Reader Question: “Open” Air Cleaners?

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Here’s the latest reader question, along with my reply!

Mike asks: Back in the day people looking for a little more performance used to replace the original air cleaner with an aftermarket “open” one. Do people still do this today and if they do it, is it a good idea?

My reply:  It was probably a better idea back in the day – when factory air cleaners were often very restrictive. Also, it was easier to make the necessary adjustments to take advantage of the increased airflow, most notably richening up the mixture by going up a size or two in jets.

You have to be more careful today because modern engine management systems are calibrated to the factory configuration and any change may upset the computer, causing a “code” to be logged – and the “check engine” light to come on. In some states, too, there may be issues as far as emissions legality.

So, check before you buy!

Also, be sure the system you buy fits properly and doesn’t “delete” any necessary connections.

Finally, modern air intake systems generally draw cold – higher density –  air from outside the engine compartment already while the “open” type may worsen performance by eliminating that in favor of hotter – not as dense – air under the hood.

. . .

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  1. I keep up with this subject. Almost every engine gains power by installing a larger air intake, esp. turbo engines. I was amazed to see how much power was gained on the diesel pickups of the big 3 by installing a larger intake and a larger tube from the turbo to the intake and even more power was gained by using a larger exhaust pipe and that was using the stock intercooler. Using a larger intercooler resulted in more power gain. All those engines benefited by using a larger turbo with those systems and maintaining the same pressure.

    The new Duramax has an intake that spans the width of the hood.


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