catch cans the what how and why we have them and should you fit a catch can to your ADT Mark [Music] 1 hi Andy here and welcome back to the channel where today we're talking all about catch cans now behind me is the project TT and it had a catch can when it arrived but what is a catch can cuz if you have a standard Audi TT mark1 it's unlikely you have one on the car so first off let's talk about what is a catch can well like its name suggests it's a can that catches something and what it's catching is oil Vapor on your car you have a PCV system which stands for positive crank case ventilation during combustion the fuel is being ignited which forces the Piston down due to the high pressure however some of that pressure will get past your piston rings and under the Piston itself which we call blowby this is creating positive pressure under the Piston to prevent this pressure in the crank case from doing damage we need to vent it and that is where the PCV system comes in handy this highpressure gas is carrying combustion deposits in it which include carbon and oil vapor from the engine lubrication the PCV system then redirect directs this gas and Vapor back into the combustion cycle for the inlet manifold to be burnt off however putting oil Vaper back into the combustion cycle is going to make your emissions even worse because you're going to be burning more oil which is going to be bad for the environment it's also not great for your valves and pistons as it encourages carbon buildup in your engine carbonization this can cause a rough running engine and poor fuel economy at best and engine damage at worst something to be avoided so that oil Vapor that's being burnt off as we mentioned is bad for the environment but also it's going to be bad for the inside of our PCV system because over time it's going to cause the rubber hoses to perish now when those hoses break down and start to perish they too are going to be adding to the contaminants that are flowing around that PCV system in burnt by the engine making the whole situation even worse so that's where a catch can can help you out by introducing a catch can to that PCV system as part of that routing it will catch the oil vapor and contain it in this pot and then pass off clean air around your PCV system preventing more contaminants from being put back into the engine and causing more damage here's a handy diagram to explain how it works the PCV hoses Supply oil Vapor to the can through the inlet and through the mesh where the vapor cools and condenses and is then trapped in the can the outlet then Returns the cleaner air off to be vented away into the turbo intake pipe so when we look at the wise for the catch can well it's pretty simple it's because we want to ensure that we are catching the oil and stopping it from going around the engine because as you can imagine when there's all those contaminants flowing around the PCV system going back into the inlet manifold such as parts of rubber from the hoses and the oil Vapor itself that is going to start to clog up and carbonize your valves and your piston heads which in turn will cause less efficient combustion and of course less power so from that we know why we would put an oil catch can in place it is to protect the environment but also to keep our engine running as efficiently as possible there is of course a third reason to do this the PCV system on these cars is 20 years is old at least the hoses are breaking down causing boost leaks and of course more contaminants and parts to replace this with an oem setup are almost non-existent you could of course replace your PCV hoses with a nice aftermarket silicon set but it would be better to simplify your setup if you going down this route and introduce the catch can a few easily available 19 mm hoses a teap piece and a catch can are much easier to obtain than unique and expensive cloudy Parts when I collected the project TT and looked under the Bonnet it already had a billy Cloud catch can fitted to the system in a 20-year old car the PCV system is going to start to deteriorate and I think that the project TT car has had the PCV system removed and this oil catch can installed to cope with the outlet of the oil Vapor here is the catch can from the project TT and looking at it on the inside it's not what I expected now I need to unscrew the catch can from the inlet and Outlet at the top so the actual can that catches the oil and if we look inside it's quite a shock it looks like well cream cheese so by looking at that you can see this is the inlet for the catch can and this is the outlet so all of the crud is coming in here and you can see it's built up on this Filter part as it goes through and then the hole the clean hole is where the air is going back to the engine now I'm going to tilt the camera downwards because if I tip this can up all the contents are going to come out so I'm going to show you what's inside so there you go there is the contents of my catch can as you can see it's pretty murky in there so as you can see the contents of a catch can are pretty nasty now I was expecting when I looked in this catch can it was just going to be full of quite dense oil but no it looks like it's got lots of contaminants in there as well so it means the catch can is doing its job I would say these are very straightforward to fit it just means there is some reworking of pipe work from the various locations around the engine and they do come with a nice clear guide and there's plenty of help on YouTube on how to fit a catch can to your car but I'm going to show you my setup on the car we're going to put this back in position and I'm going to explain how I feel it works so on the Audi TT Mark 1 you normally find a catch can positioned and hanging from the strut brace around about here so this particular catch can is held in place by one simple alen bolt and it connects up the two hoses which I'm going to reconnect here one there and one there like so and that's suspended as I mentioned from this bracket on the strp brace so here is our catch can in position on the engine and as you can see it is suspended from the strut brace by this bracket there's then an inlet and outlet pipe to the catch can to allow the vapor to come in to the can and then back out and around the engine system now the setup of the catch can is very simple the process for the catch can is the pressure comes out of the crank case here in the top of the rocker cover so the over pressure is coming out and it is being fed into the catch can here the oil Vapor will condense and sit in the can so air will then flow from the catch can to the hockey Park and the diaphragm which then in turn feeds back into the turbo intake pipe completely bypassing any oil Vapor going back into your Inlet manifold and it's connected by these rubber 19 mm pipes and various Jubilee Clips to fasten it all in place it's a very simple setup and I think it's a much more efficient way of dealing with the oil vapor in your car so that's my take on the oil catch can for the Audi TT mark1 and I think it is a really sensible solution for those of you that have got failed PCV systems or pipe workk that's starting to perish why don't you let me know in the comments if you think a catch can is a good idea for the car and if you have one fitted yourself and of course if you're thinking of fitting one why don't you leave me a comment asking questions on how to do so if you've enjoyed today's content then please do think about giving this video a thumbs up and also think about subscribing to my channel if you have not already done so where you'll find lots more helpful videos on the Audi TT mark1 as always thanks for watching see you soon take care