- Thread starter
- #61
Yes Rick, this is right, meaning PCV vacuum present under boost. See supra picture above.
SJ
PCV 101 for Forced Induction 80's
- Thread starter SUMOTOY
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Yes Rick, this is right, meaning PCV vacuum present under boost. See supra picture above.
SJ
In the Supra picture above that line is the one without the PCV valve in it. At least according to TIS.
- Thread starter
- #63
Makes sense to me, a 3 way pcv with 2 ports, that's the way the audi turbos work as well. 1) When manifold vacuum is high enough, the PCV valve is open and the crankcase feed is directly into the intake manifold. 2) When the vacuum is low the pcv valve drops, and vacuum feed for PCV goes to the inlet side of the turbo. 3) When there is turbo boost, the pcv valve is forced closed and PCV feed vacuum under boost is pre turbo.
So, in a turbo boosted toyota from the factory, PCV is present under boost. If we leave the TRD setup to a stock normally aspirated application, PCV is not present under boost.
SJ
I'm not sure about a three way, but according to the FSM for the Supra it is set up exactly as Romer's SC truck.
one hose with a PCV valve that goes to the intake chamber
And one hose that is open that goes to a spot pre throttle plate and pre compressor.
This configuration isn't as effective as what you did for evacuating the gases but does reduce the amount that passes through the compressor.
one hose with a PCV valve that goes to the intake chamber
And one hose that is open that goes to a spot pre throttle plate and pre compressor.
This configuration isn't as effective as what you did for evacuating the gases but does reduce the amount that passes through the compressor.
- Thread starter
- #65
Not like Romers SC truck, he has no vacuum feed for PCV under boost, the supra does. If he moves the feed to the brake booster line, he will have a vacuum feed for PCV under boost exactly as the supra does.
I see no concerns regarding PCV routing thru a compressor spinning at a 10th the speed of what a turbo spins at.
SJ
I realize he has no vacuum feed under boost but that's not needed. The pressure in the block will force the gases out the unrestricted line to the front of the throttle body. It's not as efficient as what you did but it is how Toyota designs their systems. I looked again tonight at the 93 Supra manual to confirm this.
The problem that I see is that the PCV valve will leak boost into the engine. It's not 100% closed when closed. Toyota only specs the PCV valve to be difficult in allowing air in that direction. So while their setup might adequately vent a NA engine, this leaking effect could overwhelm the ability of that open pipe in venting all the gases.
What you did addresses this quite well. But it also means that all the gases from the PVC system will pass through the compressor.
What might work better is a check valve on that line with the PCV valve. That way you don't get the leak from boost but still manage to limit the amount of blow by gases from entering the compressor by venting idle gases to the intake directly.
The contaminants from the blow by gases might not mean much to a SC but they can raise hell with a Turbo. We've all seen what the inside of a throttle body looks like and it's not pretty.
I'm on the road right now but can post the schematic from the Supra when I get home if you like.
For The Record, I would NOT want that crap going through the compressor there is tons and tons of filthy fluid that goes through and it will eventually make everything extremely messy. There has gotta be a better way to get the desired effect of Sumo's "invention" but without the undesired effects. JMHO.
- Thread starter
- #68
TC and LT
I chuckle a bit reading this. The supra sucks PCV thru a compressor spinning at 130k rpm. I don't know of a turbo car that doesn't move PCV thru the compressor. Wreak hell with the turbo? You must be kidding!? Aud, saab, volvo, MB, they all use PCV thru compressors under boost, all of them.
There is no reason PCV can't go thru a compressor, it does all the time. I guess I'm not sure I understand the concern. If you pull hoses off any audi turbo they are a bit wet from PCV. Rick, I got one sitting in my driveway with 150k on it, and the turbo has no freeplay, and the PCV goes to the pre compressor. This is the biggest misconception to PCV, it doesn't do a darn thing other than reduce the amount of oxygen in the combustion charge.
IF you are going for the pinnacle of HP, you put in a crankcase vent tank. BTDT. I think it's a waste on a street production engine.
Something to think about. IN the stock truck, it's obvious that the line going to the Tbody isn't enough, or there wouldn't be another one. Now you want to plug the second line under high boost high rpm? I don't, and neither does the supra turbo.
I believe this is a good mod, and supported by the toyota boosted engine PCV routing.
YOMV
SJ
I chuckle a bit reading this. The supra sucks PCV thru a compressor spinning at 130k rpm. I don't know of a turbo car that doesn't move PCV thru the compressor. Wreak hell with the turbo? You must be kidding!? Aud, saab, volvo, MB, they all use PCV thru compressors under boost, all of them.
