Do these need to be replaced after a certain mileage point, something like in a 150,000 maintenance thing, or only when they become damaged? Is there much of a point to installing performance springs? Will they help top or bottom end? And do you know if they open faster, or wider? Just trying to get some knowledge about these.

86maxima96




:EDIT: this should probably be posted in the engine section, right?
Move it if necessary

they should last the life of the car. as for performance springs I didnt know any were avaible for our cars but if some were, I'd assume quicker revving would be one of the benefits.

the only reason i would think to upgrade valve springs is when reprograming the ecu for a rpm higher then 7000