UPDATE!!!
i went ahead & got my catch can from ebay, but i decided not to install it...
instead, i attached a breather to the oil exit & capped off the intake entrance...
i figured i'd go this route being that since i live in miami will proabably never experience any condensation issues. i wanted to see what'd happen if there was a cleaner burn...
all i can say is that there is definitely a NOTICABLE THROTTLE IMPROVEMENT!!!
i reset the ECU & have been driving it around for a while now... for all i know, resetting the ECU is what gave the car that added umph... but, nobody will know for sure...
my 2nd Gen K&N sounds a bit louder & the pedal is more responsive...

 

Where is the oil vapor that naturally occurs from operation supposed to go? One of the points of the oil system being attached to the intake in some way, usually through a PCV system, is to PULL the oil vapor OUT of the system and burn it up. Without a vacuum source to pull the vapor out, it will not exit easily on its own.

You'd be better off leaving it stock than what you've done. And there's no way this mod helped with power or throttle response, it's all in your head.

 

so, what would be the drawback of not venting as much vapor as possible through the use of the vaccum hose?
forgive my ignorance...

 

thats the problem dgrx--it will not vent without a vacumn source to "suck" it out. the purpose of the catch can is to clean up the stuff being sucked out. Your throttle response was probaly from your resetting the ecu just as you said. Hook the factory system back up man-- helps the engine run cleaner and it wont get as much carbon buildup.
olddragger

 

I have to disagree. I put the breather on the oil stem and capped off the vaccum line. The second I cranked it, the rough idle stopped. The breather is puching air out at a pretty good rate. The can does a good job for what it does. However it does not keep a clean burn. The less vaccum on the intake the better anyway. It is like drinking a drink through a straw. If you poke a hole in the side, it makes it harder to get the drink in. Air rushes through the hole instead of the bottom of the straw. That is your vaccum. Depending on how dirty the filter gets, it could draw harder from the oil system vs. through the filter.

Has anyone out there tried both set ups? That is what we need. Guys with the catch can already set up should try it. Why not. We can put this dog down. Work in progress fellows.

 

dgrx8 has the same results I do. There is a big difference on the response. No bull. It feels smooth like 2nd generation rx7s ran. Very smooth and more responsive. I should add that I am in a hot climate. Prove us wrong. Try it and see. I will be waiting on results. Thanks guys.

 

well heck-- i was taught that if two people are telling you the same thing --then you need to listen. I have a catch can on and it will be really easy to place a breather --no actually--- what I can do is to leave the can as is(steel wool in the can anyway) and just detach it from the intake vacumn and plug that off with a cap.The catch can should then act like a breather. Will do tonight.
olddragger

 

sorry guys
could you explain me what is a breather ??? (perhaps my english is too poor)

do you have a picture

thanks

 

A breather looks like a mini K & N filter that will mount to the oil stem vaccum line. 9 bucks at Auto Zone. 5 min install. Leave the line hooked to the intake, with a cap on the end. I did this for winter time. Perhaps we will need then. Maybe not. If I have to change it back, I will pull the breather and connect the line back.

Does anyone know what the track cars are doing on this? Are they running cans or breathers?

 

I like to vent the vapors (basically oil smoke) into the intake.

There is no vacuum - the vapors aren't being "sucked out" at that point in the intake tubing there is no vacuum present. With my Revi intake there is even a possible positive pressure.

Venting the breather tube or catch can to atmosphere is no big deal, the only downside I can see is a possible oily film on stuff and the odor issue.

S

 

learning a lot here! My bad. I always thought that the airflow pass the fitting would provide a "suction" kind of like the front of the intake. Prehaps I am wrong. Stealth are you saying we have Ram Air affect going on?
I do know this. I tried the guys suggestion--now letting the catch can act as a breather/filter(yes there is an odor present but not bad at all) and I capped the intake fitting--------------------------- and -------there is increased throttle response-----noticeable. Dudes---thanks! I am unsure if WOT is any better but partial and anything below 3/4 throttle is much better. I already had a smooth idle so I cant verify that. If there are no negative affects from this --- then this is a good mod!
Now the question is "Why"
olddragger

 

Hi. bought a catch can set-up off of ebay last night. I plan on doing what you said above.

I think the noticeable difference is due to the car not sucking hot air in from the engine, but sucking cold air in in lieu of it....thus it is noticeable.

