K&N replacement
Outstanding HDF Member
Joined: Jul 2007
Posts: 2,609
Likes: 1
From: Indy area
RE: K&N replacement
http://www.knfilters.com/search/prod...x?Prod=HD-1499
Yes, the airbox assembly makes a difference for performance. The stock airbox has a relatively small opening compared to "stage 1" kind of stuff, but it has sufficient flow for stock tuning/exhaust, even with the replacement filter above (which really won't change intake flow characteristics enough to matter as far as needing a "download" flash, or other type of fueler).
Yes, the airbox assembly makes a difference for performance. The stock airbox has a relatively small opening compared to "stage 1" kind of stuff, but it has sufficient flow for stock tuning/exhaust, even with the replacement filter above (which really won't change intake flow characteristics enough to matter as far as needing a "download" flash, or other type of fueler).
Road Warrior
Joined: Jun 2007
Posts: 1,539
Likes: 7
From:
RE: K&N replacement
K & N makes a replacement filter for the stock Harley filter, a replacement air filter kit #3909 and athicker filterkit the #3910.
All three are great options for any bike
Good Luck
All three are great options for any bike
Good Luck
Road Captain
Joined: Mar 2007
Posts: 520
Likes: 0
From: San Diego
RE: K&N replacement
the difference in the backing plate is the velocity, there is a rubber boot that is about 2 inches deep creating a veturi effect that almost forces more air in in addition to the actual filters ability (being large) to allow more air into the engine, (more air in more volume out) = more horsepower I use the 3910 on my bikes uses the factory cover and looks nice, does stick out about 2 inches more than factory position though...
Outstanding HDF Member
Joined: Jul 2007
Posts: 2,609
Likes: 1
From: Indy area
RE: K&N replacement
The velocity stack is an impedance-matching device. It allows the graceful transition from the low-velocity/high-pressure (low impedance) condition inside the airbox to the high-velocity/low-pressure (high-impedance) condition inside the runners. Same thing as properly-designed horns on acoustic drivers. Much greater efficiency that way.
Intermediate
Joined: Sep 2007
Posts: 33
Likes: 0
RE: K&N replacement
The K&N HD1499 OEM air filter unfortunately compresses the two beather hoses due to the holes on the back of the air cleaner being narrower or closer together that stock. Stock is 5", K&N is 4 11/16 " which doesn't sound like much until you see how the hoses are compressed after installation. This causes additonal back up pressure which is not a good thing.
I have been trying to deal with K&N over this matter for nearly two years. They have acknowledged the difference in center to center breather hole measurement but have not been very interested in correcting it.
Other filters out there for OEM replacement measure the OEM 5 ".
Hope this helps.
I have been trying to deal with K&N over this matter for nearly two years. They have acknowledged the difference in center to center breather hole measurement but have not been very interested in correcting it.
Other filters out there for OEM replacement measure the OEM 5 ".
Hope this helps.
Thread
Thread Starter
Forum
Replies
Last Post
