A draw back of direct injection when combined with EGR (as required) is a buildup of "stuff" on the intake valves. Ford initially went to all direct injection and then had some real problems as the buildup progressed. They then included port injection as a means of keeping the intake valves clean. What a catchcan does is intercept some/most/all of the "stuff" before it gets to the valves. It does this by giving the "stuff" a place to condense out and accumulate on its path to the valves. Is it actually necessary? Probably not. Will it lengthen the engine life? I believe so, hence why I put one on my engine. ...And I'm the kind of guy that seeks to keep an engine for many, many years. 30 years in the case of a family GMC Suburban, original engine going strong.Is a catch can really necessary anymore with there being port and direct injection?
Depends on how much the placebo effect is worth to you. I just let the engine inhale all of those vapors vs worrying about dealing with a condenser / condensate can. The shorter your trips are, the more often you have to deal with your condensate bottle. With the PFI, the valves are as clean as they can be.Is a catch can really necessary anymore with there being port and direct injection?