ATRAC damage, discussion.

[proper4wd]

Land Rover's Terrain Response system has a sand setting which works very well. From a dead stop, it will use the traction control to keep the wheels from spinning and digging. But once the vehicle is moving, it will become more "hands off" and lets the individual wheels do their own thing to keep progress going forward.

 

[madmax718]

first generation traction controls were nothing more than "stop applying gas". It used fuel cutoff to prevent wheel spin, and thereby loosing traction.

When stability control started appearing, it then provided the key to making traction control possible- by applying brake force independently to each wheel. It required a re-work of brake lines, and actuators which were independent and separate from ABS controllers. (though some implementations use the same controllers). This allowed the torque to be redirected to the wheel with the most traction by limiting the movement of the wheel with less traction.

So yes, gen 1, turn off in sand, or snow, because it couldn't get you out of some more precarious situations that may require wheel speed to clear the tire treads.

ATRAC does work substantial better, but so do more modern traction control systems. However, many new production cars still do not have it, and its hard in some vehicles to get it to do what you want. For example, a friend's X5 (with sport tires) was stuck in 3 inches of snow, on a flat surface. Traction control kept cutting out his full throttle applications- because it detected wheel spin on all 4 tires. I turned off the control, but without it, it doesn't do the brake application, and thereby, no power transfer to the wheel with more traction. I think there was a third mode, but it didn't help either. then the abs light flashed continuously, apparently it doesnt like what I was doing.

Would ATRAC or any other electronic system help? Probably not, not with sport tires. But I believe a true locker or limited slip would have- it would have let me gun the car, and have all 4 wheels spinning. Eventually Iw ould have melted through the snow and gotten to the floor. But because the electronics didn't like it, it shut down on me pretty much. Maybe 2013-14 atrac is better.

A tug from my studded snow tire equipped subaru (with open diffs), and all was good.

 

[proper4wd]

BMW traction control is famous for doing that and can hardly be compared to most other 4wd traction control systems.

Also, I believe you have it wrong... Traction control and ABS both started appearing in 4wd's in the early 90s it was not until much later that any type of stability control was developed.

 

[cruiseroutfit]

...E- lockers and air lockers bridged this, but how many e lockers were factory provided? Not all that many. In addition, they had to program in speedo readings to turn it off under certain conditions...

How many? At least hundreds of thousands of them in Land Cruisers for the last 30 years, starting with cable and now dual e-locker in the latest models of Land Cruisers (7X Series for example). In addition Tacoma's, 4Runners and FJ Cruisers all have/had rear e-locker options. The speed limiter (easily disabled) is a minimal cost engineering/cost wise, a vehicle has a speed sensing system already (speedometer ), having the computer recognize that is a 'line of code'.

If Toyota wanted to send 100's to the US with E-lockers, no issue as they were installing them in non-US 100's, 70's, etc in the same assembly lines... they opted for a different system for A-Trac markets.

 

[REDrum]

Traction control systems also have essentially no added cost to the manufacturer, because all of the hardware and most of the software already exist for ABS. Its some extra R&D and some extra coding in the software, thats it.

And that is why ATRAC and other traction control type systems exists

no way with the aded cost to manufacturer. You know much work goes into these programs for traction control??

Yes, minimal. The hardware is already in place. If selective locking diffs were cheaper this thread would not exist.

Vehicle manufacturers are generally in business to sell to the masses. Traction control is easier to use and somewhat seamless and mindless for the average buyer. To try and rationalize that the system is targeted toward "us" is delusional.

Amen....

ATRAC is a great consumer product and all that is really needed for trucks that are used incidentally offroad and on loose surfaces, but, again, not a substitute for fully locked front, center, and rear differentials. I had it on my 4RNR and Range Rover, wish I could have used it selectively, sold both trucks that had it.... I've seen guys with only traction control (and good talent) impressively go through a lot of gnarly pooh off road, but it is just not a silver bullet to the cost or performance of locking diffs. If it was no doubt there would be a lot of aftermarket options for it.

