[928uk] 928 air filters

[Michael Parris]

As a MAF rebuilder I do not recommend using oiled filters as it could coat
the sensor.  John said the same.
The ECU will 'burn off' the hotwire on shutdown (engine 80c+) so that
should clean it but I get MAF's internally coated in oil quite often that
will change the calibration point just by running brake cleaner through
them.  If my test can change it then it won't be correct on the car.

However I do not know if the subject cars had an oil type filter or how
well it was maintained so it might have been over oiled or it could be oil
mist from the engine although that's hard to believe when the top screen
also has oil on it.

Regards,
Mike


On Mon, 20 Feb 2023 at 14:53, Jonathan Rackowe via 928uk <
928uk at lists.928.org.uk> wrote:

> I have had a K&N air filter on my 928GT since April 2012. It seems to have
> performed okay, with just a shake and clean with a paintbrush as
> maintenance
> each year. I have also had K&N air filters on my MGB since 1985!
>
>
>
> Last Autumn I decided to clean and re-oil all the K&N filters using a K&N
> re-oiling kit. The MGB ones were fine, but when I came to look at the one
> on
> the 928 I found that the rubberised plastic surround had cracks and was
> crumbling in places. As I don't want little bits of rubber-plastic getting
> onto the MAF screen, I removed the K&N filter and spoke with the company
> about it. I expressed my dismay that the 928 filter surround was breaking
> up
> after 10 years and 26K miles, when the ones on my MG are still good after
> 37
> years and 60K miles! I offered to send them the air filter for inspection
> and comment, but as I don't have my receipt from 2012 they weren't
> interested.
>
>
>
> I see that Mahle LX311 OEM filters, Pipercross PP1211, & K&N 33-2591 or
> 60131465 filters are available. So my questions to the group are:
>
>
>
> Has anyone else experienced the surround breaking up on a K&N air filter?
>
> If you are NOT using the standard Porsche air filter, which aftermarket one
> are you using?
>
> Has your experience with the aftermarket filter been good or problematic?
>
> Best regards,
>
> Jonathan
>
>
> 928 GT 1991 Amethyst Metallic
>
>