Join Date: Nov 2009
Location: Tracy, California
Feedback: 4 reviews
The airbags in the JK work off of an accelerometer that is located in the center of the vehicle under the center console. Specificaly the sensor works in conjunction with a yaw/pitch/roll sensor (same function as a gyroscope) that is co located. If the deceleration and pitch, roll or yaw of the vehicle hit certain thresholds the specific airbags and the seat belt pre-tensioning charge are deployed as needed. There are no "contact" style sensors located on the vehicle, it is all based on the two sensors located centrally. The pitch, roll, yaw sensor also feeds into the stability program.
The perpose of the bumpers in stock form is to deform over a given time (remeber we are talking 10thousandths of a second here) slowing the deceleration of the vehicle, in conjunction with the frame relief (crumple zones). By spreading the force of the impact over a few thousands of a second and a few inches of crumple space you can realisticaly reduce the peak G's in an accident by a factor of 10. Aftermarket bumpers in theory (with there overall lack of deformation) would cause your airbag to be more likley to go off than the stock set-up, but there are so many factors that feed the equation it is really hard pinpoint how much more likley it would be.
Example (basic as it may be, numbers are simply used for illistration):
If the airbag deploys in a frontal colision when the sensor detects 800 peak G:
Hitting an imovable object at 15mph with the factory set up may only generate 750 peak G
While hitting the same imovable object with an aftermarket (non deforming) bumper at 15mph may generate 1100 G
In this case the aftermarket bumper would cause your airbag to deploy where as the factory set up would not because the factory set up deformed to absorb the force of the impact.
United States Army 1997-Present
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Last edited by 09rubicon; 06-09-2011 at 10:50 AM.