K&N XD air filters use a Deep Pile Design, Extra Fine Weave Grade Cotton and alternate geometries for added efficiency and capacity for off-road conditions. This extra thick filtering medium provides the increased protection demanded by high dust conditions while continuing to provide the performance necessary to stay in the Front of the pack. The XD Cotton medium was developed for the extreme conditions encountered by race teams in the Baja 1000. This real world testing is combined with testing performed at K&N's own Dust Retention Laboratory in conformity with the ISO 5011 test protocol. XD Cotton Air filters can be cleaned in the same way as K&N's original cotton air filters.
| Automotive Item Grade | High Performance |
| Cap Outside Diameter | N/A |
| Color | Heather Red |
| Filter Material | Cotton Gauze |
| Filter Re-Oiling Amount | 8.3 oz (245 ml) |
| Filter Style | Dry |
| Flange Angle | 0 Degree |
| Frame Design | Flexible |
| Inner Wire | No |
| Inside Diameter | 11.500 in. (292mm) |
| Item Height | 5.000 in. (127mm) |
| Item Weight | 5.000 lbs. (2.3 kg) |
| Machine Washable | Yes |
| Number of Flanges | None |
| Oil Included | Filter Is Pre-Oiled |
| Outside Diameter | 14.000 in. (356mm) |
| Overall Length | N/A |
| Package Content | 1 |
| Package Contents | 1 Air Filter |
| Package Material | Paperboard |
| Package Quantity | 1 |
| Package Type | Box |
| Pre-Screened | No |
| Product Box Height | 6.750 in. (171mm) |
| Product Box Length | 18.380 in. (467mm) |
| Product Box Width | 18.380 in. (467mm) |
| Prop 65 (C, R or CR) | CR |
| Prop 65 Warning Label | https://www.knfilters.com/images/l/prop65.jpg |
| Shape | Round |
| Title | K&N E-3978XD Round Air Filter |
| Top Material | None |
| Top Style | Open |
| WARNING CA Proposition 65 | Yes |
| WARNING CA Proposition 65 Message | WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov |
| Width | 14.000 in. |
WARNINGThis product can expose you to chemicals, including WARNING: Cancer and Reproductive Harm - www.p65warnings.ca.gov which is known to the State of California to cause cancer or birth defects or other reproductive harm. For more information, go to www.P65Warnings.ca.gov.
K&N
K&N's replacement air filters are designed to increase horsepower and acceleration while providing excellent filtration. This air filter is washable and reusable and it is custom designed to fit...
K&N
K&N washable, reusable High-Flow Air Filters feature a state-of-the-art design of layered, oiled cotton media engineered to improve airflow and capture contaminants, and are designed to provide...
K&N
K&N washable, reusable High-Flow Air Filters feature a state-of-the-art design of layered, oiled cotton media engineered to improve airflow and capture contaminants, and are designed to provide...
K&N
The K&N E-4450 replacement air filter is constructed with layers of woven cotton for outstanding filtration and low air restriction to help your engine run more efficiently. This air filter can...
K&N
K&N washable, reusable High-Flow Air Filters feature a state-of-the-art design of layered, oiled cotton media engineered to improve airflow and capture contaminants, and are designed to provide...
K&N
K&N washable, reusable High-Flow Air Filters feature a state-of-the-art design of layered, oiled cotton media engineered to improve airflow and capture contaminants, and are designed to provide...
