K&N Air Filters

fletch

Opinions people? I just ordered one & was wondering what does everyone else think of em. I know they make yer car sound louder n all but they are supposed to improve performance slightly & make your car more fuel efficient?

Con9903

aye the better air flow increases performance. I'm a saturday morning mechanic so I'll let the petrolheads do the explaining

Gerry

I'd be interested in hearing as well what people think of just moving the end of the air inlet on a stock filter setup to a lower location, where it would get less hot air. Maybe the risk of extra debris getting in isn't worth it

buzz

Its down to the engine you have to notice any performance difference! IF you drive 1L micra, it wont do much for you. If you drive a type-r Integra, it might give you up to about 7bhp, depending where the filter head is located. Ie, if it is recieving cold air etc..

mike65

Ah if I had a euro for every cold air/ram air intake thread I've read I could buy you all lunch!

Apart from making noise few ppl seem that impressed by aftermarket go faster striped filters.

You can aid your cars breathing a bit with a straightish insulated air intake pipe from say behind the front bumper. But the thing is you need a filter that actually filters which means restricted movement like it or not.

Mike.

JohnCleary

K&N Filters can have different consequences to an engine. It can either 1) Improve performance or 2) Decrease performance

1) Increased performance, your talking about 1-3BHP if your lucky. There are many variables involved. Mainly the CAF (Cold air feed). This is crucial. Cold air means better performance as cold air is more dense, hence more oxygen.

2) Decreased performance. You can just as easily lose performance if there is no decent CAF getting to the filter. Ive seen some muppets fit the K&N's directly to their throttle body, losing loads of performance and BHP. But they *did* sound cool

IMHO if your after a little extra bite without the noise, get yourself a K&N/ITG PANEL FILTER and add an extra cold air feed to your OE airbox. If your after noise get yourself a de-cat (not NCT friendly)... Dont buy a sports backbox as you'll attract too much attention from chavs and the fuzz.

causal

Does the extra oxygen not thin (reduce) the fuel/air ratio and decrease performance, requiring rejetting?
Or are modern fuel injected car engines all fancy and adjust fuel injection levels to optimise the fuel/air ratio?

causal

ando

I had one on my old Focus, made the acceleration sound a bit more grunty but there was no noticable power gain

Lord Nikon

I got a used one from a mate, he gave it to me for nothing. I put it on that night and I felt that the car could go faster. I already have a performance backbox which is loud enough, and since I put on the K&N it's like i have an exhaust under the bonnet. Sounds sweet.

I guess there isn't much of a performance increase.

It's nice going down an on-ramp in 3rd and flooring it at 3000revs, that's where it sounds the best.

Beware though, frequent flooring-it can result in reduced MPG.

damo605

OK - What if one had a stock Peugeot 2.0 8 valve engine with a stock (just about welded together) exhaust.... Would a K&N help any bit? Just sound or any hope of power? Poor engine is fecked - Burns a litre of oil for every 1k miles and hasn't had it's timing belt changed in years but goes to the redline every day, about 30 times a day, in the first 3 gears without complaining and pulls like a train, ALWAYS - Even when covering 1k miles a week and being used as a company van! (Going to give it a present of a recon engine when this one fails so not being cruel)....
Would a K&N bugger MPG & reduce what's left of the engine life? I'd love the K&N sound and wouldn't mind the extra poke but have heard bad stories about MPG dropping drastically - BTW, It's a '93 605 2.0 Sli, Mighty Machine ;-)

Seth Brundle

When you say K&N I presume you mean cone filter which replaces the entire air filter housing, rather than a K&N panel filter thast sits inside the filter housing.
JohnCleary discussed the main pros and cons of K&Ns and to be honest the only thing you will gain is noise.
Many people I have come accross with K&N cone filters have lost some power due to the filter sucking in warm air from the engine bay (this doesn't really happen with panel filters).
I have a panel filter in my current car and had one in the last and I have to say that it is not that much different power wise. I don't think people actually notice a 1 or 2% gain but think they do based on the fact that the car sounds sportier. As for mpg - I don't think there should be much of a difference.
K&N type filters are also reputed to shorten the lifespan of the engine.
Have you checked why the engine is drinking oil?

causal

damo605 wrote:

Poor engine is fecked - Burns a litre of oil for every 1k miles and hasn't had it's timing belt changed in years but goes to the redline every day, about 30 times a day, in the first 3 gears without complaining and pulls like a train, ALWAYS - Even when covering 1k miles a week and being used as a company van! (Going to give it a present of a recon engine when this one fails so not being cruel)....

That IS cruel - I'm reporting you to the ISPCE*
As kbannon said did you check the source of the oil loss?
Is it leaking it or burning it, I wouldn't be too surprised if you're piston rings are fubared, did you check your spark plugs for tell-tale signs; or is there a puddle of oil under the car regularly :eek:


*Irish Society for Prevention of Cruely to Engines

causal

stratos

The K and n's let more air in, and the carb may not be able to supply enough fuel to cope with the extra air, thus causing the engine to run lean. So new jets or retuning is advised. combining the k and n's with larger jets and a larger bore exhaust should give you abt 10 hp extra. However it will strain an older engine, however you get a good induction roar off the filters as the engine sucks in the air. I fitted the k and n on their own first and the engine began to back fire and pop. A larger exhaust and new jets later, one sweet sounding car.This probably really only applies to older cars, as I presume a modern car's ecu would adjust it's injectors automaticaly.

FuzzyWuzzyWazza

The one thing I noticed most from my K&N kit was there was much more low down torque, the car could pull much easier from very low revs, and it did in fact rev much more freely. Granted this was on an 8 valve car, so I wasn't exactly starting from a very performance orientated engine.

dcGT

Also, for all you 'friends of the earth' out there, don't forget that these types of filters are washable and reusable (when oiled up properly after washing).

Won't somebody think of the landfills?!?

DC.

fletch

FuzzyWuzzyWazza wrote:

The one thing I noticed most from my K&N kit was there was much more low down torque, the car could pull much easier from very low revs, and it did in fact rev much more freely. Granted this was on an 8 valve car, so I wasn't exactly starting from a very performance orientated engine.

That's reassuring to hear because I drive an 8v engine & would like any increase in performance.