if it was bad enough yes, but none of the cars i did had knock retard problems. you just have to run a data log and see what its doing. the noise is really just the valve train and the thin walled headers. its not a heavy enough knock/vibration(all noise is vibration) to set off the knock sensors typically. every car is different and there is only one way to find out and that is to data log it during a dyno run, drag strip pass, or out on the street.