Changing Air Filter

Strider590

BeenThroughItAll wrote: »

K&N sounds like it makes sense, but few people actually keep their car for 100K miles. I change my filter every 12K or so, it costs me less than 7 quid on average. A K&N would cost me 70 quid.

Despite what K&N may claim, they are NOT suitable for vehicles in everyday use.
If you hold one up to the light, you can see gaps through it, those gaps will let in fine grit and road debris, which in turn will make it's way into your engine and cause premature valve wear.

A standard paper filter with wire mesh backing, is a far better and cheaper choice.

Their OEM replacement filters are marketed toward the boyracer crowd, on the back of the fact they are widely used in motorsports, on cars that get engine rebuilds every season.

FYI, my kitcar has K&N filters attached to a pair of race spec'd weber carbs. Unlike anything else, the one thing K&N filters do have is they don't go up in flames when the carbs spit back fuel/flames, but then that's never a problem in a normal car.

forgotmyname

K&N makes sense until you add too much oil and it flows worse than a standard filter. Or add too little and it allows more particles into the engine.

Excess oil off the filter can also cause issues with MAF sensors.

BeenThroughItAll

Strider590 wrote: »

Despite what K&N may claim, they are NOT suitable for vehicles in everyday use.
If you hold one up to the light, you can see gaps through it, those gaps will let in fine grit and road debris, which in turn will make it's way into your engine and cause premature valve wear.

A standard paper filter with wire mesh backing, is a far better and cheaper choice.

Their OEM replacement filters are marketed toward the boyracer crowd, on the back of the fact they are widely used in motorsports, on cars that get engine rebuilds every season.

FYI, my kitcar has K&N filters attached to a pair of race spec'd weber carbs. Unlike anything else, the one thing K&N filters do have is they don't go up in flames when the carbs spit back fuel/flames, but then that's never a problem in a normal car.

Yep. That's why I don't/wouldn't run one.

topdaddy_2

Filters are so cheap why mess about with k&n stuff? Its labour intensive in comparison

Zola.

Your air filter probably wouldn't even be 1/4 black after a few months.

Despite them being cheap, it would still be a waste of money. Once a year is fine.

redux

Ok, apologies for the K&N suggestion, and thanks for the warnings.

My naivety comes from my car having done nearly 200,000 miles using one, so no doubt someone would say it must be a terminal case by now, especially if you add the effect of some engine oil changes being less frequent than recommended.

JustinR1979

redux wrote: »

Ok, apologies for the K&N suggestion, and thanks for the warnings.

My naivety comes from my car having done nearly 200,000 miles using one, so no doubt someone would say it must be a terminal case by now, especially if you add the effect of some engine oil changes being less frequent than recommended.

No need for apologies


I have a pic somewhere of a torch being shone through a k+n panel filter....

[Deleted User]

I can get an air filter for less than £5 delivered from ECP and fit it myself in under 10 minutes.

JustinR1979

Deleted_User wrote: »

I can get an air filter for less than £5 delivered from ECP and fit it myself in under 10 minutes.

I do this too, no brainer


Edit:





I worked for race teams for years. One Toyota Atlantic teem I worked on the driver thought the car was losing power from the start of a race to the end. So we did leak down checks when we got new engines in. 3% leak down- New. At the end of a race we checked it again and we got 29% leak down. So we sent the head to get the valves done and checked the leak down when the head returned. 4%- Leak down. At the end of the next race 31%- leak down. So we put three dabs of grease down stream of the air filter. "K&N" The next engine came in with 3%-leak down new. And at the end of the race 32%- leak down and the dabs of grease were full of grit. So we changed the filter to a oiled fome filter. 3%- leak down new and at the end of the next race? 18%-leak down. Better still not good. So we made a new air box and used a Mustang GT stock air filter. 3%-leak down new at the end of the next race? 1%- leak down yes I said "1%". The rings bed in and the engine seals up. We went from changing a engine at 300 miles with 29 to 34% leak down to. Changing the engine at 800 miles with 7% leak down.

So the bottom line is. You mite gain a little more power (1 to 2hp) but it will not last long and befor you know it you will have a LOT less.
I work on 944s only and when I tare down a 944 engine that has had a K&N filter the cylinders have a LOT of scores from dirt that got through the filter.
If you dont beleve me do the grease test your self. Take out the filter and put a dab of grease in the air box. Then put your K&N filter in and drive the car for a few weeks and pull the filter out and check the dab of grease.

Good Luck Mike F