[eddie w.]

i noticed on a log that my dome sensor was reading up to 5psi in the higher rpms and after i left off the trhrottle it went as high as 9psi for a fraction of a second on a datalog even though the co2 wasnt even hooked up to the line....also wondering about my total boost when its not hooked up to the co2, its making 12lbs and im almost positive that i have 7lb springs in the gates...is there that much boost creep or maybe to small of gates, do i need to let the top of the gates vent to atmosphere when im not using the co2? i have turbosmart 38mm on each manifold, twin 66 turbos ...thanks

 

[para pay]

If the dome isn't vented to atmosphere then when the gate opens then the air in the dome will compress. That's probably giving you the high reading. How do you have it plumbed where is not vented? If your using a spring with boost reference to the bottom of the gate then you should have the dome to the com port of the solenoid, n/c to the bottle and n/o to atmosphere

 

[eddie w.]

that makes sense, its plumbed just like holley shows using a 2 valve setup...thanks for the info

 

[LUXFAB]

What he said. Also make sure you are using the correct calibration for the sensor.

 

[para pay]

So yes, if you're using the dual valve setup then you will need to have the decrease valve open to run wg pressure.

I first assumed you were running a single valve with pwm control, sorry.

 

[TurboII]

It is fairly common to see boost exceed even a light spring in the si gle digits if the gate is slightly undersized and/or has less than stellar priority. I have a 402cuin 18* SBC that ran a single 94mm years ago and had a single 60mm JGS WG with good priority. With a 2 - 3LB spring and no CO2 it would still make a ton of boost on the dyno with lines hooked up(not vented to atmosphere). We weren't really concerned with low psi boost creep but it also had issues up high and pretty much made 30+ psi no matter what we did. I swapped to twin 80mm turbos with a second 60mm WG. They don't have great packaging but now have enough that boost creep is no issue even down low around 5psi or so. Also not all WGs are created equal. I feel confident saying the cheap import WGs will not flow the mass that a high quality well designed WG will flow.