can you turn off the vsc?

[Uneek]

Isn't the question at hand here about how to disable ATRAC and not how to disable VSC? ATRAC is the system the prevents wheel spin by taking control of the trottle, while VSC is designed to prevent lateral spinning of the vehicle (such as hydroplaning). When wanting to crash through a snow bank, or seeking intentional wheel spin while maintaining positive throttle control, isn't this asking how to simply disable ATRAC?

In addition to my '06 T4R, I also own an '07 Lexus IS350 which has a TRAC/VSC defeat button. If I press it once TRAC is disabled allowing me to spin out the tires with throttle (basicly it gives me total control of the trottle). If I hold the button down for 3 seconds, it disables TRAC and VSC. Two completely seperate systems. Without VSC I could take the car on a track (or road) and rip around corners without the system kicking in braking preventing a spinout. So TRAC is for trottle control, while VSC is for lateral spin control. Thoughts?

Yes, VSC is vehicle skid control, intended to help keep the vehicle where you wanted it to go through some fancy algorithms and sensors, if VSC sense the vehicle is in a slide/skid and going off course. TRAC, traction control will cut power on wheel spin and I think it's intended to help when you're a stand still and about to get moving. I haven't experienced TRAC side lining me when I needed to move yet.

But I believe A-TRAC is different. Thai mentioned this on one of the stickies in another sub-forum and I remembered it when I was on ice. It's a little nerve racking at first because of the chatter the system makes, but the sweet spot is between 1500-2000 RPMs. I was on an iced over driveway backing down it and the 4Runner started to slide sideways rather than go an angle down the driveway. So I need to move forward up the driveway, but with two wheels on ice it had a tough time gaining traction to move forward. Kept on a gas a bit and raised the RPMs, the wheel spin minimized and it began to move forward up the driveway. The driveway was maybe 20%, +/-3% grade. A few other housemates, who parked their cars without chocking the wheels when the driveway iced over, found their cars slid into the stakes (rebars with plastic tubes over them) the snow plow service used to marke driveways.

 

[Falls]

Absolutely!:biggrin2: If you follow the link in my 'how-to' post you'll see the procedure was "discovered" using a V8 T4R.

Everything about the mod is the same. My pics will be 100% applicable to a V8 model.

:cheers:

Ok someday when I get the marble's to do it I'll try it . I'd probably have to have you on speed dial Chris .....lol

 

[CJ3Flyr]

867-5309 :lmao:

Now, let's see who's old enough to 'get it'.

:cheers:

 

[DaveyBoy]

867-5309 :lmao:

Your name is Jenny???


Not to sound dumb, but doesn't just locking the center diff achieve the same thing?

 

[CJ3Flyr]

Not to sound dumb, but doesn't just locking the center diff achieve the same thing?

Yes it does. The difference is the mod lets you drive on a marginal surface such as a hard packed dirt trail without have the front wheels slip in a tight turn as they would with the center diff locked. On wet clay type surfaces it's nice to be able to turn without inducing a slip and still have full control of the throttle. Bottom line is the best handling off-road rally cars in the world have some type of center diff and power when you want it. The '08/'09 T4R falls into that group (factory VSC off switch). We're saddled with modding, locking the center diff or just living with it.




I would think driving in snowy conditions would be much better with the switch. Pulling out from a parking lot onto a fairly clear road would be scary with the VSC cutting the power. I would prefer not lock the center diff as I'm about to be on a hard surface and mid-turn. I would also prefer to not "roll the dice" about whether or not I'll have power for the 0-30mph sprint. Most importantly I don't want an F250 bumper in my driver's door because the VSC was 'saving me' :bash: That's a tough box without a switch or locking the center diff and beating on the t-case. Sometimes you accept there's going to be slip and you want to just 'blast through'. In a perfect world my mod switch would resume normal VSC once the vehicle accelerated above 20-40mph (driver selectable ).

:cheers:

 

[ishium 80439]

I tried the method shown on the FJ site and it worked like a charm! I only tried quickly and then replaced the plug- that link is to a 21 page thread and I have not had the time to read through the whole thing, but I think that before long I'll have a new toggle switch in my cabin. My only concern is that the brake indicator light comes on in addition to the others. ABS is a safety feature I can agree with and would hate to lose. Although when wheeling it is much less vital than on slick roads. I think bottom line is that having the ability to turn this on and off at will by simply cutting a wire and installing a switch is a good thing.

 

[ishium 80439]

JB,

Nice shot of Red Cone. I'm glad to some feed back on the functionality of the DSC. On the surface it gave me pause to think about using it, but after a first hand account of it on that slope, I suppose that my fears were misguided.