Everyone has a different drive style off road, for me its see how far I can get with open diffs then start adding locking capability. I just got back from 3 days of wheeling and the common factor of the guys who did significant damage to their trucks was no locking diffs. They would try using momentum to go up and over tough stuff, kept adding more gas/speed, and the impact and/or subsequent bounce would rack up thousands in chassis and body damage.

Unfortuantely in the not so distant future ALL vehicles will have some form of traction control, and it will be locked into the ECU; so we will all have to relearn how to drive with it off road: both slow and fast.

 

[Chris Sandstorm Fj]

Great thread and read..

Personally, I love Atrac married with lockers. Probably, cause like Ace, I have experienced the incredible ease it gives to wheeling all kinds of terrain in Moab and Southern Utah.

We have used it for really tough wheeling and mild wheeling. I used it back in 2008, on the Rubicon and it worked flawlessly, that is not easy or occasional wheeling.

The trouble I have seen with Atrac is that your equipment and driving habits have to be right. In a 4runner or FJC, I think it is hard to destroy diffs with using Atrac, although Like Scott mentioned early on in this thread, it can happen.

I have wheeled almost the same trails, except the Rubicon with just Atrac in my 4th gen 4runner and my '01 100. On certain features, folks in our groups with only lockers and no experience with Atrac, just watched in amazement how the rigs crawled right up with ease. And how the Atrac was clearly working the feature we were climbing. Don't forget where these rigs are being tested in japan....Mt. Fuji is now walk in the park.

The front diffs are weak in the 100 series, especially in the 98/99s, you could blow a diff in snow in the parking lot.. It has been argued that Atrac contributed to this issue.. The 00-up 100s have stronger front diffs but if your going to wheel them, your going to eventually blow the front diff, unless you upgrade and at that point, perfect timing to add in a front locker. I am also sure the contributing factor to 100 series issues is the weight and power. With a 100's weight and V8 power, your gonna find the weak link in your build when pushing it in tough terrain.

Having never driven just a locked vehicle without Atrac, I can't say which is better, but having driven Atrac with and without lockers, I would say for me it is a must have. It makes easy work of very extreme wheeling and you get used to hearing that unmistakably unique Atrac sound when it is working.. Makes you feel good!!

Now with all that said, I heard from a reliable source that Toyota was considering pulling Atrac recently but after some marketing folks wheeled with Atrac in Moab/Ouray, they agreed it needed to remain in the US based vehicles.... "Now, you know the rest of the story"

 

[zimm]

Not sure why in this video the 100 series LX could not get off the rollers with the brick! Any ideas?

Check out this video on YouTube:

http://youtu.be/KxiVNfwMp7A


Sent from my iPhone

my guess is the duration of the abs pulse was to short. i think, being the rollers are 100% frictionless, a little light braking would solve that situation. ive found a little 2 foot driving solves that situation right quick.

i wonder if they can, or do, adjust ABS pulse for atrac v braking.

 

[zimm]

Everyone has a different drive style off road, for me its see how far I can get with open diffs then start adding locking capability. I just got back from 3 days of wheeling and the common factor of the guys who did significant damage to their trucks was no locking diffs. They would try using momentum to go up and over tough stuff, kept adding more gas/speed, and the impact and/or subsequent bounce would rack up thousands in chassis and body damage.

driving stupid really isnt pertinent to the discussion, everyone will eventually ruin a square peg, when they try to shove it in a round hole.

 

[zimm]

as far as the torque to the front goes, yes, yes, the diff in a front axle can see the same amount of TQ in a locked and atrac truck, but no, one wheel in that axle assembly wont.

in a locked truck front axle, when you have one wheel in the air and one on the ground, and the one on the ground has 100% traction, then 100% TQ is at that wheel. an atrac truck is nothing but an open diff, and basic physics apply. in an open diff, the tire with traction will only see as much power as the tire with little traction can apply, the rest is used up in wheelspin. all that atrac does is brake the spinning tire with brake pulses. those brake pulses are a force, that must that must be opposed equally by engine TQ so the other wheel sees an equal TQ. hence, you can only see 50% of the TQ at one wheel, max.

i think the confusion is when people constantly say traction control sends power to wheel that grips, like some sort of magic valve.

energy is energy. if traction control was distributing power like a locked diff, the brakes would never overheat, because all the power would be in forward motion. . . . or a shattered birf.

in addition, atrac has computer controlled rpm limits, which will further limit the power the tire sees. the pulsing you see as atrac searches for grip is NOTHING to a drive train compared to a locked front wheel bouncing in the rocks.