 

Sounds like more of Mazda's not acknowledging a known problem because they would have to spend money to Fit it. I'll have to pull mine to check on it.

 

i knew we were on to something here turbine...

 

I still think you're all crazy about the throttle response. But to prove it to myself I took the lines off the can, capped, and drove around for a day. Noticed zero difference in throttle response or idle, so I still think you're all crazy.

Also, the experience I got with just venting it with a filter on my 2nd gen rx7 was that the condensation problems were WAY bad. I got terrible condensation without the vapor being pulled out of the oil system. Added a catch can to it and poof, dry as a bone. So just something to look out for.

 

Checked oil yesterday. I used almost a quart. No condinsation. Quick question. Can condinsation occur in hell? I may hook it back when it stops pegging 90-105 degrees. Like I said before, the car does not have these problems unless it is hot outside. I am under the hood every other day. I will keep the breather on until I see some condinsation. Another question? How does water vapor find its way into the oil system? If there is water in the oil system, I would think my problems are elsewhere. I think the vaccum line on the oil stem is a part of the LEV equipment. The equipment has a flaw of pulling engine oil in.

So let me get this straight. I want to get the condinsation off my bud lite. The best thing to do is go into the closet and get my vaccum cleaner and stand over it for a couple of hours while it sucks the condinsation off. Please! It is faulty LEV, plain and simple. It may affect some cars, may not.

 

ok... here's my report after a whole weekend...
i did a few more things i should mention - i cleaned my MAF, K&N intake pipe, & throttle body. i noticed that i had barely sucked in any oil. i also want to mention that i live in Miami & have not experienced any condensation whatsoever.

on to my driving impressions...
what is most noticeable is defenitely the smothness. the impression of better throttle response might just be a result of feeling the car pull so smooth. it really does idle & drive a lot smoother...

oldragger is defenitely feeling what i'm feeling at about 3/4 throttle.

dDuB, maybe you're not feeling it because you went into this mod so negatively b/c of your past experience w/ the 2nd gen. you have to be able to feel the idle & smoothness difference. you don't notice the slightest difference

Jaguar MBA & Oldragger, I'm not sure that the catch can will work to seperate the oil if it isn't attached to the vacuum line. simply attaching a breather or leaving the can's exit open will not get the sudden pressure difference needed to get the oil in the can. for those that are experiencing the oil in the intake, i recommend leaving the catch can on. & for those who aren't... i suggest the breather route.

this might be another option for those not experiencing any oil sucking...
3/8" inline filter

 

I seriously noticed no difference. The way I could tell was that when idling my shifter would still shake like it did before (slightly), and when I put my hand on it I could feel the vibration that was occuring at idle. So the "roughness" did not go away.

 

Actually, it is a big deal environmentally. Crankcase fumes are an awful mix of partially-burned hydrocarbons, which is one of the reasons that PCV systems were one of the first anti-pollution measures instituted on car engines back in the 1960's.

 

any thoughts on why you couldn't just use PVC to make a catch can... because i can't think of any and its alot cheaper and easier to work with -shrug-

 

Yes you could, it's not very hard and I've seen people do it.

 

made one today from PVC for about $15 and an hour of labor... has a level guage on and I put a nice baffle design inside for extra seperation, we'll see how it works

 

thats what I did
OD

 

rOter,

How about some pics? I'd like to see your creation.

 

here you go... fairly simple

a straight piece of 2" diameter PVC pipe, 2 caps, 2 3/8" barb fittings, 3 feet of 3/8" tubing, some PVC cement, and a hose clamp ... and for the level guage I found 2 fittings and a hose from the home aquarium section

I got about a 10" long piece of pvc and cut it down to about 5", then used the scrap piece and cut a section out of it and drilled it a bunch of times to act like a baffle. If you'd see inside the curved baffle piece seals on the top between the 2 fittings and on the sides about 3/4 of the way down... figured if thats not going to make the oil drop out i don't know what will. Probably not needed as the greddy can i bought and returned was just an empty can - but i thought i'd go the extra step.

(I wanted black tubing but they only had clear - which i thought might be cool for the first month or so since since i'll be able to see if the can is doing its job by looking at the tube going in and coming out.)


In case you can't tell, its mounted between the air pump and the windshiled washer fluid tank.