OK, I'm potentially going to make myself look a little late to the party with this
but I'll post this as I'm sure that I'm not the only one who might be in this position.
Cleaning; I didn't give too much thought to this until I had reason to remove the filter for access during engine bay cleaning. I discovered then that the filter was truly filthy to handle. Black oily, gritty slightly sticky residue present mainly on the underside. The top side wasn't as bad for grit content but still dirty.
So I immediately thought 'hot soapy water, rinse and dry' and I set to it. The filth that came out was significant and plentiful, amazing in fact. Wish I had photographs.
Great job I thought, put it back on when dry and that'll be job done. The pipework to the turbo was nice and clean.
While it was drying I got to thinking about oiling it and I recalled reading and hearing that oiling these was a bad idea due to potential MAF problems and some prefer to run these dry so I phoned Revo and asked the question. They were very clear about the cleaning procedure and advised to to treat this filter as an ITG filter since the were developed alongside each other (triple layer foam construction of increasing density on each layer) and follow their cleaning instructions. On the subject of oiling they said yes, definitely. The oil is graded so as not to leave the filter, it is sticky and is essential for correct and the most efficient filtration. The quantity of oil that gets applied is also an eye opener. It's a not insubstantial quantity that is immediately massaged through all of the filter layers before the solvent carrier evaporates off.
I ordered a kit (ITG's own for around £27 with the lighter oil option) and got to it...again...and was surprised for the second time as what I thought was a clean filter turned out to be a very dirty one. The filter really does look like new.
I'll be oiling it and refitting this evening.
I reviewed my service schedule and discovered that I have covered around 16,000 miles since it was fitted and it had never been cleaned this thoroughly in this time. I asked my garage to clean it once but due to being able to return the car to me the same day I expect the extent of the cleaning was limited for practical reasons. I happen to think that cleaning these things properly takes time and the expectation is probably that the owner will do it. It really couldn't be easier but drying will take time.
It could also be why at times on my last trackday I felt the car lacked a bit at WOT and also the smoke (un-burnt fuel colour) left behind me when I left a motorway services in a hurry on the way to the Golf 40th at MK. We'll see about this in time but for the moment, if you've 'overlooked' care of your filter it may be time to give it some attention.
There's a good video on YouTube showing a chap from ITG cleaning and oiling BTW.
