Air filters are supposed to keep the dirt out of the engine. Unfortunately they are also treated like trade secrets. K&N has long been the leading after market filter provider for most street and race applications out there. Many racers and street riders alike swear by their products.

K&N offers a wide range of custom and universal filters. We use them for the Big Air Setup for ultimate performance. They have proven time and again that they are at the top of performance and longevity - especially if you treat them according to the manufacturers specs and clean them with K&N filter cleaner every 20-50k miles and re-oil them with K&N filter oil. For more information on how to clean K&N air filters see your K&N product manual.

Until now there was no official K&N filter for the VMax. Some resellers have picked closely fitting K&N filters and re-branded them as their own, selling them at a premium to the official K&N MSRP. Since the market is rather limited, K&N has not come forward with an official filter configuration. Even worse some ruthless business owners are selling cheap ($12) made-in-China look-a-likes for massive premiums, asking $60-70 dollars for more or less worthless imitations.

If you purchased a filter that is blue and where told it is a K&N or equivalent you have been scammed.

To put an end to these business practices we took a close look at all available K&N filters for the 2010 & 2009 VMax. There are in fact 3 filters from K&N that are more or less drop-ins for the new VMax.

Here are the product numbers/ids of the closest fits:

K&N 33-2006

K&N 33-2758

K&N CM-9908

All three can be used without modifications to the stock airbox. Some of them (33-2006 & 33-2758) might require a metal bracket to secure them in place and might force you to get rid of the rear top airbox funnel cover - unfortunately a significant mounting point (1 out of 3) for the VMax air-scoops.

In addition to misleading advertising 'facts', performance gains are often wrongfully attributed to the filters in question. We will do another full filter dyno comparison with a brand new 2010 VMax in the upcoming weeks as part two of this article. Long story short - don't expect significant gains from any of these filters. Most of the gains come from changes made to the airbox when installing these filters (e.g. the removal of the internal restrictor funnel).

Lets have a look at these filters:

K&N 33-2006

This filter is the drop in replacement for some of the old Chrysler and Dodge Minivans but also the 1986 Dodge Charger - amongst many other older vehicles (http://www.knfilters.com/search/applications.aspx?Prod=33-2006). Since it has been around for a while, its price is low and there are plenty of look-a-likes and versions of it in green, blue, orange and other colors at various price points. Just look up various cross reference charts like this one from K&N: http://www.knfilters.com/search/kn_cross_ref.aspx?part=33-2006.

The cheapest we found on eBay was for about $35 with free shipping within the US.

The 33-2006 has a cross pattern - meaning the structure is horizontal once the filter is installed. Because of that the top lip is a bit soft and requires the use of a bracket. We fount suitable brackets at Osh and Home Depot for as little as $1 - some cutting or drilling might be required. (for the bracket not the air box).

The filter has a decent fit and because of the variety of sellers you should be able to get a great deal on it.

The knock off equivalent from Kool-Blue is the KP2020.

K&N 33-2758

This filter is for late 1990s Renault Laguna's and Safrane II. European car models not sold in the US, but the filters are readily available. The main difference to the 33-2006 is that its filter element construction is vertical which turns out to be a better support for the top lip once installed in the VMax airbox. Same as for the 33-2006 a top bracket might be beneficial in holding the filter in place as the top airbox cover will not fit with these filters.

The cheapest we found on eBay was also for $35 with free shipping within the US.

As with the 33-2006 the 33-2758 has equivalents from various other manufacturers including the blue and green models of Made-in-China models. Expect to pay between 12-20 bucks for the asian versions. Anything more is pure price gauging. For example: The Kool-Blue (Accel) equivalent is the KP2114 and goes for about $20 at most internet outlets.

K&N CM-9908

This is really the filter of choice for the VMax if you want to keep the stock airbox. The CM-9908 is made for the Can-Am Spyder and is the closest to a true drop-in replacement for the VMax. In fact , its fit is better then the stock filter (if that is even possible). It offers you the choice of running with and without the internal restrictor funnel. Our favorite install method is clearly without the funnel (which also gives you the vast majority of gains reported. With a good exhaust systems the funnel removal is good for 4 rwhps.

Installed without the restrictor in place, the tight fit of the CM-9908 makes for a perfect seal, does not require any brackets and allows you to run the rear funnel top cover (the third mounting point for the air scoops). INstallation is very easy and can be performed by most riders without the need to head to a shop - as long as you find your way to the airbox.

We found the CM-9908 on eBay for about $54 and to our big surprise got one on Amazon for $19! Have not found another one for that low - so this might have been a one time special.

Either way the CM-9908 is the perfect drop in replacement for the 2009/2010 VMax. Along with the filter change we do recommend the removal of the internal restrictor funnel that is held in place by two plastic rivets on the inside of the main top cover. Airbox disassembly is required.

Next week we will take all these filters back onto the dyno on a brand new 2010 VMax to see what filter has the performance advantage.

So - if you are in the market for a filter change, these filters should give you all the options you need. If you are looking for top performance check out the Monster Big Air Kit in the forum/site store at www.fxtuner.com

To see more photos of the filters and how to install them: Click Here

To discuss this article in our forums: Click Here

Last year we tested the 33-2758 with and without restrictor plate on a 2009 VMax with the all mighty X-Pipe: The vast majority of the gains came from the removal of the restrictor plate (+4 hps) and 0-1 hps over the stock air-filter. To read the full article: Click here

• < Prev
• Next >