Air Filter/ Mileage

Thinking about putting 5or 6 1 in. holes in A/F box on bottom ...
Thinking about less air restriction to engine,, mileage improvement
possible ..K&N has kits for cars but not this 04 Elantra .. Tried one 3.0
on 99 Acura CL.. last trip 34 MPG 28 through mountainous area... Any other
ideas??

 

I don't know if the holes would be a good idea or quite frankly even
worth the effort. It may sound a little louder from the sucking not
going through the stock intake tubes but that is about it. From a
technical standpoint, you would also be sucking in warm air from the
engine compartment instead of relatively cold air from the fender well.
I have a K&N for my 03 Elantra but mainly bought it because it was on
sale and in theory I should never have to buy another air filter, I did
not expect any increase in performance and there is none. I can not
speak for gas mileage but on a side note. I had a cold air intake
system on my 5.0l Mustang with the stock restrictive silencer/baffle
removed. I saw absolutely no change in my 1/4 mile times or mph trap
speed with or without the device installed. If the car had more mods it
would get to the point where it may make a difference but I've yet to
meet a single person who can "feel" .05 to 0.1 seconds difference and
..5mph after having a car floored for 1320 feet. I could lose 30 pounds
myself and make up for that time. Just my .02

 

A better idea is to simply remove the stock resonator (the box in the
fender well) and the rest of the tubing that ends up behind the
radiator. Essentially, this turns the stock system into a cold air
intake. This has been discussed extensively on the Elantra GT Club web
site and there is a DIY proceedure for doing it. It's an easy job that
takes ~30 minutes and adds virtually no noise. It's also reversible,
unlike cutting holes in the system.

While K&N filters do improve breathing, they do so at the cost of poor
filtration. The independent tests I've seen have all placed the K&N near
the bottom of the barrel in terms of removing dirt from the incoming air.