I just got my-self a cheap Vacuum/Boost gauge. I know it's cheap and ugly, but for the time being, that's pretty much all I need. The gauge is marked with Hg. How dow 1 Hg compares to 1psi?

 

1 what Hg? mm? 760mmHg ~ 1bar ~ 14.7psi. Approximately. Not hard to find a conversion chart/calculator on Google.

 

By the looks of it.... It's in "in Hg" so 1 in Hg = 0.49psi. So the gauge goes up to 5 psi. Ain't much but oh well... more than enough for what I need right now I guess

 

Ah...I guess it's a little late now, but I would have sold you a VDO boost gauge that's inHG (inches of mercury, a measure of pressure that's usually only used for vac in automotive gauges) and psi for not much more than that one cost. Ah well. At any rate http://www.onlineconversion.com

The 4.9psi that thing will show in boost may not be enough to monitor your setup. Just a heads up.

 

Well... 4.9 psi will most likely be more than enough. I started thinking about a ramair design and I would like to see how the airvolume will be affected. So I probably won't ever be getting into boost

 

That's perfectly fine then. I thought you were going to be using forced induction. I'm pretty sure you'll be in vac the entire time. I don't think you even come near positive pressure without some sort of intake charge compression.

 

That's what I'm guessing as well. The positive pressure side won't be used until late this summer(assuming I can get my hands on a very cheap Cold side for another crazy idea )

I never actually saw a Vacuum gauge in action, so would I be right if I said:

Using this gauge as an example, the needle should move Clock-wise as the RPM goes up

 

Ah...I dunno on a NA car. Never even thought about it till now, but clockwise would mean more vac, counterclockwise would be positive pressure. Assuming NA is anything like FI, you'll idle around -10 to -14inHG, but from there I dont' know which way it's gonna go.

 

No, the needle will move counter-clockwise. When you turn on your car you should idle around -20, depending on what the hell the measurement conversion is on your gauge. The vac will move closer to 0 under acceleration and higher RPMs.

 

Thanks guys And for the connections.... I guess I'll look up the How To section and educate my-self

 

It's easy. Just hook up the vac line through the grommet in the engine compartment, it's tucked in behind the strut on the passenger side. Pop it out and run your vac line through there. For lighting, hook up the gauge lights to power and dimmer (cig lighter is a great wire to tap into, I think it's the green and black on at the cig bulb), so it will dim with the rest of your lights.

 

-20inHG at idle? Damn, either yours idles with a lotta vac, mine doesn't idle with much, or I'm just not remembering correctly. My Defi boost gauge doesn't use inHG.

 

idk what the hell my gauge measure in. I know it's psi on the boost side.

 

Will be easier than I taught then... that's where I ran my Amp's powercable. I've heard of people drilling a whole in there firewall to get the line in the Passenger Cabin

 

Waste of time and effort. There are two places to run cables easily. The grommet by the strut on the passengers side, and the large grommet under the drivers side fender. The first one is the easiest for the our car for a vac/boost gauge because you can tap the manifold vac line right past the grommet.