FJ Trail ride results

[crawler#976]

The FJ trail team was in AZ last weekend. We'd scheduled a run on the DeSoto Mine trail - ended up with 56 rigs!

Ended up splitting up in two groups. The factory guys went on the more difficult run. I ended up taking 19 rigs (including 15 FJ's) on an alternative run. Not being familiar with the new FJ's, I couldn't answer some questions that were brought up. Most of the owners in my group were novice wheelers, and several still had temp plates on'm.

The first question was "Can I use the rear locker and traction control at the same time?"

From my observation, the system works pretty well if you have some wheel spin. It did tear up some rubber tho - the loose sharp rocks we were in thrashed tires until the system kicked in.

The other common question was "How do I get the A-Trac to engage quicker?"

Thanks for any info.

Mark

[98taco4x]

:worthless

[Valkyrie]

"Can I use the rear locker and traction control at the same time?"

Nope. The traction control uses braking to control tire spin.. you can imagine the ramifications of trying to brake one wheel that is part of a locked axle...

"How do I get the A-Trac to engage quicker?"

It's dependent on wheel speed, so there is an inherent lag- the wheel spin has to get to a certain point before it kicks in. Unfortunately, there is no way for a system to anticipate which wheel will spin, just as cruise control can't see that a hill is coming.

[crawler#976]

:worthless

dude, I was planning to DO a trail ride, not lead one. :p


I was too busy to take many photos. I'll post up the few I took later.
Gotta say it was a real traffic stopper to have all those shiney new FJ's following a BPOS like mine...

They aint' shiney now tho - a good dose of AZ pinstripping was issued to each one :eek:

[OR_05Taco]

Nope. The traction control uses braking to control tire spin.. you can imagine the ramifications of trying to brake one wheel that is part of a locked axle...



It's dependent on wheel speed, so there is an inherent lag- the wheel spin has to get to a certain point before it kicks in. Unfortunately, there is no way for a system to anticipate which wheel will spin, just as cruise control can't see that a hill is coming.

If the A-Trac needs tire spin in order to engage it, then it should never even attempt to engage with the rear locker engaged, right? There should be no tire spin with the locker engaged, so there should be no conflict...?? I don't understand why the two systems couldn't work together (A-Trac + rear locker). I know they don't from the factory, just don't understand why :confused: .

[Valkyrie]

HUH? You can spin locked tires all day long.

I don't know if I misspoke, maybe Thomas will chime in, but I understand that they were set opposite (i.e. can't do both at the same time) because the Atrac controls each wheel independently, so the possibility existed that different braking pressure may be applied to the rear wheels, which are locked & spinning at the same rate.

It's all hocus pocus to me... :D

[BigBadBob0]

For a traction control system wheel spin is when one wheel spins at a significantly different rate from another.

Obviously, if this rate is too low, you'll have brakes flying on and off just going around a normal turn.

[OR_05Taco]

HUH? You can spin locked tires all day long.

I don't know if I misspoke, maybe Thomas will chime in, but I understand that they were set opposite (i.e. can't do both at the same time) because the Atrac controls each wheel independently, so the possibility existed that different braking pressure may be applied to the rear wheels, which are locked & spinning at the same rate.

It's all hocus pocus to me... :D

Yea, you can spin locked tires, but not at different rates in relation to each other, which is the kind of wheel spin that the A-Trac detects, right? If the rr diff is locked, the wheels won't spin at different rates, so A-Trac shouldn't engage... that's my uneducated thinking on it. I don't really know how it all works either but from the little I've read this was my understanding.

EDIT - Just re-read your post (it's late). I see what you're saying now. The A-Trac will brake a spinning tire even if it's spinning at the same rate as the other tire? That's the part I was getting hung up on. I thought it would only brake one side if it's spinning at a different rate from the other.

[seth_js]

:worthless

http://www.ttora.com/forum/showthread.php?t=37851

-Seth

[purity]

this link is better :p
http://seth.phizz.net/adventures/fj_rocks_arizona_6-10-06/

cool pics btw.

[Valkyrie]

this link is better :p
http://seth.phizz.net/adventures/fj_rocks_arizona_6-10-06/
LOL! That does simplify things.. :D

[calamaridog]

I'm guessing there is a way to enable the TRAC in front when you have the rear locked for locked rear/TRAC front. This would require a mod of some sort, I'm not sure if anyone has done this yet since I don't really follow the FJC threads much.

I'm sure the TRAC is very hard on those cheesy stock rubber.

[purity]

I'm guessing there is a way to enable the TRAC in front when you have the rear locked for locked rear/TRAC front. This would require a mod of some sort, I'm not sure if anyone has done this yet since I don't really follow the FJC threads much.

I'm sure the TRAC is very hard on those cheesy stock rubber.
that may be possible on the auto tranny, but not the manual since it is fulltime 4wd and both the front and rear share a center diff that can be locked.

[calamaridog]

that may be possible on the auto tranny, but not the manual since it is fulltime 4wd and both the front and rear share a center diff that can be locked.

I wouldn't matter, TRAC would sense wheel slip in front and do it's job while it would sense no wheel slip in the rear and do nothing.

On the 2000+ Land Cruisers, which are also full time 4wd and also have locking center diffs this is what happens. Activate the rear locker and by default, the TRAC does nothingin the rear because it is locked, while the front still enjoys the TRAC.

[purity]

doesnt the center locking diff lock all 4 wheels?

On the 2000+ Land Cruisers, which are also full time 4wd and also have locking center diffs this is what happens. Activate the rear locker and by default, the TRAC does nothingin the rear because it is locked, while the front still enjoys the TRAC.
i see you have an LC100 so maybe your right.

[crawler#976]

here's a pic of the FJC's that got a good dose of AZ pinstripping.

[calamaridog]

doesnt the center locking diff lock all 4 wheels?

Lock the center and you have a 50/50 power split between the front and rear. Unlocked, you can drive around on the street and not have driveline binding.

"A four-wheel-drive vehicle will have at least two differentials (one for each pair of wheels) and possibly a center differential to apportion power between the front and rear axles. Vehicles without a center differential should not be driven on dry, paved roads in all wheel drive mode, as small differences in rotational speed between the front and rear of the vehicle cause a torque to be applied across the transmission. This phenomenon is known as "wind-up" and can cause damage to the transmission. On loose surfaces these differences are absorbed by the slippage on the road surface. - Wikipedia"

On the 100 series, the TRAC is only enabled when you are in 4low and the center diff automatically locks in 4low. I think this is how the FJC works too.

Anyways, if you added an ARB to a TRAC equipped FJC, and you were in 4low, you could lock the rear and the front should still enjoy the benefits of TRAC. With the factory e-locker, I'm sure there is a way to enable the TRAC while the e-locker is engaged. At least I think there would be?

Like I said, I haven't really read any of the tech threads so someone may have already done all this.

I just look at the picture threads :D