visser

I just installed both krank vents and, after the car has warmed up, I'm getting a knocking sound that is loudest when I listen from under the car. The sound is coming from under the block, and it most closely resembles wooden balls being shaken in a plastic cup. It is not high pitched, it is rythmic (moderate pace), and it seems to lessen in volume as I increase rpm's.

When I remove the front vent that goes on the hose from the valve cover to the front of the air box (ahead of the SC), the sound dramatically decreases, to where I now know to listen for it but prior to the vents I likely would not have noticed or been concerned.

I have had no issues with oil loss and currently have full oil. And I have had no issues with the dip stick popping up. I've also read search results on the vents and catch cans and recall a note on such a noise, but I saved that before I installed the vents and now I can't locate it, so my apologies if this has been covered already.

Unless this noise is normal, I'm inclined to leave off the front vent. The car runs fine overall with both, but with both vents it seems to drive differently with respect to deceleration during moderate driving. Maybe I'm just being paranoid, but it feels like there's more engine braking. Even between shifts I feel like I'm having to apply slightly more gas to achieve a smooth shift. As I expected based on prior posts, with the front vent installed there is serious vacuum in the engine, evidenced by the higher effort it took for me to remove the dip stick and the schwoosh sound that resulted.

Should I leave the front vent on and not worry about the noise? If I don't use the front vent, am I basically just back to stock but with a back vent that makes up for the PCV's inability to stop boost (the reason I installed the vents)?

Thanks a bunch.

visser

Anyone?

I have since removed the front vent and driven the car. It drives much better and the noise is pretty much gone, so I'm going to stay with this setup. I also confirmed that I had the vents flowing in the proper direction.

But I am still curious if ayone else has had this noise, if they know what it may be caused by, and if it is an issue or not. I just want to make sure there isn't something else I should be concerned about.

Thanks again.