I have an 05 Cummins. The other day when I hit around 34psi of boost it dropped quickly to about 28, then went back up and dropped again. It didn't just like slowly go down, it shot right to 28, apparently around 34 the waste gate opens... I know some boxes cause boost fooling will that allow higher boost? I was just currious as I know the old (but nice) vacume based models you could change. All of this electronic stuff stinks sometimes. I don't mind that it dosn't make a massive amount of boost, but the fact that it just drops off like that seems like you loose that power? Just currious if anybody else has noticed this with a stock truck (or far as the engine is stock) Thanks

Tom

Also, is boost fooling so that the motor will begin fueling at a lower boost number, or will it allow a higher boost pressure. New guy still learning

 

That seems to be normal on stock 600 up engines. When my 04.5 600 was stock did exactly the same thing. Probably the ECM matching boost to throttle/fuel map for the stock truck. As far as the boxes that do boost fooling goes, the ones I have tried; Dr Performance, Quad, Juice and TST do allow for higher boost and at least some will cause more boost earlier. The problem with the stock turbo seems to be that it is not very effecient over 36-38psi. Just my guesses and .02.

 

My 2004 305/555 does the same thing under light/moderate load, not a problem with the TST/EDGE EZ turned up