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Crankcase evac system


TiredBirds

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Anybody run a crankcase evaluation system? I run them on my drag cars, just wondering if there is any benefit to running them on these cars. I can't see where it would hurt and it would keep blow-bye from going into the combustion chamber. Car is a 305 powered 88 Firebird...if that matters

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3 hours ago, TiredBirds said:

Anybody run a crankcase evaluation system? I run them on my drag cars, just wondering if there is any benefit to running them on these cars. I can't see where it would hurt and it would keep blow-bye from going into the combustion chamber. Car is a 305 powered 88 Firebird...if that matters

Evacuation* ?? 

We have one. They come stock on the BMW e30. Hose runs from valve cover to intake manifold (vacuum). 

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I know, a few years back, SCCA banned the system that plumbs into the exhaust collectors. Guess they were afraid of blowing oil onto the track? The other system I've seen is actually a vacuum pump, drawing a vacuum on the crankcase.  Either way, it avoids sucking crankcase vapors into the intake tract as an OEM system does. I'm not smart enough to know if any of these are better than just a catchcan in our applications. :)

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3 hours ago, karman1970 said:

Like a crankcase vacuum pump?

 

39 minutes ago, enginerd said:

Evacuation* ?? 

We have one. They come stock on the BMW e30. Hose runs from valve cover to intake manifold (vacuum). 

 

26 minutes ago, tommytipover said:

I know, a few years back, SCCA banned the system that plumbs into the exhaust collectors. Guess they were afraid of blowing oil onto the track? The other system I've seen is actually a vacuum pump, drawing a vacuum on the crankcase.  Either way, it avoids sucking crankcase vapors into the intake tract as an OEM system does. I'm not smart enough to know if any of these are better than just a catchcan in our applications. :)

Talking about one of these, dumps into the exhaust, not sure why it would be a concern about "oil on the track" 

WP_20150417_001.jpg

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4 minutes ago, TiredBirds said:

Talking about one of these, dumps into the exhaust, not sure why it would be a concern about "oil on the track"

 

I had never seen one (grew up road racing with simple catch cans) until SCCA banned it.  Seems like a simple, yet elegant system and if the separators are working properly, only gasses go to the exhaust, right?

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9 minutes ago, Team Infiniti said:

 A factory PCV system connecting   Crank case  to intake manifold does nothing under wide open throttle 

 

Owner of the machine shop I use reports very measurable difference in power with and without PCV system on LS engines. He didn't believe it either so tested multiple times. YMMV.

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16 minutes ago, Team Infiniti said:

I could see some good from a exhaust based crankcase evac system, but to the intake, it's hard to wrap my head around as there is no intake vacuum @WOT

 

 Have thought about doing but  never got around to it 

pressure builds up in the cranckcase under load and high rpms. Drag racers run them all the time (from valve cover or valley pan) into the collectors. The only way oil is going to come out is if you break something major, and the well... it's going to get on the track regardless. 

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17 minutes ago, Team Infiniti said:

I could see some good from a exhaust based crankcase evac system, but to the intake, it's hard to wrap my head around as there is no intake vacuum @WOT

 

 Have thought about doing but  never got around to it 

 

Wait... what?  Maybe I dont understand, but the intake should be under negative pressure or vacuum to suck the air in, no?  Also, the exhaust is under positive pressure to push the air out.  Wouldnt both be under lower pressure compared the whats in the crankcase in either case?

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3 minutes ago, thewheelerZ said:

 

Wait... what?  Maybe I dont understand, but the intake should be under negative pressure or vacuum to suck the air in, no?  Also, the exhaust is under positive pressure to push the air out.  Wouldnt both be under lower pressure compared the whats in the crankcase in either case?

the tube in the header has a valve in it and it is angled back...the exhaust draws the pressure out of the crankcase. Your engine is a sealed unit... under load and rpms pressure builds up and causes restrictions, it can also cause you to push oil out of your breathers and any spot a gasket isn't sealed well. 

evacsysteminstallsy2.jpg

Edited by TiredBirds
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1 minute ago, thewheelerZ said:

 

Wait... what?  Maybe I dont understand, but the intake should be under negative pressure or vacuum to suck the air in, no?  Also, the exhaust is under positive pressure to push the air out.  Wouldnt both be under lower pressure compared the whats in the crankcase in either case?

