Boost control questions (Grainger)

[DakotaKid]

There is a .020 hole drilled in one barb.

Why that size?

What happens if the hole is enlarged?
say .035 or .040

[DarkWolf]

Just a guess but the bigger the hole the bigger the boost spike would be. When the grainger first pops open some of the pressure is going to bleed off through that hole instead of controlling the wastegate.

[DakotaKid]

I was actually thinking the opposite.

and maybe even the inability to hold a certain boost level.

dunno!

[lametec]

Bigger hole will cause bigger spike.

Smaller hole will cause falling/surging boost.