Let's see some catch can setups

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John Brennan
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Re: Let's see some catch can setups

Post by John Brennan » Wed Jun 11, 2014 1:16 pm

Once again, for what I understand are server-balancing reasons, my response preceeds your post-- see last page...
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Re: Let's see some catch can setups

Post by Ghost » Wed Jun 11, 2014 1:17 pm

John, you DO want to introduce fresh filtered air to replace the blowby. The vacuum is not strong enough to remove all of it and it condenses right into the oil. Think of it as opening a window in your house to air it out (OK, maybe not a good comparison for your neck of the woods in the summer, lol :) ).
'85 XR4Ti: 8.8+T56 swap, AEM standalone, HY35 on a full rebuild... What's the bluebook on these cars again?
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Re: Let's see some catch can setups

Post by Ghost » Wed Jun 11, 2014 1:20 pm

[Turns on Borat voice] Very nice! me likey! :)

My biggest issue right now is finding room for the can (damn engine bay is getting crowded) and finding a large enough bore check valve. I'll work on it this week and post pics.
'85 XR4Ti: 8.8+T56 swap, AEM standalone, HY35 on a full rebuild... What's the bluebook on these cars again?
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Re: Let's see some catch can setups

Post by GPz11 » Wed Jun 11, 2014 2:15 pm

DAReese,

Yes, please post a picture of your set up. I'm not following how you have it connected up.

My set up is like Stingers, no PCV valve, just a hose going from where the PCV was into the catch can with large filter at the top. I also have a small hose from my Kevko valve cover into the larger hose.

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Re: Let's see some catch can setups

Post by Ghost » Wed Jun 11, 2014 5:14 pm

Lol, I think the forum servers are trying to confuse us.
So to clear things up, here's how the stock system is designed to work:

Off boost/under vacuum:
- Throttle is partially closed. Lower fitting under the intake supplies vacuum to the hose which connects to the PCV valve and opens the valve, which then draws vacuum on the crankcase. The hose from the turbo inlet supplies fresh air to the can on top of the valve cover, which causes it to flow DOWN from the valve cover, to the lower block (which is now under slight vacuum), to the can on the drivers side block, to the bottom of the PCV, which then goes to the fitting under the intake to be burned. Under these conditions the system works fine.

Under boost:
- Throttle is open, high pressure air from the fitting on the bottom of the intake forces the PCV valve closed. This pressure is greater than the pressure from the blowby gases coming from the hose and can on the drivers side of the block, so the PCV remains closed. All blowby gases are forced UP through the crankcase into the valve cover area and are then vented through the can/separator on top of the valve cover and then fed into the turbo inlet to be burned.

Problems:
1. The stock PCV valve sucks at it's job. It does not do an adequate job of closing under boost and tends to leak boost into the crankcase, which causes an even greater volume of air to be vented from the top of the motor. This is where the brake booster valve trick helps, at least it prevents the intake pressure from entering the crankcase. This is the partial solution to the oil dipstick launching itself out of the tube.
2. The little can on top of the valve cover is not even close to being large enough to separate the oil from the air, even at stock boost levels. This is why we end up with the intake system (intake, intercooler and all related stuff past the turbo) being covered by oil. It is also in a hot area which doesn't help oil condense on the sides/packing and drip down.
3. The hose going from the VC can to the turbo inlet is too small to effectively vent the pressure. This is why a high boost car will blow the can right out of the grommet on the VC (my problem). The other issue is that the air going through there is going at a fairly high speed and high temperature so the oil never has a chance to drop out of it's aerosol state. This is also why a proper catch can with large hoses will help.
4. Gases going up through the oil drain holes in the head/block are not a good thing. At some point they will impede oil flow back down to the block. I suspect the only reason we don't see the issue is because we're not under boost long enough to starve the bottom of the motor.

Stingers solution works because it gives the engine large enough hoses for the gases to slow down and cool off, allowing the catch can to finish the job. It's also a very simple setup. The reasons I don't like it:
- Venting to atmosphere - sorry, I'm not putting up with nasty oil smell at every stop light "because race car so eeees OK"
- Emissions nazis will definitely bitch about it.
- No provision for flushing the blowby gases out of the crankcase, only provision for letting out the excess gases.

Solutions:

Simple way:
A good catch can hooked up to the valve cover with a large hose (like 3/4" ID) while leaving the drivers side of the PCV system alone, except to put in a better check valve in place of the stock PCV valve. This should work OK, except we still have the blowby gases going the wrong way through the engine and impeding oil flow.

"Because race car eeees cool dude!" way: see Stingers setup. Has no place on a street car IMO.

Pain In The A$$ way:
- Larger separator can on the VC with a large diameter hose to the intake before the turbo inlet
- Crankcase hose on drivers side of the motor to a big catch can, leaving the stock separator can alone. Already uses a large diameter hose
- Small(ish) hose with a one way/check valve going from the big catch can to the intake after the throttle body to provide vacuum to the big catch can when off boost
- Large diameter hose going from the big catch can to the intake inlet, with a check valve only allowing flow from the can to the inlet. This is mainly to allow the vacuum line to draw air through the can, crankcase and the VC can/hose.
This is basically a duplication of the factory setup with much larger components which can handle the volume of gases involved and do a decent job of separating the oil mist out of the air.


I'm trying to figure where to place everything for the PITA way personally. But then again, I'm stubborn and anal retentive like that.
'85 XR4Ti: 8.8+T56 swap, AEM standalone, HY35 on a full rebuild... What's the bluebook on these cars again?
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Re: Let's see some catch can setups

Post by GPz11 » Wed Jun 11, 2014 6:28 pm

Fwiw: my current breather is down by the ac compressor. I guess it would be where the stock overflow bottle would be.

