UK-POLOS.NET - THE VW Polo Forum

Are they worth it?
Easy to fit?
Do they kill the engine?

My mate has offered my one he had on his corsa for a tenner. I know it works and is all ok just wondered about the above!

Can give a nice noise

No damage to engine

Power gain possible if set up right with cold air feed.

Don't are do not get a K&N i just purchased one to find out the stock box is miles better.

Do's are get a BMC or a cone shaped pipercross filter with a breather filter and a cold air feed (would be roughly the same as the K&N in price but miles better).

Another alternative is, replace the standard cold air feed to the filter box.

As the current system is a bit naff, the hole for the cold air feed is in a place where not much air gets in and the size of the intake is small, secondly the system is also designed to take hot air off the the front manifolds (hot air is bad).

What I did was took it all out and replaced it with a 60mm cold air feed pipe from the bottom drivers side grill directly to the airbox. But that caused some problems as for some strange reason the drivers side of the bottom grill has no holes but the passengers does so I had to cut out the bottom drivers side making it symmetrical

I found this improved performance by a bit, what else can be done is redirecting the breather pipe (these are fumes from the engine which are directed back into the inlet why... only VW know) redirecting it would be ideal with an extended pipe (I know the K&N come with these and adapters, but they do what VW did and feed it back into the inlet). Always use an extended flexible pipe and do not lock up or bend the small breather pipe (why, I did it once and found out the engine is a carefully designed plumbing system, if there is no breather pipe or it is blocked up by you bending it, what happens is the fumes build up in the engine and cause huge amount of pressure build up, which in turn causes oil to gash out of any hole in the engine even the dipstick!). So use flexible pipes to extend the breather followed by a filter if you really want but not necessary

Possible (slight) power gain, but also probable power loss if you don't get the cold air feed right.

Hot air = power loss.

Regardless of what you buy, make sure you get a decent cold ir feed on it!