Cheers

 

[CJ3Flyr]

I tried the method shown on the FJ site and it worked like a charm! I only tried quickly and then replaced the plug- that link is to a 21 page thread and I have not had the time to read through the whole thing, but I think that before long I'll have a new toggle switch in my cabin. My only concern is that the brake indicator light comes on in addition to the others. ABS is a safety feature I can agree with and would hate to lose. Although when wheeling it is much less vital than on slick roads. I think bottom line is that having the ability to turn this on and off at will by simply cutting a wire and installing a switch is a good thing.

I believe the ABS still works. When I tried unplugging at the master cylinder my ABS light was not illuminated but I didn't actually try a skid. That would be a good thing to know...


At the risk of being on a :soapbox: or beating a dead horse you do realize by with the FJ forum style mod you have no limited slip. If on a hill with the right side of the vehicle is on ice and the left side on pavement it would not go up a hill. It would need a locker or other limited slip device or to shut the vehicle off flip the switch, restart and select a mode that allowed the ATRAC to run. That's true in 2 or 4wd. If that's ok with you then putting a switch on the master cylinder wire is a great mod For me I prefer to have my limited slip working. NOTE: I am not saying one is better than the other, it's a preference.

:cheers:

 

[IS_350]

I just stopped at the dealership and picked up an '09 4Runner brochure, and it says the center-locking differential button is used to force 50/50 front/rear power to the wheels. (It discusses this right after it talks about the 40/60 front/rear power distribution on the 4WD V8 models)...

I always thought the manual locking center diff locks the both axles so that the left wheel and right wheel turn together (i.e. get equal left/right torque regardless of traction). What gives?

 

[CJ3Flyr]

I just stopped at the dealership and picked up an '09 4Runner brochure, and it says the center-locking differential button is used to force 50/50 front/rear power to the wheels. (It discusses this right after it talks about the 40/60 front/rear power distribution on the 4WD V8 models)...

I always thought the manual locking center diff locks the both axles so that the left wheel and right wheel turn together (i.e. get equal left/right torque regardless of traction). What gives?

The diff lock button locks the center, transfer-case differential. (Note:'09 TT Edition has an additional button for a right to left lock for the rear axle aka rear locker.) With the center diff locked it does split 50/50 F to R. In other words both driveshafts turn exactly the same rpm. The ATRAC then uses the brakes to control and match the RPM of the left and right wheels. If the right wheel is slipping and spinning too fast the right brake pinches to slow the wheel. The result is torque is then forced to the left wheel. If the VSC is on while this is occuring then you are in a full traction control mode. In addition to the ATRAC controlling R to L the VSC will be dramatically reducing the power to stop the spinning altogether...

With the center diff unlocked it gives a rear bias of around 60% of the torque. It can vary the bias as needed from 70r/30f though 47r/53f or something like that. I forget the exact numbers. The idea is that the center limited slip differential (Torsen style) manages the output to the axles based on need. Any right to left slipping is, again, handled by the ATRAC.

:cheers:

 

[Methodical]

In my mind, the 4runner has three traction systems.

VSC, obvious
ATRAC for Electronic Limited slip for the front and rear differentials,

and engine-throttle traction control which operates separately from the activation of either system on an as-needed basis.

 

[ishium 80439]

CJ3

I tried that mod again and did discover what you said about needing to power down to reset the system. I'm trying to decide how much that matters to me. I did discover that the ABS is not affected and that is a good thing. For wheeling this seems like a good set up because in most situations I can run it that way and when things get hairy I can lock up the diff. Still debating about the on road implications. The way that I am looking at it is that it is super easy to accomplish and if turns out that I don't like it, I just won't ever use it.

Hmmmmmm

 

[CJ3Flyr]

CJ3

I tried that mod again and did discover what you said about needing to power down to reset the system. I'm trying to decide how much that matters to me. I did discover that the ABS is not affected and that is a good thing. For wheeling this seems like a good set up because in most situations I can run it that way and when things get hairy I can lock up the diff. Still debating about the on road implications. The way that I am looking at it is that it is super easy to accomplish and if turns out that I don't like it, I just won't ever use it.

Hmmmmmm

Sounds awesome! I missed that you have a ARB rear locker. That would definately make me (a self-proclaimed part-time freak) wire two switches :bigok:

Either way given that you have a rear locker it'll rock!

:cheers:

 

[ishium 80439]

Ah the dangers of lacking specifics. I actually was referring to the t-case, ie the factory installed center lock. I still refer to it as a diff lock because up until about a month after I bought this vehicle that is what I thought it was. That'll teach me to do my research. Anyway my vehicle is a total stocker (slightly bigger tires than OE), no ARB.

