Boost gauge Q's

[ericcamaro]

Cant seem to get any good info on the subject. Please be specific as possible.
1. Just wondering how the hell to get the hi. pres. nylon line through the firewall? I have a roll of a good 12 feet of this **** so If I gotta run it some distance I dont really mind. I think I want the line to come out near the steering wheel, I would like to get a swivel pod and mount it right to the side of the steering column.
2. The boost gauge is sitting right at 5hg vac when it should be at 0. Is this gauge screwed or can it still be calibrated? It is a megan racing boost gauge I bought off a member on here. It has 3 wires coming out black, red, and purp. any ideas what the purple is for?? Im gonna try and get this thing mounted tomarrow so I can monitor my vac and boost while driving.
3. What are the best wires to tap into to power the boost gauge? the thing has a tinted face so it needs to be lit up at all times. As said b4 I have 3 wires. Black, Red, and Purple. Wires near the column would be easiest as the boost gauge will likely be mounted there.

[ericcamaro]

noone wants to contribute??

[Martin in Bellevue]

OK, there's a rubber knock-out block on the firewall, left of the steering column.
The purple wire might be a dimmer lead for the backlighting of the gauge, if it is backlit at all.
Did you figure out the valve cover venting situation, regarding how to keep from pressurizing the top of the motor? My dynan vortech m3 has a 3x1"ish metal cannister with a check valve that keeps the valve cover scavenged without pressurizing the valvetrain. Todd (tcd), had one of these listed for sale a while back on the mye28 site.
If the boost gauge you have turns out to be junk, look at the digital gauges from DynoTune. Also, I've found that taking vacuum readings from the test port on the check valve to the brake booster provides an unreliable vacuum signal.

[ericcamaro]

OK, there's a rubber knock-out block on the firewall, left of the steering column.
The purple wire might be a dimmer lead for the backlighting of the gauge, if it is backlit at all.
Did you figure out the valve cover venting situation, regarding how to keep from pressurizing the top of the motor? My dynan vortech m3 has a 3x1"ish metal cannister with a check valve that keeps the valve cover scavenged without pressurizing the valvetrain. Todd (tcd), had one of these listed for sale a while back on the mye28 site.
If the boost gauge you have turns out to be junk, look at the digital gauges from DynoTune. Also, I've found that taking vacuum readings from the test port on the check valve to the brake booster provides an unreliable vacuum signal.
thanks for the info. This sounds like what ive been waiting for. Now this plug in the firewall, is it to the left of the steering column if your sitting in the drivers seat or if your looking at the car straight on?? Is it easier to get to it from inside the car or under the hood? I am not having any trouble venting the crank case now, Turned out I just needed 1 small check valve for the vac line that runs from the back of the intake to under the crankcase vent line. The boost gauge is working alright. I popped the glass of it and forced the needle back till it would zero out instead of go to 5hg of vac. Its still about 1 psi low but at least I can get a decent reading. I have been using the port on the brake booster check valve and have had no problems reading vac or psi.

[ericcamaro]

^^^^bump, still have some unanswered questions. ^^^^

[Jon K]

Eric - I run a vacuum line into the cabin but from the other side - near the ecu there is a knock-out thing there and runs behind the glovebox. I tapped the fuel pressure regulator but I am actually going to drill another port in my manifold. The best way of getting a dead accurate manifold reading is, of course, to put a hole in it, epoxy a threaded barb fitting in it, and run the line from there. I did it with my BOV this way also. the hard nylon lines are great for minimal expansion/compression, but they can kink pretty easy. I prefer the ECU box side of things just because the E34 doesn't have a spot for a gauge (cleanly) anyway, so throught one in the glovebox would be easy.

[attack eagle]

1: Take hard nylon line.
2: bundle it all in your hand
3: throw into trash or street.

Go get either normal vacuum line or silicone line. 3mm or so usually is the right size.

purple is probably illumination lead, but who knows? Could be a signal wire if it's an electronic boost gauge, not likely being ebay-tronics, but ???
Hook up red and black and see what powers on?

it's been knocked out of calibration. not user adjustable. GO buy another one for $30 off ebay if you really like it. Otherwise cheap and good old school unit = Spearco boost gauge. mechanical unit, no power needed except for illumination.