legacycentral bbs

ok so heres the deal. i took my intercooler pipes off last night and found a ton of oil mainly around the couplers, in between the couplers and the pipes. there also seems to be a good collection of water condensation mixed with black oil collecting in the endtanks. i know my oil is sill clear because i just checked it and the oil collected in the low spots of the pcv vlave system from when i redid it was still verry clear. this also wories me at the same time because the 16g was more used than the 39 but even though it has no play whatsoever in the shaft it still is a little disconforting espcialy since my butt dyon doesnt like the 16g.

ok so because subarus have this funny pcv valve system which has been discussed to death here that has the F piece which goes to 2 different places it makes it hard to put in the catch can. but heres where i have a slight advantage. when redoing my pcv system i had to find a way to do the F piece without buying another f piece so i use a mandrel bent 3/4 inch od to wrap around the turbo and i welded a smaller piece at a 45* angle to go to that ventrui thing connected by heater hose.

so with this new piece i can get away with 2 fittings on the can (one in one out) instead of 3 fittings.

heres where i have some confusion though. in our coolant system if theres high or low spots it can effect the flow of coolant to the turbo form the tank. i want to put the can in front of the abs system because in that position i already know i can fit a can in a 3.5 inch diamater at about 6 inches tall. its fairly easy to mount it there and also easy to empty. so in this position will the flow be effected in a negative way in that it wont work as well as its suposed to. in my mind putting it there should have no ill effects as long as i use the vuntri thingie on the intake side.

lastly im gonna be building this myself in the next week and i just need to make sure i have my shoping list in order.

i need"

1 - 3.5 inch exhaust pipe 6 inches long
2 - 3/4 inch 90 degree brass or other metal fittings from home depot
1 - 5 foot piece of 3/4 inch heater hose
2 - 1/8 inch 90 degree brass or other metal fittings barbed from home depot
1 - 6 inch clear plastic tube 1/8th inch (for measruing amount of stuff inside)
1 - ball twist valve ( to drain)

one last thing, will i have problems welding brass to steel when using a gas welder and bronze as the welding material.

To make a true catch can, you would need to run the hoses off the heads into the can so you would end up with 4 diff hoses run into one side of the catch can if i remember right. I took a look at how it was run on a wrx and the guy said its pretty much the same on the legacy. When i had my catch can on the F fitting, i collected a good bunch of rust colored liquid that smelled like gas.

I wouldnt worry about the turbo much, its the added pressure on the pistons that causes more blowby.

thanks for th imput dzx,

anyone else.

also i was thinking, couldnt you just vent everything to the can and block off the ends to the intake.

What does the cooling system have to do with the PCV system?

Putting a catch can down by the ABS unit, you don't have to worry about coolant.... unless you want to run your coolant through it?


The Greddy and Perrin can's go between the PCV return line and the intake.

I would think the correct place to put the can in the stock setup, would be on the lower line of the F, between the stalk and the intake. The PCV valve injests the oil mixture into the intake manifold, which isn't going to harm the turbo or intercooler efficiency at all.

ok i was planing on putting it on what is now the lower part of the f piece, but should i plumb the crank case lines in there too.

the coolant has nothing to do with it. i was just relating coolant flow with pcv and crank case flow.

I doubt it's a big deal. Every catch can maker out there, recomends in front of the battery to mount the catch can. Coming from makers who do lots of mods to the cars, it's probably OK.

sweet, now that we got that covered.

whadaya think about NOT plumbing back to the intake and pluging the holes in boot B

I wouldn't fuck with that. I'd run it back to the intake.