Atrac aint up to the task.. Locker choices?

[RonJR]

as i got into bigger and bigger rocks my atrac just couldnt help enough (a lot of stop and start on obsticles and what not), so i bought a used elocker from a 96 runner on ebay for 330 bucks. had it rebuilt and installed it with a 12vguy harness. the difference is night and day vs just Atrac. honestly modifying the housing wasnt too bad. just 2days with a dremel and a good drill was all it took. and i love it. however the actuator does take some maintenance to keep it 100%, but being a EE student helps with understanding what the issues could be and how to address them, so its not a big deal to me either.

Since you're an EE you can maybe appreciate this theory. One of the issues I've read about when setting up control of the Toytota elocker with aftermarket wiring and relays, etc., is that the motor tends to jam at the ends its travel. The common solution to that is to put resistors in series to slow down the motor so it doesn't run into the stops as hard.

I've often suspected that's not the proper solution. I would suggest instead using a SPDT relay for each direction, and when the limit switch trips, wire the relay to open the connection from +12V to the high side of the coil, and at the same time short the high side of the coil to ground, which will put short across the coil. Putting a dead short across a permanent magnet DC motor will stop the motor immediately, so it won't run into the stops and jam. That way you can dispense with the resistor and run full power during actuation.

Not sure if you've had those issues, but something to consider. It might require a couple of DPDT relays to wire it to do that and still operate in both directions, but I'm sure it can be done. I strongly suspect that's what the Toyota controller does, or something similar.

 

[CruzadoBlanco]

Since you're an EE you can maybe appreciate this theory. One of the issues I've read about when setting up control of the Toytota elocker with aftermarket wiring and relays, etc., is that the motor tends to jam at the ends its travel. The common solution to that is to put resistors in series to slow down the motor so it doesn't run into the stops as hard.

I've often suspected that's not the proper solution. I would suggest instead using a SPDT relay for each direction, and when the limit switch trips, wire the relay to open the connection from +12V to the high side of the coil, and at the same time short the high side of the coil to ground, which will put short across the coil. Putting a dead short across a permanent magnet DC motor will stop the motor immediately, so it won't run into the stops and jam. That way you can dispense with the resistor and run full power during actuation.

Not sure if you've had those issues, but something to consider. It might require a couple of DPDT relays to wire it to do that and still operate in both directions, but I'm sure it can be done. I strongly suspect that's what the Toyota controller does, or something similar.

ive never had it jam, ive had it bind but thats just from cross load on the fork when trying to lock and unlock it. you could very well run a relay setup, its a very popular way to do it, SLEE offroad actually sells a built relay box for it that you just wire in. the way the limiters are set up works pretty well as long as the switch is a good DPDT and the motor in the actuator is clocked properly.

 

[fromLRtoT4R]

Yeah, cross-axled and stopped is the worst case scenario for the way the 4th gen atrac works, but I gotta ask just to make sure -- are you giving it some gas and just holding steady while letting the unweighted tires do their obligatory 1 or 2 spin rotations before the atrac grabs and the truck vibrates and sounds like a giant coffee percolator before crawling forward?

If so, pardon the interruption but if not, give it a try.

On a separate note, some aggressive tires at about 18psi would probably do as much or more for you there as a rear locker. Could be I'm talking out my a$$ as I've never had a rear locker, but I'm also unfamiliar with the severity of problem you seem to be describing.

Definitely.. I have tried everything.. Moving forward at constant speed, throttle, and rpm is your best chance to get up anywhere. thats in 4low with center locked off course.. the problem is when you are going up hill, it starts to slow down and you have to compensate with much more throttle.. the system its just too slow, too violent, too clumsy, and too easily defeated. its just not a good system.. Realtive to other systems I have played with anyway... otherwise, I love the 4Runner! anyway, my aussie locker is on the way!! very excited! then this thing will be complete!!

cross-axled and stopped is exactly when you need a system like this to work.. otherwise what is point of the system anyway?

as far as the tires are concerned, airing down the tires will not keep them of from getting off the ground, not with me anyway.. and thats when these things get int trouble

 

[Drunner97]

well people, after several more obstacle tests I have determined that Atrac just plain sucks! I am saddened to say that a 2010 Explorer, and all honda/acura awd systems I have tested performed better when 2 or more wheels start to loose traction. I now have zero confidence in atrac and am too worried to try a true track so the aussie it is! Just ordered it though amazon and everything cost me about 1000.. I have not had the time to take someone with me who could record some the testing I did but I will just leave you with this picture and let you know that it took 4 attempts to make it up this small hill and it finally made it after I began the hill at no less than 10mph and just stayed on the gas and Atrac barely was able to keep it moving.. Just to compare, neither my 2005 LR3 or 2010 LR4 ever broke a sweat getting up this thing.. I was alerted to the weakness of Atrac many months ago when I was guiding by friend who just bought a brand new taco TRD offroad (2014 model year) and damn near had to activate his locker to make it up this tiny hill.. I just though it was just him at first.. sadly it wasnt

You don't look like you're aired down, and those tires don't exactly look like ATs. To be honest, I've done harder than that and made it up no problem in 4lo and 1st gear w/ center diff locked. I'm talking loose rocky terrain with boulders in the middle of it going straight up the side of a hill.

