Airbox trimming for air flow

Could the intake hole to the air box be cut to allow more air flow?...or would that just be a useless mod? Like everyone I'd like better mpgs and power. Please :helpme:

The stock airbox setup offers more flow than the engine uses.

what about insulating it from the heat of the engine compartment somehow.... i've always wanted to find a way to get cooler air past that hot engine area and into the intake. i know the 4.0 gets pretty hot and any colder air will make a difference in mileage.

OK thanks :yelclap:

Only do it if you're never going to be around high water. I've got my filter wet a few times from cutting the hole bigger on the front. Plus I want to make a snorkel using the stock airbox and the hole is too big to close now.

Trade?

Blaine B: get a piece of 1/8" flat ABS plastic from a radio install shop, online plastics supplier,etc, and glue it to the air box with ABS pipe cement. hole filled.

if you have a 91 & later remove the baffle in the radiator support & duct it to your airbox. the renix motors all come that way, you could maybe use an 87-9 airbox, same size opening,just ducted thru the grille. big holes in the airbox does make it sound cool, but I doubt if it does any good. my kid did it to his 95 but has since gone to a cold air setup. ditto on the high water problem I thought all the air up where you live is cold,but that stick on foil backed stuff might do some good:idea:

if you have a 91 & later remove the baffle in the radiator support & duct it to your airbox. the renix motors all come that way, you could maybe use an 87-9 airbox, same size opening,just ducted thru the grille. big holes in the airbox does make it sound cool, but I doubt if it does any good. my kid did it to his 95 but has since gone to a cold air setup. ditto on the high water problem I thought all the air up where you live is cold,but that stick on foil backed stuff might do some good:idea:

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Do you have any pictures of this airbox setup?

mine is stock as stock can be and it gets wet easily, just backsplash from a big puddle will soak the filter, might be better of with some type of cowl intake

warmer air is BETTER for mpg
colder air is better for HP
warmer = leaner mixture
colder = richer mixture
I cut the entire front off my airbox and half of the left side. I get 25mpg on the highway if I drive steady (aka cruise set at 70mph)


it sounds backwards but cutting a bigger hole in the airbox makes it HARDER to suck up water.
think of it like this
wrap you lips around a straw in a glass of water and suck works nicely thats what the small factory hole is like
now take the straw out of the glass and place your entire mouth around the top of the glass and try and suck the water up. I bet it wont work.
the only time it will be easier to suck up water is if the airbox is completely submerged and then it wont matter if you have the stock opening or a bigger one.

but if you are really worried about it go to the junkyard and buy a stock airbox.
I have a spare in storage just incase I change my mind

does anyone else support the statement that warmer air is better for mpg?

warmer air is BETTER for mpg
colder air is better for HP
warmer = leaner mixture
colder = richer mixture
I cut the entire front off my airbox and half of the left side. I get 25mpg on the highway if I drive steady (aka cruise set at 70mph)

Click to expand...

This may be true, however its not because its leaner or richer. The PCM will always try to adjust the air/fuel ratio to around 14.7:1 for optimum cleanliness no matter what the temperature. It uses the O2 sensors as a way to check up on the mixture, if there is more oxygen in the exhaust, then its lean and vise versa. When an intake sucks in cold air, the intake air temp sensor picks it up and tell the PCM to increase the fuel injector pulse width to compensate for the cooler, more oxygen dense air. If the air is hot, the PCM will decrease the injector pulse width to comensate for less dense, hot air. Overall, the air/fuel ratio is the same, but with colder air there is more oxygen AND more fuel in the mixture.