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TUNDRAWOODY · 04-09-2008, 10:17 PM

HERES A POST FROM ANOTHER SITE.

Re: Help me understand my traction control and VSC.

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I think I have a better understanding now that I looked through the Tundra brochure. I'll re-type the relevant sections here:

BRAKE CONTROL SYSTEMS

Tundra offers an advanced brake control system that includes massive vented rotors, front and rear. But it is the software that makes Tundra's brake control system so comprehensive. In addition to an ABS, Tundra also comes standard with:

Traction Control (TRAC)
TRAC helps maintain traction on wet, icy, loose or uneven surfaces. When one of the wheels begins to slip, TRAC applies a wheel brake individually and reduces engine output to help assist the driver with control of the vehicle

Vehicle Stability Control (VSC)
VSC helps prevent two factors that frequently cause drivers to lose traction during cornering: front wheelslip and rear wheelslip. VSC monitors your steering angle and compares it to the direction in which your vehicle is actually traveling. If VSC detects a loss of traction, two things happen to help correct the problem: First, engine output is reduced. Then, brake force is applied to individual wheels as needed.

AUTOMATIC LIMITED SLIP DIFFERENTIAL (AUTO LSD)

Auto LSD uses the brakes to simulate the action of a mechanical limited slip differential. By applying brakes individually to wheels spinning with no traction, torque is sent to the wheels with grip. Even a 4x2 Tundra can dig itself out of many difficult low traction situations.

Typically, engine torque is distributed to the rear wheels through an open differential. An open differential sends power down the path of least resistance. Great for turns, when the outside wheel has to spin faster than the inside wheel. But not so great if a wheel loses traction, because the differential will send all of its torque to the spinning wheel. With Auto LSD, Tundra will apply brakes to the slipping wheel. This increases resistance at the wheel with slip, feeding power to the wheel with grip. Tundra will advance forward until traction is restored to both rear wheels.

OK - so back to the modes I originally listed:
1) Traction control off, Auto LSD
2) Traction control off, Auto LSD, VSC Off
3) Traction control off, VSC off (no Auto LSD)
To that I guess I should clarify mode 0 (default):
0) Traction control on, VSC on, Auto LSD off

In default, the traction and VSC modes are on, and the differential acts like an open differential. That makes sense for normal driving.

Mode 1 makes sense if one of the wheels is stuck. You'd want the differential acting like a limited-slip differential and apply power to the wheel that's not spinning.

I still can't figure out modes 2 and 3, even with the above explanation. Seems like it might be something for off-roading, but I don't know for sure.

04-09-2008, 10:17 PM	#3 (permalink)
TUNDRAWOODY Junior Member Join Date: Mar 2008 Posts: 7	HERES A POST FROM ANOTHER SITE. Re: Help me understand my traction control and VSC. -------------------------------------------------------------------------------- I think I have a better understanding now that I looked through the Tundra brochure. I'll re-type the relevant sections here: BRAKE CONTROL SYSTEMS Tundra offers an advanced brake control system that includes massive vented rotors, front and rear. But it is the software that makes Tundra's brake control system so comprehensive. In addition to an ABS, Tundra also comes standard with: Traction Control (TRAC) TRAC helps maintain traction on wet, icy, loose or uneven surfaces. When one of the wheels begins to slip, TRAC applies a wheel brake individually and reduces engine output to help assist the driver with control of the vehicle Vehicle Stability Control (VSC) VSC helps prevent two factors that frequently cause drivers to lose traction during cornering: front wheelslip and rear wheelslip. VSC monitors your steering angle and compares it to the direction in which your vehicle is actually traveling. If VSC detects a loss of traction, two things happen to help correct the problem: First, engine output is reduced. Then, brake force is applied to individual wheels as needed. AUTOMATIC LIMITED SLIP DIFFERENTIAL (AUTO LSD) Auto LSD uses the brakes to simulate the action of a mechanical limited slip differential. By applying brakes individually to wheels spinning with no traction, torque is sent to the wheels with grip. Even a 4x2 Tundra can dig itself out of many difficult low traction situations. Typically, engine torque is distributed to the rear wheels through an open differential. An open differential sends power down the path of least resistance. Great for turns, when the outside wheel has to spin faster than the inside wheel. But not so great if a wheel loses traction, because the differential will send all of its torque to the spinning wheel. With Auto LSD, Tundra will apply brakes to the slipping wheel. This increases resistance at the wheel with slip, feeding power to the wheel with grip. Tundra will advance forward until traction is restored to both rear wheels. OK - so back to the modes I originally listed: 1) Traction control off, Auto LSD 2) Traction control off, Auto LSD, VSC Off 3) Traction control off, VSC off (no Auto LSD) To that I guess I should clarify mode 0 (default): 0) Traction control on, VSC on, Auto LSD off In default, the traction and VSC modes are on, and the differential acts like an open differential. That makes sense for normal driving. Mode 1 makes sense if one of the wheels is stuck. You'd want the differential acting like a limited-slip differential and apply power to the wheel that's not spinning. I still can't figure out modes 2 and 3, even with the above explanation. Seems like it might be something for off-roading, but I don't know for sure.