This is not a good idea. First let me start by saying the stock air intake is a cold air intake. There are no gains to be made here.
x2. Pretty much all air intakes on all cars are cold air intakes. The engineers do that for performance reasons. The only reason you'd want to change it is to allow for less restriction. The only real way to do that on an Explorer is to cut a hole in the hood or fender and suck air in from there. Unless you're doing other mods like exhaust headers and a cat-back system, there likely won't be any measurable improvement.
You'll see people stuck the cone-style filter on where the airbox goes and that's fine, it does flow more. However, I'd only do that on a vehicle that sees a lot of highway miles. On an offroad vehicle or one that gets driven in the city, there's not much airflow under the hood and intake air temps are likely to go up. More flow of less dense air isn't worth it, especially for the cost of the kit.
You don't have to take my word for it, Kurtz Kustomz did all the testing when they released their kit and I talked with them last year about it, this is an exact quote of what they had to say:
Back in the early days of KKM, we tested under hood air temperatures on Ranger and Explorer models. When driving down the road, the under hood air temp will average around 4-5 degrees warmer than outside air. This can be attributed to the fact that the under hood area has plenty of fresh airflow.
It should also be noted that the vacuum operated heat damper door is notorious for leaking and drawing in hot air from the exhaust manifold stove box. All that to say that simply mounting the kit as shown on the website is much more efficient than the stock system and no other modifications are required.
All of the tests were performed back in ‘97 on our local main thoroughfares which are 35 and 45 mph in the months of April or May. If you have a lot of stop and go driving, a kit like this may not be ideal for you, but is still probably better than stock.
As for mileage, we have had all sort of good reports over the years. Some of the reports of 4mpg better mileage seem almost ridiculous, but if they had a dirty filter and leaking damper door, it would make sense. Most come in around 1 to 1.5 mpg better, not really anything worth advertising.
