Can someone explain why the '01-02 "Active" Trac is bad?

[JayRolla]

Before calling anything "absurd," you should realize that
All evidence, including the manual itself, explicitely contradicts the two major aspects of your post:

1) It is the VSC, not ATrac, which has the ability to control throttle.

2) Only VSC, not ATrac, is disabled with the center diff locked.

Thus, only ATrac would be a factor in a 4Lo, diff-locked situation, and none of the functions and outcomes you mention (dethrottling) actually apply to ATrac.

As to the bolded part of your post, can you articulate why? I know it is very well-regarded in the FJ and 5th Gen communuty (and I have seen it work with good results). I am just curious what specifically makes it worse in the 3rd gens (longer response times? Less smooth brake inputs? Higher wheel-speed differentiald required? We do have one reasonable hypothesis that the weaker 3rd gen engine can't keep up with the doubled effort required.).

But, really, it sounds like I'll need to do my own testing, because apparently nobody really has the answer, heh.

You pretty much discredited every ones post and opinion. Why ask if that's all your going to do. Entire threads and modifications have been done to disable it.

If you actually wheel your 4runner you would have answered your own question. Literally multiple threads of people disabling and explaining why they did it.

 

[JayRolla]

10+ years of testing & development coupled with much bigger-faster CPU and memory for programming, and higher bandwidth closed-loop control system. Kinda the way todays HIDs are just a little better than the oil lamp headlights on the early cars.

GL, pack a shovel.

Well said! Crawl control equipped ones are amazing!

 

[SnowLizard]

Far as I know VSC showed up in 2001, along with the ATRAC and end of e-lockers. ABS of course existed prior to '01 but it was 3-channel with just one brake line going to the rear axle.

Yeah, you are correct. thanks!!!

This is what I am starting to gather.

While I will always support good data gathering and experimentation, the intent of this thread wasn't to compare ATrac to a locker, and I don't think anyone expects the former to really match the latter.

ok, so I hi-jacked the thread a little... just wanted to know about all of them

 

[Lindenwood]

Eh, no need to continue the bickering.

I think we can all agree that there is a lot of data that needs to be gathered before we can move forward with our collective understanding of the 3rd gen's ATrac.

 

[Lindenwood]

Yeah, you are correct. thanks!!!


ok, so I hi-jacked the thread a little... just wanted to know about all of them

Well, I do really like the idea of collecting the data for future searchers to explore, sk expect some data and videos from me!! :cheers:

 

[Darren]

You pretty much discredited every ones post and opinion. Why ask if that's all your going to do.

He did that because folks like 4R#3, who even though he's apparently gone through three of these models with the features in question, continues to have the opposite understanding of what they do, while everything Lindenwood has stated and understood has been correct, including quoting the manual. I'm not sure it's wise to dispute the manufacturer. This is also why he started the thread to begin with, as he evidently saw many other mistatements as well. As I also stated previously, dethrottling is not a function at all of A-TRAC, and I believe this is the only negative aspect of either system. VSC is now known as Traction Control on the current 4Runners, so maybe that is adding to his (4R#3) confusion.

Lindenwood, I wouldn't be concerned with this any longer. Put it in 4WD (as opposed to AWD), and it will work like a 4Runner should. Thank you for taking your vacation for the rest of us. It is appreciated.

 

[WallyWest]

Didn't read the whole thread, so apologies is this has already been said.

3rd gens do not have ATrac, it's the first gen system simply called TRAC. It's certainly not as good as a locker but it does help. I have driven up the side alley behind my house that is very steep and never gets plowed when there was snow and ice on it, in 2WD, and TRAC worked pretty good. I doubt I would have gotten up without it. In 2WD anyway.

VSC is the one you want to disable in off-road conditions. That will cut power and prevent any wheel spin, which will leave you stuck in situations where some wheel spin is wanted.

ABS is also very crappy on the 3rd gen for off-road. At low speeds on slippery surfaces it basically disables the brakes.

I don't have a problem with TRAC. I plan on installing kill switches for ABS and VSC, but I'll leave TRAC alone.

 

[SnowLizard]

Well, I do really like the idea of collecting the data for future searchers to explore, sk expect some data and videos from me!! :cheers:

I guess, now that I think about it, we already need a vehicle that has vsc+trac, but we should have a 'control' vehicle that doesn't just so we actually know what vsc+trac does, granted we could disable it, but that's not factory. so I figured a 99-00 ltd with a locker would be a good candidate to get just a little extra data from.

