DennisRB30

Brownie, just do it the way you drew it. It looks at least you understand about the fumes through the IC thing. But if you would also like the benefits of active crankcase scavenging (how ever minute they might, or might not be) Hook it the way I showed. Theres a bit less plumbing too. You just need to find some decent one way valves. Heres a modified version for a RB20.

Do not block off the PVC valve. How many times do I have to say it. The way you brownie drew the pic is good. If you block it off, all fumes will go through the intercooler and turbo at all times as it is the ONLY path. There will always be some oil left in the gasses even after it has been filtered so it will block your intercooler over time. With the PCV system in place the filtered fumes will go straight into the plenum and not through the IC around 98% of the time. The filtered fumes will only go through the IC under heavy throttle with the valve in place. This has nothing to do with crankcase scavenging. It just makes logical sense and to dissagree would just be down right subborn. The silver RB20 is one of a minority of engines that does not SUCK the fumes out of the rocker cover. This is done to reduce oil consumption in a highly stressed engine. The usual way of doing it sucks most of the oil fumes out before they can condense back into a liquid. If it were me I would revert it back to the normal system by removing the hose that connects the rocker covers together. Just think about what would happen inside the crank case. There are oil fumes in there, and unless your rings make a 100% seal there will be raw fuel and combustion by products in there aswell. It only makes sense that when the oil fumes recondense, they will mix will all that other nasty crap and end up in your sump. Having the PCV system hooked up the way it was originaly designed sucks a lot of this crap out before it ends up mixing with the oil. I would rather have this crap sucked out before it contaminates the oil. And for the 6th time. Even in the sliver RB20's case, THE PCV VALVE WILL DO NOTHING FOR EMMSIONS. Looks at Brownies pic and pretend the PCV valve was blocked off. The fumes would make there way out to the intake and get sucked back into the engine anyway. Hopefully we can all see how this would happen. Understanding that, you might ask why its there in the first place. That answer lies in my first paragraph! To stop 98% of the oil vapours going through the intercooler and dreamatically reducing its thermal effeciancy over time.

I think you need to do some more reading.

I think its a good idea. It seems like no-one has even bothered to make a tough NA RB engine. Considering some of the NA boat anchors people work, I think twin cam RB engines have huge potential for NA. How far do want to rev it out? 8K+?

Yep. That will work. It just doen't use active crankcase scavenging, but if your not worried it will be fine. It looks good.

Thant would work, but it would only filter fumes on heavy throttle, during light thottle fumes would enter the plenum (although its not a huge issue but why not prevent that too if you can, I'm sure it would prevent the sparkplugs fouling a bit.) According to a pic of a redtop RB20 I have infront of me, the system is how you drew it but there is no hose connecting the 2 rocker cover pipe connections. For best results you would hook it up the same way as my drawing but the brown hose would connect to the right rocker cover and the blue hose would connect to left rocker cover.

I have also seen a pic of a RB25 where the left rockercover hose connected straight up to the PCV valve and I did not see a hose comming up from that location. I'm not sure if it is a variation or if it was changed. Does yours have it?

Its where the stock PCV valve hooks up to.

Fair enough. As long as you realise what will happen when you block it off, and you are fine with the idea that you won't have positve crankcase ventilation and all the gasses will pass through your turbo and intercooler at all times, as oppesed to only under heavy throttle. Sure they will be filtered, but whats better? (remembering that the can can't filter all the fumes) (a) Having crank case gasses go through the whole intake tract, turbo and intercooler 100% of the time, with no positve crank case ventilation. (B) Having crank case gasses go through the whole intake tract, turbo and intercooler maybe, say 2% of the time while still having the positive crank case ventilation (Hell, if you do it my way even the PCV gasses are filtered). Its your call, I know what has the worse potentinal of clogging the intercooler over time. If you don't belive in the benefits of positve crank case ventilation to prevent corrosive reactions in the oil, just think of it as a way to drastically minimise the amount of fumes that can potentially clog the intercooler.