Yeah, cross-axled and stopped is the worst case scenario for the way the 4th gen atrac works, but I gotta ask just to make sure -- are you giving it some gas and just holding steady while letting the unweighted tires do their obligatory 1 or 2 spin rotations before the atrac grabs and the truck vibrates and sounds like a giant coffee percolator before crawling forward?

If so, pardon the interruption but if not, give it a try.

On a separate note, some aggressive tires at about 18psi would probably do as much or more for you there as a rear locker. Could be I'm talking out my a$$ as I've never had a rear locker, but I'm also unfamiliar with the severity of problem you seem to be describing.

Yeah, he's convinced he needs a locker. I think better tires and aired down would be a much much better choice as well.

 

[AKmoney]

OP: The picture you posted above doesn't seem to different than the terrain seen in the following two videos. In both cases, the axles got crossed, ATRAC did its thing and off I went.

Just curious...





Here's one from Moab:

 

[alia176]

This has been an educational thread, learned quite a bit. I've played with the Disco II so the traction control back in those days were young. We learned that larger tires severely slow down the response rate of the LRs and you CAN'T move the gas pedal once the system was working. Ultimately, we ended up installing True Tracs in the rear of those Discos.

My '03 Runner is the first vehicle I've owned with ATRAC and I'm stock height with stock size tires. One thing I've noticed and someone with more knowledge please chime in, and that is the ATRAC system needs to have a steady throttle input. Every time you oscillate the gas pedal, the computer needs to relearn and then reapply the ABS/VSC/anti slip or whatever else it's doing. Coming from a 80 series Landcruiser with dual ARBs this was an interesting revelation. So, once the tires starts to spin for me, I simply just hold it there and eventually ATRAC pulls me out. This has worked for me on muddy, wet rock climbs to very dirty rock climbing situations. Mind you, I'm not rock crawling with this rig but try to put it through tougher situations whenever I can.

Now, slap on a set of larger tires and the ABS rings at each wheels are rotating slower so ATRAC is even slower to response. So, I can see this being annoying in certain situations.

Has anyone mentioned Eaton lockers on the Terraintamer site? I see a set for the 120 series and the FJC so would one of those work for our application?
Harrop Eaton ELocker

 

[fromLRtoT4R]

OP: The picture you posted above doesn't seem to different than the terrain seen in the following two videos. In both cases, the axles got crossed, ATRAC did its thing and off I went.

Just curious...





Here's one from Moab:

Yes, very interesting and I think I have an answer to this.. But first let me announce that my tires have been upgraded to a much much nicer set.. Long sory short, Discount tires lost my original wheels and and tires and agreed to upgrade me to 33" BFG A/T KO2.. very nice tire.. but Atrac still gives up.. and I will air them down when I hit a long trail when I wont really want to get stuck.. BTW all the testing in the LR4 was done with stock size Bridgestone Duelers at full pressure.. My LR3 had 32" Nitto Terragrapplers

anyway, in the first two videos you were not in a climb. you were going straight and I think I mentioned earlier that going up hill becomes a challenge because its hard to keep constant momentum without a throttle surge.. I was able to make some of those hills by starting at a much higher speed so I could keep the throttle pretty constant and maintain just enough speed at the end to make it over the crest.. I can definitely feel and hear atrac working very hard, but I was really spoiled in the Rover.. I mean I could easily stop anywhere I wanted on some of those hills and get going again as I pleased.. A little off topic but still let me clarify to anyone who may care, the stop and go up hill shenanigans worked much better in the LR4 and not the LR3 because the 3 has a very crappy torque curve for a heavy SUV and really bogs below 3k rpm.. I find the 4Runners V6 much much more pleasant, useful, fun to drive, and efficient then the LR3s V8.. Feels like a proper truck engine with the perfect torque curve.. But the LR4s 5.0 V8 is a gem and perhaps almost on par with Toyotas 5.7L Iforce

