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vacuum ?

1845 Views 1 Reply 2 Participants Last post by  not2XS
i have a booost guage and manual transmission.
if i shift early with same pressure on the pedaal like going up hill the vacuum will almost go to zero. does the vacuum pressure have anything to do with engine wear. is it beter to keep more negative vacuum pressure for engine life or milage.?

could someone explain what exactly goes on with engine vacuum and what does it really mean reference to the engine working. ?
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Vacuum is kind of a rough measure of "how hard" the engine is working. There is an argument that more vacuum helps the PCV system to work, and so reduces chances of gumming the oil. I don't know if that makes sense personally, seeing as the PCV joins the intake before the throttle. Another aspect is that a "harder working" engine sees more stress and that may not be a good thing. More stress may or may not translate into faster wear, supposedly depending on whether the oil films can still maintain clearance.

As for fuel economy, the engine has a performance curve for that like it does for horsepower. I haven't seen it, but would guess there is a good chance that a lower gear might get better mileage than lugging the engine.
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