turbomad, does yours plumb back? What is happening is that the PCV system is still doing its job of sucking air through the crankcase. **************************************************** Under most conditions air goes IN through the 2 rocker cover hoses not out. **************************************************** The PCV system SUCKS air through the 2 hoses on light throttle, that is why your catch can is clean. The only time that gas comes out of these 2 hoses is when you boot it. THIS IS A GOOD THING as most of the time crap does not go through all the inlet piping turbo and cooler. (do an experiment, disconnect the the pipe that goes to the intake and put your finger over it you will see for yourself that it sucks and does not blow) The gasses will not have any meaningfull adverse effects to the engine under light throttle. They will just be burned up. We all want performance right? Then the aim is to stop any crap going in the engine under heavy throttle when it actually matters, and to stop residue clogging the intercooler etc. When you boot it the PCV valve will close and the blowby will then PUSH its way through the other 2 hoses, if you have a plumb back the fumes will be filtered by the can before they go back into the intake. If you have an atmo the fumes will escape into the air. So what matters is most is being achived, ie no crap going into the engine under heavy throttle. Under light throttle the fumes will go into the plenum unfiltered (which does not realy matter anyway as its only on light throttle, and no fumes go through the inlet trackt and intercooler etc) In most of the plumb back systems meantioned in this thread, closing off the PCV valve defeats the overall purpose of fitting a catch can in the first place. Sure, when you do it your catch can will actually do something under light throttle and not just heavy throttle, BUT... All the fumes will be forced to travel along the whole intake track AT ALL TIMES not just heavy throttle. The fumes will go through all the pipes, turbo and cooler all the time, you might want to kid yourself that there is no oil left in the gas after the catch can but there will always be some crap left in it. It WILL build up in the cooler over time. Is it starting to make sense yet? I'm not even going to get into the possble idle probs and vaccum leaks some of the mentioned systems can cause. The system I drew up takes all of this into accout (when done in plumb back style, see attached text). Under light throttle the air is sucked through the 2 pipes and crank case, goes through the catch can and in to the plenum and not through the intercooler and turbo!! Most of the systems discribed in this thead don't filter the gas under light throttle when it is being sucked through the PCV valve but mine does. Plus the system has the bonus of active crank case fume scavenging under light throttle (unlike the system of disconnecting the PCV valve where gasses must pass through the cooler and turbo at all times). If your are sceptical about the PVC stytems use (even though I debunked the misconsptions 5 times) you can think of it as an added bonus!! Under heavy throttle only, the filtered fumes will go back into the intake. It won't effect the idle because the PCV system still works like stock, only filtered. It also won't effect the idle when used it atmo mode because, there is no parralell path for unmetered air to go into the plenum, ie getting sucked in through the catch can filter. Also when the system is used in atmo mode, the only time gas escapes to the air is under heavy throttle, this will stop the filter clogging and is much better for the environment. I'm just trying to make the point clear, so you can all decide what is the best, but for people to decide, they first have to understand what is happening. It just seems like a lot of you don't understand the opperation of standard and modified systems (not picking on anyone inparticular) My overall point is to try and explain how the various systems work so you you can decide the pros and cons of each for yourself. I am just trying to make people understand how my system works, as it seemed it was being dismissed without being understood first Any questions?

Man, why do you think they put a valve behind the TB where there is vacuum? Like I said for the 5th time, you don't need a PCV system to get rid of the gas. The gas will push its way out of the hoses on the rocker cover and enter the engine that way without the PCV system in place. Understand?

The PCV valve is after the TB, where there is strong vacuum, the gasses will be SUCKED out and fresh air will be sucked in from those 2 hoses on the rocker cover after it has been filtered and metered by the AFM. You could do away with the PCV valve and direct the hoses into the intake and all the fumes would be burnt in the engine anyway. Yes, recuculating the gas is not good for performace, but it is good for emmissions. That is why it is done (like I said you dont need a PCV system to get the gasses back into the engine). When you accelerate the manifald vacuum decresses and the PCV valve closes, the gasses then get PUSHED through the rocker cover hoses and go in to the intake, fesh air replaces the fumes. My system works like stock under closed PCV valve conditions (plus filtering) , but when you put your foot down no crap is sucked back into the engine. So it only sucks in fumes under light throttle when fumes won't make your car ping and the power loss from burning blowby is not an issue. You still get the benefit of positive crankcase ventilation and the benefit of not sucking crap when you are accelerating hard.

Just spotted an error in the heading of my pic, is should read "it will not let ANY vapours get sucked into the engine under heavy throttle" Which in the only time that it realy matters.

