Hyrbid C:B ratios

[rna_duelers]

Ohhk,well for a usual comebustion the optimal C:B is 1.5:1 so what is the best C:B ratio for a hybrid on say a 2x mix does that mean the barrel ratio should be doubled?And doubles for every x mix after that for the optimal use of the power produced by the hybrid?

[Shrimphead]

Hybrids are generally going to be using metered propane. This means that the optimal c:b ration is .6-.8:1, not 1.5:1. I would assume that you are correct and you would want about a .4:1 ratio for a 2x mix.

[huse_spud]

so how much more powerful is a hybrid to a well-built pnuematic? ive never seen a hybrid in person.

[djt]

guess it depends on the mix and chamber size. normal combustions produce about 60 psi with the right fuel mixture right? so a 2x hybrid would create 120psi, 3x, 180 and so on. at least that seems like the way it should work.

EDIT: oh and i forgot to add that hybrids should have a faster flow than most pneumatics too.

[boilingleadbath]

Pressure increases are going to be a ratio by absolute pressure, not gauge;
I belive that a 2x mix, close chamber, produces about 115 psig (measured), or 130 psia (relitive to vacume). So a 1x mix produces 65psia, or 50 psig, and a 3x produces 195 psia or 180 psig.

However, the 'optimal' ratio for a hybrid is contested. See the thread on spudtech for tecnical details.

Not that it matters too much. The 'optimal' barrel on a hybrid would vary by the mix used, and would probably be too long to be practical anyways.
Unless you want to make a quiet hybrid.

It wouldn't be too hard to figure out the (approximate) optimal barrel-chamber ratio, however. A binary too-high too-low search utilizing different mixes could find it extreamly fast, declaring the mix too high if it is loud, and too low if it is quiet...
The optimal mix for a certain barrel could probably be detirmined to within a few percent using less than a dozen shots.