how is forced induction even possible!? Half the engine bays requires or runs on vacuum, hard to have a vacuum on the intake when a blow is pressuring it positive 8 lbs!

 

There are OEM inducted Cars as well ... and 100% of it's time isn't under boost especially turbo cars. At lower rpms there's really no boost....but I would highly recommend you get a book titled "Maximum Boost" by Corky Bell....Here's the book:

http://www.volkspage.net/technik/04/maximum_boost.pdf

 

what cmax said.
when you're not deep in the throttle/rpm it's not in boost hence natural tendency to be in vac.

 

what keeps it from whacking out once under boost?

 

It's only in boost for 2-3 seconds at a time. 99% of the time driving around you are in vacuum unless you're being a total ricer everywhere you go.

What do you mean "whacking out" anyway? There are these fancy inventions called "one way check valves" to prevent your crankcase etc from seeing boost. Your power brake booster already comes with one from the factory.

Besides, it's not like you're going to slam on your brakes while actively flooring the gas pedal/keeping it boost simultaneously.

 

During the Silver State challenge you can run speed of 90 MPH and up for 90 miles of public highway ...legally. also if you tracking the car i suppose.

i guess your right about check valves, that's probably a big reason why vacuum depending devices are getting pressure instead of vacuum but, if it's on boost for extended periods of time that would at least mean no vacuum or pressure, just nothing.

also i'm gonna check out that book.

 

I was thinking the same thing to tell him...that's funny!

 

You mean "0 psi" or "0 in/hg" ???? Impossible, I've never seen that for extended period of time it might pass thru 0 but not stay there! Get that "Maximum Boost" pdf and read it please...it'll answer alot of your questions...Get some theory and get some boost and you'll be an addict for life!

 

wait...you mean you guys don't do that?

 

check valves keep the air flowing in the right direction and vacuum canisters keep enough of it around so they can operate. 3rd gens even came with them from the factory on the intake power valve because they tend to operate under lower vacuum conditions.

The real challenge comes in running tight LSA cams and not generating enough vacuum in the first place

 

I've had them stay at 0in/hg for 10 minutes or so in the past, but we have decent mountain passes around here