Maybe not. If you want to try the other style valve I will send you my home built one, with no diaphram from the sticky. It opens from bowl pressure only. It worked very well I just could never get rid of the lean spot off idle and cruise. But that is a metering plate mod as far as I know and yours is already built for BRPVs.

 

I see what you mean . The PV is already using Hat pressure to open it , so it would still open at Hat pressure regardless what the manifold is seeing .

And if the compressor is slightly higher it would just keep it open better against the bowl pressure .

Like you said , it would just take some fine tuning .

 

I'll keep that in mind . Thanks .

 

Got some numbers .

WOT .................... Manifold 11
Hat 13
Compressor 14.5

 

I say plug that hole in the top of the carb and reference that PV to the compressor. If you havn't done it before I just used a indexed drill set and a pirce of 3/16 brake line. Just measured the O/D of the line and chose a drill bit a couple thou less. Gives a nice press fit... Yes I a bored going stare crazy in this cold weather.l

 

One more question .

If the hat and bowl pressure is the same , and a 5 psi spring holds the PV shut .

Wouldnt that mean that the PV chamber would need 5 psi more than the bowls to keep it open ?

The fuel side must have less effect on the PV , or the BRPVs I have wouldnt work at all .

Correct ?

 

In theory, yes this would be correct.

I think this is correct in real life, because the PV cavity pressure has more area to push against than the bowl side does, untill it actually opens, then the vacuum the booster passages that link to the pv passages keep the valve open after it lifts off the seat. So in simpler terms. The air pressure in the PV cavity has no where to go, thus keeping a even pressure on the diaphram, unlike the float bowl side of the PV where the pressurized fuel can go into the pv/booster circuit thus effectivly reducing the pressure on the bowl side of the pv. Hope this makes sence.
Bowtie Guy

 

Also to add it probably is rated at 5psi but it doesn't need 5 psi diffrence to open. Just means it opens fully at 5psi. I found on my BRPVs that I had 1" springs cut down some to make them really open properly.

 

Makes perfect sense .