With the throttle blade all the way open, intake and atmosphere are of equal pressure (assuming adequately sized throttle body/carb) factory systems are not going to do anything.

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25 minutes ago, TiredBirds said:

.the exhaust draws the pressure out of the crankcase.

With the angle described +check valve, exhaust can create a low pressure effect making a PCV work @ WOT

 

This racing stuff is hard enough, why are we talking about free HP here where anyone can see?

Edited by Team Infiniti
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17 minutes ago, Team Infiniti said:

With the angle described +check valve, exhaust can create a low pressure effect making a PCV work @ WOT

 

Why are we talking about free HP here?

Thanks guys!! This must be why I’m down 15hp compared to the RVA e30. I’ll install one of these this winter!

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We mount our cans as high as possible to keep any dips in the vent lines. I mounted a catch can in my Mazda RX-7 really low once because i was struggling to find a mounting point. It didn't work as well as mounting it high up. bing new to Hondas most of the guys seam to be running one vent line form the block and 2 form the valve cover.

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3 hours ago, Team Infiniti said:

With the angle described +check valve, exhaust can create a low pressure effect making a PCV work @ WOT

 

This racing stuff is hard enough, why are we talking about free HP here where anyone can see?

SOOO is it A. Legal and B. Is it legal... I have a kit hanging on my garage wall and the black car is ready to be assembled. 

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This evac system is very useful in reducing the Crank case vacuum.  You will need a plate over your valve train to keep the oil splatter from the valve train under control and not sucked out into your header collector. If you see puffs of blue smoke out the exhaust it is a sign of oil splatter getting through your system. Adding splatter plates is easy enough to control ingestion in to the exhaust. Drag racer used it for decades and have no issues. 

 

I would still clear it with TAC.

Edited by Cam Benty
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1 hour ago, TiredBirds said:

SOOO is it A. Legal and B. Is it legal... I have a kit hanging on my garage wall and the black car is ready to be assembled. 

 Doesn't say anything prohibiting...

 
9.11.1.Non-stock engine, transmission/transaxle, and differential
breathers shall be equipped with catch tanks.
9.11.1.1.Minimum catch tank capacity shall be one U.S. quart
9.11.1.2.Catch tanks shall vent outside the driver’s
compartment.
 
But,you introduce a fail point if the new evac pipe or weld or header break.
Edited by Team Infiniti
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I have a GZ Motorsports vacuum pump (the whole belt driven system) for sale, if you're interested.  It was used on a turbocharged FA20 and made a big difference.  I have no use for it now.  It is in excellent condition and I will sell it cheap.

 

It's a GZ Motorsports VP102.  https://www.gzmotorsports.com/CPVK102-vacuum-pump-kit.html

 

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If you put the exhaust pcv evacuation system in just remember to carefully pick your location for the tap into the engine....some guys use the vacuum pumps to draw oil from heads back into the pan. Hook that port to the exhaust and there will be no more mosquitoes at the track. 

 

I would probably do an air oil separator can first, and have the top of that drawn by the exhaust evacuation. Drain the bottom to the oil pan or have a big volume you can drain each stint\race.

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12 hours ago, Team Infiniti said:

 Doesn't say anything prohibiting...

 
9.11.1.Non-stock engine, transmission/transaxle, and differential
breathers shall be equipped with catch tanks.
9.11.1.1.Minimum catch tank capacity shall be one U.S. quart
9.11.1.2.Catch tanks shall vent outside the driver’s
compartment.
 
But,you introduce a fail point if the new evac pipe or weld or header break.

We already have a catch can off one breather,  If I break a header I won't be racing. And if you break the header the evac will likely fail as the air will not be passing the tube. 

 

12 hours ago, Cam Benty said:

This evac system is very useful in reducing the Crank case vacuum.  You will need a plate over your valve train to keep the oil splatter from the valve train under control and not sucked out into your header collector. If you see puffs of blue smoke out the exhaust it is a sign of oil splatter getting through your system. Adding splatter plates is easy enough to control ingestion in to the exhaust. Drag racer used it for decades and have no issues. 

 

I would still clear it with TAC.

We are using factory valve cover with the factory baffles...should not be an issue. 

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