converting Sport Model to A-TRAC

Thanks for the great reply.

The lockers will be ARBS with ECGS doing the install with 4.56s. There was never a question about that. I wouldn't dare put a non-selectable locker in a daily driver let alone an IFS!

The Sport was because I considered 4 doors mandatory as well as the bigger bed. My truck is used as a truck AND a people carry. I had another truck with a longer bed and 2 seats that the Tacoma replaced. I regularly use the bed to haul and couldn't imagine it being any smaller than it already is!

As far as bumpers go... I have a Line-X'd front and rear All-pro.


This was me ...pretty stuck. Yay for winches and trees.

I'm an engineer by education and trade, so this post was a fact gathering missions so that I might make a determination if it was possible. Obviously, with enough money and determination, you can do anything...

 

Absolutely incorrect. I spent almost all of last Saturday with it on, and it ONLY needed to kick in in crawl sections where one wheel was losing traction, either from being off the ground or breaking loose...this was mostly over mud-slicked rocks in 4Lo 1st or 2nd gear.

Absolutely correct.

 

Wow.... Thanks for making it clear why I must not give up my crusade to educate Tacoma owners (who don't have A-TRAC or don't understand their A-TRAC) on how it works.

Seriously, we drive Toyotas because of how good they build trucks, right? Would Toyota put A-TRAC in the Tacoma unless it could perform?

Well, the A-TRAC works at any speed you would want to drive in LOW RANGE... which is usually under 25 mph, because the low range is for crawaing over/ through, up or down difficult terrain... Get it:? CRAWLING...

Who is on the gas in low range... except when climbing steep hills?! There's a video of me taking a run up a steep, dusty hill... and when my upward momentum came to a crawl... THAT, is when the A-TRAC took over and began transfering torque to the tires with traction... biting and biting with all fours until it pulled my truck to the top.

In Baja, the Widowmaker grade near Mision Santa Maria is a rocky CRAWL grade... and A-TRAC performed flawlessly... Previous trips with my other Tacomas, I used the rear locker to climb the Widowmaker and other grades on that road.

A-TRAC, it isn't just for breakfast anymore!

 

It requires wheel slippage to activate.

On the rocks (real rocks - boulders), spinning wheels is a great way to break things.

 

Thanks a lot mxpatriot now you have done it...

There goes the thread...

 

To get the brake to lock the wheel up and transfer power, it needs to detect slippage. When you're in a giant pile of boulders, wheel slippage causes the vehicle to bounce and abruptly crown boulders and slam the vehicle down on them. I'm talking big rocks here, rock crawling.

 

That is the point... A-TRAC doesn't allow slippage, it matches wheel rotation across the axle so the loose tire rotates the same speed as the traction tire... as if it were a locker.

 

No it doesn't. It quickly pulses the brakes to stop one wheel from spinning, which transfers the power to the other wheel, which gives the vehicle more traction. That's not the same as forcing both wheels to turn with each other at the same speed and same time (mechanical locker).

If you can explain to me how applying the brakes to one wheel makes both wheels rotate at the same speed, at the same time, under power, I'll send you a "Master of Defying Physics/Open Differentials" trophy.

The brake pulsing action is enough to overcome most obstacles - but it does not compare to a mechanical locker for rock crawling applications. That's all I've ever said. 99% of guys on this forum, let alone general tacoma owners, will rock crawl their Tacoma so it's not even that big of an issue!

 

disagree

agree

 

I found this interesting you might as well. http://www.tacomaworld.com/forum/technical-chat/51946-4low-trac.html

 

No, it requires a difference in wheel speed rotation in the same differential. Difference.

Which is why it stops that from happening.

No, it doesn't pulse. It clamps. It uses the brakes to stop the wheel. I don't know that it will perform exactly like a locker in all situations, but it's pretty damn close on a slick muddy/rocky trail. I was skeptical of A-TRAC til' I used it.

Have a comparison of two videos. The first is Namyo running the bowl on Dickie Bell with his rear diff locked (skip to 8:15 - Indigo Ink truck with topper):

http://www.youtube.com/watch?v=_RzyYXS40yY&feature=player_detailpage#t=495s

The second is me running the EXACT SAME BOWL about 2 minutes later with A-TRAC only, no locker. The sound you hear is A-TRAC kicking in:

http://www.youtube.com/watch?v=Z_1Ii0WmA9s&feature=player_embedded

Good call. But Hey...I like a good ol' shitstorm

 

This debate needs to get AWAY FROM LOCKERS VS A-TRAC ANYWAY. It's a shitty comparison.

Lockers are one approach to a problem. A-TRAC is a different approach to the same problem. They are BOTH very effective but need to be thought of in different terms.

My recommendation: Lockers are lockers. A-TRAC is the *best* traction control system currently on the market. BOTH should be had if possible.

I can think of situations where I would want one and not the other. I actually turned it off several times, most notably for a descent of a muddy, very steep hill that we essentially slid down one after the other.

 

So I guess that when the rear locker is engaged, the 3MPH maximum speed for A-TRAC to be active is useless then?

Try the thing before bashing it.

 

In an attempt to get back to the OP's question...

Just want to x2 this....we did all come to the same conclusion that if your truck doesn't already have A-TRAC, converting makes no sense. It's going to be expensive, time consuming, and will NOT offer enough advantages over lockers (such as steering control) to make it worth that extra price. Especially considering lockers are better in many ways and much less expensive.

Lockers make far more sense if you're already working with an open diff or LSD truck.

Converting for A-TRAC is a lot like converting to 4x4...it just plain makes more sense to trade your current vehicle in for one with the capability you're looking for.

 

AFAIK A-TRAC will become innactive, when the rear locker is engaged, when vehicle speed goes over 3 (maybe 5) MPH.

 

And that's a great application of A-TRAC. I've never said that A-TRAC doesn't have its place.

But that's not rock crawling, so it doesn't address the point that I've made.

 

There is not a 3 MPH maximum for A-TRAC. See the videos of David_K climbing hills at a decent speed with it engaged.

 

It addresses some points - you can clearly see the wheel stopped and matched to the opposite side by the brakes, you can clearly see the truck is crawling (I actually came to a complete stop in the bowl) - you can clearly see that it was smoother than the locker in this instance (there are variables...different suspension, different tires...I am not suggesting it's smoother than a locker every time).

I have no reason to believe A-TRAC would make you ANY more likely to break something during rock crawling than any other device. It's actually going to be less stressful on the truck overall because the diff doesn't undergo the stresses a locked differential sees. At the same time it's being less stressful, it may not get you to the same places. I have yet to take this truck down a dedicated rock yard like Rausch or build a rock sluice in my back yard. Stay tuned for further developments.

Anyway, can we all get back to the original topic and agree that converting to A-TRAC is not a good idea?

 

+ repped.

 

Again, I'm not talking about trails like the one you posted the video of. That's rough terrain and the A-TRAC can do very well there, but it's entirely different world than rock crawling.

Just ask yourself why the guys who wheel hard on this site and have newer trucks still purchase air lockers, even though they have A-TRAC...

I'm talking about situations like this:

sub-0.5 MPH, large rocks, require the tires to climb the rocks. Wheel slippage, even minute amounts (like those required to activate A-TRAC), sucks in situations like this. Trust me, I abuse the hell out of my truck getting through stuff like that on the LSD.