Read all the text I have written, it explains the opperation. The plenum is supposed to draw air from the breather so the crank case is cleared of harfull fumes by positive crankcase ventilation. But it only does it under light throttle, when you boot it, the PCV closes and the air goes out the filter (or back to the intake depending on how you hook it up, again read all the text) If you read the text it explains the benefits of having the blowby go out of the filter and it tells you how to hook it up without the filter if your worried about it being legal (but your engine will suck in blowby, but at least it will be cleaned by the catch can) Not having a PCV won't make gaskets blow etc if there are hoses comeing out of the rocker cover, the pressure just comes out of the hoses. I explained what the PCV system does, its to clear the harfull gasses by displaceing them with clean air. The whole idea of my system is that the PCV system still opperates on light throttle, but under heavy throttle no fumes go into the engine. I urge you to read the text I have written with the pic. Browny, your system does not use positive crankcase ventilation. The gasses have to make there way into the catch can under there own pressure at all times. The PCV valve does nothing but suck in the fumes that have come out under there own pressure. The outcome would be the same if it was not ther at all as it does not replace the fumes with clean air.

The fact is you can't filter out the used air as it has already been combusted. The filter simply can't absorb it. To get picky, the gasses have already been measured by the airflow metre so by plumbing back before the AFM it will be measured twice making it run richer. It would also clog up the filter quickly and coat the AFM hot wire in oil, not good. You will find that the Magna had the hose connected inside the round filter holder. The gasses don't go through the filter they just go straight down the carbie.

This took me ages to draw up, take a look and tell me what you think. It uses one way valves to stop idle probs and to ensure that only clean air is sucked into the engine. I think it has many benefits over any other system I have seen.

The harmfull gasses come down past the rings as combustion bypoducts and fuel etc, these mix and react with the oil and contaminate it. It is not for pollution control (even though listed as part of emmission equipement) Having this gas vent to the air is harmfull to the environment so it is burned in the engine. There is NO NEED for a PCV system for the redirction of this gas back into the engine. By simply connecting the rocker cover hoses back to the intake before the turbo the gas emmisions will get sucked back into the engine and the EPA will be happy. PCV stands for positve crankcase ventilation, ie forced ventilation of crankcase. I am in the process of drawing up catch can system that won't cause idle probs with a PCV valve and will filter the gas at all times. I will post it when done.

The hose connects to the PCV valve on the plenum so the vacuum it creates makes airflow through the engine. This is to suck away the harmfull gasses that can build up in the sump and cause acidic residue that contaminates the oil. The PVC valve is a one way valve so it can only flow from your rocker cover to the plemum, when there is pressure in the plenum the valve closes, so the crap can be redirected through the catch can. In this scenario the valve will do its job of cleansing out the harmfull gas but when you are booting it the gas will go through the catch can and not enter the engine. I would do it this way otherwise you are not preventing your oil from being contaminatd. In my opinion this will increase the life of the engine over the long term. The gasses won't do any harm to the engine when they are being burned under light throttle. The only time the gasses cause lost power and produce pinging is under load. Since the PCV will close then its not an issue.

An interesting thing about spooling turbos is, its not just the capacity of the of the engine that counts. Remember Workhorse wakeup in Zoom, where they put 2X RB20 turbos on a 4 litre ford 6. You would expect the turbos to spool up the same fast as on a RB20 becuse they are fed by 2L each. In practice it was not the case, they reported almost zero lag, they were on full boost somwhere around 1800RPM from memory. It was somthing to do with the large stroke pushing out exhaust gas with a much greater force than an RB20, even though the size per turbo is the same. So I recon that the extra 20% size the RB30 has might do more than just a 20% increase in spool time....?

Boostd, the only thing more surprising than the speed of you run was the slowness of the 350 escorts. Judging by the slip he didn't back off or abort during the run. I'd be wanting low 11's at a minimum for the hassle of putting 350 in escort. Good time for you though, your car looks sweet too.

I don't know where the link is but I done it the other day without any information, its not rocket science. Remove the crossover pipe, remove the plastic plate thing pull the coil packs of the plugs and change them. You will know what to do once you get into iy.

When I mentioned bonnect clearance earlier in the thread i was told there was no issue. I thought it would be cutting close.

You cant keep the 25 rods and pistons when you change to the 30 block can you? I thought that would result in a megga low CR.

Ahh I didn't see 25t was a from NZ

That is cheap. What head gasket did you use, RB30E, RB30ET, RB25DET? You done all the work yourself didn't you?