08 st 4.0 cai

[08XLTSporttrac]

So I bought the CAI for my 4.0 ST from KKM and was expecting some improvements in power and fuel mpg, but after a month of driving I actually lost .4 of a mile per gallon and less throttle response than with my stock air box! Truck is a lot smoother with the factory air box too. Anyone experience the same results?? Also I disconnected the battery to let the ECM remap and nothing changed there either!

 

[Dlkjr18]

The KKM uses the stock ducking right? And the filter isn't any bigger surface space than the stock filter. The stock air box takes air from the outside through the duct that goes through the bottom half of it. The KKM doesn't even have a heat shield so it's sucking hot less dence air. From what I have read and heard you will get better bang for your buck by just replacing the stock air filter for a K&N or similar. I did. I didn't see the power gain but got a little better mpg.

 

[Tech By Trade]

Psst, the factory induction is cold air, probably colder than the hot air you are pulling off the top of the engine with your aftermarket. The only way to improve the factory is to get rid of the bumps in the hoses, and even then the improvements would be minimal. About the only bigger waste of money is a programmer, all they do is change the throttle and shift points making the pedal more sensitive. Also, all K&N filters do is plug your MAF sensor up with oil, I wouldn't bother.

 

[08XLTSporttrac]

Well that was my thought when I looked at the the factory box that unit is pretty big and yes it pulls in cold air way better than the KKM unit. So I went back to the factory box with a stock Motorcraft filter cause it is only a month old! Truck runs way better now! i think i will sell the CAI on Ebay!

 

[JohnnyO]

Another satisfied customer. Should have asked us first.
On a Gen 1 Trac you can pick up a little by removing the airbox silencer but on Gen 2's it's not really an issue. I've owned both.
Again, the stock intake is already a cold air. Unless you need it to look zoomy underhood, there is nothing to be gained. I just use a K&N drop-in in mine and have no issues.