Originally Posted by xjzaped

Depends on more than what was just tested. All they really tested are what is known as stage 1 intakes.

There really isn't much point in a stage 1 kit.

Stage 2 kits don't usually perform as well as they can. Why? Most vehicles sporting multi point fuel injection or direct injection have this little thing called a mass air flow sensor. Let me explain MAF logic…not getting a lot of air, lean out the fuel supply or getting more air, make it richer. Very few modern engines lack MAF sensors and very few CAI owners retune their computers to get the MAF to compensate for the extra air.

The big question. Why do most XJ owners go with a CAI or snorkel? Look at the location of the factory air box…right behind the driver's head light. What usually gets wet first on little plunges (or Lubbock style flooding)? The factory air box is also fairly poor in design with that 90º bend…como sé dicé turbulent flow?

I saw an average of 3 mpg increase (from 16 to 19) on my daily driver when I installed a Stage II kit. Not much more throttle response or even noticeable from the seat of the pants dyno. One thing to remember, my dd doesn't have a MAF sensor.