I know this has been posted in here before...

[Big_H316]

What should the stock turbo on an '03 H. O. read on the boost gauge? Mine, at wide open will get to 25psi and decrease as the engine load levels out. I'm reading on here that people are getting almost 40 psi!!! Just cruising mine will hold steady at 5-7 psi and 0 psi until the rpms get to about 2000. Has anyone experienced this on their '03? Also, when the local diesel shop had their scanner hooked up to it several weeks back he thought it was dd because the scanner should 19 psi at idle. Later on a diesel tech at Dodge told me that the common rail engine should have at least 15 psi at idle. My readings are coming off of the boost bolt in the manifold. Would the boost elbow give a different reading?

 

[CLAYTON]

Stock psi on an 03 is right around what you are seeing. People are seeing higher boost readings because they have added horsepower. With my boxes turned down I'll only see right around 24-25psi.

 

[TCluff]

Only Could Boost, 24-26psi Wit Stock Truck, Turned Stock Turbo Up To 48psi With A Tst And Kaboom, The Next One Held For 8 Months At 43psi Before I Took It Off, But It Is Still Tight, As For Boost At Idle, No Way, You Should Actually Be In A Slight Vaccum At Low Idle

 

[Vaughn MacKenzie]

One thing for sure, forcing the stock turbo much past 30psi results in sky high drive pressures and discharge temperatures (ie temp of air entering intercooler) because this turbo shoots out of its efficiency map VERY early.

 

[TSRAM]

Later on a diesel tech at Dodge told me that the common rail engine should have at least 15 psi at idle. QUOTE]



Um... ... . If you DO start seeing boost at idle, it wouldn't be good. I'd be thinking combustion pressure and bad head gasket. Another fine example of an ASE certified nut, er... mechanic at the dealer.

 

[Scrappy]

a diesel is fuel throttled engine(no throttle butterfly) Gas engines are air throttled with a butterfly in the intake. the butterfly is what will cause a vacuum so a diesel will never see a vacuum in the intake unless the air filter is plugged.

 

[Big_H316]

I appreciate the comments guys. That makes me feel a little more at ease. As for the other part of my post... would a boost elbow off the turbo give a different (higher) boost reading?

 

[sag2]

The boost should be equal anywhere in the system (assuming the air compressed instantly). What you might be thinking about is the DRBIII reads in absolute pressure. So at idle, you will see about 14-15 psi because of atmospheric pressure. Add the boost to that for total pressure, or about 40 psi.

The first time you look at the screen, it really throws you.

 

[nickleinonen]

The boost should be equal anywhere in the system (assuming the air compressed instantly). What you might be thinking about is the DRBIII reads in absolute pressure. So at idle, you will see about 14-15 psi because of atmospheric pressure. Add the boost to that for total pressure, or about 40 psi.

The first time you look at the screen, it really throws you.

i get the same thing at work... the emd loco's running modified DDEC3&4 [renamed emdec] shows up to like 45psi under load, but 15-17 idling, while the ge's show up to 45psi under load... the emd's are reading psia, while the ge is reading psig...