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Carrera RSR · Joined: 08 Jan 2010 Posts: 2312 Location: Somerset, UK

I'm interested to learn what improved crankcase breathing is being employed with modified turbo engines, descriptions and pics please
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1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
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GeorgeV · Posted: Tue Nov 05, 2013 8:42 pm Post subject:

Carrera,

If this is what you mean, they put in this big hose to reduce blowby in mine.

G
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1981 932 with mods:
http://www.924board.org/viewtopic.php?t=37921

Grenadiers · Posted: Wed Nov 06, 2013 12:40 am Post subject:

George, is that blue hose connected to something, or to atmosphere? Dave.
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'83 944 Track car.
'88 924S Track car.
'89 944 Turbo
2004 Winnebago Vectra monster RV
2012 Jeep Wrangler
2014 Kia Soul
2001 Ford F350 powerstroke

Carrera RSR · Joined: 08 Jan 2010 Posts: 2312 Location: Somerset, UK

Thanks George. Any additional modifications to the crankcase as well? Where does the cam cover vent head off to? Steve
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1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252

GeorgeV · Posted: Wed Nov 06, 2013 9:50 am Post subject:

The blue hose definitely connects to somewhere, but I don't have the car at the moment so I can't say exactly where. I can post a photo once I've got it again.

I don't think there were any mods to the crankcase, but I'll have to check.

Steve, what is the problem you are trying to fix?
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1981 932 with mods:
http://www.924board.org/viewtopic.php?t=37921

Carrera RSR · Joined: 08 Jan 2010 Posts: 2312 Location: Somerset, UK

Hi, George. I have oil pooling in the piston crowns which is down to blow by caused by positive crankcase pressure. The stock and indeed the Porsche breather update which i already have is inadequate. I know of an update to be applied now but wondered what others with boost and bhp upgrades were running.

Your update emulates the Porsche head breather I have and the improvements Porsche made to the GTS. I now also need to improve the crankcase breathing which will allow the piston rings to reseal and also stop some oil being pushed through the newly refurbed turbo seals.

Have you run your car in anger yet?
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1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252

ideola · Joined: 01 Oct 2004 Posts: 15550 Location: Spring Lake MI

You may need to consider a proper vacuum pump such as the ones by GZ Motorsports. This option has been discussed a couple of times in various threads. Here's a link to their website:
http://www.gzmotorsports.com/vacuum-pumps.html

The shining example I can think of is Bass GT's build, but he was fully dry-sumped, so would've had proper vacuum from the scavenge pump. It might be worth looking up a few of his old threads just for reference, even though I doubt you would want to go dry sump at this point.
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erstwhile owner of just about every 924 variant ever made

Carrera RSR · Joined: 08 Jan 2010 Posts: 2312 Location: Somerset, UK

Thanks Dan. I did read through all (?) his posts a few weeks ago and don't recall anything on breathing, but will look again. Unfortunately Steve's car is no longer. It has been totally broken up by his father. I am picking up the stainless exhaust systems tomorrow afternoon from him. Additionally I missed out on buying the engine block, heads and plenums he had. All the go faster bits are now I believe all sold! If anything is left of use I'll be buying them tomorrow.

I have a plan on the crank case breathing. I'll be commissioning the work over Winter and will see what the outcome is in the Spring. Would still be interested in what is being employed out there. Have you, Dan, done any or have plans to mod your cars for breathing? Any links to threads? I'll redo some search but it really is hard to search this forum.
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1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252

ideola · Joined: 01 Oct 2004 Posts: 15550 Location: Spring Lake MI

Oh no...am I to infer from your comments that bad fortune has befallen Mr. Bassington?

Regarding my own projects, I am running the stock S2 breathing setup on all three of my currently-running turbos (937, 941 and Club Sport). Of course, the Club Sport is down until I have time to replace the head gasket, but when it was running, I did not notice any issues with breathing issues or blowby. The rings sealed exceedingly quickly, and I had virtually zero oil burn from day one. I've only put about 1000 miles on that motor, but I was running it pretty aggressively on the street, at about 12PSI of boost (equivalent to 937 boost level). The 941 I've run as high as 15PSI of boost (after installing the meth injection kit), and no issues whatsoever. I have nearly two full seasons and several thousand miles on that build now.
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erstwhile owner of just about every 924 variant ever made

GeorgeV · Posted: Thu Nov 07, 2013 8:16 am Post subject:

Raceboy · Joined: 01 Mar 2004 Posts: 2327 Location: Estonia, Europe

I will throw in my 2 cents too.

I am running three hoses into one breather tank: one from block, one from head (stock 931 updated piece) and one from the turbo oli drain.
So far absolutely no blowby, tested it with the small filter removed and routed a hose near windshield so I can see if something reaches the oil catch tank.

And it is not possible to achieve actual vacuum or negative pressure in 924 crankcase without special crankshaft oil seals. 911 GT3 Cup cars have negative pressure thanks to special breathing system, high capacity dry sump pump and special oil seals.

I changed the oil catch can location with new exhaust manifold but connections remain the same.

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'83 924 2.6 16v Turbo, 470hp
'67 911 2.4S hotrod
'90 944 S2 Cabriolet
'78 924 Carrera GT replica
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GeorgeV · Posted: Fri Nov 08, 2013 3:35 pm Post subject:

Dutch924-racer · Joined: 23 Jul 2007 Posts: 1081 Location: The Netherlands

Carrera RSR, is there comming light smoke out of your K&N breather filter ?
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937 trackday car
Series 2 engine
951S turbo and intercooler
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Forge recirculation valve + boost controller