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Message: <blockquote data-quote="mcglsr2" data-source="post: 1244904" data-attributes="member: 15705">Nice write-up! A couple corrections/suggestions/clarifications: For the most part, true.  However, the engine is still rotating the pulleys/gears, so some N/A power is being used regardless.  Depending on your driving style, it might not be noticeable, but it is not a free lunch.  There is additional friction there, boost or no boost. You mention it here regarding atmospheric pressure - typically this is expressed as psia (psi atmosphere).  A gauge shows psig (psi gauge), which is the boost OVER atmosphere.  It is typically accepted that when someone talks about the boost they are making and psi, they are really talking about psig - though it's usually expressed as psi.What actually causes detonation is heat, not necessarily the pressure.  Heat is a function of pressure, and the efficiency of the boosting mechanism (supercharger or turbocharger).  As air is compressed, heat is generated.  In a low boost situation, the denser air easily compensates for the added heat to the intake air temp, so one sees a positive effect of boost.  As boost is increased (or the boosting mechanism strays out of it's efficiency range), more and more heat is imparted into the air stream.  So even though the air is denser, it's much much hotter.  The hotter air, coupled with less room in the combustion chamber to move around (because of denser, thus more, air in there) is what causes detonation.  If one could cool the air (via an intercooler for example), then much higher boost pressures can be used (and thus higher pressure) without fear of detonation.  There are limits of course.For systems that use the engine's oil, it's a very good idea for the owner of these vehicles to use synthetic oil (if possible) and increase the frequency of oil changes.  The oil is used to lubricate the supercharger, but also some heat from the supercharger will transfer to the oil, heating it up more.  This will cause the oil to break down faster over time.  In boosted applications that use engine oil (superchargers and turbochargers), oil is the life blood.  Change it more frequently.Personally, I wouldn't say it this way - rather, the plumbing challenges with adding an intercooler are typically the reasons an intercooler is left off (and cost of kits).  If one was made out of money, ALWAYS use an intercooler.  The enemy is heat.  Even at 6 to 9 psi, heat is being generated.  If you could run this through an intercooler, you would reduce the heat (and probably pick up some power for "free").  It's *safe* to not use an intercooler at 6 to 9, on a low compression engine like ours (around 9:1).  But if you raise the compression ratio, or you run more boost, you will have more heat, and potentially more problems.  You can handle this via the engine tune and timing (as newer cars with higher compression ratios and no intercooler do) or via an intercooler.  Any car that is serious about boost really should have an intercooler or some other form of cooling the intake charge.  Good job man, thanks for taking the time to write this up <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite1" alt=":)" title="Smile    :)" loading="lazy" data-shortname=":)" /> :thumbsup:</blockquote>