Vacuum Question For The Experts
08-07-2007 | 06:11 PM
#1
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Vacuum Question For The Experts
Running a '88 5.7 TPI. Did a vacuum check on it (hooked into the pvc hose) and it held steady at -19 but when i slowly opened the throttle to about 1500 rpm's the vacuum increased to -22 and held steady until I closed the throttle. Is this normal? I checked several repair manuals, and non of them made any referance to an increase in vacuum with increase of rpm's.
08-07-2007 | 06:22 PM
#2
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From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Normal.
The "pump" is moving more air at higher RPMs. With no load, the intake manifold vacuum will also go up.
The "pump" is moving more air at higher RPMs. With no load, the intake manifold vacuum will also go up.
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