Which Mod?

[pbzmag]

I am in the works to mod my 99 Explorer XLT and don't know which to mod. The current mod I have is a Gibson exhaust. I plan to do a mod that gives the best low-end torque and. I am looking at a K&N FIPK kit or the TB spacer. Does anyone know which gives the best performance?

[wileys_farm]

If you put a K&N filter in do NOT expect a dramatic horsepower increase. The increase will be so small you wont feel it. Only way you can tell that it is it there is the better fuel economy the K&N gives you.

WILEY

[4DR-SS]

the spacer wont do squat.
Since you increased the exhaust flow you now need to increase the intake side.
The K&N works on fuel injected cars cause the PCM notices the increased air flow and adds more fuel. More air + more fuel= more POWER. With a carb you need to adjust the A/F mixure screws to get the increase.
MAF or speed density fuel injection systems read off the O2 sensors to operate at a certain O2 reading. If you increase the amount of air- the engine starts to run lean and the O2 sensors send a lower # to the PCM - it inturns adds fuel to reach the proper A/F ratio.

good luck