Thoughts of venting crank case preasure into exhaust.
10-04-2005, 04:34 PM
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Thoughts of venting crank case preasure into exhaust. Ive been putting a lot of thought into this lately. I have a homemade catch can, and its still a good amount of oil in the intake, and at times I have a "more than acceptable" amount of oil being burned in the motor (back bumper has a visible amount of oil residue). With venting it in the exhaust it will still cause the oil to come out the back, but atleat it wont get there from being burned through the motor. Anyone have any other thoughts on this.
10-04-2005, 04:39 PM
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Its how alot of "old school" motors are done.
fittings from the valve cover to a hose welded to the exhaust... the exhaust pressure is supposed to "suck" the pressure out...
A few friends have explained it to me along time ago, but havent really thought too much about it.
fittings from the valve cover to a hose welded to the exhaust... the exhaust pressure is supposed to "suck" the pressure out...
A few friends have explained it to me along time ago, but havent really thought too much about it.
10-04-2005, 04:52 PM
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I did a search on here and saw where someone did it to theyre LS1, but they didnt vent the preasure into the exhaust untill right before the tips. Id prolly vent it into the y-pipe close to the collector (dont wana weld anything on the collectors).
What ive gathered from searching here, other forums and yahoo. At WOT theres no vac in the intake, so the PCV dosent work too well in that situation. With the exhaust, it will always have vac in the pipes, so it should work a lot better than whats on the car now.
What ive gathered from searching here, other forums and yahoo. At WOT theres no vac in the intake, so the PCV dosent work too well in that situation. With the exhaust, it will always have vac in the pipes, so it should work a lot better than whats on the car now.
10-04-2005, 05:12 PM
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so connecting this to exhaust can it create a vacum in the engine block? if so I believe hp can be gained by this. anybody got info about vacum in block could give you more hp?
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10-04-2005, 05:25 PM
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Huh? Last time I checked, the exhaust is positive pressure not vacuum. You could weld in a ventury and port that for vacuum however...
Are you sure the residue is burned oil, not partially burned fuel/HC? If your bumper is that bad, imagine your plugs.
Are you sure the residue is burned oil, not partially burned fuel/HC? If your bumper is that bad, imagine your plugs.
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10-04-2005, 05:53 PM
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Originally Posted by SSpeedracer
Huh? Last time I checked, the exhaust is positive pressure not vacuum. You could weld in a ventury and port that for vacuum however...
Are you sure the residue is burned oil, not partially burned fuel/HC? If your bumper is that bad, imagine your plugs.
Are you sure the residue is burned oil, not partially burned fuel/HC? If your bumper is that bad, imagine your plugs.
Seems like that would solve the oil getting into the intake problem 100%. It'd seem tho that the vacuum affect would be stronger closer to the engine, like you said at the beginning of the Ypipe (after the cats if they are present).
10-04-2005, 11:48 PM
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Originally Posted by FstBlkz28
Scavanging ... with LT's on the primary that isn't exhausting, the exhaust current in the header collector from the other primary that is exhausting causes a vacuum.
Seems like that would solve the oil getting into the intake problem 100%. It'd seem tho that the vacuum affect would be stronger closer to the engine, like you said at the beginning of the Ypipe (after the cats if they are present).
Seems like that would solve the oil getting into the intake problem 100%. It'd seem tho that the vacuum affect would be stronger closer to the engine, like you said at the beginning of the Ypipe (after the cats if they are present).
The LT's you mention must be amazing
. Nominal pressure inside the primary is below 14.7 psia? Where can I get some? Is there an air pump further downstream that blows the exhaust gasses out the muffler?****, I just sold the camaro for a perpetual motion machine. Who needs internal combustion anymore.
All joking aside, PCV is plumbed to the intake for two reasons: emission, and oil contamination. EPA/CARB dont allow the release of hydrocarbons. A cooling engine could possible suck dirt and crap back through a valve cover breather as the air inside contracts.
10-05-2005, 03:40 AM
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Residue on the rear bumper is more often than not from leaks, not exhaust. I don't understand how if you have your catch can hooked up properly you are still getting oil in the intake?
10-05-2005, 10:56 AM
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Originally Posted by SSpeedracer
Agree that it would solve oil getting into the intake 100%... 'cause nothing is plumbed there anymore.
The LT's you mention must be amazing . Nominal pressure inside the primary is below 14.7 psia? Where can I get some? Is there an air pump further downstream that blows the exhaust gasses out the muffler?
