think ive discovered what my "secondary" catchcan is for!

[jimGTS]

The ideal place to have your PCV vented is into the exhaust after the turbo ... preferably as close to the end of the piping as reasonable/possible. It does help pull air out of your crank and having it go to the exhaust does not dirty your intake air.

I do know there are very good reasons that an owner and builer of a race car made sure to "vent" his PCV into the exhaust. There was also good reasons for him to move the connection point to the exhaust. ... which resulted in increased performance.


these are quotes from the US forums, when i was researching the PCV system and breather filter....



am pretty sure this is exactly was has been setup on my rev5.
is this an extreme thing to do on an mr2? what real advatnages tho?

i thought about sticking a breather filter on my stock catch can, (and blocking the other end on the intake), but if this other can plays an additional role in pulling out the pcv gases, then obviously blocking it wont be benifical to the setup?

any thoughts?

[LimeyMk1]

You might need to re route the system for your MoT, as it'll send the hydrocarbon readings well into the fail dumping crank fumes into the exhaust.

Can't see owt wrong with it otherwise.

[jimGTS]

im confused how it would have pasted its last mot then, lol...

[LimeyMk1]

Dunno, I was kind of going by the amount of oil mist my Mk1 used to kick out. I guess the catch can is really doing its job well or there's very little coming from the PCV.

Reckon I'll do the same with my V6 PCVs.

[Bender Unit]

The ideal place to have your PCV vented is into the exhaust after the turbo ... preferably as close to the end of the piping as reasonable/possible. It does help pull air out of your crank and having it go to the exhaust does not dirty your intake air.

I do know there are very good reasons that an owner and builer of a race car made sure to "vent" his PCV into the exhaust. There was also good reasons for him to move the connection point to the exhaust. ... which resulted in increased performance.

This is why the internet is dangerous. People post tripe like that and others will potentially believe it.

Pull air out of your crank hahaha.

The PCV vents pressure that builds in the head whilst the engine is under load, the reason it’s fed back into the intake is an emissions thing – nothing else. If your engine is breathing hard under load then you might get a small drop in performance as oil will effectively reduce the octane rating of your fuel (in the cylinder)

You do not need to suck these gasses out of the head, that’s stupid, they are under pressure – they will find their own way out! Just install a filter onto the end of the catch can vent it to atmosphere.



What does that 2nd tank go to on your car? At the moment I cant see it performing any useful function. It wont be acting as a catch can thats for sure. The japs do some random crap sometimes.

[jimGTS]

i dont think the guy ment suck it out, simply that the gases vented after the stock catch can then feed into the turbo...
this other catch cans exhaust pressure, or suction or whatever takes these gases and puts them down the exhaust.

it doesnt literally suck it direct from the head, lol...

just diverts the gases to the exhaust, instead of turbo inlet...


those quotes were were JekyllandHyde btw, well respected mr2 owner in the states afaik.
(and used to be a member here)

[jimGTS]

What does that 2nd tank go to on your car? At the moment I cant see it performing any useful function. It wont be acting as a catch can thats for sure. The japs do some random crap sometimes.

this is my point, and question at the same time....
if you read my post, youd realise where its hooked up to, lol.
it is obviously serving a function otherwise why bother??
it is routed to the downpipe...(im 95% sure)

this is the not the first high spec jap car ive seen with two catchcans...

perhaps its techincally not a catchcan, maybe refered to as something else.

[Bender Unit]

Ok looking at the picture you have 3 pipes connected to your air intake. The middle 1 is the PCV and connects to the factory catch can. The one on the left goes to this second can – what happens after that? Also where does the one on the right go to?

FYI you set up isnt acting as a catch can, it wont be catching any fuel vapour coming from the head.

i dont think the guy ment suck it out, simply that the gases vented after the stock catch can then feed into the turbo...
this other catch cans exhaust pressure, or suction or whatever takes these gases and puts them down the exhaust.

it doesnt literally suck it direct from the head, lol...

just diverts the gases to the exhaust, instead of turbo inlet...

Um I am lost, the information you posted said the gasses were being sucked from the head?

I cant understand what you have subsequently written, random to say the least.

Feed the catch can into the turbo?
Catch cans exhaust pressure?
Suction or whatever takes their gasses and puts them down the exhaust?

WTF lol … are you smoking something?

if you read my post, youd realise where its hooked up to, lol.

No its not obvious, where is it connected to do you know?

it is obviously serving a function otherwise why bother??

The japs do stupid things, FYI they have dumbo’s over there too, they aren’t all cutting edge tuning gods. I have an idea what its doing but it isnt anything like what you think.

it is routed to the downpipe...(im 95% sure)

Do you know for sure?

this is the not the first high spec jap car ive seen with two catchcans...

Lots of people fit 2 catch cans as its easier than removing the stock unit. No big deal.