Anyways, IF anyone is near me (Gilbert AZ), I don't mind setting time aside to do some experimenting. I do have a place we can go to for some steep inclines on loose surface, which should be perfect and not too challenging.

 

[ToyotaBrah]

Well, isn't this something. I was reading on this thread just last week and was wondering to myself if the VSC had any merit at higher speeds. Yesterday morning I found out first hand how it responded to black ice on the highway.

I was on the highway (35N for those in the midwest) going about 60mph due to it drizzling. The temp was hovering at ~30-32°F and the ground temp was warmer than that so it wasn't sticking. I was driving under a short overpass where it was presumably colder given that the drizzle/rain froze there, and at this particular overpass the road also involved a slight turn. As I turned and went underneath the pass, the 4Runner completely lost traction and the tail end came out. Immediately then, the system took over and corrected itself within a second or two and put me back in my lane. I was beyond impressed with it given that this system was probably developed somewhere in 1999-2000.

I've been in situations before when the rear end kicks out on other RWD cars I've owned and I've corrected them successfully. However, yesterday in particular, with how fast I was going, my 4Runner would have bit the dust had it not been for the VSC.

It may be a nuisance for off-road purposes, but for a pavement princess like mine, I have no desire to ever disable it.

 

[JayRolla]

Well, isn't this something. I was reading on this thread just last week and was wondering to myself if the VSC had any merit at higher speeds. Yesterday morning I found out first hand how it responded to black ice on the highway.

I was on the highway (35N for those in the midwest) going about 60mph due to it drizzling. The temp was hovering at ~30-32°F and the ground temp was warmer than that so it wasn't sticking. I was driving under a short overpass where it was presumably colder and the rain froze, and at this particular overpass the road also involved a slight turn. As I turned and went underneath the pass, the 4Runner completely lost traction and the tail end came out. Immediately then, the system took over and corrected itself within a second or two and put me back in my lane. I was beyond impressed with it given that this system was probably developed somewhere in 1999-2000.

I've been in situations before when the rear end kicks out on other RWD cars I've owned and I've corrected them successfully. However, yesterday in particular, with how fast I was going, I think my 4Runner would have bite the dust had it not been for the VSC.

It may be a nuisance for off-road purposes, but for a pavement princess like mine, I have no desire to ever disable it.

Yes the system works wonders on road. In some situations like you stated its a life saver.

But yeah offroad and trying to have fun. Thats why they add a disable button.

 

[sab7896]

Lindenwood,

You pose a great question and I commend you for asking it. I asked the same question myself. I determined the answer on my own without giving those with experience a chance to voice their opinion. I may've passed on first-hand experience in doing so but from reading all of the posts on the subject I was convinced that many folks don't understand the difference between VSC and TRAC.

I'm sure I'm in the vast minority but when looking for a 3rd gen I preferred the '01-'02 with VSC/TRAC. Why do you ask? Several reasons:

1. VSC on the highway can be a benefit. There's plenty of examples (several in this thread) of vehicles that were saved by it.

2. TRAC is a benefit off road. TRAC DOES NOT DETHROTTLE THE ENGINE. It simply applies a brake force to an individual wheel that is spinning (this may drop RPM and give someone the impression of dethrottling... but it is not robbing the motor of power). TRAC brakes a spinning wheel so that torque may be applied to the opposite wheel (which has traction).

3. I plan to retrofit an e locker from a '99 (picking up a full rearend assembly tomorrow). A locker in the rear with TRAC is better than the sought after '99 setup to me... if the electronics of the e locker fail you still have TRAC that will brake the spinning rear wheel. If TRAC fails, you have a locker in the rear. If both systems remain active (as they most likely will), you have a locker in the rear with the ability to brake a spinning front wheel. '99s have an open diff in the front... I'll take an open diff that can brake the spinning wheel simulating a LSD.

4. I plan to add the Bagel Mod to disable VSC (disable VSC only... I still want TRAC operational). I would use this when in AWD (center diff unlocked). This would prevent VSC from dethrottling the motor when trying to accelerate from a stop on snow/ice (there's several examples of members here that have experienced this).

In summary, I'll take a VSC/TRAC equipped 3rd gen that's been retrofitted with an e locker over a '99 any day. I understand how both VSC and TRAC operate and that both can be a benefit.