There is no reason PCV can't go thru a compressor, it does all the time. I guess I'm not sure I understand the concern. If you pull hoses off any audi turbo they are a bit wet from PCV. Rick, I got one sitting in my driveway with 150k on it, and the turbo has no freeplay, and the PCV goes to the pre compressor. This is the biggest misconception to PCV, it doesn't do a darn thing other than reduce the amount of oxygen in the combustion charge.
IF you are going for the pinnacle of HP, you put in a crankcase vent tank. BTDT. I think it's a waste on a street production engine.
Something to think about. IN the stock truck, it's obvious that the line going to the Tbody isn't enough, or there wouldn't be another one. Now you want to plug the second line under high boost high rpm? I don't, and neither does the supra turbo.
I believe this is a good mod, and supported by the toyota boosted engine PCV routing.
YOMV
SJ
Chuckle all you want, tell you what, I'll send you all the awful crap that comes out of my PCV catch can and you pour it into your compressor if you are so sure of yourself. Deal?
- Thread starter
- #70
When I read 'crap in the intake', sorry but I'd rather my compressor sent that crap downstream to get burnt off, than put it back into the crankcase and sand down the bearings.
Sure of myself? TC, turbo PCV operates this way in every single turbo application from porsche to supra I've ever seen, it's an EPA mandate that's tough to work around without doing it that way. I've got dozens of turbo cars with 300k on them that use PCV thru the compressor.
I'm sure when I read posts like the above, there is a basic misunderstanding of the benefits of proper PCV and it's routing. I also think that if someone wants to put a catch can on their machine, that's fine. IME, chances are something else will cause the motor or compressor to fail first anyhow. Put a K&N filter in the airbox for example. The reason for a catch can is better air in the combustion, not catching any material. In fact, most catch cans dump that crap back into the crankcase on shutdown.
I work on turbo cars daily, and drive a SC truck, and understand the benefits of vacuum feed of PCV under boost. So posted. When I read PCV "can raise hell with a turbo" I'm really sure I can be allowed to laugh out loud. At the thought mind you, not at the person saying it. They just aren't familiar with how PCV works.
Scott Justusson
FZJ80 Supercharged and Sumotoy PCV mod
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Sumo, I have to disagree with you here. My setup catches the oil that would normally be sent into the intake. i know it is not 100% but this does effectivly reduce the oil vapor thay is going through the S/C which is why I did it. No dumping back into the crancase.
See example here;
Sumo you are perhaps the most irritating, insulting and smug person ever posting on Mud ... STOP labeling these little "misunderstandings" on people ... they are NOT misunderstandings I know exactly what we're talking about ... I do not care what Audi does, I do not care what you do, I do not care that the EPA wants me to put that crap back through the system, ALL I care about concerns the FACT that I drain almost .5 liters of filthy fluid from my catch cans at each and every oil change and then put that into my old oil which is then returned in really enviro friendly ways to the local collection site. It is absolutely absurd to think that all that crap is cycled back through the crankcase, absolutely absurd, YOU are misunderstanding the concept of catch cans if you indeed think that. There is nothing you can say to sway me; you think that you have come up with some superior way to route the routing of the PCV system, then in an insulting way when another member simply states that you are adding alotta crap to the compressor, which is indeed accurate, you go back to the fact that the stock setup on all these makes and models does the same thing, so have you actually improved anything at all, NO! So, again, stop all your beating around bushes here, are you or are you not willing to put the stuff I drain off of my catch cans through your compressor, no this or that, a simple "yes" or "no" is ALL I'm looking for here, if you are so sure of yourself you should not have had any problems with that.
I addressed this specific point in an earlier post in this thread.
I asked my TRD friend a point blank question about venting throught the rotor pack and he stated that it was NOT an issue AT ALL.
Still better much better, if given a good choice, to avoid all that, I never stated it was harmful to the supercharger just that it would get "extremely messy eventually" this included in my case the complete intake tract from turbo to intercooler to intake plenums and absolutely all the hoses there. Further, I never even stated it was "harmful" to the turbo, again, just that it would get extremely messy eventually, which it did. As I've made a metnion of in other threads it took a solvent tank soaking to get the crap that accumlated over time outta my intake. Now, the thing is sparkling clean after another 10K miles from my catch can contraption install. I think Sumo confused my statements with someone else's (no harm, no foul on that one by the way), my main point is simply that my catch cans catch alotta filthy fluid that does NOT return to the crankcase and that catching that crap is inherently better than force feeding it through the system, especially with the turbo there. The argument here isn't even in how PCV gasses treat the supercharger, its that if yer gonna "reinvent" the wheel at least make the thing better! Additionally the argument is if yer gonna reinvent something and show it for improving other members' rides, don't be difficult about asking alotta subsequent questions, teaching with patience and with personality, and in general helping good folks understand these things. The whole approach about "this is what i worked out" and then telling people they have really remedial understandings about this or that is downright insulting and irritating. I think that we need an "Interacting With Others 101" thread somewhere!
