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CAI Myths Busted



I got +50 rwhp after installing my Spectre intake, I think it was due to my porting and polishing the pcv pipe I used and wrapping it with black duct tape.
 
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2009antz2009 said:
PSI= POUNDS PER SQUARE INCH.

if vacuum wasnt measured in pounds your boost gauges wouldnt be by PSI.
Click to expand...

So just to clarify your stating that because most decent boost gauges go below zero that somehow vacuum equals psi as well?....be forewarned science is about to destroy u..
 
When one considers gauge pressure (the way we perceive vac/pressure), anything below zero is read in inches of mercury. Pressure is, for all intensive purposes, a positive value. In terms of absolute pressure, what you see on a gauge as zero is approximately 14.7 PSI(abs). What one sees as ~30 inHg in vacuum is close to 0PSI(abs). It is never actually called "negative pressure".

If you look closely at many boost/vac gauges, you'll notice there is a little script in the vac section that actually says "inHg", indicating that the vacuum portion of the gauge is read out in inches of mercury. (If you want to make a simple conversion, 10 inHg of vacuum would equate to approximately 5 pounds of "negative pressure")

As far as the cold air intake theory is concerned, it has been proven that the benefit of plumbing in cooler air is typically negated by the distance the air has to travel inside that pipe (especially for our platform). The longer distance a turbulent 'fluid' (air being considered a fluid in this case) flows through a pipe, the more restriction there is to flow. That restriction creates pumping losses which generally offset the benefit that might have been gained by the cooler air. Ideally, the pressure at the S/C inlet would be the same as the atmospheric pressure (0 PSIG or 14.7 PSIA). Having a long intake duct allows for more vacuum to exist before the rotors, effectively reducing the blower's efficiency.

If one were to design an intake that began with a ~6" opening and gradually funneled down into the TB over 2-3 feet, pumping losses could be lowered, and the benefit of cooler air might be appreciable. But, then one has a section of 6" pipe (and a rather large filter) to find a home for in a relatively crowded engine bay...
 
This simple physics concept is too much for you young high school child who probably hasn't even taken a physics class before. You do realize boost gauges read in things other than psi? PSI is just the most common form.
 
Thank you dan.
Most cold airs are inefficient.
And if you can measure boost and vacuum with PSI then it is measured in PSI. That was the arguement. Yeah you can measure water by quarts but doesnt mean measuring it by gallons is wrong.

Get it yet or do i need to break out the crayons?
 


Who says most cold air intakes are inefficient? I would like proof of this since it's just your opinion. Kid just go to bed. It's a school night anyway.
 
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