crank case pressure
#22
Elite Member
Thread Starter
iTrader: (5)
Join Date: Jan 2005
Location: Atlanta
Posts: 7,486
Total Cats: 372
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
I think the exhaust scavenging would be perfect for a track (road course) car where the run through the gears is perpetual. Ideally you'd want a combination of all these "passive" systems to optimize evacuation/release of the pressure/vapor. IMO - First step in the stock system would be to enlarge hoses/passes and remove restrictions (improve flow) like mod the baffles in the vent chambers.
#23
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
Might be worth a try, not too expensive either
http://store.summitracing.com/egnsea...115+4294851516
hrk
http://store.summitracing.com/egnsea...115+4294851516
hrk
#24
Junior Member
Join Date: Feb 2007
Location: 11368 miles from where i would like to be
Posts: 269
Total Cats: 92
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
http://i50.photobucket.com/albums/f3...4/21344ev2.jpg
just an idea for a breather box location. i dont like their plumbing... but the location is nice enough.
vacuum is definitely a good thing for at least two reasons.
fred.
just an idea for a breather box location. i dont like their plumbing... but the location is nice enough.
vacuum is definitely a good thing for at least two reasons.
fred.
#25
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
Honda guys apparently love them some crankcase ventilation...
![](http://a593.ac-images.myspacecdn.com/images01/41/l_028e0d06486e1cc5265738ddbde99408.jpg)
Check out this thread for more inspiration, the photo above has -12AN lines.
http://www.honda-tech.com/zerothread?id=1970101&page=19
![](http://a593.ac-images.myspacecdn.com/images01/41/l_028e0d06486e1cc5265738ddbde99408.jpg)
Check out this thread for more inspiration, the photo above has -12AN lines.
http://www.honda-tech.com/zerothread?id=1970101&page=19
#26
Elite Member
Thread Starter
iTrader: (5)
Join Date: Jan 2005
Location: Atlanta
Posts: 7,486
Total Cats: 372
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
![](https://www.miataturbo.net/images/smilies/werd.gif)
I plan to use the OE vent on the back and then create another behind the intake cam since there's an OE flange cast in the cam cover to shield the new vent hole from oil. I believe it's more critical for the FE to have vents on both sides since the "valley" is closed off from the cam cover (the B engines are open). And the only side to side connection is at the front.
#27
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
Crank vacuum pumps:
http://www.gzmotorsports.com/vacuum-pumps.html
Their **** pics:
http://www.gzmotorsports.com/sample-installations.html
Nothing plug and play for Miatas, but probably their kit for EVOs is the closest in the engine size components choice:
http://www.gzmotorsports.com/4G63T-kit.html
http://www.gzmotorsports.com/vacuum-pumps.html
Their **** pics:
http://www.gzmotorsports.com/sample-installations.html
Nothing plug and play for Miatas, but probably their kit for EVOs is the closest in the engine size components choice:
http://www.gzmotorsports.com/4G63T-kit.html
#28
Elite Member
Thread Starter
iTrader: (5)
Join Date: Jan 2005
Location: Atlanta
Posts: 7,486
Total Cats: 372
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
Decided to tackle the cam cover since the rain put a stop to the boost control testing. The modded factory venting (pic below) worked reasonable for 10psi, but just a few runs near 17psi and I had some cam cover gasket leaks. With the new setup the pcv will return to the stock location and two vents at the rear will go to the can.
I managed to get two 3/8" NPT ports on each cam bank of the cam cover. I was amazed to see just how small the existing vent port at the back of the exhaust side was - about half the size of the actually opening - maybe 3/16". Pics show the difference - white circle highlights the actually interior passage. I used the step drill bits (if you don't have a set they're worth buying) to overbore the existing vent and to enlarge the pilot hole on the intake side. These should provide the venting I'm looking for (like the honda photo) - now on to the catch can. (Go kia power
)
![](http://i158.photobucket.com/albums/t86/m2cupcar/current%20FEmx5t/ventportoldnew.jpg)
![](http://i158.photobucket.com/albums/t86/m2cupcar/current%20FEmx5t/ventportI.jpg)
![](http://i158.photobucket.com/albums/t86/m2cupcar/current%20FEmx5t/ventportsnew.jpg)
current modded: OE ports swapped, better flowing pcv port goes to the can
I managed to get two 3/8" NPT ports on each cam bank of the cam cover. I was amazed to see just how small the existing vent port at the back of the exhaust side was - about half the size of the actually opening - maybe 3/16". Pics show the difference - white circle highlights the actually interior passage. I used the step drill bits (if you don't have a set they're worth buying) to overbore the existing vent and to enlarge the pilot hole on the intake side. These should provide the venting I'm looking for (like the honda photo) - now on to the catch can. (Go kia power
![wink](https://www.miataturbo.net/images/smilies/wink.gif)
![](http://i158.photobucket.com/albums/t86/m2cupcar/current%20FEmx5t/ventportoldnew.jpg)
![](http://i158.photobucket.com/albums/t86/m2cupcar/current%20FEmx5t/ventportI.jpg)
![](http://i158.photobucket.com/albums/t86/m2cupcar/current%20FEmx5t/ventportsnew.jpg)
current modded: OE ports swapped, better flowing pcv port goes to the can
![](http://i158.photobucket.com/albums/t86/m2cupcar/current%20FEmx5t/currentVENTmod.jpg)
#29
Junior Member
Join Date: Feb 2007
Location: 11368 miles from where i would like to be
Posts: 269
Total Cats: 92
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
Wow rob, nice!