- Thread starter
- #75
TC
I look at the simplest of mods on this list, and think you must be kidding! LEGAL catch cans have to return oil to the sump or burn it. You can put a catch can that you empty (I've used a tube into a oil bottle at the track before in a pinch). I'm intrigued by an argument that it's doing something about particulate. I also would bet that if you put a perfectly cleaned intake tract on the dyno, you couldn't isolate the 'crap', at the very most you could isolate the lack of oil vapor in the combustion chamber making combustion more efficient.
What you have in your catch can has already *been* thru my motor and every other closed loop PCV truck on this list. More in fact, if anyone uses cheap dyno oil.
If it makes you feel better, please do it. But understand clearly that the majority of folks do it for better combustion, not for catching "crap", that's the function of the oil filter. Add a second oil filter, audi did in the early 80's on the turbos, but it was to catch any coking from a non water cooled turbo, not for PCV, it ran pre compressor back then.
I also believe that the mod I used avoids the common PCV problem that a port (on the 80 closest to #1 cylinder) in the manifold tends to unevenly distribute oil vapor into the cylinders. I look at hundreds of cars a year, that have turbo PCV routed thru compressors running 10 times the speed of the SC.
I've also heard stories that wet oil reduces the efficiency of intercoolers after turbos too. On the dyno, it's not significant enough to isolate or measure, in my experience.
Sorry I guess I upset you. Maybe it's defining oil vapors as crap that has me confused.
SJ
- Thread starter
- #76
I might even argue a light coating of oil would be beneficial. I hope some folks read what you wrote Dan. Eaton and Magnuson don't see a problem with it either.
SJ
Sumo, look man, i sway from thinking that you do these things on purpose to just thinking that you are incredibly innocently ignorant (I'm trying to make that sound sincerely sweet) about your web persona or personality. In any event, First ... I do not understand your first sentence from the above quote any at all, Second ... "crap" is crap, do you have to stick yer finger in it and taste test and all that to realize? Where did we start saying "particulate" and how the hell does the oil filter filter out the "crap" that goes into the intake, how the hell would adding audis' second oil filter that you made a mention of filter out the "crap" that goes into the intake, and when the hell did I start talking about doing dyno runs pre and post catch can install ???!!!??? Holy Moly Man, all I'm saying is that the "crap" / "stuff" / "condensed oil vapor" plus "condensed water vapor" plus "other engine output" plus whatever else that goes through the tract of our intake systems can indeed be avoided and that causes more cleanliness of our intake systems. I never stated that such "crap" harmed anything just that it typically make a mess "eventaully". Again, in any event, I'm really happy I have catch cans (whether they are legal puleasse I could care less - I collect all the assorted "crap" out of them and dispose of it legally while really reducing whatever "emissions" would have been produced by combusting that "crap" through our engines) that catch the "crap" that goes through the intake. THAT'S ALL MAN!!!
You know though this thing's a blessing cause now we can all agree that this is one "CRAPPY THREAD" !!!
Ohh, I've gotta buy your beer one of these days and get to know the man behind the myth! I do appreciate the apology for any upset, that was cool!
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I wouldn't!!!
If it were perfectly pure oil perhaps but this stuff is sorta more like, well, "crap" !!! (In my best fat bastard accent! )
enough with this BS already! You want respect then start giving some.
- Thread starter
- #80
Guys:
Address post 1. I am no expert. I can certainly give as much information/experience in turbo PCV applications as anyone here. We have something like what 10 turbo 80's on this list, maybe half again as many SC's. Call it 30 force inducted motors. I see more than that in a single month.
Bragging? Hardly. But I'm intimately familiar with how force induction PCV works, and know when opinions are eclipsing reality. PCV has been mandated since 1968, and I can't remember the last time I saw a turbo PCV line that wasn't pre turbo causing PCV vacuum under boost.
I've seen posts and forums about catch cans, turbo blade gunk, clogged intercoolers, lower HP. Don't see it doing a thing on the dyno. On an all out race car, I see and have built catch cans to make the combustion cleaner (as in the chamber, more air, less oil vapor), which allows more boost, more advance at the limit of a given motor. On the audis, that's over 26psi. At 15psi or under I don't see the need, at 8psi, it makes no sense to me.
I solved an issue that TRD didn't care/want/bother to address. AND Dan confirmed no harm/no foul from his TRD contacts on what I did. Don't let it upset you, you don't have to do it. I put up the issue, problem and solution as I saw it. Doesn't really matter to me if you choose to do it or not. It confirmed my suspicion on the seals, and solved the oil smell problem I was trying to address. Hope it helps someone (else?)
Want less stuff in a catch can, or going thru the crankcase? Change your oil more often with a good synthetic.
Want PCV vacuum under boost, do the 5 minute mod I described in post 1.
The rest is just good
I hope.
SJ
