Chris Wilson Posted January 5, 2009 Share Posted January 5, 2009 The throttle side one is the intake for the idle control valve, not part of the breather system. I'd get the breather system closed again by plumbing the turbo side one back into the intake pre-turbo -Ian I agree, very annoying noise, especially on fast idle warm up. re routing the intake of the idle speed control valve into the pre turbo air pipe will all but silence it altogether. Quote Link to comment Share on other sites More sharing options...
jevansio Posted January 5, 2009 Share Posted January 5, 2009 I agree, very annoying noise, especially on fast idle warm up. re routing the intake of the idle speed control valve into the pre turbo air pipe will all but silence it altogether. My ISCV vents to atmosphere too, sounds like a Dyson on a cold start. Quote Link to comment Share on other sites More sharing options...
paul mac Posted January 5, 2009 Share Posted January 5, 2009 I'd get the breather system closed again by plumbing the turbo side one back into the intake pre-turbo -Ian yep agree with that Quote Link to comment Share on other sites More sharing options...
imi Posted January 5, 2009 Author Share Posted January 5, 2009 (edited) attached is a pic with both breather filters circled. The throttle side one is the intake for the idle control valve, not part of the breather system. understood I'd get the breather system closed again by plumbing the turbo side one back into the intake pre-turbo -Ian as in remove the filter and fit a pipe from that outlet into the air filter pre-turbo without the filter? wont that introduce oil into the breather system? should I not just extend the filter using a pipe further away from the engine? Edited March 27, 2013 by Littler (see edit history) Quote Link to comment Share on other sites More sharing options...
imi Posted January 5, 2009 Author Share Posted January 5, 2009 yep agree with that oh I see...... Quote Link to comment Share on other sites More sharing options...
jevansio Posted January 5, 2009 Share Posted January 5, 2009 (edited) Is a better solution not to go to a catch tank, then back into the intake???? I'm interested as I have both mine breathing to atmos at the mo. See Pauls car here: Edited January 5, 2009 by jevansio (see edit history) Quote Link to comment Share on other sites More sharing options...
paul mac Posted January 5, 2009 Share Posted January 5, 2009 wont that introduce oil into the breather system? should I not just extend the filter using a pipe further away from the engine? you would think venting a crankcase would be quite a simple topic, however after going round in circles for a while i finally followed a guide posted by Ian C a while ago and tried to get it as stock as possible, why mess with what Mr T spent ages soughting out, i do agree with Jevansio as well though as i used to run a catch can off the turbo inlet pipe and since i took it off have noticed a thin smear of oil now on the intercooler piping internals at some point it will be going back on Quote Link to comment Share on other sites More sharing options...
paul mac Posted January 5, 2009 Share Posted January 5, 2009 Is a better solution not to go to a catch tank, then back into the intake???? I'm interested as I have both mine breathing to atmos at the mo i know Pauls car is banzai machine but i have read so much both on here, SF and tuning books about the benefits of the PCV, i plan on running a tad more boost when i finally get round to re-building my motor, i will be upping the ventilation on the crank but i will be keeping the PCV Quote Link to comment Share on other sites More sharing options...
imi Posted January 5, 2009 Author Share Posted January 5, 2009 you would think venting a crankcase would be quite a simple topic, however after going round in circles for a while i finally followed a guide posted by Ian C a while ago and tried to get it as stock as possible, why mess with what Mr T spent ages soughting out, i do agree with Jevansio as well though as i used to run a catch can off the turbo inlet pipe and since i took it off have noticed a thin smear of oil now on the intercooler piping internals at some point it will be going back on Glad it is not just me that isnt getting a conclusive answer on this. I for one do favour the Toyota knows best line of thinking, the only issue I have with it in this circumstance is that we have changed the character of the engine, boost, temp, pressure, AFR, etc.....so under these changed parameters what are the implications of hooking the turbo outlet directly into the intake system. why is it not best to hook it up to the breather filter but isolate it from the hot turbo side by using a piece of pipe. Quote Link to comment Share on other sites More sharing options...
paul mac Posted January 5, 2009 Share Posted January 5, 2009 Glad it is not just me that isnt getting a conclusive answer on this. I for one do favour the Toyota knows best line of thinking, the only issue I have with it in this circumstance is that we have changed the character of the engine, boost, temp, pressure, AFR, etc.....so under these changed parameters what are the implications of hooking the turbo outlet directly into the intake system. why is it not best to hook it up to the breather filter but isolate it from the hot turbo side by using a piece of pipe. IMI its nothing to do with heat, its to do with positively venting the crank case ie creating negative pressure to suck the blow-by gas out of the crank case rather than just letting it find its own way out, just moving the filter will have no effect, the optimum set up (this is my personall view) is to keep the PCV (which you have) then run the turbo side to a catch tank in a cool place so it will condense the oil out of the vapour then run in back to the turbo inlet Quote Link to comment Share on other sites More sharing options...
