Boost vs. Boost/VAC

Which one is better, straight up boost or a boost/vac gauge? I've been looking into gauges recently, and am just trying to narrow down the field.

Vac/Boost without a doubt

I don't think lunar would look bad... but note that you can replace the bulb on the Phantom series with any color you'd like in LED.. or you could stick to bulb. It's cheaper.

vac/boost is not as accurate as a boost only guage. I've seen several that were pretty far off. You dont need to see vac every day. I have a vac guage that I used to use to setup the carbs on my old american cars, they're real cheap at parts stores. If I'm curious what my vac is after a cam swap or if I think there is a problem, I just hook it up.

I've been running an autometer sport comp 0-35 psi guage for 4 years and its still dead on with all of the electric pressure trasducers the car has been hooked up to (dyno).

I just install a Stewart Warner 30hg to 40psi guage. Most guys in the import scene never heard of them. So i decided to try them out.

Considering that i should be getting 14 to 15 psi from my upgrades the guage was dead on.

I tapped into the line leading to the fuel pressure . Between the manifold solenoid if that makes any differance.

nobodys given a reason yet why you need or dont need a vac gauge in a turbo

A vac gauge is no more useful to a DSM than any other car. There's no answer why it's needed, other than it helps in the same situations it helps on a motorhome. The reason not to get one said by 95 GSXracer is the issue of accuracy.

well on a non turbo a vac gauge can be useful. its just a measure of how fast the engines sucking in air, but the only time it would have vacuam on a turbo would be if there was a problem with the turbo

Turbo motors have plenty of vacuum at idle. It STILL can diagnose problems the same. 17-22'' Hg if I remember correctly.

Here's another mildly related question: what compatability issues are there between turbo timers and the factory alarms? My 96 tsi awd has a factory alarm (haven't driven the car enough yet to know what exactly it does though lol), but I'm also shopping for TT's and wondering which ones will work okay or not. Ideas?

i know the Apexi TT will work just fine, i have heard Greddy does too... but i just installed a Apexi TT in a 2004 SRT-4 and it works fine with the factory alarm!!

I just hooked up my boost/vac gauge and the gauge is showing roughly 10-15 psi of vac at idle. I haven't driven the car yet with the gauge, but will later tonight unless someone tells me not to soon! Hopefully nothing is wrong...just wondering if showing significant amounts of vac is normal? (stock T25 btw in case you didn't know).

Sounds about right, i idle steady at 15 to 16 Hg.

Make sure that you secure all your splices and connections.You can blow the lines off when you get on the gas hard. I used a combination of zip ties and electric tape to make sure every thing held tight.

Also, i have an apexi TT and it's worked fine for over a year now.

i was just thinking about the lunar too.. still can't decide on either Lunar or Phantom. any suggestions?.. price wise the phantom is cheaper.