Exhaust EVAC reducing scavenging signal?

[ELS]

so I want to plumb the EVAC into the exhaust to get vacuum from there, but wouldn't the loss of scavenging signal reduce more power than the less windage will gain?
with my current stock cam it probably doesnt matter, but could it kill some power with a high overlap cam?

[af2]

so I want to plumb the EVAC into the exhaust to get vacuum from there, but wouldn't the loss of scavenging signal reduce more power than the less windage will gain?
with my current stock cam it probably doesnt matter, but could it kill some power with a high overlap cam?

3 years ago the race car started leaking oil for no reason and spitting out the oil fill tube. Problem was the 1 way valve at passenger side the header was stuck closed. Kind of says how much they work.

[steve cowan]

so I want to plumb the EVAC into the exhaust to get vacuum from there, but wouldn't the loss of scavenging signal reduce more power than the less windage will gain?
with my current stock cam it probably doesnt matter, but could it kill some power with a high overlap cam?

It is another try it and see type of deal.
Are you using mufflers or open headers ?
General consensus is evac don't like mufflers.
I am also curious how it can reduce scavenging?
Is the valve in the collector a cause for concern??

[ELS]

so I want to plumb the EVAC into the exhaust to get vacuum from there, but wouldn't the loss of scavenging signal reduce more power than the less windage will gain?
with my current stock cam it probably doesnt matter, but could it kill some power with a high overlap cam?

It is another try it and see type of deal.
Are you using mufflers or open headers ?
General consensus is evac don't like mufflers.
I am also curious how it can reduce scavenging?
Is the valve in the collector a cause for concern??

a single straight trough muffler, exhaust tube is a single 2 inch (50mm) aluminized pipe, engine is an NA 96cui (1.6L) 4 banger.
I was thinking it pulling blowby gases from the crankcase would reduce scavenging vacuum in the header

[steve cowan]

so I want to plumb the EVAC into the exhaust to get vacuum from there, but wouldn't the loss of scavenging signal reduce more power than the less windage will gain?
with my current stock cam it probably doesnt matter, but could it kill some power with a high overlap cam?

It is another try it and see type of deal.
Are you using mufflers or open headers ?
General consensus is evac don't like mufflers.
I am also curious how it can reduce scavenging?
Is the valve in the collector a cause for concern??

a single straight trough muffler, exhaust tube is a single 2 inch (50mm) aluminized pipe, engine is an NA 96cui (1.6L) 4 banger.
I was thinking it pulling blowby gases from the crankcase would reduce scavenging vacuum in the header

Muffler and exhaust changes everything, this is a lot of work but only way to find out.
Place vacuum gauge in header position where you think it might work ( could be anywhere)
Take vacuum readings if there are any and try and make a decision from there,even with open headers it is not guaranteed you will have a good working evac.
There is a thread on here about using a PCV to pull crank case vacuum, I don't have a link but it was in the last month or so.
Remember to pull crankcase vacuum you need a sealed up engine with no air leaks.

[skinny z]

There is a thread on here about using a PCV to pull crank case vacuum, I don't have a link but it was in the last month or so.

I think this is the one you're referring to.

viewtopic.php?f=1&t=64622

[steve cowan]

There is a thread on here about using a PCV to pull crank case vacuum, I don't have a link but it was in the last month or so.

I think this is the one you're referring to.

viewtopic.php?f=1&t=64622

Yes that's the one Kevin,
Thanks for putting up that link.
I really like that set up with the rocker cover cross over .
I am building another 383 sbc at the moment for my weekend cruiser and it will be dynoed as well so I would like test that style of system.

[modok]

I think the idea would be.... that the VOLUMe of the blow-by gasses is so low in comparison to what the header is flowing that it won't make any real difference.
If done right.