Circuit to translate MAP signal to boost gauge?
 

Anyone have a clue how I'd tap the MAP signal on my TDi to get a real time reading of manifold pressure in a convenient little gauge?

I don't wanna buy an analog boost gauge. They're entirely too expensive.

Buy a cheap pressure gauge!
Surplus Center

There are several cheap boost gauges on eBay as well, just didn't wanna get something that'll crap out quickly and also thought it might be neat to see what the MAP sees in real time.

Sure, just put a VOM on the signal line.

I used one of those LED oxygen sensor gauges and a potentiometer to drop the voltage from the 0 - 5V of the MAP sensor down to the 0 - 1V for the gauge. It works very well!

That's actually a very good and creative way to do it but the o.p. Indicated they didn't want to spend a dime.

In another thread I have posted a simple circuit that does this. Yes, it works! <$20. The proviso is that the MAP signal puts out a 0-5V signal.

An alternative is to connect the voltage divider to a cheap digital multimeter (volt meter). I can buy these for <$5.

Use the voltage divider to avoid shorting the MAP signal through the (1M ohm impedance) meter and to scale the signal from 0-5V to the units you want to see.