K&N air filter (in airbox) Are they worth it?

[COLVERT]

Gotta disagree.---


No benefit to fitting a K&N filter unless you drive with the rev counter on the red line all the time.----

The standard filter will do all you want of it.

A formula 1 car might benefit but our old bread and butter bangers wont.----

[minimutly]

Interesting discussion.
Less restrictive filter = more airflow? Well only if the rest of the restrictions on the way in and out allow - the most frequent one being the throttle plate.
Electronic fi adjusting the fuel to compensate if there is more airflow? Only while the lambda is controlling - or more accurately compensating. At full power the efi is in open loop so if there is a pile more air going into the engine it will run weak.
Finally, how many people on here extoling the k&n run a turbo k? And of these, how many also run a vvc inlet manifold? Well I have news for you - the step at the manifold to head joint causes a way bigger restriction at full power than your K&N will ever recover.
Are the worth the cost? Up to the owner, I have one in my zt190 airbox, but it was sort of free....

[Sheraton]

Originally Posted by minimutly

Interesting discussion.
Less restrictive filter = more airflow? Well only if the rest of the restrictions on the way in and out allow - the most frequent one being the throttle plate.
Electronic fi adjusting the fuel to compensate if there is more airflow? Only while the lambda is controlling - or more accurately compensating. At full power the efi is in open loop so if there is a pile more air going into the engine it will run weak.
Finally, how many people on here extoling the k&n run a turbo k? And of these, how many also run a vvc inlet manifold? Well I have news for you - the step at the manifold to head joint causes a way bigger restriction at full power than your K&N will ever recover.
Are the worth the cost? Up to the owner, I have one in my zt190 airbox, but it was sort of free....

I'm aware of the Inlet Port Bore mismatch between VVC and Standard k-series heads - and the theoretical implications - is this something you have verified ? i.e any detrimental affect on performance with a VVC vs Standard Manifold ? - it's something i'd be keen to investigate on a dyno - 1.8t Paper vs K&N and Standard vs VVC Inlet manifold for Comparison

I stated at the time of fitting the VVC that any Improvement in driveability was likely a Placebo affect - but.............. throttle response did feel Improved....yep that Old Chestnut


I feel the need to state Again - K&N filters (and VVC inlet mods) for me are NOT about "Improved Performance" the way that term suggests - it's Not about Race Tuning Performance at full throttle

my 1.8t has(d) No issue delivering Air at Full throttle - the Turbo needs Electronic Control to prevent too much Air being delivered


the way we drive in reality is rarely full throttle - minor Improvements in Performance at varying throttle positions/Gear/Rpm/Running temp/Ambient temp/Elevation etc.. are something that may not be measured but can be Noticed by an Observant Owner/Driver.

or we Can just repeat Hype and theoretical Performance "Facts" without Gauging for ourselves



Paul.

[stevestrat]

Originally Posted by gnu

My experience of K&N's on old motorcycles are, that you have to upjet the carbs, or you will probably damage the power in parts of the rev range. Less restriction, leads to more air, leads to weak mixture, leads to power loss and more heat. I assume the k with its sensors and ECU will automatically adjust the mixture?

I had a K&N cone filter and larger jets on a 500cc single. The induction noise almost drowned out the exhaust