I have a single turbo and I still have a bunch of oil in the intercooler pipes. Any idea why? The turbo doesn't have that many miles on it, apparently.

Also, do I need to keep the tiny stock catch can (the one that bolts to the throttle body elbow) if I have an aftermarket one? Can I just bypass with vacuum hose?

FWIW I don't know if my dipstick is actually blowing off (it seems to be in place after runs).

Also, someone pointed out a track day that my catch can's routing was questionable, but I left it how it came on the car. How should it be run? I think I just have one of the nipples on the oil filler neck hooked up to it, and the other nipple is hooked to a nearby metal vacuum line (in front of the ignition coil).

I think the other hose on the catch can is vented down toward the ground.

 

That's part of your fuel evaporative system. It has nothing to do with oil blow by. It collects fuel vapor from your gas tank and burns it when the purge valve opens.

Basically, the catch can is usually between the oil fill neck and the primary turbo inlet (for stock twins)

Remove PCV Valve

Or it is drained

https://www.rx7club.com/3rd-generati...ce-car-792344/

If it is hooked to a vacuum line, you need to make sure that it doesn't see any boost, otherwise you're blowing the opposite way. This is the stock '93/'94 configuration where the PCV valve would restrict boost backwards.

If one hose is "vented down", that may be your drain line to empty the can. There should be a valve somewhere if it is (or it just drains on the street)

 

Oh. Ok. Don't have emissions on the car although I do think if I want to pass it through emissions (it can be done here with the right cat and paperwork) I need a working fuel evap system.

There's a drain on the bottom of the can. There may or may not actually be a second hose on the can. I know there's one nipple with nothing on it. I think it's the return line for people who feed it back into the intake. In this case it's vented to the atmosphere. There may have been a third fitting though.

 

How is your catch can plumbed?

 

I took a look and it's just one silicone hose (ID of about 8-10 mm?) from the oil filler neck to the can. The second nipple on the can is left open.

I realized that the soft silicone hose is very easy to pinch, and that might be why I'm getting oil everywhere. It would also explain why I'm getting so much blowby in my intake but very little in the can. Might have to switch it up to something stiffer.

I wonder if I should have something filtering the other nipple.

 

There's no reason to filter the other nipple necessarily, it's not going to intake any air—but it might help a little bit if oil is leaking out of that vent line. I assume it's a GReddy style catch can?

I'd get rid of it for one with a big filter on top and a larger line.

Here's what I use:

http://www.jazproducts.com/store/1-quart-breather

If you don't want to run a -10 line you could get it with a smaller line and adapter to a barbed hose fitting that would match the line coming off your OE filler neck.

 

Also, dumb question—the nipple that comes off the OE filler neck actually has a 2nd nipple coming off of it in a T... is yours plugged, or is it running someplace else?