My bad for not making it clear. It reminds me of the old Daffy Duck, Bugs Bunny, Elmer Fudd bit "AHA! Pronoun trouble!"

 

[CJ3Flyr]

Ah the dangers of lacking specifics. I actually was referring to the t-case, ie the factory installed center lock. I still refer to it as a diff lock because up until about a month after I bought this vehicle that is what I thought it was. That'll teach me to do my research. Anyway my vehicle is a total stocker (slightly bigger tires than OE), no ARB.

My bad for not making it clear. It reminds me of the old Daffy Duck, Bugs Bunny, Elmer Fudd bit "AHA! Pronoun trouble!"

I must confess... I was baiting you. :biggrin2: The center diff lock will still leave you stuck if the right side is off of the road in the snow and the left is on dry pavement. If "hairy" for you would be navigable with open F&R diffs then... Certain gravel/sand might be just fine with totally open diffs.

This being the case scroll up 5 posts (within this thread). You're looking for my response to IS350 and read that...

Know that I'm not trying to tell you my way is the only 'cool way' to do the mod. I just want you to fully understand what each version of the VSC defeat mod does and know my mod is not any harder than running a wire through the firewall. I'll gladly PM you my phone # and when you tear into it you can call if something doesn't make sense.

:cheers:

 

[ishium 80439]

OK. I am slowly trying to wrap my head around this whole thing. These systems are all new to me so I'm doing my best to try and absorb all of this. Let me see if I have this right in my head.

CJ, I read through the link in your sig and the way you did yours. It seems the biggest drawback to your method is that it does not function in 2wd. In FL the closest you'll come to a snow bank is loose sand. With your mod if you needed to blow through a section of loose sand you are saying that you will get no power loss and be able to build up the wheel spin/ momentum you need if in 4wd but in 2wd your still at the mercy of the factory settings.

In the other mod (playing w/ the plug on the master cylinder) you can defeat these systems in 2wd but there are 2 drawbacks. First the need to turn the vehicle off to reset the system. Second the loss of limited slip. My question about that second issue is whether or not that applies in 4wd and how the "diff" lock would affect perfomance in that condition. And overall what the performance differences would be in snow conditions and also while off roading.

I know there are a few points in here that have been covered but I just wanted to assemble them in one place. The whole concept of a t-case acting as a differential, and drive-by-wire in general is new to me so I'm trying to make sure that I understand it the best I can. An NP-205 and 14 bolt rear I can wrap my head around, a car that is trying to think and make my decisions for me seems to be getting close to Isaac Asimov territory. Or maybe it's A Brave New World.

 

[CJ3Flyr]

OK. I am slowly trying to wrap my head around this whole thing. These systems are all new to me so I'm doing my best to try and absorb all of this. Let me see if I have this right in my head.

CJ, I read through the link in your sig and the way you did yours. It seems the biggest drawback to your method is that it does not function in 2wd. In FL the closest you'll come to a snow bank is loose sand. With your mod if you needed to blow through a section of loose sand you are saying that you will get no power loss and be able to build up the wheel spin/ momentum you need if in 4wd but in 2wd your still at the mercy of the factory settings.

In the other mod (playing w/ the plug on the master cylinder) you can defeat these systems in 2wd but there are 2 drawbacks. First the need to turn the vehicle off to reset the system. Second the loss of limited slip. My question about that second issue is whether or not that applies in 4wd and how the "diff" lock would affect perfomance in that condition. And overall what the performance differences would be in snow conditions and also while off roading.

I know there are a few points in here that have been covered but I just wanted to assemble them in one place. The whole concept of a t-case acting as a differential, and drive-by-wire in general is new to me so I'm trying to make sure that I understand it the best I can. An NP-205 and 14 bolt rear I can wrap my head around, a car that is trying to think and make my decisions for me seems to be getting close to Isaac Asimov territory. Or maybe it's A Brave New World.

You got it! :bigok:

If you have a NP205 and a 14bolt sitting on an inclined driveway (with open F& R diffs, aka non-limited-slip) that iced on one side the following will occur: It won't move. If you selected 4wd on the NP205 it still won't move. You'll now have both wheels on the ice side spinning instead of just the rear. That's how a T4R with the master cylinder switch will behave in 2wd, 4wd or 4wd locked (4WD locked most equates to the NP205 in 4wd). On your NP205 truck a positraction rear (or some form of limited slip, Sure Grip, Traction-lok etc.) would fix everything in my scenario, you may not even try 4wd. On the NP205 truck a rear locker and a posi in the front would be the bomb! A T4R's ATRAC emulates the positraction in our NP205 truck, F & R.

