The 40 compressor is not pumping the same mass at 47 PSI. The pressure is there but the mass flow is less than it is at 38. Mass flow is more of a power making factor than pressure.

The engine always uses the same volume of air. You fill the same area everytime. How much that air weighs is the important factor.

Cooler boost at lower pressure in many cases has more density or mass than high boost at warmer temps. i.e. HX40 at 47 psi VS 38 psi.

Don~

 

Yep, generally if the stack is clean, a diesel has enough air for combustion. Any additional boost might help EGT's (at least until compressor discharge temperatures go out of sight), but it takes drive horsepower to produce that extra boost.

Rusty

 

Well with the filter on it seemed to bark alot more like it was starving for air? As far as getting razzed for no filter, come on guys the air up here in colorado is totally free from dirt, bugs, etc. The wire mesh i have on there its about the same as looking through a k&n filter so that has no affect same ****. Turbo clean as a whistle and no shaft or end play whatsoever!!!!!!!!!!

 

You guys probably wouldnt like the fact i took my fuel plate out either huh. Oh yeah by the way what is an egt gauge!!!!!! ha ha ha

 

A stock turbo on these trucks see around 150,000 RPM's.

 

When I have my PM3 set on level 9 the turbo barks every time I let off fast. I didn't expect it to be as violent as it is. The hole truck shakes when the compressor stalls. I can see that I need to upgrade turbos and get a relief setup.

 

The HKS super sequential blow off valve will work, bit spendy though. I just got rid of the slincer ring and it has never happened again.

 

Strange, I've never read that before.

 

Tis true, used to happen everytime I would enter expwy full throttle and when it shifted into od it would do it bad, sounded like a gasser with bad timing. yanked the ring out and never heard it again!