From How I See It
It all boils down to two main issues
1 Appearance
2 Performance
I'll not deal with #1 as you like how it looks or you don't
As for #2 ... I'll give ya what I've found out
Bends ... they offer restriction to the flow
Corregated pipe ... it is restrictive as well
Pipe material ...
Most store bought CAI's are made of metal
A lot of home made CAI's are made of pvc
A lot of folk feel metal is bad cause it transfers heat to the flow
however
When you get the flow really moving its almost a moot point
So ... getting all that out of the way ............
What REALLY MATTERS is .........
Getting better air than can be found in the engine compartment
It goes without saying ...
Ya gotta draw in the flow from outside the engine compartment
I mean ... Pipe with a filter stuck on it next to the motor ain't a CAI
You will get a hp gain with cooler air cause it is denser air
Final thought ... If its hot outside .....
Gain from a CAI is gonna be little if anything
Now ... On those cool evenings ... You're gonna feel a gain
Why do you think et's fall as it gets late in the day and at night
Grady