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Old 08-01-2010, 10:55 AM   #38 (permalink)
EdKiefer
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Quote:
Originally Posted by comptiger5000 View Post
Whether or not EGR is beneficial depends on the cam profile. Sometimes they have enough "in-cylinder EGR" due to the cam that additional egr isn't beneficial. Other times, there is less of that effect, so it's beneficial (for either FE or emissions, or both) to add EGR.
Right , A lot of newer engines with variable value timing don't need a EGR valve but the do the same thing (dilute charge) by varying overlap at low speeds-part throttle just like a EGR does .
If the vehicle runs better and gets better mileage w/o EGR then maybe the ignition timing is not advanced as much as it could with EGR on .
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