anti-sub straps

[bobt993]

The seat back brace is important in the case of a rear impact.  eg, car spins at high speed backs into a solid barrier.  The seat can slide or break lose sending the driver under the roll bar or cage folding you in half (seat sandwich).  The seat guides the harness and shelters the driver, but does not restrict your movement by staying completely in the seat.  The harnesses are designed to give with elasticity reducing the initial gforce (somewhere around 30%).  My data logger showed how intense this delta can be after reviewing a crash at the Glen.  The pulse exceeded my DAS logging scale (off the charts) and the car was still driveable.  A car spun in front of me sending me off the track to avoid him, coming back on my car had no more traction (rain race).  I hit the inside wall with both feet in still going between 70 and 80mph.   I was not hurt by the impact, just pissed off by a sloppy racer trusting PSM to save him. 

Harness roll bar or full cage with a seat back brace is an important component.  Treat the harness system the same.  The sub belt does hold the movement of the other straps, but must also reduce the risk of sliding under the lap belt.  Seems improbable, but actually can happen very easily.    BTW,  Terry has a lot of knowledge on the GT3 and can offer some options on belt locations.