So I've seen lots of request on Catch Cans of late and there are lots of threads on how to fit etc, but I wanted to do a thread on how to modify it to actually work rather than just be an asthetic piece of bling in the engine bay.
What you will need:
1 x Universal Catch Can - Any Shape 1 inlet, 1 outlet type
1 x Piece of Tin, Alloy or similar (Stainless Extractor Fan or Deep Fat fryer Filter is best option though)
1 Pair Tin Snips
1 x Profile Gauge
1 x Tube decent sealant
Small drill bit
Allen Key for Lid
Adjustable Spanner for Inlet and Outlet Ports
1 x Oil Breather Filter - to be Broken so eBay is a good cheap place.
Standard Can, unwrapped - Remove Ports and Lid
Inside, nothing but air - this is no good as the oil vapour will just get sucked straight from the inlet to the outlet.
What you need is a baffle for the vapour to pass through, thus cooling the air and turning the vapour back to liquid droplets, here's where you can use my cheap method or buy the stainless extractor fan or deep fat fryer filter for the best application.
Take your tin, alloy or metal sheet and cut a few mm wider than the tin and as tall, then using a profile gauge take the profile of the inside of the lid and mark it on the tin with a marker, or score it as its only tin / alloy etc.
Cut the sheet to shape, fold the edges as pictured this will form the seal needed to create two chambers inside the can.
Check your deck height:
You need to make sure the baffle will sit snug in the lid, so I checked the height and fit before continuing, trimming as needed.
Test - Fit Lid On:
Perforate the sheet with your drill, quite a few hols spread all over the baffle. You are now ready to seal, a decent bead of sealant over the folds will ensure a good seal and bond of the baffle.
I used some Ambersil which is a sealant / adhesive used by the M.O.D.
I also bent the tin around the drain plug and left a small gap at the bottom of the baffle.
I allowed this to cure for a few hours before finishing off, this depends on the sealant used of course, some will take longer.
The last thing I decided to do was take apart an oil breather filter and use the filter element over the edge of the baffle on the ports side, to rensure a seal at the top.
I put this over the top and bent it downwards, when the ports were replaced they also pushed the filter down, this is optional and I thought it would add some more filtration to the catch can, if I had used the filters mentioned from an extractor fan or fat fryer I would have left this piece out and the drilling:
Filter and Ports:
Once done everything was back on and bolted up nicely, ready for fitting to the car:
I plumbed this into the standard brather line from the rocker cover to the turbo intake pipe using braided line and some unions and mounting where the carbon canister used to be fitted.
Mounting location is important for a catch can, if the can is exposed to too much heat the vapour will not cool and turn to liquid, the front of the car is ideal, maximum cooling capacity which should ensure the vapour returns to its original state.
Either side of the radiator where you can fit it, avoid near the turbo side of the engine bay middle or back... the bulkhead is not the most ideal, as the air passing over the back of the engine has already been heated.
I hope this helps all you guys considering one?