Hello guys.

Do you know aftermarket pistons which works with the standart knock-sensor from evo 7-9?
I heard, most of the aftermarket pistons will make problems with the standart knock sensor, because they rattle inside the cylinder and the knocksensor would be activated.

 

you shouldnt have an issue as long as your piston to wall clearance is done correctly.

 

And if the engine is run in correctly the first time

 

These are unrelated items--the piston isnt going to rattle unless you have timing way off or your out of tolerance.

 

he's asking because generally forged pistons require more clearance, so they "rattle" until they get warm from thermal expansion. So it's related.

 

The stock knock sensor is tuned to recognize knock harmonics from the engine's accoustics. Once parts are added the accoustics change so the knock sensor looses it's tune, even with simple bolt-ons such as cams and exhaust.

 

Exactly. But I heard, it exist some pistons, which dont need so much of clearance - so they work with stock knock sensor. Do you know some pistons?

 

Correctly fitted aftermarket forged pistons will not have an adverse effect, simply because the additional clearance is reduced when the piston comes to operating temperature and expands.

Aftermarket pistons, rods, cams exhaust, etc., will not adversely affect the frequency of detonation, and will not affect the ECU's ability to detect knock. The ECU's knock detection capability works very, very well with a built block and every popular upgrade.