anyway, back to the videos

The 3rd video is more impressive but the angle of the camera doesnt show what was happening to the rear wheels, and my assumption is that they were both on the ground.. if they were, than Atrac can take care of one wheel up in the air, but not two.. now if you had one front and one rear wheel up in the air, I dont see how atrac can help while you are in a climb.. the video didnt made it seem that that you had two wheels up, but I can only assume because we can only see the front tires.. if you did have two wheels in the air and your 4runner was still moving, then somehow your atrac works better than mine.. but I doubt that

maybe I will have a video in the future for you guys to see, and we can view precisely when atrac quits.. Maybe if I even have time I will record both the Yota and the Dico4 but I dont have much time these days.. I have a small bakround in some engineering so I am fascinated by how these systems work. I actually deliberately try to make them quit to see what they are made of and my point at the beginning was that land rover terrain response (2005 and up) is so far superior to anything, its insane.. nothing I have ever driven even comes close..
not Mercedes 4matic, not jeeps brake lock diffs (BLD) although those are pretty good, not the VW system, not the honda system, and not atrac which unfortunatly for me left much to be desired.. but I have never tried Toyotas newer crawl control and based on some of stuff that I have seen, it is a very ompressive system.. but something about off road cruise control sounds a little unnatural to me

I guess the ARB rear will fix me right up and I did get it delivered already, now just need to install it.. very exciting.. I also wish truetracs were available for the front.. that would be a nice set up

 

[AKmoney]

I'll readily admit the Land Rover traction control is impressive. When I was in Moab I went wheeling w/ a buddy of mine who had an '03 Disco II. Here's him climbing the exact same section:



Compared to my truck you'll see the front passenger wheel spin like crazy. IMHO this is because the disco has an open center diff whereas my truck had the center diff locked. More theatrics in the Disco for sure but he made it up no problem. With regards to your question about whether I had both rear wheels on the ground in that climb I think the answer is "yes, mostly" - if the front wheel is spinning then at least one of the rear wheels is also spinning at the same speed due to the center diff lock. It may have had both wheels on the ground but at least one of them had really lousy traction at best.

Regarding the first two videos the terrain there is a little more uphill than it appears - it's never as steep in photos/videos as real life. Definitely nothing like the 3rd video.

The ATRAC in the 4th gen is definitely primitive but in my case it hasn't left me in a situation I haven't been able to get out of... at least not yet, anyway. It'd be great to have a rear locker. That can't ever possibly hurt!

 

[fromLRtoT4R]

I'll readily admit the Land Rover traction control is impressive. When I was in Moab I went wheeling w/ a buddy of mine who had an '03 Disco II. Here's him climbing the exact same section:



Compared to my truck you'll see the front passenger wheel spin like crazy. IMHO this is because the disco has an open center diff whereas my truck had the center diff locked. More theatrics in the Disco for sure but he made it up no problem. With regards to your question about whether I had both rear wheels on the ground in that climb I think the answer is "yes, mostly" - if the front wheel is spinning then at least one of the rear wheels is also spinning at the same speed due to the center diff lock. It may have had both wheels on the ground but at least one of them had really lousy traction at best.

Regarding the first two videos the terrain there is a little more uphill than it appears - it's never as steep in photos/videos as real life. Definitely nothing like the 3rd video.

The ATRAC in the 4th gen is definitely primitive but in my case it hasn't left me in a situation I haven't been able to get out of... at least not yet, anyway. It'd be great to have a rear locker. That can't ever possibly hurt!

Very interesting.. In that video you can clearly see that both the rear wheels do stay on the ground, but you did mention that was most likely the case.. The Dsco 2 traction control was also very primitive. And the lack of center diff was ridiculous.. I think the game changer for Land Rover was in 2005 on the 3rd gen Discos (LRs in America) with the Terrain Response system, center locker, and if you get the HD package a rear locker but for this thread I am comparing apples to apples so center locker only. Neither my previous LR3 or current LR4 has the HD package because its almost impossible to find those.. Imo, they don't need them. My 4Runner does.. which is OK, I was kind of planning for that anyway.



I am really hoping I will have time to make a video. I think it will clear up a lot

 

[JB.]

as far as the tires are concerned, airing down the tires will not keep them of from getting off the ground...

Actually, in many cases it will.

The aired down stuffed tires increase the effective flex, often allowing the extended tire to get some new found bite.

But zooming in too specifically can sometimes lose the forest for the tress. With aired down ATs, the whole operation just goes better and many of the former problematic situations just don't come up anymore.

 

[CruzadoBlanco]

This has been an educational thread, learned quite a bit. I've played with the Disco II so the traction control back in those days were young. We learned that larger tires severely slow down the response rate of the LRs and you CAN'T move the gas pedal once the system was working. Ultimately, we ended up installing True Tracs in the rear of those Discos.