Ever drive a NP203 truck? You drive those in 4wd all the time, even on the pavement. Our 4hi is a more advanced, better version of that until we lock it and it becomes the NP205 in 4hi. Having a center diff is what allows us to drive on the pavement in 4wd (unlocked). The front wheels travel a different distance than the rear wheels. Turns and slight differences in laden tire diameter cause this. The differential in a NP203 or T4R t-case allow for those differences without binding or excessive wear. (Your NP205 truck really should not be on dry pavement in 4wd. Same is true for your T4R with the center diff locked. The NP203 has a 4hi locked and 4lo locked position those shouldn't be used on dry pavement either.)

What we don't like on our T4R is the VSC and the ATRAC ganging up and voting to cut the power output. (More correctly it's the sub-function of VSC, Trac that we don't like. It cuts the power.) We like the ATRAC as it provides similar results to old school posi.

My mod does not work in 2wd That definately sucks. However in 4hi mine would drive up the iced driveway. The master cylinder mod would not help the T4R in any way, it'd be like the NP205 truck with open F&R differentials. Of course, if you restarted in normal, center diff locked mode it'd go right up the driveway with no VSC interfence.

Truth be told it'd bang, bump and make noise but it'd probably go up the driveway SLOWLY (due to VSC cutting the power) in 2wd with no switches because ATRAC would help provide the limited slip.

Does that help?

:cheers:

 

[ishium 80439]

I may be overly simplistic and cynical but truly it seems that the only thing the VSC does is prevents us from learning to countersteer. I have been in a few vehicles (a particular Ford Ranger comes to mind) that this system may have been to some advantage. However most vehicles (esp newer ones) seem to have the balance worked out to the point that only slight countersteer is needed to correct course. It seems that the perfect solution would be to find some sort of small explosive device to disable the VSC yet leave everything else untouched.

 

[CJ3Flyr]

I may be overly simplistic and cynical but truly it seems that the only thing the VSC does is prevents us from learning to countersteer. I have been in a few vehicles (a particular Ford Ranger comes to mind) that this system may have been to some advantage. However most vehicles (esp newer ones) seem to have the balance worked out to the point that only slight countersteer is needed to correct course. It seems that the perfect solution would be to find some sort of small explosive device to disable the VSC yet leave everything else untouched.

Yes!

Statiscally there are many high-speed, deadly accidents that center around drifting out of a lane and too much, too fast of a correction. VSC helps dramatically in reducing the resulting oscillations thereby reducing the incidence of a full-blown, out-of-control situations.

In the end game it is good. IMHO it should not affect power output below 20 or 30mph and it should be defeatable as it is in the '08s.

:cheers:

 

[runner6m]

In my mind, the 4runner has three traction systems.

VSC, obvious
ATRAC for Electronic Limited slip for the front and rear differentials,

and engine-throttle traction control which operates separately from the activation of either system on an as-needed basis.

I think that's a good way to think of it, and call the engine throttle control "trac".
The systems must be different, as the switch on the '08 4r's allow you to control them sort of separately.

We finally got a small amount of ice on the grass the other day, and I was able to test how the switch worked, as the wording in the owner's manual was confusing.

According to the manual, pressing the VSC disable switch does not disable VSC. If you just press it briefly, it disables TRAC, enables Auto LSD on the rear wheels (even in 4x4), and leaves VSC activated.
The "auto lsd" part confused me, as I thought atrac already did this. The manual also states auto-lsd will make turning more difficult.

If you hold down the vsc disable switch for 3 seconds, it disables TRAC, disables VSC, and enables Auto-LSD.

When testing (in 4x4, with center diff unlocked), I found that indeed, pushing the switch disables ALL engine throttling, even with VSC still enabled. Even when VSC kicked in during a deliberate fishtail, it still didn't cut throttle. I couldn't feel any dethrottling, and my scan guage verified the throttle wasn't being touched by any system except me. The VSC still worked great without any de-throttling.

Holding the switch down for three seconds, VSC cut off. Again, verified by some creative driving on ice covered grass. No engine throttling.

The auto-lsd thing seemed to be a more, much more, aggressive implementation of atrac on the rear wheels. When taking off in a straight line, the rear brakes went nuts, much more so than before I turned on the auto lsd.
Now, this could have been because the engine wasn't cutting power so the brakes had to work harder... I'm not sure. All I can say is that ATRAC lsd works in 2wd, 4wd, and turning on auto-lsd seems to make the ATRAC more aggressive on the rear wheels.


Yay, first post on this forum!