How to know what psi spring to use on blow off valve

 

For TiAL, there is a chart on their website showing which spring to run based upon the vacuum reading of the engine. 9 times out of 10 in a honda it is about 21 inches, or 500-550mm/HG. This means either an 11 or 12 psi spring.

But VERIFY your vacuum and compare to TiAL's website, under TECHNICAL