The K&N RG-1001BL is a round tapered, universal clamp-on intake filter with a chrome metal top and a blue oiled cotton gauze element. Its height is 5.5 in (140 mm), the top outside diameter is 4.75 in (121 mm), and the flange length is 1.125 in (29 mm). The rubber flange is molded and pliable, and can be stretched up to 1/16 of an inch (1.5mm) to fit in-between sizes. The cotton media is built from four to six layers of cotton gauze treated with a special grade of filter oil. Compared with a paper element, the RG-1001BL is designed to be washed and reused instead of replaced. The manufacturer says the engine air filter only needs cleaning every 75,000 miles under normal highway driving conditions. K&N also offers a recharge kit for cleaning and re-oiling the element. For a builder fitting a custom intake tube where a stock-size filter will not seat, the included 3.5 in and 3 in flange inserts give you more than one fit option on a single filter. This filter has no vehicle-specific application, so confirm that the intake tube's inside diameter matches the 4 in flange or one of the inserts before ordering. The manufacturer designs these universal filters for applications including racing vehicles, radio-controlled cars, generators, snowmobiles, tractors, and others. Search terms for this part include 4 inch universal cold air intake filter, washable clamp-on high flow air filter, and K&N RG-1001BL flange insert.
Yes. The manufacturer's specifications list flange inserts that step the inside diameter from 4 in down to 3.5 in and 3 in, and the rubber flange can also be stretched slightly to fit between sizes.
The manufacturer states that the filter needs cleaning about every 75,000 miles under normal highway driving. Its recharge kit is meant to clean the oiled element and restore its airflow, after which the filter can be reused.
This is a clamp-on filter, so the job is typically a matter of fitting the correct flange insert to the intake tube, seating the rubber flange, and tightening the clamp. The manufacturer notes that some K&N air filters need to be installed into the air box lid first because of how they are manufactured, so check your air box design before you start. When reassembling a housing, the manufacturer advises making sure that the air filter is seated into the groove on the lid and that the lid is properly seated onto the air box base, since forcing misaligned halves together can break the air box. The manufacturer also warns that the clip pressure may feel slightly firmer than with an OEM foam seal, and that excessive force means you should stop and recheck the fit.
