I've read the sticky and didn't find the answer in it although someone did ask the question.

The question is: What are the disadvantages of running the twin hi flow setup in series (from 1 intercooler to the next) instead of running them in parallel (split the pipe with 1 feed to the left intercooler and 1 to the right with the pipes coming back together before going to the intake)? Does it not cool as well? Does it have more boost loss?

It looks like the plumbing would be a lot simpler to run in series but there must be a reason both Procharger and Willie ran them in parallel instead.

 

to give equal amount to each intercooler

 

Splitting up the flow sends less velocity to each intercooler resulting in less pressure drop and better cooling efficiency.

 

Wouldn't this mean a twin setup is always going to be better than a single though?

 

Not really. A single is usually quite a bit larger than a set of twins.

 

The real answer is it depends on what you want to do. 2 running in parallel is like running an intercooler with longer end tanks and shorter cooling passages basically, better flow. Running them in series is like running one with longer passages/finned area and shorter end tanks, basically less flow and better overall cooling.

The fact is that running 2 will never be as efficient as a single larger one, and what will work better for you will depend on the application, how much cooling area/flow you have available, how long you're likely to be under boost and how much time there is between the times that you're under boost with sufficient airflow moving over the heat exchanger.