Yeah, those are small, i pulled one out of mine years ago, but I'd forgotten completely about that! if you aren't going to and don't mind I'd like to hijack these pics and add them to that thread on mx6.com.
Thats going to work MILES better for sure :-)
Well done.
Fred.
Yeah, those are small, i pulled one out of mine years ago, but I'd forgotten completely about that! if you aren't going to and don't mind I'd like to hijack these pics and add them to that thread on mx6.com.
Thats going to work MILES better for sure :-)
Well done.
Fred.
#32
Elite Member
Thread Starter
iTrader: (5)
Join Date: Jan 2005
Location: Atlanta
Posts: 7,486
Total Cats: 372
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
Exhaust side vent chamber plate is now modded and installed. Dramatically shortened, it still uses one cast fin from the cam cover and an opposing tack welded plate fin, plus the added fin/bend at the end of the plate.
![](http://i158.photobucket.com/albums/t86/m2cupcar/sIMG_2262.jpg)
![](http://i158.photobucket.com/albums/t86/m2cupcar/sIMG_2264.jpg)
![](http://i158.photobucket.com/albums/t86/m2cupcar/sIMG_2262.jpg)
![](http://i158.photobucket.com/albums/t86/m2cupcar/sIMG_2264.jpg)
![](http://i158.photobucket.com/albums/t86/m2cupcar/sIMG_2263.jpg)
#34
Elite Member
Thread Starter
iTrader: (5)
Join Date: Jan 2005
Location: Atlanta
Posts: 7,486
Total Cats: 372
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
Just trying to keep the oil out while maintaining a similar volume for pressure passage. It was less about length and more about getting two of those "fins" in for oil trapping. I think bending down would probably encourage the trapping of oil w/o any benefit of pressure relief. Tin snips did a good job for providing three drain back avenues for oil.
#36
Elite Member
Thread Starter
iTrader: (5)
Join Date: Jan 2005
Location: Atlanta
Posts: 7,486
Total Cats: 372
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
Under boost there is no vacuum. But when you let off the throttle that vacuum is what pulls all the vapor from the crankcase. So boost blows it out via the vent(s) and the vacuum sucks it out via the pcv. Both are beneficial.
#39
Elite Member
Thread Starter
iTrader: (5)
Join Date: Jan 2005
Location: Atlanta
Posts: 7,486
Total Cats: 372
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
I don't think a vacuum pump is necessary. The problem is managing the cc pressure occurring from boost blow-by. The oe vent system was not designed with that intent (obvious since it has a ~3/16" vent passage). So the addition of the two larger ports should manage the "new" pressure fine. This is essentially the same thing done to the honda engine pictured and what comes OE from nissan on the their turbo engines pictured above. I'm only using two 3/8" npt ports because my engine has a valley, separating the intake and exhaust sides. This way pressure from one side doesn't have "travel" to opposite side. In this case, I don't think there's such thing as too big or too much.
#40
Junior Member
Join Date: Feb 2007
Location: 11368 miles from where i would like to be
Posts: 269
Total Cats: 92
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
Rob, if you have a spare head, take a closer look at the middle and two ends, there is plenty of open area between the two that connect them. there can not be a pressure differential there really. i'm not sure how the rb one is laid out inside, but ours has good sized 1.5" x 1.5" channels in three places already. (not sure what i was thinking when i agreed with you about that on the last page, seemed like it was correct anyway :-) )
The other part of the vacuum pump is that it actually increases ring seal in the first place and reduces the blowby from the start. thats why its good. the increased seal A keeps things cleaner, B makes more power. its not necessary. but generally, its a very very good thing if you can afford/fit it.
i still havent got to writing what i think of your tin snipping in detail :-) i will though, i promise :-)
fred.
The other part of the vacuum pump is that it actually increases ring seal in the first place and reduces the blowby from the start. thats why its good. the increased seal A keeps things cleaner, B makes more power. its not necessary. but generally, its a very very good thing if you can afford/fit it.
i still havent got to writing what i think of your tin snipping in detail :-) i will though, i promise :-)
fred.