StabiliTrak ?

[hopdaddy]

Is there any truth that the stabilitrak option on a 5.3L can potentailly decrease MPG by as much as 2-3 due to all wheels being engaged?

 

Hopdaddy

[GM-Tech]

Is there any truth that the stabilitrak option on a 5.3L can potentailly decrease MPG by as much as 2-3 due to all wheels being engaged?

 

Absolutely no truth at all.

 

What do you mean, all wheels being engaged? Stabilitrak has nothing to do with 4 wheel drive, if that's what you mean. In fact, Stabilitrak is on vehicles that don't even have 4 wheel drive. It's unrelated.

 

Stabilitrak is not active during normal driving. The VSES (vehicle stability enhancement system) is only engaged during aggressive manuevers, usually in turns. Try taking some really sharp turns, to the point the tires are breaking loose, and you'll probably see, or more accurately, hear and feel, the VSES system in action. If you have your foot on the brake, you'll feel the pedal pulsate.

 

We get one or two of these in a month where the customer complains of a "noise on sharp turns". We have a hard time convincing them it's supposed to do that.

[GM-Tech]

Here's a description of how the system works and maybe explains it a little better than I did...

 

Remember that VSES = Stabilitrak

 

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VSES provides added stability during aggressive maneuvers. Yaw rate is the rate of rotation about the vehicle's vertical axis. The VSES is activated when the EBCM determines that the desired yaw rate does not match the actual yaw rate as measured by the yaw rate sensor.

 

The desired yaw rate is calculated by the EBCM using, primarily, the following inputs.

 

The position of the steering wheel

The speed of the vehicle

The lateral, or sideways acceleration of the vehicle

 

The difference between the desired yaw rate and the actual yaw rate is the yaw rate error, which is a measurement of oversteer or understeer.

 

When a yaw rate error is detected, the EBCM attempts to correct the vehicle's yaw motion by applying brake pressure to one or more of the wheels. The amount of brake pressure which is applied varies, depending on the correction required. The engine torque may be reduced also, if it is necessary to slow the vehicle while maintaining stability.

 

VSES activations generally occur in turns during aggressive driving. When braking during VSES activation, the pedal may pulsate. The brake pedal pulsates at a higher frequency during VSES activation than during ABS activation.

 

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As you can see, this would have no effect on gas mileage, unless you're checking your mileage while doing a slalom.

[hopdaddy]

Thanks GM-Tech. Very informative. I've ask several people at GM to explain the stabilitrak and I get three different answers. One sales person even went as far as to tell me there is no way I can have a 4X4 with stabilitak. Image the look on his face when I showed him otherwise. Another told me it was AWD.

 

Hopdaddy

[PewterC3]

question....I have a 2WD Yukon SLT with Stabilitrac. I wanted a locking rear diff (standard on SLT) but it was unavailable because of the Stabilitrac. I got the stabilitrac as it was part of a package and included other features I wanted. The salespeople tried to tell me stabilitrac would work as well for traction in snow/ice/mud as a locking diff. I disagreed but bought the vehicle anyway. My C3 is AWD for when traction is a real issue, and in Dallas...that doesn't happen often.

 

So my question is...since I can't have a locking rear diff with this system, can I put a limited slip in? Or will it "fight" the stabilitrac too? Now when I take off in rain I get right rear wheel spin until the stabilitrac pulls it down.

 

Not the traction solution I wanted.

[hopdaddy]

that would certainly be a question for GM-Tech...

[GM-Tech]

It's not really clear to me why a locking or limited slip differential would not be available with VSES.

[99-2door]

Is there any truth that the stabilitrak option on a 5.3L can potentailly decrease MPG by as much as 2-3 due to all wheels being engaged?

 

Hopdaddy

 

<{POST_SNAPBACK}>

 

 

 

You may be thinking of Autotrac. But that is only when you have the swicth in that position.