vacuum / turbo gauge for diesel ?

[groar]

I have an old turbo diesel which isn't compatible with a scangauge.

Having followed success stories by people using a vacuum / turbo gauge, I would like to know if such gauge exists for turbo diesel ?

Nobody around me have seen such a thing on a diesel, while much have already seen one on a gas. On the online stores I randomly visited no vacuum / turbo says that it's compatible with diesel, while some tell they aren't compatible with diesel.

Thanks in advance,

Denis.

[Daox]

If your diesel has a throttle body you can use a vacuum gauge. Chances are it probably doesn't.

[thecheese429]

Some vacuum gauges will have a positive pressure side as well. If that is the case, you could hook one onto the intake manifold because when you are in turbo range, the pressure will be in the whole intake manifold.

You don't necessarily need a vacuum gauge. If you are looking at boost, you could use just a straight pressure gauge. One that reads from 0 to (I guess) about double the max you expect to see.

I don't know if you would ever see a vacuum. In theory, no, because diesels don't have a throttle plate. But my friend's (1970s) mercedes (non-turbo) diesel does have a throttle

[Piwoslaw]

I think a pressure sensor is the way to go if you want to watch boost. My turbodiesel has one built in (I guess it's for the ECU to calculate injection timing) and my SGII sees it, but I don't watch it. Maybe I should?
I seriously doubt that your diesel has a throttle, check if you have a vacuum pump on your engine for the brakes and EGR. If so, no vacuum gauge needed.

[slowmover]

Manifold pressure ("boost") and pyrometer gauges are what you are looking for. If boost is low (before turbo really starts cranking), and exhaust gas temperature (pyrometer) is low, then so is fuel consumption.

Depending on your vehicle it may be the point that, on a graph, where the HP and TQ curves cross. And just a little before.

On my truck that equates to below 600F and up to about 1,725 rpm.

Most modern on-highway diesel are capable of BSFC's in the low .300's or better (high .200's) at cruise rpm.

Find that match and benefit.