How long should a A4LD vacuum modulator hold a vacuum?

[Devo55]

I just bought a new aftermarket vacuum modulator and I've be conduction a series of tests pulling 20 inches of vacuum with a vacuum pump. How long should a modulator hold a vacuum? My new modulator can hold 20" steady for about 4 minutes then it starts to drop at little, at 6 minutes it's at 18". Still pretty good, it think. What's the consensus out there? Anyone?

 

[wankel1308]

I just bought a new aftermarket vacuum modulator and I've be conduction a series of tests pulling 20 inches of vacuum with a vacuum pump. How long should a modulator hold a vacuum? My new modulator can hold 20" steady for about 4 minutes then it starts to drop at little, at 6 minutes it's at 18". Still pretty good, it think. What's the consensus out there? Anyone?

That seems like it should be plenty.

 

[Roadrunner777]

That's very good, I shouldn't expect much better from a mass-produced part. 2" of hg (inches of mercury) is a pressure drop of less than 1 PSI (forgive the mixed terminology). You're good.