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Old 04-30-2006, 01:58 PM
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air speed 'inside" intake manifold ?

lets say, but not limited to, a typical HiPer 350 sb. how "fast" is the air going inside the intake manifold ? say, through the throttle body/carb/plenum.

thanx

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Old 04-30-2006, 02:13 PM
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That is pretty variable by port cross section (cc's) and rpm, but I read that at high rpm it has been measured at 400 feet per second/ 270 miles per hour at the push rod pinch. I think that referred to the maximum velocity point in the manifold system.

That is what I read.

Sorry I can't give a source location.

At idle I bet it isn't 15 fps.
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Old 04-30-2006, 02:37 PM
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260 ft/sec is considered in the ideal range at HP peak. 300 ft/sec is considered a bit too high.
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Old 04-30-2006, 03:36 PM
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Quote:
Originally Posted by Rick WI
260 ft/sec is considered in the ideal range at HP peak. 300 ft/sec is considered a bit too high.

Measured where? Wet or dry?
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Old 04-30-2006, 04:35 PM
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In the intake runner.
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Old 04-30-2006, 04:51 PM
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Quote:
Originally Posted by Rick WI
In the intake runner.

OK so an intake manifold runner velocity of 260 fps WET is considered the limit? Is this due to the fuel separation?
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Old 04-30-2006, 05:08 PM
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wonder what it is with a blower?
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Old 04-30-2006, 05:13 PM
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Quote:
Originally Posted by steve t
wonder what it is with a blower?

Velocity is proportional to engine rpm. It wouldn't be any faster, but it would be under PRESSURE...more air/oxygen per volume....... yyyyyyyeeeeeeehhhhhaaaaaawwwwwwwww.

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Old 04-30-2006, 06:06 PM
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It's not considered the maximium, it's considered optimum. Spin a 355 with 18 degree bowtie stock intake to 7500 and it will spec around 310.

I don't really know exactly what happens in the intake when the intake is too small and the velocity is too high other than the engine just hits a wall and the torque takes a dump. I would guess shear is a good guess.
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