rickybobby

As part of my build I've done a lot of reading before asking questions but the 1 confusing part I keep stumbling on is catch cans.

I will be running a turbo with 76mm intake initially, early 400's bhp wise, in a Blob STI with forged avcs engine. I already have an RCM intake pipe but there is no take-offs on it for breathers etc, just the recirc valve port.

From what I've read, the most common method seems to be a 3 port catch can with either return to sump or vent port. 1 port for each cam cover, cap the pcv valve, run the larger port that was the pcv to catch can and cap the one that usally goes to the intake pipe.

Only problem I'm thinking is theres no method of extraction In my mind the stock system uses the turbo to suck from the crank to intake pipe, and I assume the cam cover breathers vent minimally compared to the crankcase. Can I run a 2nd can and run from both rear crank case takeoffs?

The car will be used on track, or at York/santa pod as well as spending most of its time on the road. I feel I have all the other bases covered in terms of engine, fuelling etc, its just the catch can part that gets me.

I've read all the links in other posts to american pages etc, I'd just like someone thats actually done it on here with a similar spec newage car to explain their setup please. Thanks all

trevsjwood

iTrader: (2)

I've always run 2 catch cans, one for crank breather the other for cam breathers, using the stock system, the cans just interrupt the crank/ cam breather lines running back to the turbo inlet. The PCV works normally.
The crank breather can is the important one, it catches a lot when doing launch starts at the Pod, would be about a third full after 4 launches sort of level but is easily drained if needed. Gets very little on track and road use, just a small amount of gunk.
The cam breathers can is always dry. Of course this is just one car and driver.
Trev

rickybobby

Thanks Trev, why does launching cause so much to end up in the catch?

I have a spare 2 port baffled can and I'm thinking of running from the smaller crank breather port to the can, then can to intake pipe BUT I would have to drill a hole in the intake pipe and use an insert to create a port.

trevsjwood

iTrader: (2)

I have launch control set at 4800rpm so quite aggressive and get massive oil surge front to back and then forward, fouls the breather and combined with full boost sucking it up, pcv closed and straight route to catch can and intake. Wether not having LC and just fettleing the throttle would help I don't know but wouldn't be happy risking that amount of oil getting up into the turbo/intercooler.
On track/ road you would never reasonably repeat the circumstances of the 1/4 mile.
I have the silicone 58mm intake from Lateral which has the necessary ports. I wouldn't part do it, either run all lines, including cams to turbo intake or blank off completely.
I have a Y piece on the cam breather pipes so 2 down to 1 port.
Grimmspeed do an air/oil separator which sits on the engine oil filler pipe but you're prob aware of it.
Trev