Stock gm air filter gauge

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According to an Oak Ridge National Laboratory study entitled "Effect of Intake Air Filter Condition on Vehicle Fuel Economy" Conducted in 2009, a similar factory OEM indicator taken from a 2001 Chevrolet Silverado with 5.3L V-8, measured 5.7 kPa (23 " H2O) at the level that the indicator entered the red zone. I suppose that the percentages apply to the full scale reading. They found no effect on fuel economy with computer controlled engines from air filter restriction but some power loss at full open throttle with high restriction. Since air filter efficiency improves with restriction, a reasonable air filter change point might be at the 80% level unless you are into drag racing this vehicle.
 
As the filter becomes clogged and becomes restrictive the spring becomes less visible. Is it color coded?
 
Originally Posted By: Warstud
As the filter becomes clogged and becomes restrictive the spring becomes less visible. Is it color coded?
no color code till the bottom. Its red.
 
Originally Posted By: Chris142
Originally Posted By: Warstud
As the filter becomes clogged and becomes restrictive the spring becomes less visible. Is it color coded?
no color code till the bottom. Its red.


Red means it's time for a new filter.
 
Originally Posted By: compratio10_5
According to an Oak Ridge National Laboratory study entitled "Effect of Intake Air Filter Condition on Vehicle Fuel Economy" Conducted in 2009, a similar factory OEM indicator taken from a 2001 Chevrolet Silverado with 5.3L V-8, measured 5.7 kPa (23 " H2O) at the level that the indicator entered the red zone. I suppose that the percentages apply to the full scale reading. They found no effect on fuel economy with computer controlled engines from air filter restriction but some power loss at full open throttle with high restriction. Since air filter efficiency improves with restriction, a reasonable air filter change point might be at the 80% level unless you are into drag racing this vehicle.


Excellent post. Need more members like u plz
 
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IIRC that Oak Ridge study (available online last week) gives 10 inches of water (in excess of the negative pressure generated by a new filter) as a reasonable rule-of-thumb restriction for a filter change.
 
Yes, the study does recommend 10 " H2O above the clean filter restriction as a "rule of thumb" air filter change point, but on a factory installed gauge I believe that the manufacturer selects the red zone as the normal filter replacement point. In any case, if the drop in power is objectionable just change the filter earlier at 50% for example. In most situations, if you are not often driving on dirt roads, the air filter will last far longer than you expect. Installing these filter minder gauges is one of the best things that General Motors has done on its trucks. This saves the owners money on filters and extends engine life. A rare win-win situation.
 
You would think with the push on fuel economy today and CAFE, that air filter indicators would be standard equipment today on most vehicles. ?!?
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Originally Posted By: StevieC
You would think with the push on fuel economy today and CAFE, that air filter indicators would be standard equipment today on most vehicles. ?!?
No, I wouldn't think that, because replacing the air filter doesn't help fuel economy in most vehicles---as already explained in this thread and many others. It may help in vehicles too old to have self-adjusting fuel mixture control. Even in those, the restriction has to be pretty bad to make much difference in normal driving.
 
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