6.5 Boost and Vacuum Mixup
 

Hey my friends got a 6.5 turbo diesel and he just purchased a boost gauge and hes claiming that there is no place to tap in with a boost gauge he thought you needed to drill and tap a hole in manifold so now hes saying the boost gauge doesnt work. Manifold is vacuum isnt it? Where do you put it so you can pick up a reading on boost? Boost is the push from your turbo via the intake if im not mistaken... correct? The turbo works off of exhaust and intake right? I mean afterall thats why your intake goes to your turbo in the first place. But regardless hes claiming that there is no possible way to tap into boost and I disagree I would just like to know if there is a well-known location to tap it. Thank you.

The intake is after the turbo correct?
So it must be under pressure-not vacuum,even with no boost the intake on a diesel is under atmospheric pressure,they seldom ever see vacuum even when cranking.

Your friend is correct about installing his boost gauge,there is no stock provision for it and he must drill and tap the (upper)intake for a barb fitting.

Another option is to get a boost bolt from leroydiesel.com,the 2 center upper intake bolts go into open holes that can register boost.

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Another way to look at is like this:
Gasoline engines are controlled buy regulating the amount of air they ingest by a throttle plate;the fuel is then metered in accordingly,the throttle plate is what allows them to make vacuum.

Diesel engines don't have throttle plates and they do not regulate airflow-no vacuum unless the air filter is plugged;they regulate fuel only.

i have a question and i could be missing part of how the system works but if you switch to a turbomaster system and no longer use the stock vacume set up could you not remove the stock boost sensor in the intake and use that hole for a gauge or does it have another purpose. i havent really looked at it but it was a thought.

No the boost sensor is still reading the pressure in the intake and that is used for deciding the fuel rate,the boost solenoid is also still needed with a turbomaster just to let the ECM think it has some control over boost,otherwise it will throw a code.

Drill and tap the upper intake for a hose barb or get the boost bolt for the gauge.
Another option would be to drill down through an upper intake bolt(one of the center 2)and braze or weld a barbed fitting to a stock bolt if that is in your skillset?

Added this to the reply after to save a merged post:
You could remove the boost sensor,remote mount it,add a barb fitting in that hole,then use a Tee to feed the sensor and the boost gauge with the appropriate sized vac/pressure line.