 

[REDrum]

driving stupid really isnt pertinent to the discussion

Oh really....

Well I look at TC and/or ATRAC kinda like all-season tires, they promote a false sense of capability, (albeit some people in SW have magical experience with TC on the sedimentary rock there). The problem isn't with the product it self, its what people think they can do with it. My point being less about stoopid driving than perception of ones self and a performance feature. For example, the tricky sections at VOT, look how much time people took, with some sort of TC, trying to get through them (and holding up others with lockers): 10, 20, 30 minutes each....then winching. I would not call them stoopid, but no doubt by the end of the VOT event they learned a lot about capability of lockers vs TC in New England mud...

And, thus, that learned experience may be the impetus of this thread

 

[zimm]

Oh really....

Well I look at TC and/or ATRAC kinda like all-season tires, they promote a false sense of capability, (albeit some people in SW have magical experience with TC on the sedimentary rock there). The problem isn't with the product it self, its what people think they can do with it. My point being less about stoopid driving than perception of ones self and a performance feature. For example, the tricky sections at VOT, look how much time people took, with some sort of TC, trying to get through them (and holding up others with lockers): 10, 20, 30 minutes each....then winching. I would not call them stoopid, but no doubt by the end of the VOT event they learned a lot about capability of lockers vs TC in New England mud...

And, thus, that learned experience may be the impetus of this thread

my my... paragraph 3 portends to the reader that paragraph 2 was directed towards me... but...

i was last on the course every day, all i could have held up was darkness... and i have a locked and lifted 40... and a locked and lifted G.

personally, after ignoring and poo pooing it for all these years, im having fun exploring this technology. its better than you think. use your left foot and less your right.

ultimately, TC still isnt as effective as lockers, but it will be.



and cost was never an issue for locker availability in the US as its a mark up option, that generates more profit. you dont save a dime by not offering it. the issue has been liability. lockers by their nature disable stability and traction programs that in this country could open you to civil court action, when the new england couple of jamie and biff waterford, push every button they see when on ice. availability depends on how risk adverse they are feeling in management. im sure the unintended acceleration suits didnt do much help toyota offering full locking diffs no matter the per unit profit. . . . if it were my call, i wouldnt.

 

[2000UZJ]

I wrote this a while back, it goes over the basic functions, and how atrac responds to driver inputs. Let me know if you have any questions.

http://forum.ih8mud.com/100-series-cruisers/537946-trac-101-a.html

Nick

 

[REDrum]

I'mm 98% certain A-Trac is standard on all USDM UZJ100s after 1999. You can check Slee's FAQs on used buyers guide for used Land Cruisers too.

 

[RobRed]

I'mm 98% certain A-Trac is standard on all USDM UZJ100s after 1999. You can check Slee's FAQs on used buyers guide for used Land Cruisers too.

Wow Three years later. Holy Late reply Batman.

You are correct 2000+ Land Cruisers have ATRAC standard. I think my FAQ on this is more thorough than Slee's. http://forum.tlcfaq.com/viewtopic.php?f=51&t=162

You commented above: "Well I look at TC and/or ATRAC kinda like all-season tires, they promote a false sense of capability..." There is no false sense. ATRAC literally adds capability.

 

[REDrum]

Very odd, a guy posted this AM asking the following:

"reviving a old thread, ive searched all I think of, I have read a lot on a-trac , but I cant find if the A-trac standard equipment on post 99's hundys or optional ?? any help is appreciated, thanks Dave"

And now its gone....