Huw wrote:

>
>>I think people that make a big deal out of feeding an engine ultra-clean
>>air are chasing the wrong red herring. Dirt in the intake air is rarely
>>the life-limiting factor for any internal combustion engine other than an
>>off-road diesel earthmover.
>>
>
>
> A road engine on a damp day will injest clean air regardless. However,
> following a lorry carrying sand without an element could well cause damage
> within a few minutes.

IF the intake path actually allowed sand-sized grains in, yeah I could
see that.

But really, what is the difference between 96% filtration and 99% in
terms of ultimate engine life, and given that you stop the boulders in
any case?

> As far as ultimate cleanliness is concerned, I would tend to agree with you.
> But I was roundly condemned when I suggested that it is perfectly
> permissible to wash and reuse elements by people who suggested that some
> dust would somehow get past the pores after this and get through to damage
> the engine. Like you, I am pragmatic and realistic about what it takes to
> make a lump of metal continue to tick, because I own and run very many of
> them. Given the choice however, I would use elements with the best
> filtration efficiency or at least use the original equipment element model.
> However, any element is better than none.
>

Absolutely agreed. My comments are geared more toward people who seem to
have a terror of talc-sized dust getting past a filter and want
semiconductor fab-room clean air for an engine that makes carbon grit as
a NORMAL PART of its operating process.