Vacuum, air flow, etc...

[FrankR12]

OK boys and girls, I have a question concerning CAI, vacuum, air flow etc. The pictures below are the opening to my "stock air box". I am assuming that there is a "certain amount of vacuum" that pulls air into the opening, through the air filter and through the throttle body (?).

So let's say that I want to run a 3" (+ -) duct from my front grille to this air box opening. The duct would be approximately 18" in length and the duct would be "sealed" around the air box opening.....meaning any air would be drawn from the end of the duct at the grille. My question is.....will I have enough vacuum to pull the "sufficient amount of air" that is required for the engine to operate correctly, especially at start up and with the vehicle stationary (stop sign, red light)?

Being a "non techie", I do not know if the added length of the duct would impede / prevent the required amount of air to enter the throttle body. My intent is to keep the stock air box and only add the additional length of duct. Thanks for your input.

 

[HARDTRAILZ]

Not sure it needs vacuum seeing as I cut most of the front off my box and ditched that lil tube.

 

[AtlWrk]

Without getting technical: there will be no problems whatsoever with what you're proposing in terms of airflow.

An 18" piece of 3inch duct is nowhere near adding a noticeable amount of restriction to the intake. Next time you have the filter off look down through the MAF...the ID necks down to about half the diameter of the rest of the intake.

 

[BlazingTrails]

Are you trying to reduce air intake temps? If you are that is not going to work. You would have to get rid of the resonator and run a new pipe all the way to the throttle body and with heat wrap. The intake is right on top of the exhaust.....the resonator is bolted to a 200° engine. That's where your heat is coming from.

 

[IllogicTC]

Are you trying to reduce air intake temps? If you are that is not going to work. You would have to get rid of the resonator and run a new pipe all the way to the throttle body and with heat wrap. The intake is right on top of the exhaust.....the resonator is bolted to a 200° engine. That's where your heat is coming from.

Blazing brings up some good points. I mean after my engine's warm if I stay traveling at 55MPH my IAT temps never go above like 5-10 above ambient, but if I sit idle for a bit after that it goes well above ambient, and seems pretty hesitant to move back down quickly. But the duct may be a viable option as part of an overall DIY CAI setup.

 

[FrankR12]

Thanks GT and others for the info / opinions. I am anxious to see what the duct setup at the front grille vs. inside the engine compartment does or doesn't do. As long as I have enough vacuum to pull "outside air" through the duct than I am okay either way. I don't plan on spending a lot of $$$ with the initial setup.....just experimenting....thanks again.