06 5.9 Stock Pressure

On the stock table for the 06 5.9 Cummins there is an area at relatively low fueling of 45-55mm3 and 1,200rpm-2,200rpm where there is a big jump is rail pressure(17,000-19,000psi). Why would this big spike be there? Is it ok to just interpolate those pressures down and smooth it out? The pulsewidth and timing are all low so its not like it needs such high pressure. Thanks in advance.

Ryan,

My best guess is that the factory engineers felt compelled to build the part throttle FP and timing tables that way for emissions control or NVH reasons. you can smooth it out without any ill effects to the engine.

Nick

Nick,

Have you messed with the turbo speed map for wastegate control in HP tuners. Instead of just changing the min duty cycle I want to see if there is a better way to control boost. The ECM must have some type of reference for that map to be useful. If you reduced the map or even the top end by a certain percent wouldn’t it think the turbo is spinning slower based on its reference and allow for higher boost?

I haven't messed with that map on the 2006 Cummins but your theory makes sense. I've used it on other applications with good luck. Try it out and report back.

Thanks,

Nick