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TIL my air filter minder gauge was lying to me and I'd been dusting turbos for 8 months
Pulled the intake boot off a Pete 389 last Tuesday in Amarillo and ran my finger inside the turbo inlet, came back with a grit film I could scrape with a fingernail. The dash gauge showed maybe 12 inches of restriction, still green, still "fine" according to the book. So I stuck a Magnehelic on the same port and got 27 inches at full load, way past the 25 inch service point. Turned out the minder's little rubber seal had dried out and it was pulling clean air past the piston instead of reading the actual vacuum. New minder was $31 and the difference on a pull up the grade was instant, boost came in cleaner and pyro dropped about 60 degrees at the same weight. Now I pull the intake and finger the wheel on anything over 200k whether the gauge says so or not. How are you guys checking filters on trucks where the minder is buried behind the cowl?
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the_jenny5h ago
My finger has better calibration than any gauge I own apparently.
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ruby_bell475h ago
My grandpa was a machinist and he always said his thumb was more accurate than his calipers after 40 years. Something about feel just beats numbers sometimes. Though I did read that even trained fingers can be off by a few thousandths depending on the day.
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