Welcome to the 2GNT Forum!
Home Site Background Info & Specs Mods & Tech Info CAPS Part Reviews Donate 2GNT Stickers
Search Printer-friendly copy 1 User in Chat
Top 2GNT Technical Turbo/Nitrous Tech topic #97375
View in linear mode

Subject: "Turbo...What to do with PCV Hose" Previous topic | Next topic
Jacque766Sep-21-06 07:33 AM
Member since Apr 04th 2006
86 posts, 		Click to send email to this author Click to send private message to this author Click to view this author's profile Click to add this author to your buddy list
#97375, "Turbo...What to do with PCV Hose"


          

Qoute: "Third, and the biggest culpret: I didn't have the crankcase vent line running to the intake of the turbo. I just blocked it off. That was the biggest offender. PCV connected correctly = no smokey"

I just read this and it does make sense becasue if you hook the PCV hose to the intake mani when boosting it will try to feed pressure instead of trying to purge it from the head.

Right now mine is connected to the original spot on the intake mani. Is this completely wrong? Should I install a fitting on the intake pipe before the turbo run a hose to it for the PCV? or is it ok to leave the PCV connected to the mani?

JC~

1999 GS, 420a, Airwerks K26 Turbo, All custom piping, Tial 40mm WG, Tial 50mm BOV, Apexi SAFC II, AVC-R and turbo timer, 255 walbro pump, 38lb INJ, Venom Fuel rail, FMIC, 60mm Modern Performance TB, Ported Mani, AGX struts, 19" Rims, blah blah blah....

  
Report This Post to Admin Printer-friendly copy | Reply | Reply with quote | Top

Replies to this topic

TeamAvengerSep-21-06 07:45 AM
Old School 2GNTer
2453 posts, 		Click to send email to this author Click to send private message to this author Click to view this author's profile Click to add this author to your buddy list
#97376, "RE: Turbo...What to do with PCV Hose"
In response to Reply # 0
 Sep-21-06 07:47 AM by Avenger



          

There are two fittings on the valve cover. One in the back and one on the side. The one in the back needs to go to the intake manifold BUT there should be a check valve (PCV) in place that will not allow positive pressure from the manifold to the valve cover. Make sure its installed in the right direction.

The side should go to an oil catch can.

-"Easy Mac"
05 Mazda RX-8 (RR8 #88)
99 Eclipse RS 398whp & 372lb-ft emoji

  
Report This Post to Admin Printer-friendly copy | Reply | Reply with quote | Top

turbo8uSep-21-06 07:51 AM
Member since Jun 15th 2003
10552 posts, 		Click to send email to this author Click to send private message to this author Click to view this author's profile Click to add this author to your buddy list
#97377, "RE: Turbo...What to do with PCV Hose"
In response to Reply # 0



          

Originally posted by Jacque766
Right now mine is connected to the original spot on the intake mani. Is this completely wrong? Should I install a fitting on the intake pipe before the turbo run a hose to it for the PCV? or is it ok to leave the PCV connected to the mani? JC~


The stock setup is still functional under vaccum and decel, once under boost the crankcase becomes more and more pressurized and then vents out of the breather.

In my experiences, running it before the turbo without a catch can is just asking to blow all sorts of oily blow by into your intercooler (big problem on stock turbo cars, supra for example)

One way to do it, is leave the stock PCV for vacuum conditions (once its in boost, the valve blocks anyway) and then in a boost condition, route the breather (other vent in the valve cover) to a vacuum source (exhaust has a mild vacuum, best source is before the turbo) but run an inline catch can if you decide to route it before the turbo otherwise your compressor wheel is going to take the brunt of your crankcase pressure.

its kind of a win win situation when the PCV is working effectively under boost though, if there is a - pressure on the bottoms of the pistons, and a seriously + pressure on the tops of the pistons...it works together increasing power, increasing ring seal and thus reducing blow by...

on the other hand, with no effective crankcase relief under boost...its a + pressure on both sides of the piston, causing oil leaks, oily blow by, etc

check out the crankcase vents that run it down into the exhaust with a check valve. I did this about maybe 2 years ago and it works damn good. The exhaust is a mild vac, maybe -3hg at idle so thats why you need the stock PCV hooked up drawing -10, -15, -25hg vac under cruising and decel conditions.

hope I helped some...