[jimGTS]

i was simply quoting someone on the US forum talking about routing similar to how i have it, but they were refering to there "friends" drag car....

he stated from the crank, tho am sure he was refering to the crankcase, valvecover...(as the thread was talking about breather filters on the pcv pipe)
i was messing around when i said the head, he never mentioned the head, i was simply refering to the cover.

when i say "feed", i mean the pipe from can to intake pipe, that pipe is feeding/directing gases is it not, to the intake.
the 3rd pipe, connects to the bracket/pipe junction over the dizzy cap, like the stock black 12-15inch pipe does.


am trying to read between the lines of what the guy is trying to express.
hes saying that the gases that have been released into the intake pipe from the stock catchcan, are then forced/sucked into the exhaust through that other can when on load...


if you got any ideas as to what it actually is, that would be useful.

i believe this engine/car to be phoenix power tuned, so i wouldnt call them dummies, lol (well you might, but thats up to you, lol)

thanks

im just trying to make sense of whats going on, cause noone seems to know.

hense why i posted info on what i "think" it could be used for based on the statement i found...

[simmo490]

Jim what makes you think it's pp tuned

[lockys96]

its at least been through the hands of pp

[murf]

So, one end of the silver aftermarket can goes to the intake and the other end goes to atmosphere?
I would have said that that setup does nothing other that allow unfiltered air into your intake pipe?
The stock catchcan is connected as it normally is and theres a pipe coming from it that drains the condensed oil vapour back down into the sump so even if the 2nd can was connected inline and was being used as a catch can there wouldnt really be any vapour for it to catch.

[jimGTS]

I need to be 100%, but its either sump
or downpipe.
Not to atmos murk.

As far as pp bits go, quite a few, including the other none pp made items that they normally install to there cars, tho am not saying it's a pp car, just possibly tuned/built going by the mods similar to there demo cars (and the numerous pp items it has already)

[Razor04]

The ideal place to have your PCV vented is into the exhaust after the turbo ... preferably as close to the end of the piping as reasonable/possible. It does help pull air out of your crank and having it go to the exhaust does not dirty your intake air.

I do know there are very good reasons that an owner and builer of a race car made sure to "vent" his PCV into the exhaust. There was also good reasons for him to move the connection point to the exhaust. ... which resulted in increased performance.


these are quotes from the US forums, when i was researching the PCV system and breather filter....



am pretty sure this is exactly was has been setup on my rev5.
is this an extreme thing to do on an mr2? what real advatnages tho?

i thought about sticking a breather filter on my stock catch can, (and blocking the other end on the intake), but if this other can plays an additional role in pulling out the pcv gases, then obviously blocking it wont be benifical to the setup?

any thoughts?

Hi Jim
is that secondary catch can venting into the intake? if so where is it drawing from? at first glance i thought the primary can was venting in and the secondary was venting out of the intake! but that would just be stupid

cant work it out, would it not be better to vent the primary directly into the secondary can, and not go into the intake at all? like when you run the stock PCV out to a bottle or breather filter?

[C50]

just vent it to atmophere

longish hose with breather filter on the end away from mot eyes

[jimGTS]

ok i will double check the weekend where the other feed is coming from, defo downpipe/exhaust or the sump...
theres no where else it can came from in that area.

to recap

stock can is setup like stock, the right pipe on the intake goes to the inlet manifold (pic below), and the left pipe goes to the secondary can. from that can the line goes to the sump/downpipe.






am just after reasons why its setup like this, and am i ok modifying this setup? ie, breather filter on oem catchcan...and maybe removing that other can?

[greeny]

to recap

stock can is setup like stock, the right pipe on the intake goes to the inlet manifold , and the left pipe goes to the secondary can. from that can the line goes to the sump/downpipe.

If that right pipe does indeed go to your inlet manifold and is unrestricted then your car would have a constant supply of air, i.e bypassing the throttle plate, and would be idling sky high around 4k~ It would be like keeping the throttle plate open.

If i were you id either leave it like it is(if its working fine, and your not sure what your doing with it), or take peoples advice and do away with the extra can etc and just put a breather filter on the end of your stock can, and cap thoses three take offs on your inlet pipe.

[jimGTS]

my bad, its going to the TB, not the IL....
either way, the one going here is like the stock pipe.
so i need that pipe still there.

but if i were to remove the other can, and put a breather on the oem catch can....

would it just be a case of blocking/removing, finding out where that other pipe goes and taking it off/block it.

[greeny]

my bad, its going to the TB, not the IL....
either way, the one going here is like the stock pipe.
so i need that pipe still there.

but if i were to remove the other can, and put a breather on the oem catch can....

would it just be a case of blocking/removing, finding out where that other pipe goes and taking it off/block it.

I think you need to see exactly where everythings going and then suss out what everythings doing and go from there lad. No point in us guessing.

Whats making you wanna change it? You having probs with it?

[jimGTS]

well 2 of the pipes are going where it would as standard. i know that much.
its just the extra pipe for the secondary can that has come off the intake, and is plummed into somewhere else.

either way, id still like to know the advantages or disadvantages of this setup if it was going to the sump, OR if it was going to the downpipe.

i just wanted to put a breather filter on, so the intake is as clean as a whistle so octane levels are kept high (and not mixed with oil vapour lowering the octane)...

this was my main reason.
on top of me wanting to get nice new hoses for it, but no point getting the hoses if im going to ditch the setup.

but obviously i got another can in place doing something, so not sure whether me putting a breather on would make that other can redundant, or ruin some sort of airflow or whatever.

hense all my questions, lol....
id appreicate peoples ideas of what the other can is doing as well.