The LT's you mention must be amazing
. Nominal pressure inside the primary is below 14.7 psia? Where can I get some? Is there an air pump further downstream that blows the exhaust gasses out the muffler?Im just stating theory .... I've never stuck a pressure gauge inside my headers, nor do I plan to ... In theory, it'd seem that the exhaust would be able to cause a vacuum. If theres actual data that says it's wrong ... then the theory would be wrong.
Last edited by FstBlkz28; 10-05-2005 at 12:56 PM.
10-05-2005, 11:32 AM
#14
Here's another thought... what if you utilized the factory air pump to suck air from the engine.. hook up the suction side of the pump to one of or both of the valve covers,and have the exit tube jsut routed so that it was dumping under the car. I'm not sure if that would be enough, or if the oil would be a problem for the pump though. I'd bet that you could probably somehow turn that pump on thru the tune so that is it on all the time too, so no additional wiring would be needed. It would be a really neat way to make a totally useless piece of hardware actually serve a god purpose.
Even if the pump didn't last too long ( say 10K or so ) because of this duty or whatever, I'm sure you could pick them up used on here for next to nothing.. most people just throw them away anyway.
Even if the pump didn't last too long ( say 10K or so ) because of this duty or whatever, I'm sure you could pick them up used on here for next to nothing.. most people just throw them away anyway.
10-05-2005, 11:54 AM
#16
What yo do is weld some sort of bung or nipple on your exhaust at an angle. that points downstream of the exhaust. As the exhaust passes by that nipple there will be a vacum on the nipple. Now if you angled the nipple backwards then it would blow exhaust out just like a cutout on the exhaust. This will work. It has been used for years on racecars. Question is will it work too good? I guess one could always put a valve on the tube to adjust the amount of vacum pulled on the crankcase.
10-05-2005, 02:40 PM
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This kit is made by dynatech. If I do go this route, it will be the setup that I use. its 18 bux and I have acess to a welder so install wont be a problem.
10-05-2005, 05:08 PM
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that was my setup with it near the tips. I figured if there was any sort of pressure in the exhaust then it would not be able to use the venturi effect to pull the gasses out of the crankcase. so mounting them as close to the end of the exhaust as possible will let it scavenge a lot better. Drag race cars hook them into the ends of the headers because they do not run any pipe or muffler to restrict air flow.
If you run them at the back you don't need 2 hoses running to the front 1 hose is enough. I ran the hose from the passenger side over to the drivers side using a T fitting then ran it up to the front using a smaller size hose so it was easy to tie to the fuel lines without getting in the way.
I have a bit more details and pics on the website I have been working on for my car in my sig, you can look on there for more info but it is not really a finished site yet
If you run them at the back you don't need 2 hoses running to the front 1 hose is enough. I ran the hose from the passenger side over to the drivers side using a T fitting then ran it up to the front using a smaller size hose so it was easy to tie to the fuel lines without getting in the way.
I have a bit more details and pics on the website I have been working on for my car in my sig, you can look on there for more info but it is not really a finished site yet
10-05-2005, 05:16 PM
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One thing I forgot to mention is I tried it out with a vacuum gauge hooked up to the hose instead of going to the valve cover and took it out for a wide open throttle run with the gauge stuck under the windshield wiper and I saw it get a few inches of vacuum before the gauge moved and I wasn't able to see it. I can't remeber what the exact number was but it was higher than 0 so that means it works.
Experimenting with the angle the fittings are mounted can make a huge difference in how well it works so don't just stick them in and weld them down first thing. Spot weld them in and test them by revving the engine to see what angle works the best. I used a plastic bag full of air on the end of the hose held on by a rubber band. I then messed with the angle then revved the engine and adjusting it to suck the bag empty as quick as possible. It was a quick and easy way to set them properly before welding them solid. After that I ran the hoses and tied it all together nicely and it has been trouble free for a while now.
Experimenting with the angle the fittings are mounted can make a huge difference in how well it works so don't just stick them in and weld them down first thing. Spot weld them in and test them by revving the engine to see what angle works the best. I used a plastic bag full of air on the end of the hose held on by a rubber band. I then messed with the angle then revved the engine and adjusting it to suck the bag empty as quick as possible. It was a quick and easy way to set them properly before welding them solid. After that I ran the hoses and tied it all together nicely and it has been trouble free for a while now.
10-06-2005, 08:43 AM
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As long as the pressure inside the engine is greater than the pressure in the exhaust it will work. In like nascar and stuff they are always at full throttle so it isnt a problem, but on a street engine you might have some problems with exhaust entering your engine at lower rpms. Although the exhaust will suck on the pcv if the pressure is less inside the engine it might try to get inside.
The idea od using the AIR pump to relieve crankcase pressure sounds pretty cool.
The idea od using the AIR pump to relieve crankcase pressure sounds pretty cool.