Making sense of TRAC, Auto LSD, ATRAC, VSC, & Rear Diff lock. - Page 3

Thai · 07-02-2006, 06:12 AM

Here is a piece of trivia for you guys...did you know that traction control does not work after certain speed??

For Mercedes and Land Rover traction control systems, after about 40 mph, traction control stops working. Why? Well, at highway speed, momentum is the main thing. Thus, VSC (stability control) is the main workhorse...and has the dominant function. At these speeds, the one that will be saving your life is VSC.

I doubt that Toyota's system is any different from MB or LR. Mercedes and Land Rover were the pioneers of these electronic traction systems in the 1990's. MB focused more on on-road safety...thus, their traction control systems are less effective than Toyota's (esp. FJC's) and Land Rover's. Land Rover system is more off-road oriented and is somewhere between FJC's TRAC and ATRAC in function.

Thai · 07-02-2006, 06:18 AM

Here is a piece of trivia for you guys...did you know that traction control does not work after certain speed??

For Mercedes and Land Rover traction control systems, after about 40 mph, traction control stops working. Why? Well, at highway speed, momentum is the main thing. Thus, VSC (stability control) is the main workhorse...and has the dominant function. At these speeds, the one that will be saving your life is VSC.

I doubt that Toyota's system is any different from MB or LR. Mercedes and Land Rover were the pioneers of these electronic traction systems in the 1990's. MB focused more on on-road safety...thus, their traction control systems are less effective than Toyota's (esp. FJC's) and Land Rover's. Land Rover system is more off-road oriented and is somewhere between FJC's TRAC and ATRAC in function.

Tranman · 07-02-2006, 06:25 AM

Great posts KLD and Thai. I was wondering how long it would take for you guys to step in.

I didn't know that bit of trivia Thai, but did know VSC was for preventing rollovers during cornering while Trac was more for staight line traction on slippery surfaces.

Wow great write up Thai......My favorite line from your write up..

Quote:

Thai previously said:

When slippage is encountered, these electronic nannies kick in. Part of it's effect is cutting your throttle (aka engine power)...so you bog down.

big daddy · 07-02-2006, 09:37 AM

Since I am partially retarded...can someone please clarify the actual speed you can drive in H4? I have automatic...and understood that you should slow to 50 mph to shift "on the fly" from H2 to H4...after that you could drive as fast as safety dictated...even if it was say... 65 mph? Why? northern Michigan winters produces,icey,slippery HWY's...sometimes it's just sporatic spots and you just don't want to slow and shift back & forth? Thanks...

Thai · 07-02-2006, 09:51 AM

Quote:

big daddy previously said:

Since I am partially retarded...can someone please clarify the actual speed you can drive in H4? I have automatic...and understood that you should slow to 50 mph to shift "on the fly" from H2 to H4...after that you could drive as fast as safety dictated...even if it was say... 65 mph? Why? northern Michigan winters produces,icey,slippery HWY's...sometimes it's just sporatic spots and you just don't want to slow and shift back & forth? Thanks...

Why would you want to go fast in 4HI anyway?? In theory, you can probably go fast in 4HI...if you go in a straight line. I would not do it simply because you have VSC to bail you out if you lose control at high speeds.

Does going into 4-HI turn OFF VSC??? If it does, then you really do NOT want to do it!

JLam · 07-02-2006, 11:04 AM

Quote:

big daddy previously said:

Since I am partially retarded...can someone please clarify the actual speed you can drive in H4? I have automatic...and understood that you should slow to 50 mph to shift "on the fly" from H2 to H4...after that you could drive as fast as safety dictated...even if it was say... 65 mph? Why? northern Michigan winters produces,icey,slippery HWY's...sometimes it's just sporatic spots and you just don't want to slow and shift back & forth? Thanks...

Again, you don't want 4H when you're going that fast. It's VSC, not the 4x4 system that's going to save your ass when you're going fast and you start to lose control. When you're in 4x4, the VSC gets turned off.

VSC off + High speed + Slippery road = Bad.

***Landrover*** · 07-02-2006, 02:47 PM

Quote:

cruiserlarry previously said:

Alocking diff will prevent doughnuts, not assist them - you need an open differential to get one wheel to overpower the other for a doughnut, unless you're on wet / icy pavement...

.....or snow, or mud, or gravel........that's the point. Doughnuts are much easier if both of the back wheels are spinning otherwise you just end up with a one wheel wonder.

big daddy · 07-02-2006, 10:07 PM

Quote:

Thai previously said:

Why would you want to go fast in 4HI anyway?? In theory, you can probably go fast in 4HI...if you go in a straight line. I would not do it simply because you have VSC to bail you out if you lose control at high speeds.

Does going into 4-HI turn OFF VSC??? If it does, then you really do NOT want to do it!

got it...thanks

big daddy · 07-02-2006, 10:07 PM

Quote:

JLam previously said:

Again, you don't want 4H when you're going that fast. It's VSC, not the 4x4 system that's going to save your ass when you're going fast and you start to lose control. When you're in 4x4, the VSC gets turned off.

VSC off + High speed + Slippery road = Bad.

got it...thanks.

Tranman · 07-02-2006, 10:22 PM

Big Daddy, I'm glad you pose that question b/c prior to having VSC I was in the habit of putting my taco into 4H in a hard rain for that added traction while going 40+ mph. Never thought it was the wrong thing to do. Now, with vsc, I'll know better.. Thanks for the tips all.