A Catch Can and EGR Delete Module are two separate things which we discuss below.

Catch Can

A Catch Can is used to catch most of the oil vapour (no catch can will catch 100% of the vapour) released from crankcase pressure (engine blow-by).

Why do people choose to run a catch can?

In extreme cases (e.g. high-performance scenario) oil vapour coats the surface of the intercooler and internal piping of the intake system, this can cause surface tension which can slow up air flow.

People choose to run a Catch Can as (we believe) they are under the impression that it will eliminate all oil from the intake manifold, resulting in no build-up of carbon deposits recirculated by the EGR System. This is not entirely true, because as long as there is plumbing returned to the inlet manifold, there is still a chance of oil vapour passing the baffles/filter of a Catch Can and lining the internals of the intercooler and plumbing. 

EGR Delete Module

The EGR Delete Module does just that, it deletes the EGR System. It shuts it down into a dormant state but keeps the throttle control valve open which still allows the system to relieve excess boost if required (similar to that of an internal blow off valve).

With the EGR System deleted, carbon deposits are eliminated from the entire recirculation system. The carbon deposits are the solids that actually build up in the manifold and passes into your sump, causing all the issues that we know of with EGR systems.

What Does This All Mean

If you run an EGR Delete Module, the carbon deposits are no longer present. This means the oil stays clean and passes through without issues and the sump oil is no longer blackened by the carbon deposits. Therefore you do not need a Catch Can.

Warranty Issues

We were advised by our dealer that installing a Catch Can to minimise the oil in the intake would void our new car warranty.  This is even after we had signs of oil weeping from our EGR Valve. Their reasoning for this is a Catch Can, being a filter, causes a restriction in the natural breathing of the engine. This restriction, in some cases, can cause oil seal issues in the head of the motor.

So if you are turned away from an EGR Delete Module due to the warranty issues, keep in mind, an EGR Delete Module can be simply unplugged before services, however, a Catch Can is a much bigger job to physically remove. Both can void warranties if found. 

My Personal Views / Experience on a Catch

Don't run one, mine was thrown in the bin by my mechanics following a large bill to repair blown oil seals and gaskets, caused by increased crankcase pressure, caused by the Catch Can.