The LT4 Knock Module Mod

This modification will help your car out tremendously if you plan on doing any work to the LT1. Since the valvetrain is louder on the LT4, the LT4 Knock Module is less sensitive than the LT1 sensor to engine noise. Therefore, when the engine is under load, it won't retard the timing as much with the LT4 chip installed. The stock chip can retard timing as much as 20 degrees! Once you start doing work, like deleting the homeplate and first base air silencers, it will cause more "noise" to be picked up by the sensor. This is also true of the stamped steel valve covers. The Corvette has magnesium covers which are quieter, so we're picking up more noise there as well.

I'm sure your next question is: how do we do this mod? The first step is to disconnect the battery (and for those of you with the Delco radio, remember what your code is to "unlock" it). If your intake is stock, you'll need to remove the air pump breather hose from the airbox, take off the cover and push it out of the way, and remove the air filter. Next, you have to take off the base of the air box (use an allen wrench in the bolt head, and a 10mm socket inside the fender to loosen the nut). Once the bolt is out, the base snaps off the cover for the PCM. Remove the clips that hold the cover of the PCM in place, and pull the brain out. The chip is on the underside of the PCM, covered by a plate with two #15 torx screws. Squeeze the tabs on the chip and remove it, and then the new one pops into place. Now, just follow this procedure in reverse, and you'll have your car back together in no time! If you already have an aftermarket intake setup installed, this will be an even easier mod.

You wil definitely feel a difference, especially if you have headers on your car, because the stock knock sensor picks that "noise" up also. On my Impala, the difference was most amazing going up hills under load. The power increase is definitely there. This is a super easy mod, and is worth the price of the chip for the improved drivability alone.

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