Just installed my boost gauge - I show 0 boost unless i'm into the throttle very hard. Do I possible have a leak, feed line too long or something else? Is this common?

Here's the setup and how I have the boost gauge installed:

From my S-Trim discharge tube I have the small line going from the Vortech BPV into the T fitting that then feeds the boost gauge and routes into the drivers side vaccuum port next to the brake booster on the intake manifold.

Does this setup sound correct?

 

Thanks Rob - i'm only pushing 7lbs of boost max so I really didn't expect to show much - if any - simply driving around town at low rpms.

 

i have a procharger with 8# of boost and i start making about one pound at 3k, then it goes up from there. so i would say its normal

 

That is the nature of a centrifugal supercharger. You will not ever be in boost at part throttle. The surge valve is always open (venting) air whenever there is vacuum in the intake. Once you get into the throttle and the vacuum drops to near 0, the valve will shut and you will build boost.

 

Boost is not rpm dependent, it's load dependent...in other words your need to have your foot in it or driving up a steep hill to get into boost.

 

If it were a turbo.... Anything belt driven is rpm dependent.

 

You are correct. BUT you still have to have your foot in it. You could rev it to 5500 rpm, but if you don't have it floored, it won't make boost.

 

Belt driven is RPM dependent, it won't make 8 lbs of boost at say 2 grand when you first floor it, but like was said, once the intake is no longer under vaccum the surge valve will shut and allow the motor to see the boost the blower is making.

My car has to be above 60-70% throttle before it will start seeing boost, so I would say you are completely normal..

 

It's load-dependent first, rpm-dependent second. Has nothing to do with the bypass/blow off valve. You will only build as much boost in the intake manifold as the throttle valve will let in.

 

You also don't need boost to show up on the gauge to enjoy the power of the blower.. You throw VE up big time even while still making vaccum.

 

[hijack]Alvin, did y'all ever find the accelerator shot in the '94-'95 ECM's?[/hijack]