TS feels the limit valve wont open till 30,000 psi. and they stay below that.
Depends on your model year. Also, when it opens is not as important as what damage it could be causing before it finally opens. People have already popped them. It's a STAR part, expensive, and not recommended for those concerned about warranty situations.
Extracted from Bosch articles:
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The Bosch common rail system is featured on the new Cummins 5. 9 liter ISB-E engine. The inline six-cylinder engine is the most powerful turbo diesel engine available in the 2500/3500 segment, producing 305 horsepower at 2,900 rpm and 555 lb. -ft. of torque at 1,400 rpm.
Common rail is a fuel injection system that separates pressure generation and injection events, providing engine manufacturers with a large degree of application flexibility for meeting stringent emissions. The Bosch common rail system is capable of injection pressures up to 1600 bar (^23500psi).
The Bosch third-generation common rail system operates at a maximum working pressure of 1,600 bar (model year 2003), and will expand to 1,800 bar by 2005.
Bosch currently is developing two concepts for its fourth-generation common rail, the next technological advancement to the common rail system. Both designs are intended to provide injection pressures of more than 2,000 bar. One of the fourth-generation design concepts utilizes a combination of piezocontrolled injectors and a vario-jet nozzle spray hole geometry. Improvements in the fourth-generation system will support further reductions in engine emissions, engine-specific fuel consumption and combustion noise, while increasing available engine output. Bosch plans to unveil the new system in 2006.
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Some articles here:
http://www.boschusa.com/News/ViewNews.asp?NewsType=PR&ID=53
http://www.boschusa.com/News/ViewNews.asp?NewsType=PR&ID=17
Happy reading
Jim