Big black box, removing it help intake?

[jk1w]

That big black box on top of the throttle body, does it hamper performance on an I4 zetec? :shrug:

If it does, can you remove it, I've seen pics of other cars without it on, but did they have to do a lot of modifying?


** Ah ok after looking though the old threads, its called an Air Intake Resonator, but still doesn't answer my question would it hurt the car?

 

[jrichardson]

From what I understand that box is used to reduce intake noise. it can be removed by taking out the 3 10mm bolts/nuts that hold it down and replace it with a rubber 90* bend.

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kinda like this, but there are elbows make specifically for this purpose using this setup the elbow is only like maybe 1/2" from the hood.
As far as performance reduction anything that reduces intake speed will hamper performance, but I don't this that this stock intake reduces it by much.

 

[amc49]

The 'resonator' box reduces air intake noise but at the same time can reduce very low bottom end power a bit. The term resonator means sound waves that resonate back and forth that either enhance or screw up low end performance by lining up or not lining up with other later occurring sympathetic (or not) engine waves. The actual box volume is carefully selected to enhance low end. I've messed with them on Tempo, Contour and Focus, almost every one completely removed will increase engine noise at low rpm as well as drop torque a bit say in slow turn from a light onto a rising ramp like freeway exit and U-turn to cross freeway overpass to go the other way. The slow rpm climbing the ramp really shows the lack of the resonator there, the motor will tend to lag down low where it didn't before. Shows more on ATX than MTX. If no resonator used then careful choosing of intake tube length and diameter can get some of that back.

 

[jrichardson]

^^^look at that, you learn something every day.

 

[amc49]

Yeah, more scientific bullsh-t. It's enough to drive a man crazy.

In an extreme of this, if you remove the common airbox on many four cylinder motorcycles, if they have CV type carbs they will proceed to run like absolute pure crap. They need the give and take of wave reflection from each other in the airbox (our 'resonator') to produce enough complementary vacuum to open the carbs all the way since you are not directly opening them there. Put the snazzy looking individual race filters on there and then carbs won't open up more than say 3/4 of the way, or much lost power there.