Mechanical boost gauge install help

[gpxsrx]

Just installed a mechanical boost gauge on my sr viper installed line to the long T that comes off the throttle bodies but getting no reading. What am I missing ? Bruce

 

[tnc110]

Just installed a mechanical boost gauge on my sr viper installed line to the long T that comes off the throttle bodies but getting no reading. What am I missing ? Bruce

How are you testing?

 

[gpxsrx]

Is the boost gauge run by vacuum or pressure ?
i have the gauge hooked up to the T that comes off the throttle bodies start machine raise rpm but no movement on needle.
Now if i blow into tube needle moves.

 

[tnc110]

Boost probably won't build until the engine is under load. Take it for a rip across a field, it should work fine.

 

[gpxsrx]

thanks

 

[alexm2816]

Your gauge reads 'relative' pressure. At sea level, we have 14.6 psi of air pressure from the weight of the atmosphere above us. This changes with elevation and weather to a small extent but according to your gauge the pressure is 0.

In your engine, the action of a piston moving will create a low pressure zone in your intake that will actually read as a negative number on a gauge capable of reading vacuum. This means the pressure in the intake is below 14.6 psi and is 100% normal and necessary to the physical function of an engine (the pressure differential is what gets air in and out of a motor).

Actual boost of say 5# means your intake is seeing an absolute pressure of 19.6 psi and that will take time and load for your turbo to develop.

 

[Studroes144]

Some gauges read both pressure and vacuum, other just pressure. So if u have a gauge that reads just pressure you won't get a reading unless sled is in motion with a load on the engine like mentioned above. Even revving up the sled won't give a positive reading, sled will more than likely need to be ridden at 1/2 throttle or better before there is any actual pressure that will be readable.