_ _ _ _ _ _ _ _ _

96 Black ESi
91 Red TSI AWD (RIP)
02 WRX


"turnin wrenches for nine hours in the pouring rain, just to get the beast up and running again"

Aerospace Certified TIG welder for Precision Castparts in Portland, OR.

JoshSpair.com

  
Report This Post to Admin Printer-friendly copy | Reply | Reply with quote | Top

    
Jacque766Sep-21-06 08:39 AM
Member since Apr 04th 2006
86 posts, 		Click to send email to this author Click to send private message to this author Click to view this author's profile Click to add this author to your buddy list
#97380, "RE: Turbo...What to do with PCV Hose"
In response to Reply # 2

          

Thanks, that was some good info. Im not quite sure what the little tube on the driver side vents? I know it feeds into the Valve cover like the PCV hose does on the passenger side but I didnt know what to do with it so currently it just has a filter on it.

But what i gathered from your post, having the PCV valve hooked up like the stock config is ok but applying a vac source to the tube on the drive side would be better than just putting a filter on it.

I only run 5-7psi for now(stock internals) but i'll definetly try a setup like that when i rebuild the engine stronger.

Thanks, JC

1999 GS, 420a, Airwerks K26 Turbo, All custom piping, Tial 40mm WG, Tial 50mm BOV, Apexi SAFC II, AVC-R and turbo timer, 255 walbro pump, 38lb INJ, Venom Fuel rail, FMIC, 60mm Modern Performance TB, Ported Mani, AGX struts, 19" Rims, blah blah blah....

  
Report This Post to Admin Printer-friendly copy | Reply | Reply with quote | Top

        
turbo8uSep-21-06 10:08 AM
Member since Jun 15th 2003
10552 posts, 		Click to send email to this author Click to send private message to this author Click to view this author's profile Click to add this author to your buddy list
#97391, "RE: Turbo...What to do with PCV Hose"
In response to Reply # 3



          

Originally posted by Jacque766
Im not quite sure what the little tube on the driver side vents?


thats exactly what it is, a vent (for the crankcase) The system is designed like this: PCV (first hole, big tube) draws out crankcase pressure under normal driving and cruising (vac). When you get on it, vaccuum goes away and this is what the drivers side VENT is for, to vent all the gasses being built up in the crankcase into the intake pipe and thus back into the combustion chambers to burn again. It's pretty dumb, but the gasses coming out are hydrocarbons, its more to comply with emissions laws.

I never had a whole lot of blow-by until boost went past about 10psi on a s16g. you should be ok.

Originally posted by Jacque766 But what i gathered from your post, having the PCV valve hooked up like the stock config is ok but applying a vac source to the tube on the drive side would be better than just putting a filter on it.


yea, and even better...would be to drill out that hole larger so it can actually flow a good volume, but thats another thing. vaccum on that barb when the motor is under boost is a hell of a lot better then just a filter. people just put a filter there because thats what everyone does.

_ _ _ _ _ _ _ _ _

96 Black ESi
91 Red TSI AWD (RIP)
02 WRX


"turnin wrenches for nine hours in the pouring rain, just to get the beast up and running again"

Aerospace Certified TIG welder for Precision Castparts in Portland, OR.

JoshSpair.com

  
Report This Post to Admin Printer-friendly copy | Reply | Reply with quote | Top

Top 2GNT Technical Turbo/Nitrous Tech topic #97375 Previous topic | Next topic
   

Powered by DCForum+ Version 2.2
Copyright 1997-2005 DCScripts.com, Copyright 2005-2026 2gnt.com
Generated in 0.053 seconds, executing 22 queries.