2jz Catch Can

[1jz68u]

hey guys this could be a bit of a noob question.

I bought a catch can today. Can someone please tell me how to install it on a 2j?

I tried 2 different ways.

1. Disconnect hose on driver side from rocker cover and connect to catch can. Blank off position on
intake.

2. Disconnect hose on driver and passenger side run both hoses to catch can, blank off spot on plenum and intake.

Results.
1. Small amount of smoke from exhaust when backing off.

2. Lots and lots of smoke all the time.

Help please.tried searching here sf and google.

[Pube]

Hose #1 - Rocker cover to catch can
Hose #2 - Intake (pre throttle body) to catch can

[1jz68u]

ok dont know if i made sense the first time so i will try with pics

1st time: Connected #1 to catch can, blocked #2. left 3 and 4 alone.

2nd time: t pieced 4 and 1 together (guy from shop told me to do this) blocked 2 and 3 off.





hope that makes a little more sense.

now i had the 2nd hose off the catch can just venting to atmo, so does this need to go back into the engine somewhere? if so where?

sorry for the stupid questions, last catch can i did 1 hose to catch can and that was it.

thanks

[LeeRoy]

1st time: Connected #1 to catch can, blocked #2. left 3 and 4 alone.

2nd time: t pieced 4 and 1 together (guy from shop told me to do this) blocked 2 and 3 off.

I wouldn't be going back to that shop for advice any time soon then.

Both the hoses out of the rocker covers will have pcv valves in them and both do the exact same thing.

However, the one going into the inlet side will have a 1 way valve to stop you getting a vac leak, and the inlet side will just be straight fed without any restriction other than pcv due to this side always being in Vac.

The first way: Would have smoked cause youve gotten rid of one of the PVC hoses.
The 2nd way: Would have smoked heaps cause you had blocked both of them off.

This is how you need to do it.

Run both rocker cover lines into the catch can. Then to draw all that air out of the can you need to run the two lines back to 1. the inlet manifold, and 2. the turbo intake tract. Just make sure the can has enough of an internal baffle so that the misty oil getting put in is not just going to be sucked straight out.

Seems like the supra setup is the same as any other but just twice as many hoses.

[1jz68u]

the catch can has 2 holes.

So join the hoses from rocker cover together then run into catch can?
Then return line into number 3 or 2 on the pic? or do i have to join those ones together as well???

sorry for my retardation

[LeeRoy]

1 and 4 are pcv fittings. 2 and 3 are vacuum fittings - but on boost #3 will have posititve pressure so it will more than likely have a 1 way valve to stop it pressurising the can and only allowing it to draw air in not blow it out.

I guess join 1 and 4 together then join 2 and 3 together and run 1&4 into one fitting on the can, and run 2&3 from the other. Just check that the can has enough baffles between the two fittings because if not then your not going to be improving on the standard setup. Alternatively you could buy another can or buy one with 4 fittings.

Simply put, the can just goes in the middle of the hose. So imagine if u just cut the hose in half - thats where the can would go.

[1jz68u]

awesome thanks will give that a try.

[1JZ~lux]

I've got a few problems with what you've said so far.

Both the hoses out of the rocker covers will have pcv valves in them and both do the exact same thing.

However, the one going into the inlet side will have a 1 way valve to stop you getting a vac leak, and the inlet side will just be straight fed without any restriction other than pcv due to this side always being in Vac.

I have a 1JZ-GTE but I beleive the engines still breathe the same. There is only 1 PCV on the rocker cover on the plenum side. The way I thought it was meant to work was, the PCV blocks possitive pressure from boost but allows the plenum to suck excess gasses from the motor and preventing positive pressure from building from blow by and such. The hose from the intake piping (before the turbos) to the rocker cover is simply to prevent vacumn pressure from being created by the hose to the plenum. This is how I think it works anyway.

1 and 4 are pcv fittings. 2 and 3 are vacuum fittings - but on boost #3 will have posititve pressure so it will more than likely have a 1 way valve to stop it pressurising the can and only allowing it to draw air in not blow it out.

I guess join 1 and 4 together then join 2 and 3 together and run 1&4 into one fitting on the can, and run 2&3 from the other. Just check that the can has enough baffles between the two fittings because if not then your not going to be improving on the standard setup. Alternatively you could buy another can or buy one with 4 fittings.

Simply put, the can just goes in the middle of the hose. So imagine if u just cut the hose in half - thats where the can would go.

What I see wrong with this, is that the plenum would just be sucking straight from the intake and not through the engine. The excess pressure should still be able to escape though.

I'd recommend doing a search for JZA-80 Supras in the members rides and ask some of the owners if they don't already have pictures up.

[1JZ.747]

im a bit confused why you would put a catch can on a stock engine.

they are a smelly bugger of a thing and leave you open to be defected.

if your running big boost through a single conversion then yea theres a good reason to have one.

[LeeRoy]

What I see wrong with this, is that the plenum would just be sucking straight from the intake and not through the engine. The excess pressure should still be able to escape though.

I think your right.

He will either need to get 2 catch cans, or block the intake manifold bung and only use the turbo inlet pipe vacuum feed.

If you join both hoses then you will create a vacuum leak and give yourself a nice and high idle. Apologies for the incorrect info.