I have a 1992 Camry 2.2L 4 Cylinder, and have been thinking about adding a cold air intake on it.

Since no one makes it, I decided i would build it myself, and have been wondering what diameter i should use for the intake.

The stock diameter is 2.5", but currently I have the Weapon R intake installed, which ups the diameter to 3". It seems to be running at least as well as stock, if not better, but it's hard to judge without actual dyno results.

So, Im aware that too big of an intake diameter would essentially choke the engine, and too small would do the same. Now I assume the stock intake size is a little on the conservative size, so Im hesitant to go any smaller than 2.75", but Im not sure if 3" is too big or if even bigger would be better.

Do anyone have any insight on to what the ideal intake size would be? Im running no other modifications currently, except later i will be building a custom catback exhaust which will bring up the exhaust diameter to somewhere imbetween 2.25" to 2.5".

I'm not sure about being able to go "too big" on an intake, but for sure too small will hurt you. The bigger factors to me are smoothness of the air flow, and maintaining the cold air temperature as it is sucked through the pipe as it is bathed in engine heat.

I see no real reason to up the diameter since you'd have to choke it down to fit the TB anyways. I"d concentrate on getting a good source of cool air and keeping it that way...then routing it smoothly into the TB...ah, gets the brain juices flowing...good luck!