View Full Version : k&n or stock flame arrestor

06-18-2010, 06:00 PM
i own a 22zx 454 efi and i have a k&n flame arestor who reccomends the stock flame arrestor or perfer the k&n

06-19-2010, 08:51 AM
I had K&N filters on my Formula, and I hated them. They crush out of shape when you put them on. I guess they'd be ok if you were born with six arms.:eek:

06-19-2010, 08:59 AM
has anyone actually noticed any performance gains with the K&N? (on a boat of course)

06-19-2010, 03:49 PM
No Difference.... I've had mine on for several seasons, and it doesn't add any power. I like it becuase you can clean it an reuse it. The K&N Cleaner and Oil Kit. I feel like it's a far better filter than the original that came on my 496HO. Better Filtration but no performance gains.

Dr. David Fleming
06-20-2010, 01:36 PM
The K&N setup is what Mercury Racing uses on most of the 500EFI and 525 race engines. This should give you a clue. Usually water travel is relatively dustless as most dust gets into the water and out of the air. However, many fiberglass hulls have dust from manufacture or repair in them and when this gets sucked into the engine you are feeding it glass particles which are very very hard and abrasive. Whenever some repair person gets to work in my hull they usually leave a mess of dust where you cant see it or clean it.

Here is a general idea of the factory air cleaner setup on say the 454/502 MAG MPI

MEFI 1 - first generation - large paper cartridge air filter - circa mid 90's
MEFI 3 - MEFI 3 - second and third generation - metal grid flame arrestor

K&N replacement for above stock setups was a wide base unit filter after a few years they came out with this reverse cone base filter unit that looks sort of bogus - like it restricts the intake area.

Vortex K&N unit designed for their supercharger fits the 454/502 and is sold for these engines by Teague and others. - this is probably the best setup.

Other engines - most stock engines come with the metal grid flame arrestor there is a pretty good post on this site about the design of these items which kill any backfire flame by dividing the flame gas and cool it into submission.

Engine builders like Tyler Crockett test these motors on the dyno regularly and if there was much need of the K&N would insist on it. Usually they sell it to customers who want it. My conversations with them indicate there is very little if any difference with K&N - do I run one - yes, the Vortex K&N unit.

Dr. D

06-20-2010, 06:50 PM
In my 1996 502 22 with mefi1 and stock Flame arrestor I ran exactly 75.5mph gps run, switched to the KN and 10 minutes later ran exactly 75.5mph gps. Get my point....