Ian C Posted January 6, 2009 Share Posted January 6, 2009 Oh crikey, there is a comedy of misunderstandings going on here First, the idle speed control valve. Saying it "vents" is misleading as all it ever does is "suck". It is also not part of the "breather system", it is part of the "intake system". Confusing terminology I know but I didn't invent it. Also, I wasn't talking about that when I was talking about getting things plumbed back into the pre-turbo intake (and yes it is rather loud on cold start but anyway). That's the one at the back of the plenum on the intake side sorted out. Now, onto the wonderful subject of breather systems once again. You lucky people had Digsy about to write this guide: http://www.mkivsupra.net/vbb/showthread.php?t=46158 It really is everything you ever wanted to know about them, and it explains why closing them is a good idea. In a nutshell, the pipe with the filter on it venting to atmosphere is the wide open throttle breather. The idea is, when you're booting it, the act of the turbo sucking in air produces a vacuum that sucks blowby gases out of the cam area and crankcase, stopping a buildup of pressure behind the various seals. With this vented to atmo instead, it doesn't work anywhere near as well. Running higher than stock boost pressures means it's even more of a good idea. Yes it puts some oil into the intake, but it really isn't a lot. Doesn't affect anything. Think how many litres of air the engine sucks up compared to the minute amounts of oil that would be mixed in. Which leads us onto catch cans. Oh yes, I love these things. A catch can, to work properly, actually needs some serious design thought put into it. It has to swirl the air that comes into it in order to drop the oil out of suspension, but also must avoid interfering with the breather system function (that of evacuating blowby gases from the crankcase). There are a few ways of doing this right, and there are many (usually polished, shiny, and brand-named) ways of doing it wrong. But that's besides the point anyway. Catch cans are for racing applications as far as I know, not street cars. If your car is blowing enough oil out the breather system to need a catch can, there is a bigger problem at hand and you're treating the symptom, not the cause. If it isn't doing this, you'll find your catch can pretty much empty all the time. Which begs the question - what's the point? So there you go Put a pipe from WOT breather to post-filter pre-turbo pipe and smile at the money saved on a catch can. -Ian Quote Link to comment Share on other sites More sharing options...
imi Posted January 6, 2009 Author Share Posted January 6, 2009 Oh crikey, there is a comedy of misunderstandings going on here First, the idle speed control valve. Saying it "vents" is misleading as all it ever does is "suck". It is also not part of the "breather system", it is part of the "intake system". Confusing terminology I know but I didn't invent it. Also, I wasn't talking about that when I was talking about getting things plumbed back into the pre-turbo intake (and yes it is rather loud on cold start but anyway). That's the one at the back of the plenum on the intake side sorted out. Now, onto the wonderful subject of breather systems once again. You lucky people had Digsy about to write this guide: http://www.mkivsupra.net/vbb/showthread.php?t=46158 It really is everything you ever wanted to know about them, and it explains why closing them is a good idea. In a nutshell, the pipe with the filter on it venting to atmosphere is the wide open throttle breather. The idea is, when you're booting it, the act of the turbo sucking in air produces a vacuum that sucks blowby gases out of the cam area and crankcase, stopping a buildup of pressure behind the various seals. With this vented to atmo instead, it doesn't work anywhere near as well. Running higher than stock boost pressures means it's even more of a good idea. Yes it puts some oil into the intake, but it really isn't a lot. Doesn't affect anything. Think how many litres of air the engine sucks up compared to the minute amounts of oil that would be mixed in. Which leads us onto catch cans. Oh yes, I love these things. A catch can, to work properly, actually needs some serious design thought put into it. It has to swirl the air that comes into it in order to drop the oil out of suspension, but also must avoid interfering with the breather system function (that of evacuating blowby gases from the crankcase). There are a few ways of doing this right, and there are many (usually polished, shiny, and brand-named) ways of doing it wrong. But that's besides the point anyway. Catch cans are for racing applications as far as I know, not street cars. If your car is blowing enough oil out the breather system to need a catch can, there is a bigger problem at hand and you're treating the symptom, not the cause. If it isn't doing this, you'll find your catch can pretty much empty all the time. Which begs the question - what's the point? So there you go Put a pipe from WOT breather to post-filter pre-turbo pipe and smile at the money saved on a catch can. -Ian Thankyou for the excellent reply and the clear summary Quote Link to comment Share on other sites More sharing options...
paul mac Posted January 6, 2009 Share Posted January 6, 2009 (edited) have to disagree with Ian slightly on the subject of catch cans, the problem with any oil that enters the intake tract/intercooler is its there for good, it does not evaperate it just accumulates and over a period of time coats everything and builds up thereby reducing the effeciency of the intercooler, with regard to the design of catch cans yes i agree a lot are really useless bling, i made my own baffled version that was also filled with stainless wire wool Edited January 6, 2009 by paul mac grammatical incorrectness (see edit history) Quote Link to comment Share on other sites More sharing options...
jevansio Posted January 6, 2009 Share Posted January 6, 2009 First, the idle speed control valve. Saying it "vents" is misleading as all it ever does is "suck". Sadly I don't know any any words which are the opposite of vent, and at 10:30 last night I wasn't going to speed hours thinking of one, vent seemed reasonable to anyone who knows what an ISCV does Quote Link to comment Share on other sites More sharing options...
