Crankcase exhaust ventilation questions

[wirenut]

Hi All,
I have a 440 in an A body drag car with fenderwell headers. The crankcase is vented with exhaust evac via nipples in the 4" long bolt on collectors, and piped up to each valve cover. Works fine. I want to add a o2 sensor and was advised by the manufacture to have the sensor upstream of the evac nipples as the oil/water mixture being pulled from the crankcase may effect the sensor.
What I thought I would do is fab up some 30" or so collector extensions, move the evac nipples onto these about 10" from the end of these 30" extensions and put the sensors where the evac nipples were which is right at the end of the header. Someone suggested that the vacuum may not be as strong in this location, and that the oil/water that is pulled from the crankcase would effect the rear tires.
Any thoughts?

 

[famous bob]

Hi All,
I have a 440 in an A body drag car with fenderwell headers. The crankcase is vented with exhaust evac via nipples in the 4" long bolt on collectors, and piped up to each valve cover. Works fine. I want to add a o2 sensor and was advised by the manufacture to have the sensor upstream of the evac nipples as the oil/water mixture being pulled from the crankcase may effect the sensor.
What I thought I would do is fab up some 30" or so collector extensions, move the evac nipples onto these about 10" from the end of these 30" extensions and put the sensors where the evac nipples were which is right at the end of the header. Someone suggested that the vacuum may not be as strong in this location, and that the oil/water that is pulled from the crankcase would effect the rear tires.
Any thoughts?

u could always point them away from the rear tires!:-k

 

[TrailBeast]

If you pull enough oil and condensation to affect traction, you have a WAY bigger problem to deal with.

 

[wirenut]

If you pull enough oil and condensation to affect traction, you have a WAY bigger problem to deal with.

That's what I thought! If I swipe my finger through the collector It comes out with a VERY light feeling of oil.

What do you think about the proposed position of the nipple in the extended collector pipe?

 

[wirenut]

Can anyone tell me if the nipple in the exhaust can be close to the end of the 30" extension ? Or will it not perform properly?

 

[TrailBeast]

Can anyone tell me if the nipple in the exhaust can be close to the end of the 30" extension ? Or will it not perform properly?

My instructions for my wideband A/F kit says you can put the sensor anywhere in the exhaust as long as it is a heated sensor and no less that 30 inches from the end of the pipe so it can't get fresh air to it.
If it's not a heated sensor, then put it right after where the collector and as much before the engine case vent tube as you can. Like right after where the headers bolt to the rest of the pipes.

Your plan sounds fine to me.

 

[Fast01]

Here's a pic of where I put my wide band. It is actually behind the evac tube as the tube enters the collector at an angle and protrudes in some as seen in the second picture. Seems to work.

 

[wirenut]

Thanks guys. What I'm asking is about the evac nipple location towards the end of the new extension

 

[womanator]

This worked on my 10 second street car.

 

[TrailBeast]

Thanks guys. What I'm asking is about the evac nipple location towards the end of the new extension

That should work just fine, as long as it is after the 02 sensor.
Pulling extra air into the exhaust before the sensor will give you false reading.
I'm sure you already considered that.

The case vent can go almost anywhere in the pipe and as long as you don't have highly restricted mufflers it's going to pull vacuum.

 

[wirenut]

That should work just fine, as long as it is after the 02 sensor.
Pulling extra air into the exhaust before the sensor will give you false reading.
I'm sure you already considered that.

The case vent can go almost anywhere in the pipe and as long as you don't have highly restricted mufflers it's going to pull vacuum.

My thoughts as well just wasn't sure if I wasn't considering something. Womanators pic firms it up.
Thanks everybody.

 

[boosted]

The closer the evac nipple to the head the volume of air that is being pushed by it resulting in more vacuum to pull the pressure out of the motor. Evac nipples past the mufflers probably only pulled 1" of vacuum. You want to pull anywhere from 10 to 17" of vacuum to really work on a motor.

I would keep them as close as you can..

 

[moper]

I would think anywhere even with the evac nipples would be fine too. The flow is not running back up the collector at WOT when the evac system is working so as long as you're not downstream I'd think you're fine. Haven't personally tried that tho..

 

[wirenut]

Thanks again everyone