Venturi Crankcase Evacuation

[cammmy]

Hi Guys

I ordered some stuff from Summit Racing recently and got one of their crankcase evacuation kits.

I've since seen this:

http://www.youtube.com/watch?v=SQxVKMYRu9A

It looks like a similar thing but rather than simply terminating in the exhaust, it's welded into a small venturi.

It looks like there is improved vacuum in the video but does anyone think it would outweigh added restriction to gas flow?

[cammmy]

Or alternately, what if you used venturi type merge collectors and placed the tip of the evacuation system just in front of the venturi? Would this have the same effect?

[kiwicar]

Hi
Yes I am pretty sure it would. . . but it would be a very fancy collector and a damn shame to hide it under the car!
Best regards
Mike

[conrod]

just be careful if you are using one of these kits on a road car. They were originally desgned by drag racers running open exhausts (and do work!)

If you fit one to a road car you may have problems. The backpressure in the system caused by the mufflers can cause the exhaust gases to feed into the engine (unless a one way valve is fitted) I saw a case recently where the oil seals blew out of an engine for this reason. I can't see that they would work on any system other than an open or very low restriction exhaust.

[stevieturbo]

And make sure that you have adequate protection from it sucking the oil from the crankcase and damaging oil seals if it creates too much suction.

Normal vented to atmos cans can gather a lot of oil....so something sucking and expelling everything could potentially leave you in a bad way.

And if it did draw any fluids out....drivers behind you may not be impressed. So any oil/air separation before the evac would need to be top notch.

[cammmy]

Cool, I'll be doing the exhaust from scratch to be very low back pressure. The kit also includes check valves.

Thanks for the advice. I'll pay attention to making sure I'm not sucking oil out.