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Re: Let's see some catch can setups

Post by GPz11 » Fri Jun 13, 2014 12:26 pm

Well, I've been chatting with Stinger a bit about this. What he said is to remove the filter at the top of the catch can, somehow attach a hose to where the filter went and run that hose into the turbo inlet after the air filter / vam.

So I got the filter off last night and brought it into work today. I was able to cobble together some bits to go from the pipe on top of the catch can to a 1" hose to go to the turbo piping. I'll disconnect the Bosch recirc valve from the piping and put the hose from the catch can to it.

I'll leave the Bosch valve connected but it will become a blow off valve for a little while till I can get a dual piston blow off valve to replace it.

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Re: Let's see some catch can setups

Post by GPz11 » Fri Jun 13, 2014 6:52 pm

Well, that was a quick test. The Bosch valve leaks too much air and the car won't run with it open. I'll have to get a dual piston bov ordered up.

Well, the car ran with some duct tape over the end of the valve. :mrgreen:

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Re: Let's see some catch can setups

Post by Ghost » Sat Jun 14, 2014 11:07 am

Finally got started on this :)

You can see all the pics in my "Catch can" photobucket album here: http://s27.photobucket.com/user/jacekp/ ... t=2&page=1

Yours truly cutting out the various pieces on the bandsaw:
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All the pieces cut out and ready for welding & threading:
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Getting there. Threading 1/2" NPT is a PITA:

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Partially assembled:
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Filling the separation chamber with some wadding:
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And now it's closed up and ready for final welding. I also had to close up the end of the inlet tube: :
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'85 XR4Ti: 8.8+T56 swap, AEM standalone, HY35 on a full rebuild... What's the bluebook on these cars again?
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Re: Let's see some catch can setups

Post by Ghost » Sat Jun 14, 2014 11:12 am

Top welded on:
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View from the bottom of the can:
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The can all welded up:
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Added the 3/4" inlet "whistle" (vacuum source for catch can outlet) to the intake:
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Now all I have left is to make the mounting bracket, then bolt up and plumb the whole mess. I'll be mounting it on the drivers side under the frame rail. Back to the garage to do more work!
'85 XR4Ti: 8.8+T56 swap, AEM standalone, HY35 on a full rebuild... What's the bluebook on these cars again?
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Re: Let's see some catch can setups

Post by In XS 7 » Sat Jun 14, 2014 11:13 pm

WOW!!! Looks so great! :cheers
Miguel.
89 XR4Ti Monique; Waking up a real "Night/Mare-Coor".
T5, NPR IC, PIMP ECU, Walbro 255, Dual piston BOV, Manual BC, 3" exhaust, One piece Aluminum drive-shaft, mc2 LSD, Boport 1.5 cam, Ported and polish head, big valves, 80# injectors, Bob's log, (soon HY35).

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Re: Let's see some catch can setups

Post by Ghost » Sun Jun 15, 2014 12:12 am

All done and plumbed in. Car idles well but it does pull in some extra air from the turbo inlet (I still need to find a large enough check valve for 3/4" line, looks like an air pump check valve from a 1990 Corvette will fit the bill, just have to order it). I can't drive the car until I finish wiring in the E85 sensor.

Some pics of the finished product and plumbing. Ignore the straight brass nipple, I had to rethink that since the outlet hose wouldn't bend without collapsing.

Mounting bracket:
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Hoses (center is the inlet from the crankcase can, small fitting goes to check valve/upper intake, second large fitting goes to turbo inlet):
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Proper fittings in their final position:
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Can mounted on the drivers side rail and plumbed:
Image Image

Image Image

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'85 XR4Ti: 8.8+T56 swap, AEM standalone, HY35 on a full rebuild... What's the bluebook on these cars again?
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Re: Let's see some catch can setups

Post by In XS 7 » Sun Jun 15, 2014 12:22 am

:headbang Awesome! Very nice job. :cheers
Miguel.
89 XR4Ti Monique; Waking up a real "Night/Mare-Coor".
T5, NPR IC, PIMP ECU, Walbro 255, Dual piston BOV, Manual BC, 3" exhaust, One piece Aluminum drive-shaft, mc2 LSD, Boport 1.5 cam, Ported and polish head, big valves, 80# injectors, Bob's log, (soon HY35).

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Re: Let's see some catch can setups

Post by DAReese » Mon Jun 16, 2014 5:20 pm

David Reese

88 XR4Ti - mono white T5, someday to be bi wing
89 Scorpio - waiting on some parts before it hits the road again
88 XR4Ti - mono red C3, parts car
used to own 86 dark blue traded in on a min van, what was I thinking?

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Re: Let's see some catch can setups

Post by Ghost » Tue Jun 17, 2014 12:31 pm

Looks good, but are you venting both the valve cover and the crankcase into the catch can? How are you venting the catch can itself?

Update on mine: drove around yesterday, works beautifully. No more oil out of the top can and no oil smells even at 25 PSI :) What's interesting is that I can feel a little bit of vacuum on inlet to the valve cover can even without the check valve in the large vent hose going to the turbo inlet. Might not need a check valve on that line after all.
'85 XR4Ti: 8.8+T56 swap, AEM standalone, HY35 on a full rebuild... What's the bluebook on these cars again?
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"All cruelty springs from weakness" - Seneca

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