Quote:
Originally Posted by KevM2
Reviving old thread! Can anyone comment as to their experience with long term use of OCC on either the N55 or the S55? Also if you've noticed any difference in what's in the OCC based on what engine oil it's used (ie NOACK score).
|
For the n55 the results are varying, some cars have alot of blow by, some cars have none. For the S55 it typically looks like there is always some blow by produced, it could be a result of the higher boost pressures it runs.
In terms of blow by vs. NOACK of oil this is very hard to quantify. Generally good oils are only a few percentage points different from one another so in a low mileage oil change interval the difference might be very small and hard to quantify. But it is still absolutely worth it to run a high quality oil with a low NOACK rating to ensure that long term effects do not add up.
Also these cars have head ports so some blow by does by pass the main pcv route and get sucked right into the intake tract, so results will always flucctuate. An oil catch can will still help reduce the carbon build up though, as it will catch the blow by produced via the standard pcv tract.
In summary an oil catch can doesn't hurt to have, especially if your car is one of the few that makes alot of blow by or you're starting to tune and increase boost as that will generally increase blow by production.