program you need to run the system.

Cars/suv's with stability control use the rear brakes independently as cutting brakes to steer the car if the driver does a sudden swerve. It puts drag on the inside wheel to help pull the car back straight. All the safety and restraint systems are designed to work in a frontal collision, so it's better to keep the car going straight than letting it slide sideways into something or roll over.

If a car has traction control, it has 2 channel brake force distribution. If it has stability control, that's usually 4 channel brake force distribution. The only difference between that and A-trac is the programming.

The two handbrakes works, but it's doing the job manually when the hardware exists to do it automatically.

#11 1 Lucky Texan

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Posted 07 November 2012 - 12:05 AM

would brake-throttle modulation work even better with ABS? That is, keeping some throttle applied, left-foot the brake pedal, the ABS stops any spinning wheel and the diff moves torque to the stationary wheel.

might be worth a try

#12 88Subi4x4

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Posted 07 November 2012 - 03:49 PM

I think a better/easier application would be the dual ebrake. Just mount 2 handles, one for each front wheel. if one starts to slip, pull up on that handle.


Yup did this in my wagon a few years back works great:headbang::headbang:

#13 Fairtax4me

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Posted 07 November 2012 - 04:34 PM

Problem with ABS based traction control systems is they aren't designed to be constantly in use. A few seconds here and there is all the typical ABS system ever has to work, so if used as a traction device to prevent wheel slip for an extended period the pumps will overheat.
ABS control units are designed to work in an instant and provide pulses that generate up to around 2,000 psi in the hydraulic lines, so they use high torque motors and actuator solenoids which are very power hungry. The ABS is one of the first things to be disengaged if the battery gets low, because it can cause a large enough electrical drain to shut the ECU off which would stall the engine.

ABS traction control is also hard on the brakes, and can cause overheating of the pads and rotors if run for an extended period.
In short... It sucks.

You're better off with a locker, and I bet a locker is cheaper and easier to install.

#14 maozebong

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Posted 08 November 2012 - 12:23 AM

^^ what he said.

many off-roaders typically disable abs/traction control before hitting the trails.


also, ************ing christ, this is a 6 year old thread!

#15 Qman

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Posted 08 November 2012 - 06:14 PM

^^ what he said.

many off-roaders typically disable abs/traction control before hitting the trails.


also, ************ing christ, this is a 6 year old thread!


Which proved he used the search function! Back off!

#16 Gloyale

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Posted 12 November 2012 - 02:41 PM

yup did this in my wagon a few years back works great:headbang::headbang:


+3

#17 WoodsWagon

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Posted 13 November 2012 - 12:01 AM

many off-roaders typically disable abs/traction control before hitting the trails.

Except for the newer Toyota 4x4 owners who enjoy a traction control system designed to actually work offroad instead of just in a snowy parking lot. Go look at some videos of A-TRAC in action and tell me it doesn't work or is a waste of time.




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