Ian C Posted January 7, 2009 Share Posted January 7, 2009 have to disagree with Ian slightly on the subject of catch cans, the problem with any oil that enters the intake tract/intercooler is its there for good, it does not evaperate it just accumulates and over a period of time coats everything and builds up thereby reducing the effeciency of the intercooler, with regard to the design of catch cans yes i agree a lot are really useless bling, i made my own baffled version that was also filled with stainless wire wool Having taken various intake pipes off my engine several times I've only ever found a thin bit of pooled oil at low points. Can't say I've sawn the intercooler in half to check though so who knows I still think it's a non-issue considering any oil that got into the IC would percolate down to the bottom of it under gravity anyway, rather than evenly coat its insides with a thermic barrier. What I think hasn't ever stopped you breaking the rules though How much oil have you caught in your can so far -Ian Quote Link to comment Share on other sites More sharing options...
Ryan.G Posted January 7, 2009 Share Posted January 7, 2009 Must admit im not a fan of venting the breather back into the intake also. Any light oil vapour into the intake system will actually lower the octane level of the mixture. The 3sgte is a good one for this as they always have abit of oil vapour out of the breather and for this Toyota actually fitted a small catch can on the later revisions. On the earlier ones i always find you can get abit more power out of them by removing the breather input into the intake. Ryan Quote Link to comment Share on other sites More sharing options...
paul mac Posted January 7, 2009 Share Posted January 7, 2009 How much oil have you caught in your can so far -Ian very good point Ian, as i mentioned my home made catch can was baffled with stainless wool in and it was positioned away from the heat of the engine, i took it off after it had been on about a year in a frenzy of weight saving , the intercooler pipes did not have a hint of oilyness to them so i can deduce it was effective, when i opened the catch can out of interest it was quite oily internally but there was not even enough oil in it to pour out, i think your probably right it is a non even on well maintained engines, however when i still had the old stock twins on which were on their way out i could literally pour the oil out of the intercooler Quote Link to comment Share on other sites More sharing options...
paul mac Posted January 7, 2009 Share Posted January 7, 2009 Must admit im not a fan of venting the breather back into the intake also. Any light oil vapour into the intake system will actually lower the octane level of the mixture. The 3sgte is a good one for this as they always have abit of oil vapour out of the breather and for this Toyota actually fitted a small catch can on the later revisions. On the earlier ones i always find you can get abit more power out of them by removing the breather input into the intake. Ryan interesting and good input Ryan Quote Link to comment Share on other sites More sharing options...
dandan Posted January 7, 2009 Share Posted January 7, 2009 Mine will be headed out the tailpipe! Quote Link to comment Share on other sites More sharing options...
imi Posted January 8, 2009 Author Share Posted January 8, 2009 (edited) interesting and good input Ryan And exactly to what Ryan and myself discussed on Sunday I have now moved the air breather away from the engine near the air filter. Temporary measure using a rubber hose until I manage to get some suitable stainless steel hose (if required) Edited January 8, 2009 by imi (see edit history) Quote Link to comment Share on other sites More sharing options...
JamieP Posted January 8, 2009 Share Posted January 8, 2009 My breather is currently vented under the car via a catch can, only problem i can see with that is if i do lose a piston and the catch can overflows then it will pump oil over the rear tyres, should be fun:D What FTLB did your car make imi? Quote Link to comment Share on other sites More sharing options...
imi Posted January 8, 2009 Author Share Posted January 8, 2009 My breather is currently vented under the car via a catch can, only problem i can see with that is if i do lose a piston and the catch can overflows then it will pump oil over the rear tyres, should be fun:D What FTLB did your car make imi? Sorry, just havent had the time to scan the graphs yet. Here are the numbers. Max Power 555.7bhp @ 1.4bar Max Torque 490+ ft lb AFRs are 11:1 or just a touch over 11...... imi Quote Link to comment Share on other sites More sharing options...
Jazzy Posted January 8, 2009 Share Posted January 8, 2009 Nice figures imi, gotta be happy with that Quote Link to comment Share on other sites More sharing options...
imi Posted January 8, 2009 Author Share Posted January 8, 2009 Nice figures imi, gotta be happy with that More power can easily be made with a bigger free flowing exhaust, but this is a street car and I am happy with the way it drives. The numbers are a bonus. I am nervous about the 1st track session on Saturday......I hope the car comes back home safely. Quote Link to comment Share on other sites More sharing options...
Wez Posted January 8, 2009 Share Posted January 8, 2009 I am nervous about the 1st track session on Saturday......I hope the car comes back home safely. Where you going? Just remember its not a race and build your speed up slowly, most accidents on track are in the first couple of sessions where people go mad and dont get themselves or the car warmed up. Quote Link to comment Share on other sites More sharing options...
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