All that being said, I have not driven all the various factory equipped T4Rs in all possible conditions and therefore do not have the experience that others might. I do, however, have an understanding of vehicle dynamics and the application of torque (whether drive torque or brake torque). I see TRAC as an innovative means of improving a vehicle's tractive capabilities using an already existing system (ABS) without having to add any additional mechanical or electrical systems. How well this system works may be debatable but when someone mentions TRAC and dethrottling the motor in the same sentence I immediately discredit their argument.

Just my take.

 

[RedSled]

Lindenwood,

You pose a great question and I commend you for asking it. I asked the same question myself. I determined the answer on my own without giving those with experience a chance to voice their opinion. I may've passed on first-hand experience in doing so but from reading all of the posts on the subject I was convinced that many folks don't understand the difference between VSC and TRAC.

I'm sure I'm in the vast minority but when looking for a 3rd gen I preferred the '01-'02 with VSC/TRAC. Why do you ask? Several reasons:

1. VSC on the highway can be a benefit. There's plenty of examples (several in this thread) of vehicles that were saved by it.

2. TRAC is a benefit off road. TRAC DOES NOT DETHROTTLE THE ENGINE. It simply applies a brake force to an individual wheel that is spinning (this may drop RPM and give someone the impression of dethrottling... but it is not robbing the motor of power). TRAC brakes a spinning wheel so that torque may be applied to the opposite wheel (which has traction).

3. I plan to retrofit an e locker from a '99 (picking up a full rearend assembly tomorrow). A locker in the rear with TRAC is better than the sought after '99 setup to me... if the electronics of the e locker fail you still have TRAC that will brake the spinning rear wheel. If TRAC fails, you have a locker in the rear. If both systems remain active (as they most likely will), you have a locker in the rear with the ability to brake a spinning front wheel. '99s have an open diff in the front... I'll take an open diff that can brake the spinning wheel simulating a LSD.

4. I plan to add the Bagel Mod to disable VSC (disable VSC only... I still want TRAC operational). I would use this when in AWD (center diff unlocked). This would prevent VSC from dethrottling the motor when trying to accelerate from a stop on snow/ice (there's several examples of members here that have experienced this).

In summary, I'll take a VSC/TRAC equipped 3rd gen that's been retrofitted with an e locker over a '99 any day. I understand how both VSC and TRAC operate and that both can be a benefit.

All that being said, I have not driven all the various factory equipped T4Rs in all possible conditions and therefore do not have the experience that others might. I do, however, have an understanding of vehicle dynamics and the application of torque (whether drive torque or brake torque). I see TRAC as an innovative means of improving a vehicle's tractive capabilities using an already existing system (ABS) without having to add any additional mechanical or electrical systems. How well this system works may be debatable but when someone mentions TRAC and dethrottling the motor in the same sentence I immediately discredit their argument.

Just my take.

Welcome, great first post.

 

[Lindenwood]

In case anyone has been curious, so far I have yet to get the VSC to cause any dethrottling despite even moderate yaw in 2WD in loose dirt (basically doing a burnout and deliberately wagging the wheel back and forth to cause fishtailing).

Also, I have observed the Active-TRAC system activating the rear brakes independently after deliberately getting stuck in a slightly crossed-up situation in 2WD. Unfortunately, my rear brakes are shot (going to replace the pads this weekend). Still, I could hear the brakes rumbling, I could lean out and watch the spinning wheel being slowed (was sitting at about 1500-2000 engine RPM), and I could feel the vehicle try to pull itself out through the other side of the axle.

I didn't take video due to the aforementioned brake deficiency, and because my wife was already pulling ahead of me in her 4Runner and I had to catch up .

 

[JayRolla]

In case anyone has been curious, so far I have yet to get the VSC to cause any dethrottling despite even moderate yaw in 2WD in loose dirt (basically doing a burnout and deliberately wagging the wheel back and forth to cause fishtailing).

Also, I have observed the Active-TRAC system activating the rear brakes independently after deliberately getting stuck in a slightly crossed-up situation in 2WD. Unfortunately, my rear brakes are shot (going to replace the pads this weekend). Still, I could hear the brakes rumbling, I could lean out and watch the spinning wheel being slowed (was sitting at about 1500-2000 engine RPM), and I could feel the vehicle try to pull itself out through the other side of the axle.

I didn't take video due to the aforementioned brake deficiency, and because my wife was already pulling ahead of me in her 4Runner and I had to catch up .

Me and my brother talked on this some more. He said in some situations in mud it helps from a stop but has gotten him stuck also where he could have powered through but the braking slowed him down.

