Diesel Boost Gauge
 

I'm wanting to fit a boost gauge to my 3.0d but need some advice on the different types.


I have attached pictures of 2 that I'm looking at. One starts at 0 and goes up to 3 bar, the other has what I assume is vacuum to 0.8 and maxes out at 2 bar.


Which should I get? :dunno:


Do I need/can I read vacuum? Also, where is the best place to attached the T piece? How much pressure does the 3.0d even make?

(Yes I realise this forum is 90% american and you didn't get the e53 diesel :stickpoke)

How many diesel owners does this forum have? :(

wpoll should be able to answer your questions. He may be busy but he should chime in as he is the diesel authority from down under. We didn't have any here in the states so I have no idea how to direct you.

On diesel there is no throttle valve so no vacuum like on petrol engines when throttle is closed. Pre-facelift M57 engine max boost is 1,15 bar with factory map, usually 1,25 bar when mapped. Facelift M57N ~1,4 bar and with map upto 2 bar. EGR valve housing the usual place for metering hose. (Though in my honest opinion installing a boost gauge is total nonsense.)

I don't have any experience with boost gauges per se but I've certainly spent some time monitoring the boost levels via INPA etc.

INPA indicates absolute pressure (in hPa), so it never goes negative (a vacuum) - but some mechanical boost gauges may read pressure relative to atmospheric and so may read a vacuum (negative pressure) if the absolute manifold pressure is below atmospheric pressure.

Which gauge you get depends on what you want to know - absolute pressure or relative pressure.

And I'm not sure if there is a boost hose somewhere you can simply snip and "tee" into - I'm pretty sure the MAP (manifold absolute pressure) that the DDE uses is bolted directly to the inlet manifold.

FWIW, I think the boost pressure max is a little under 2 bar (26-28psi).

https://i.ytimg.com/vi/gt6vYU_am1k/maxresdefault.jpg

Thanks for the info guys! :D