Tom, have you tried the Moroso crankcase evac system? There is a nozzle
that welds into the exhaust down pipe. There is a backfire valve which
screws onto the nozzle and that is connected to a breather cap. Typical
V8 uses 2 of these and it pulls a pretty fair vacuum in the internals
side of the engine. Cost is about 50 bucks for a dual setup. I use it
on the TWFS (w). Supposed to reduce windage in the crankcase, improve
sealing because ait flow is into the engine rather than the other way
and the reduction of pressure hepls the rings seal. Increases power a
bit but how much I do not know. I use it because I did not want vented
caps blowing oil everywhere. And yes, I do get some popping but that is
in my case just typicall low load lean popping, kinda like a turbo
porsche backing off the throttle with the fire coming out the pipes...
kinda cool... Do I recommedn thsi for the street? YMMV...
mayf, way off and far out in pahrump..
Tom Hall wrote:
>At 10:54 AM 12/27/2006, you wrote:
>
>
>>Definitely don't plug the engine breathers. For best performance
>>you'd like to run the crankcase at some amount of vacuum, to improve
>>ring sealing, but barring that you want to make sure that the
>>crankcase is adequately ventilated. You could run the right side
>>breather into the header collector - that would burn off any fuel
>>and oil vapors that come up through the breather, and the scavenging
>>effect would ensure a constant flow of air through the crankcase.
>>
>>
>
>The addition of air from any source to the exhaust system is a
>complex situation. OEM air pumps make this "injection" very close to
>the exhaust valve. Injecting air farther down the exhaust system
>generally leads to the same cracking and snapping you get with a
>leaky exhaust system. It becomes very apparent when you go into
>close throttle mode.
>
>I attempted to build a negative pressure crankcase system in the
>early 70's (great theoretical concept), dumped the discharge half way
>into the cast iron exhaust manifold, and ran headlong into a Tiger
>that snapped and popped every time I backed off the throttle. I
>lived with that for maybe a month and decided that wasn't the way to
>reduce crankcase pressure, and pulled all the hardware. Never did
>spend the time to develop a functional design. The properly
>installed PCV system is hard to beat.
>
>Tom Hall
>ModTiger Engineering LLC
>www.tigerengineering.net
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