My '03 Runner is the first vehicle I've owned with ATRAC and I'm stock height with stock size tires. One thing I've noticed and someone with more knowledge please chime in, and that is the ATRAC system needs to have a steady throttle input. Every time you oscillate the gas pedal, the computer needs to relearn and then reapply the ABS/VSC/anti slip or whatever else it's doing. Coming from a 80 series Landcruiser with dual ARBs this was an interesting revelation. So, once the tires starts to spin for me, I simply just hold it there and eventually ATRAC pulls me out. This has worked for me on muddy, wet rock climbs to very dirty rock climbing situations. Mind you, I'm not rock crawling with this rig but try to put it through tougher situations whenever I can.

Now, slap on a set of larger tires and the ABS rings at each wheels are rotating slower so ATRAC is even slower to response. So, I can see this being annoying in certain situations.

Has anyone mentioned Eaton lockers on the Terraintamer site? I see a set for the 120 series and the FJC so would one of those work for our application?
Harrop Eaton ELocker

the harrop locker would work just fine for our trucks. aslong as it say it fits a toyota 8" v6 third itll work with any toyota 8" rearend from 197x-2009. they also have a locker for the 8" clamshell in the front. we tried getting a groupbuy together last year or the year before but just didnt have enough people. i would love to get one for the front since i already have a retrofitted rear end i dont want to take all the effort to run all the stuff for an arb in the front.

 

[Frontline]

Any idea what the harrop locker costs uninstalled?

 

[fromLRtoT4R]

just a quick update, got my ARB rear locker in and naturally it made a huge difference.. Got my new BFG A/Ts KO2 33" tires, and replaced the rear Fox shocks with Icons..

I will try very hard to make some comparo videos soon with the land rover.. have a new baby therefore I have very little time for much else.. but I still do some testing here and there and there are few very interesting things I discovered.. now to some it will come as no surprise that when cross axled, the 4runner is a lot more capable it 2WD rear locked than 4wd (4low center locked rear open) as long as your not climbing too hard.. what was more shocking to me was that in some cross axled situations it actually did slightly better in plain old 2wd everything open rather than 4wd with center locked and rear open.. as strange as it sounds but in 2wd the Atrac and Traction Control (still on in 2wd) focus on the rear wheels only and seem to be have a better handle on things.. it was a bit shocking at first but then it made a bit more sense.. going up a light slope cross axled in 2wd the system seemed liked it was about to quit but after thinking for a few seconds with steady light throttle it just started to move.. I was amazed so I did it again and agian, in 2wd and 4hi, 4lo, center locked and unlocked and almost every time it did a little better in 2wd. off course keep in mind it was nothing extreme but still a descent enough test.. in the same test, keeping it in 2wd with the ARB locked, it doesnt even break a sweat..

anyway, hopefully soon I can have some videos to back some of it up...
once again though, love the ARB locker.. feel like I made the right choice and would definitely recommend for the 4th gen 4Runner

 

[fromLRtoT4R]

Here is a little something for now.. sorry its so grainy but it was way after sunset already and pretty dark out..

 

[fromLRtoT4R]

shot a couple of videos in the last few days, both the 4runner and the land rover.. just need to put them together, add some comments and I will post them as soon as have more than 30 seconds to my self.. hopefully soon!

 

[CruzadoBlanco]

another approach i forgot to mention earlier is the addition of longer rear shocks and springs such as the Metaltech rear longtravel setup that me and a few others are running. i rarely if ever lift tires after i installed that but i also have no swaybars and extended front travel with a very soft setup.

 

[fromLRtoT4R]

I am going to remove my front sway bar and try that out. In the rear I have the Toytec long travel spring and the Icon lift shocks.. they seem to extend pretty well.. definitely happy with the flex of the rear, but not so much the front.. I have Bilstein 6112s in the front and they ride great but not much travel up there right now..

anyway, I have the video ready..

I started a new thread so more people can see it
here it is

http://www.toyota-4runner.org/4th-g...nse-test-quick-comparo-video.html#post2306741

 

[Drunner97]

I am going to remove my front sway bar and try that out. In the rear I have the Toytec long travel spring and the Icon lift shocks.. they seem to extend pretty well.. definitely happy with the flex of the rear, but not so much the front.. I have Bilstein 6112s in the front and they ride great but not much travel up there right now..

anyway, I have the video ready..

I started a new thread so more people can see it
here it is

http://www.toyota-4runner.org/4th-g...nse-test-quick-comparo-video.html#post2306741

This is with the MT rear + extended icons and both front/rear sway bars removed. Pretty sure your rear tire wouldn't be in the air in that last picture with this setup.

 

[fromLRtoT4R]

hmm.. dont know about all that

 

[fromLRtoT4R]

I like this picture