He said think of out like this. If you watch Top Gear when they get the best track times they disable ALL traction control features. You just want full control on the trail. It really sucks when your car takes over and your not expecting it.

 

[Lindenwood]

What tires does he have on the vehicle?

I still can't imagine how allowing a tire with lower traction to continue spinning at modest speeds** would help a vehicle more easily get through an obstacle, but I do appreciate your inputs.

**(Yes, an aggressive MT will clear mud if allowed to spin, but it is my understanding that the brake-biased traction control systems do not interfere at the large throttle openings or higher engine speeds required to actually get this mud-clearing effect).

 

[idlingmike]

I looked into this and ran into all the same threads you probably did where people just say "it sucks" because that's what they heard. I think it largely comes down to Toyota dropping the coveted actual locking differential and substituting it with TRAC, then later ATRAC.

I don't think anyone argues the E-locker performs better than TRAC. However, compared to only having an open differential, TRAC would help in some scenarios like when you have one or more wheels off the ground.

Personally, I specifically looked for an 01/02, I can always add an ARB rear locker, then still have TRAC (hopefully) functional up front. You're never going to realistically going to add VSC and vastly superior ABS to a 96-00. Lastly, you can always disable the TRAC system.

 

[fblainen11]

From what I understand the Atrac system basically helps control wheel spin. And losing grip when off-roading by applying the brakes automatically to the wheel that is spinning, thus sending power to the wheel that has more grip.

There are videos of locked vs Atrac Landcruisers on YouTube that demonstrate the difference. While the locked Landcruiser works much faster, the Atrac LCs are still plenty capabale of tackling the same obstacles.

Basically, I think the engineers followed the ol 20/80 rule where they found they could do 20% of the effort/money/resources into a braking and tech system, vs more complex and expensive locker. And this 20% of the effort still provides 80% of the capability when compared to the locker.

I know some of the locked guys may get all up in arms about that claim, but it's just a broad generalization that is subjective, but also may be backed up by some of the objective comparisons i mentioned earlier.

Edit: from experience I've taken my 01 in mud following my friend in his Jeep Cherokee with LSD.
He had mud grips and I was on street tires. In 4Lo there was no issue keeping wheel speed high enough to get through the holes we went through. Additionally, many times throughout the trip the Atrac system would kick in, it was very muddy so I really couldn't "feel" anything different, but I went through everything with no issues. I think it is a proficient system; again I'm not saying it is superior to a locker, but for what it is, Id say it is proficient.

 

[poopypants]

I think people keep saying "de-throttling" or "engine braking" in these threads and they are saying this just probably based on the idea that they are being slowed.


Example:
If in a situation where momentum is key and a tire is quickly lifted, and you are not beyond the "threshold RPM" of disabling the TRAC system, then you will get immediate braking and the scenario where you would have otherwise quickly planted that tire again and maintained fwd momentum once traction is regained, you've now been slowed going uphill due to braking.



In this case, the imperfect TRAC system in the third gen could certainly be seen as a hindrance, and the sudden slowing and loss of power could EASILY be mistaken for "de-throttling".

Having the more refined ATRAC system like is available with the 4th gen, or FJ in conjunction with the locker, makes good sense and tends to work fairly well with a stronger power plant under the hood....

In the 15 year old, poor braking and less powered 3rd gen, a driver mod is MUCH better than having intervening systems, and at the least TRAC should be selectable through all drive modes.

Doing the mod to turn these off as desired is most definitely preferential... Once failed in an attempt, then see if by chance the system can be of help... But by NOT doing the mod you only limit your ability to manage the vehicle in a manner that may surpass what it "thinks" it should do for you.

 

[poser]

Yesterday on a single lane dirt road in Colorado, I entered a tunnel that I ended up having to back out of because there ended up being two cars entering on the other side. I was in "AWD" mode, it was wet and a little muddy on the gravel road. My 4Runner almost wouldn't back up (slightly up hit) because one wheel kept slipping and it would cut all power. Super frustrating.


Sent from my iPhone using Tapatalk

 

[aegarci16]

I created a 4WD reference guide for 01-02 that describes the functionality of each possible mode selection. The Owners Manual does a horrific job of explaining this. So much so that even when I tried digesting it through ChatGPT it still failed to properly put everything together. Let me know what you think.

2001 - 2002 Toyota 4runner 4WD Guide - Google Sheets