My Weekend Experiment

[speedybenz]

This weekend I connected the drivers side valve cover breather to the passenger side valve cover breather. I did this because the passenger side breather is connected to the intake manifold and pulls some 35 inches of vacuum at idle, while the driver side breather is normally connected to the intake elbow prior to the thottle plate and pulls no vacuum.

The reason was to create a stronger vacuum to the crankcase which can increase piston ring seal and create more Hp.

Sadly the drivers side valve cover is not baffled enough or for some other reason, ie very high blowby at the piston rings I ended up pulling engine oil into the intake manifold. This was caught in my air/oil seperator but it was enough to cause concern and I need to find the reason for the excess oil.

On our Supersport motorcycle motors this was worth some Hp and will most likely add Hp here too as soon as I find a way to keep the oil in the drivers side valve cover, maybe better baffling.

I will have to add some big one way PVC valves in the system that come off big rig trucks. Sometimes these valves can allow the intake to pull a big vacuum on the crankcase and then if pressure drops they seal off keeping the higher vacuum in the crankcase.

Jeff

[MBATF]

i have faith in u meng! u r da man!

[714guy]

wow how did you measure the vacumm pressure on the intake side that pretty tight. Are you making a catch can to seperate the oil from the air?? if so Greddy makes a really nice one.

Good luck.

[speedybenz]

For the air/oil seperator I use a unit made for an air compressor. It's small and works pretty good and it was $12 or so.

To measure the vacuum I just tee'd in a std. vacuum gauge and took the measurements.

I am shooting for 300 Hp at the wheels of my C43. I am pretty sure I won't get there unless I pull the heads. Man is that going to piss off the wife. I am going to have to do something really nice for her before I do that.

Jeff

[CKlasse]

Originally posted by speedybenz
For the air/oil seperator I use a unit made for an air compressor. It's small and works pretty good and it was $12 or so.

To measure the vacuum I just tee'd in a std. vacuum gauge and took the measurements.

I am shooting for 300 Hp at the wheels of my C43. I am pretty sure I won't get there unless I pull the heads. Man is that going to piss off the wife. I am going to have to do something really nice for her before I do that.

Jeff

Buy her a new exhaust system

[Brabus]

Wheeling and dealing...

[speedybenz]

Alright I figured this out and found I had connected the wrong hoses.

There is a crankcase vent coming off of each valve cover and so I cut those hoses and inserted a 3/4" one way PVC type valve in each hose and and reconnected them to the intake manifold.

Then installed the same type valve in the hose also coming off the drivers side valve cover that goes to the intake elbow on my C43.

Set-up like this I am able to get about 10in of vacuum in the cases. The car is making more torque and pulls better down low and runs strong all the way through. I will run some PDA dyno tests soon.

When you stop you can hear the oil flowing to the pan, it sounds like water. Plus the o-ring at the oil dip stick did not seal well at first so it would hiss untill the pressure came back to zero in the cases.

Jeff

[cyclocross]

Originally posted by speedybenz
...There is a crankcase vent coming off of each valve cover and so I cut those hoses and inserted a 3/4" one way PVC type valve in each hose and and reconnected them to the intake manifold.

Then installed the same type valve in the hose also coming off the drivers side valve cover that goes to the intake elbow on my C43...

Hi, Jeff. Does this mean that there are two breather hoses from the driver's side valve cover to the intake manifold? BTW, the Cosworth DFV Grand Prix motor was designed to "pull" a vacuum in the crankcase to yield additional HP. Also, my old gear-drive Ducati V-twins had a one-way flapper valve in the breather line to allow a crankcase vacuum.

Another question:
The C43 grill is blanked-off near the stock air intakes. The intakes are actually located behind the steel part of the hood not behind the grill. Why is the grill blanked-off? I had understood that it was to prevent water entering the intake. However, several newer cars, like the G35 Sedan and Passat, have a direct path from the gap between the grill and the hood to the air filter. In fact, after you raise the hood on the G35 you can see the pink air filter in its housing. These cars do not have any intake problems in the rain.

Is there a problem specific to the C43? Has anyone removed the covers and driven the car in the rain? Any comments are appreciated. TIA

[Denlasoul]

Originally posted by cyclocross
Is there a problem specific to the C43? Has anyone removed the covers and driven the car in the rain? Any comments are appreciated. TIA

I have removed my covers since the first day in my possession. I have not had any problems whatsoever, and I live in Seattle. Please note that I do not drive my car as often as most, but on rainy days I can go WOT no probs.

PS. Inspect the airbox and filters more often. It will show any problems that may arise.

[cyclocross]

Originally posted by Denlasoul
...PS. Inspect the airbox and filters more often. It will show any problems that may arise.

Thanks for the input. I inspected the filters when I brought the car home from the dealer. The filters and the housing needed to be cleaned. Whether or not the covers are in-place does not seem to affect junk entering the filter housing.

[speedybenz]

There are two breather tubes coming off the drivers side valve cover. One is connected to the intake manifold and the 2nd is connected to the intake elbow before the throttle body, so it sees very little vacuum.

I installed very high quality one way diaphram valves in each breather line and this sealed off the crankcase and allows a vacuum to be pulled. Up to 10 in-Hg.

Car seems to pull much better at part throttle.

Jeff

[cyclocross]

Jeff, thanks for the explanation. The rear of the engine compartment is certainly crowded. Pulling a vacuum in the crankcase is worthwhile pursuing.

[cyclocross]

I must be getting slow in my old age. If I understand the description of these hoses correctly, there a hose from before the throttle to a valve cover and another hose from the intake manifold (after the throttle) to the valve cover. Unless there is a one-way valve in the first hose the throttle will almost always be bypassed. Jeff, are you sure there are not any one-way valves already installed in the manifold or valve cover? It seems strange to have a breather system that by-passes the throttle.