[TitaniumTT]

Originally Posted by RETed

I'm assuming this is for an FC.
Is this purely a "crankcase" evac system?
Since I didn't read anything about the gas tank vapor purge, I'll assume this is not part of your system...

Yup, on an FC with a 13B-RE. There is nothing for the fuel tank. I built my own cell with an in tank surge tank and have the cell vented to atmosphere. Works well, no smell.

Originally Posted by RETed

I like the idea of running the crankcase with some vacuum.
Having the crankcase pressurized could possibly hurt power and / or cause headaches like smoking turbos.
The hard part is...how do you do it?
The stock system is overly complicated.
Mazda's stupid "purge valve" is another one of those engineering-bragging doohickeys that makes things a headache.

When we run race cars on the track, we 1) cap the bottom nipple on the center iron, and 2) run a single vent off the top of the oil filler neck.
Whether you want to run it as a recovery system or a purely purge / vent system is up to you.
Oil *will* creep up the oil filler neck to easily spew out the lower fitting in the center iron when you toss the car around the track.
Even with oil baffle pans, you can still get oil puking out that lower fitting.
We've never had too much problems with oil puking out the top of the oil filler neck.

I've got both nipples t'eed together and run to the puke tank. Yeah, it does creep up badly. But, if you cap the iron nipple, run the oil filler to a vac source, does that ceate enough flow through the crankcase to clean things out? I would imagine that you would want a constant flow of air in one port, out another. With that center iron nipple capped, the only source to relieve the vac is the blowby or the oil entering the pan. I would imagine that it would be a little more effective to leave the iron nipple open, but filter the air going into it, no?

[QUOTE=RETed;131045]I'm also assuming that this is for a turbo 13B.
This is good and bad.
Running vacuum in the crankcase relieves pressure that would end up puking oil out the piston compressor ring in the turbo turbine.
Effect?
Oil spews out the hot turbine section and burns in the exhaust causing embarassing oil smoke.
Bad?
Push the turbo hard enough and this causes the oil to foam more after the CHRA.
Foaming, hot oil causes more vapor crap, which causes more crap to get puked out the system.[QUOTE=RETed;131045]

Yes, you are correct, twin turbo 13B. The twins are notorious for not liking pressure and puking/burning oil easily. Even the rebuilds. Both my CHRA's are damp with oil, but she'll only burn and puff smoke if sitting for a LONG time or if overboosted slightyl. Kinda why I want to get a bunch of vac in the pan and was THINGKING about overcomplicating the whole thing with a vac tank..... but then slapped myself out of that idea.

Originally Posted by RETed

Another bad thing...
With a turbo engine, the only "spot" that has constant vacuum is before the turbo.
If we're talking purely vapor, this would not be a problem.
In reality, we're also ingesting (hopefully) minute amounts of liquid that's hitting a (delicately) spinning compressor wheel.
Mazda decided to do this full-time with their system.
It's probably the best, passive system that could be integrated into engine at that time.


-Ted

This is exactely why I wanted to run the vac source through the filtered puke tank before it heads to the turbo. Was also thinking about running a clear fuel filter inline as well just as a last ditch effort to catch anything that migh do damage hitting a comp wheel spinning way too fast. Like you said, purely vapor would not be a problem, but some sort of debris or the sludge that often collects, would be a huge problem hitting those comp wheels under full song.

So, would you change anything on the setup that I have in mind?

Thanks Ted, I appreciate it