Dinan CAI filter

[01L2Cobra]

OK so I got an IM on another forum from someone wanting info on the Dinan CAI and I thought I would share what I found out for those of you who have one. Everything out there seems to contradict the next thing you read about the filter on the Dinan CAI. So I contacted Dinan and K&N to find out some info and hopefully this will clear some things up for those of you running these.

The filter itself
The filter does have the wire mesh and a light coating of oil like you would find on rechargeable filters which may be why some people think it is a rechargeable filter. But from talking with the people at Dinan the filter (made by K&N) is made of paper inside like disposable filters not cotton gauze that you find in rechargeable filters. So it is best that you do not try and recharge the filter. Recharging a filter can be dangerous, putting too much oil on or not allowing it to sit the proper amount of time can result in oil getting in to the MAF which is not a good thing.

K&N aftermarket replacements?
From doing measurements on the one that I had on my car originally there is no K&N filter you can buy off the shelf that is the same size. I called up K&N and talked to a rep and confirmed that they do not make a rechargeable filter to the exact measurements of the filter found on the Dinan CAI. K&N does make a couple of rechargeable filters that have the correct inside diameter (ID) on the neck of the filter but lengths and widths of the filter are larger. More measurements will be needed to verify that they will fit without running in to clearance issues.

Fitment issues on the filter and pipe?
I have the carbon fiber Dinan CAI kit on my E36 and found some fitment issues. The ID of the neck of the filter is significantly smaller than the outside diameter (OD) of the carbon fiber pipe so it is not easy to get the filter on. It took me some time, a little bit of liquid soap on the rubber neck of the filter (not much one drop will do and don’t let it drip inside the filter), elbow grease, and a lot of cursing to get the pipe inside the neck of the filter.

Now for you E46 guys the filters in the E36 and E46 are the same, BMW of Austin confirmed this for me by running part numbers. At some point Dinan did go to a plastic pipe for the E46 so there may be a difference in the OD of the pipes on the E36 vs. the E46.

Why is it a good thing to check on the condition of your filter?
Mine had about 60K miles (bought the car used so I’m not sure of the exact mileage on the filter) on it and it was coated with grease and pea gravel that was severally restricting air flow. I would recommend that you just check it maybe once every other month or so. Just unbolt it from the fender well and at the rubber hose connecting it to the MAF and pull it out to check. I find it easier to do it that way so I don’t have to fight with taking the filter off the pipe.


Hope this helps
Mitt