[~C~]

Ok, this is going to be a little bit weird.....but since I am new to the boost world, I would like to know why I am seeing what I am seeing. Hope you guys can pull through.

My boost gauge goes from 30 vac to 20 boost. At idle, the vac is at 20. Upon applying the gas, obviously the gauge moves down closer to zero. Usually, at normal shifting and fuel application (around 2000-3500) the gauge will read between 5-0 vac. I dont see any boost unless I lay into the throttle. The higher the rpms, and the more I have the throttle down, the higher the boost (0+).

For a bit of background, the car runs better than it ever did. No matter what the throttle is at or the rpm, I feel like it has more at the wheels than it did before at the same accelerations. I would say this is strictly due to the tune, but for understanding purposes.....

Here are my questions:

1. If you hook up a boost gauge to a N/A car, will it read at a max zero boost for any given throttle position and rpm? In other words, you should never see any boost (1+)?

2. Although I am seeing the gauge reading the vac side (15-0 vac), does this mean there is no boost at all? Does this mean that the intake is acting as a N/A vehicle? OR, since the blower is online, it is still forcing air into the intake, but not pushing it in under pressure (what I would assume)?

I am sure I will have more questions after the above ones are answered, but for now, that's all I can think of.

[Trick Tuners]

Originally Posted by ~C~ Here are my questions: 1. If you hook up a boost gauge to a N/A car, will it read at a max zero boost for any given throttle position and rpm? In other words, you should never see any boost (1+)?

Right. Its possible to see very small amounts of boost <<1psi due to compression wave tuning in the intake.

Originally Posted by ~C~ 2. Although I am seeing the gauge reading the vac side (15-0 vac), does this mean there is no boost at all? Does this mean that the intake is acting as a N/A vehicle? OR, since the blower is online, it is still forcing air into the intake, but not pushing it in under pressure (what I would assume)?

Right, there cannot be boost if there is vacuum. Normally you will operate in vacuum during part throttle operation. The BPV/BOV will make sure there is no boost going in when there is vacuum. As you give it gas the vacuum will decrease and the BOV/BPV will close to force the boost into the manifold and you will start to see boost. This is why there will be no boost in neutral at 4000rpms, but loads of boost at 4000rpms and WOT. You should know this stuff if you are really pushing 20psi, as well as having all kinds of monitoring equipment (wideband) to keep things safe.

[~C~]

Ahh, so its all due to the BOV. So then if the BOV was not operating right, the car wouldn't run properly? I checked the BOV before install and it was operating as procharger told me to check it. I would assume that if it was bad or faulty, or it goes bad, then I would def know it.

So to the next question, does that mean that you have to be at or close to WOT before you will see boost?

[Trick Tuners]

If the BOV was not working the car will still run because you can really force much air past a closed throttle body. The pressure will back up in the intake pipe and put extra load on the impeller (not good). You do not need to be close to wot necessarily, but that is normally the case. A common case of low vacuum and low to medium throttle input where you may begin to see boost is lugging in 5th gear at low rpms. Please do not boots at these low rpms in 5th gear!!! It takes a special tune to richen the AF up and may tuners do not do this so you could be at 5psi but at 15:1!!!

[~C~]

Gotcha. Just trying to understand what I am seeing. Thanks for the answers!

One more though....since now I am worried about the BOV, I do hear it when I shift at a higher rpm, say around 4000+. This is normal right? I shouldnt hear it unless I am under a boost application right?