I am installing a boost gauge sometime in the next two days. I will tap into the vacuum line leading into the FPR. My question is this:

What's the best way to test boost? I saw in an earlier post that simply revving the car at idle (i assume they meant in park/neutral) won't work (why is that?). If that is the case, how do I test boost without putting the car in motion (or jacking the car's drive wheels up and revving the car)?

I am a bit confused- help appreciated.

 

Why not just drive the car after you hook up the boost gauge? I did that so I can see the needle move above the zero mark.

 

As of right now I have no gauge pods and really don't want to tear apart the whole car to install the gauge inside the cabin. That can wait.

Any explanation for why I won't get an accurate boost/vacuum reading if i just rev the car at idle???

 

You can hook up the gauge temporarily so you can watch it but eventually you'll need a pod to mount it inside the cabin on the A pillar. Not much tearing apart if you go that route.

Revving from idle will blip the needle towards zero but you have to lay into the pedal to kick it into boost territory which is around 3000rpm.

 

So then revving the car above 3k rpm (or into boost range) while in Park/neutral SHOULD yield accurate boost readings?

To be honest, I don't know where I can run wire into that area from the car from the engine bay without drilling...

 

If you look behind the fuse box towards the firewall you'll see some wires running into the cabin to the fuse box through a rubber grommit. I inspected the firewall from the left wheel well to see how the wires in that corner ran. You'll have to take out the left front wheel well cover (or move half of it) to do that.

I started by taking off the A pillar cover and pushing the boost tube down until it showed up behind the fuse box.

 

Mechanical boost guage? Full sweep electrical boost gauge? I ask, because you have to wire any electrical boost guage to a switched power source. This will allow the boost guage to recalibrate itself each time you start the car and yield accurate boost readings.

 

Mechanical. I lso got my safc-II, and I have a Z32 MAFS sitting around... It's like I wanna... tune my car or something.

Seriously, this is scaring the **** outta me, especially since I havent gotten to the bottom of the stalling issue I reported earlier.

 

are you t/c or s/c? i dont think reving the car will yield an accurate reading for t/c cars since it boosts most under load and you didnt specify which one you where.

 

There's not enough heat energy in an unloaded engine to get full boost in a turbo charged application. this is why it's easier to launch a turbocharged car with an automatic (IMO). you can load the motor to build a little bit of boost before the lights go green where as in a manual car you have to slip the clutch to achieve the same result. Pulling trucks, if you've ever watched a truck pull, they load the motor before they take off to build up the boost rather than starting from vacuum. So unless there's some load on the motor you won't get an accurate reading.