Reason for deleting pcv valve and pipework with catch can.

bengal

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Hi all just a quick question im going to put a catch can on my car and iv seen that others have removed the pcv system. What is the reason for this is a catch can a good vacuum source so you dont need the source from the inlet manifold or is it just a case of minimising the chance of boost leaks? Also do you remove the breather valve on the tip or just leave it in ? Its a 1.8 T AGU thanks
 
Mostly its to stop oil from diluting the fuel as this reduces the octane rating and if excessive will potentially bring on detonation (although the ECU will try and combat it with pulling timing)...

<tuffty/>
 
Hmm i wasnt very clear with the question was i lol. I didnt mean whats the catch can for i know that i meant why delete the pcv valve but i suppose if you left it in you would still get oil going into the inlet manifold so il get rid of it. Thanks for the replies though. Oh and i didnt know that excessive oil in the system could cause detonation so iv learnt something there.
 
Main reason for getting rid of the pcv valve is to minimise the chance of leaks. The pcv pipe work under the inlet is notorious for boost/vac leaks, and the vacuum drawn breathing on idle isn't really needed, by fitting a catch can you're just letting the engine breath naturally. You can leave the pcv system in place and still fit a catch tank, and it's also possible to remove the pcv part of the breather system without fitting a catch tank, although it's best to do both
 
Hmm, considering I have a few leaks that need sorting under the inlet, what is the total cost for this??

Doc, let me know how you get on with yours mate :)
 
I believe so, but its supposed to be better to do both together.
 
great info Doctor , didnt see any mention of the amk unit though so presumably this mod applies to most or all the vag audi 5v turbos ?
 
Duktor, I believe its the same across teh 1.8T range.
 
its pretty much the same idea.....different engine codes do throw up different problems, ie an AUM engine will have a bit more complication to it than an S3 IMO.....
 
Yeah, not sure re any difference between engine codes, but send a PM to OllieH who started the PCV Simplification thread above and he may be able to advise you.

Nilz18t - I'll update you next week (hopefully with +ve news...). Can't remember the total cost but scan though the pages of the link above & you'll see how much the catch cans, pipework and bits & pieces were.