Emission system mods, turbo
Posted: Sun May 20, 2001 4:18 am
Hi group,
Purpose of this : to stop oily, blow-by gases getting into the air let.
-General Description (diagram attached) of workings, normally.....
At part or nil throttle, the blow-by gas in the crankcase is drawn into the inlet manifold through the connecting hoses and PCV valve by strong vacuum in the inlet manifold (strong vacuum opens the PCV valve). Under these conditions, fresh air is introduced into both the rocker covers via the air inlet duct and connecting hoses. The crankcase (blow-by)gases, mixed with the fresh air, are drawn through the hoses, PCV valve and into the inlet manifold.
At open throttle, under turbo boost, positive pressure is created in the inlet MANIFOLD ,ie. the inlet MANIFOLD has no vacuum and hence the PCV valve is shut. Instead, the turbocharger asking for maximum air, is creating a kind of vacuum in the air inlet ducting.
Under these conditions the system works in reverse. Blow-by gases are drawn into the air intake duct via the rocker cover hoses and hose off the crankcase, prior to the PCV valve (shown in diagram below).
During these conditions, the inlet air being fed is not 100% fresh air but a mixture of fresh air and blow-by gases. This also leaves an oily film, over time, in the inlet ducting, turbo and intercooler.
100% fresh air would be a better alternitive.
What I did.....
1. The hoses from the both the rocker covers come together as one and lead to the air inlet duct. I have pulled this hose out and plugged the hole in the air inlet duct. On the end of the pulled out hose, I have fitted an oil foamed filter, a mini version of a uni-fliter if you like. Now the system can draw fresh air into the rocker covers whenever required but will not allow blow-by gaes to be drawn into the air inlet duct. It now 'breathes'. This is similar to the pre-emission days when engines used to 'breathe' through the rocker cover oil filler cap.
2. There is another hose that links from the air inlet duct, to the crankcase hose and PCV valve. (see diagram) I have plugged the section leading from the air inlet duct. This now allows crankcase vapours to be drawn in the inlet MANIFOLD via the PCV valve but stops the crankcase vapours being drawn into the air inlet DUCTING. This is now 'one-way' if you like.
I realize this is not allowed under emission control laws but the only thing that can be visually seen is the tiny foam air filter. I plan to hide this.
This must make a difference as the airflow meter now has the exact amount of air entering the engine, as is couldn't know what was being drawn in through the blow-by hoses. Physically I noticed that the chrome tailpipes on the rear muffler are not 'sooting' up as much.. if at all.
I also removed the air ducting / intercooler and cleaned the oily film off everything and it is still spotless. I have been running like this now for 2 months.
Any comments please. I'm interested to know what you guy's think.
Regards, Rod
Emission system Turbo
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Purpose of this : to stop oily, blow-by gases getting into the air let.
-General Description (diagram attached) of workings, normally.....
At part or nil throttle, the blow-by gas in the crankcase is drawn into the inlet manifold through the connecting hoses and PCV valve by strong vacuum in the inlet manifold (strong vacuum opens the PCV valve). Under these conditions, fresh air is introduced into both the rocker covers via the air inlet duct and connecting hoses. The crankcase (blow-by)gases, mixed with the fresh air, are drawn through the hoses, PCV valve and into the inlet manifold.
At open throttle, under turbo boost, positive pressure is created in the inlet MANIFOLD ,ie. the inlet MANIFOLD has no vacuum and hence the PCV valve is shut. Instead, the turbocharger asking for maximum air, is creating a kind of vacuum in the air inlet ducting.
Under these conditions the system works in reverse. Blow-by gases are drawn into the air intake duct via the rocker cover hoses and hose off the crankcase, prior to the PCV valve (shown in diagram below).
During these conditions, the inlet air being fed is not 100% fresh air but a mixture of fresh air and blow-by gases. This also leaves an oily film, over time, in the inlet ducting, turbo and intercooler.
100% fresh air would be a better alternitive.
What I did.....
1. The hoses from the both the rocker covers come together as one and lead to the air inlet duct. I have pulled this hose out and plugged the hole in the air inlet duct. On the end of the pulled out hose, I have fitted an oil foamed filter, a mini version of a uni-fliter if you like. Now the system can draw fresh air into the rocker covers whenever required but will not allow blow-by gaes to be drawn into the air inlet duct. It now 'breathes'. This is similar to the pre-emission days when engines used to 'breathe' through the rocker cover oil filler cap.
2. There is another hose that links from the air inlet duct, to the crankcase hose and PCV valve. (see diagram) I have plugged the section leading from the air inlet duct. This now allows crankcase vapours to be drawn in the inlet MANIFOLD via the PCV valve but stops the crankcase vapours being drawn into the air inlet DUCTING. This is now 'one-way' if you like.
I realize this is not allowed under emission control laws but the only thing that can be visually seen is the tiny foam air filter. I plan to hide this.
This must make a difference as the airflow meter now has the exact amount of air entering the engine, as is couldn't know what was being drawn in through the blow-by hoses. Physically I noticed that the chrome tailpipes on the rear muffler are not 'sooting' up as much.. if at all.
I also removed the air ducting / intercooler and cleaned the oily film off everything and it is still spotless. I have been running like this now for 2 months.
Any comments please. I'm interested to know what you guy's think.
Regards, Rod
Emission system Turbo
<http://rd.yahoo.com/M=201903.1443829.30 ... yahoo.com/> Yahoo! Domains <http://rd.yahoo.com/M=201903.1443829.30 ... yahoo.com/> Yahoo! Domains
<http://us.adserver.yahoo.com/l?M=201903 ... =371001730>
To unsubscribe from this group, please send an email to:
BC-BFLegacyWorks-unsubscribe@egroups.com
zZz <http://docs.yahoo.com/info/terms/> .