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+--- Forum: Technical Discussion (https://forum.mmsports.org/forumdisplay.php?fid=11)
+--- Thread: Intake/blowby (/showthread.php?tid=1886)
Intake/blowby - Andy - 03-15-2005
I pulled my intake manifold off today. I suspected that my vacuum leak had something to do with the retard shop that messed everything else. So long story short, the plenum gaskets were fouled with blowby. They were wet. And there's little reliefs in the plenum where all this blowby collected. At least I hope it's blowby. When that stuff collects and cools, it kind of looks like a real thin oil right? I'm not burning oil and my plugs are clean. On another note, Extrude Hone is cool. My plenum which was honed was pretty dirty, where as my runners which were honed, was clean as could be. Pretty cool
- .RJ - 03-15-2005
You will get blowby in vtec... run a catch can between the PCV and intake manifold
It doesnt take much oil to make a mess inside there.
- christo - 03-31-2005
What are the adverse effects of excessive blowby?
- white_2kgt - 03-31-2005
christo Wrote:What are the adverse effects of excessive blowby?
Detonation and a hole in your piston.
You can also plumb an oil/air seperator between PCV and intake. About $20 and some rubber hose.
--chad
- christo - 03-31-2005
I've got some breather filters lying around, i'll slap one of those on.
- .RJ - 03-31-2005
Do not do that
- white_2kgt - 04-01-2005
christo Wrote:I've got some breather filters lying around, i'll slap one of those on.
yea, not a good idea.
--chad
- christo - 04-01-2005
worse than blowby?
- white_2kgt - 04-01-2005
christo Wrote:worse than blowby?
allowing unmeter air into or out of an engine? yea, that's pretty bad. Engine was designed for a little blow by, not leaks.
--chad
- Mike - 04-01-2005
you say unmetered air, but how is the air in the intake tube metered? edumacate me please!
- Andy - 04-01-2005
Ford's have MAF sensors, so chad's air is metered. Honda's uses speed density so as long as Chris plugs the intake manifold, he shouldn't have a problem using a breather filter on his valve cover. I've seen people do but it can leave a mess. Is there another solution to venting blowby other than a catchcan. My car hasn't seen track duty so I feel a little ricey having a one in the engine bay.
- .RJ - 04-01-2005
jackstands Wrote:so as long as Chris plugs the intake manifold, he shouldn't have a problem using a breather filter on his valve cover
No, no, no, no.....
That is not how it works. On a honda b/d/h-series motor.... air goes from the block, through the pcv, to the manifold. And from the intake tube *into* the valve cover. You cant just start pulling hoses, adding breathers and plugging shit up. The only thing I would do is put a catch can between the pcv and the manifold.
- CaptainHenreh - 04-02-2005
jackstands Wrote:Ford's have MAF sensors, so chad's air is metered. Honda's uses speed density so as long as Chris plugs the intake manifold, he shouldn't have a problem using a breather filter on his valve cover. I've seen people do but it can leave a mess. Is there another solution to venting blowby other than a catchcan. My car hasn't seen track duty so I feel a little ricey having a one in the engine bay.
I'm pretty sure the speed-density tables are based on some kind of intake diameter. I always wondered this.
The computer takes a temperature reading and a compound reading. Now, it can't figure out how much air is going into the engine from that, it can only tell how much is going in per cube. So there has to be a third variable, the maximum number of cubes the engine can recieve. This would have to be the diameter of the intake tract, at some point. The best point, I would think, would be the intake valve, but I don't know for sure. I doubt this is where the signal line to the MAP sensor originates (it would be impossible) so it must be somewhere in the intake manifold.
If the "intake leak" were somewhere after the point that the computer determines the maximum flow rate (am I even making sense?) than yes, that flow is unmetered, because it increases the maximum amout of air that can go into the engine without telling the computer first.
So, yeah. It's late.
- Andy - 04-04-2005
The MAP sensor measures absolute or total pressure in the manifold. The computer knows the volume of the manifold, so it can determine density using the Intake Temp sensor to compensate for temp variances. So far as running a filter at the pcv, I would think the IAT and MAP would pick up the temporary increases in temp and pressure from the PCV system, so it would be able to compensate if those pulses of blowby aren't there either. Having said all this, I would say running a catchcan might be a better idea but I wouldn't think running a filter would negative affect your car and it would save you the hassle of running additional crap for the catchcan.
- .RJ - 04-04-2005
jackstands Wrote:I wouldn't think running a filter would negative affect your car
But it does.
- Andy - 04-04-2005
.RJ Wrote:jackstands Wrote:I wouldn't think running a filter would negative affect your car
But it does.
How so?
- CaptainHenreh - 04-04-2005
jackstands Wrote:.RJ Wrote:jackstands Wrote:I wouldn't think running a filter would negative affect your car
But it does.
How so?
Magic.
- .RJ - 04-04-2005
Wrong.
Voodoo.