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Compound Boost Formula

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Old 02-01-2020, 06:11 PM
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Default Compound Boost Formula

Hey guys! I'm new to the forum so I'm hoping this gets seen.

I'm currently working on a new engine project, and I was wondering if anyone here has the basic formula for finding the total compound boost of running two forms of forced induction? I used to know it but now when I search for it on google I can't find the original thread I found months back on any forums. I know there's probably some other forums out there specifically relating to this subject, but I figured I'd try my luck here, since I know a couple users like patsmx5 have done compound boost in the past.

Thanks for any help!
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Old 02-01-2020, 08:18 PM
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PR1 x PR2 = PRtotal.

Boost is a pretty meaningless relative term, you need to use absolute and PR.
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Old 02-02-2020, 08:58 AM
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Boost is a measure of backpressure, not volume or mass or something more useful.
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Old 02-02-2020, 11:08 AM
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Originally Posted by sixshooter
Boost is a measure of backpressure, not volume or mass or something more useful.
So in your opinion, how should I go about finding rough estimates for how much the engine would handle? The fully engine should be able to handle ~600hp, but obviously that doesn't take into account the fact that the supercharger is going to be running a much larger 865cfm and around 20psi, which is a pretty massive amount already, so now I'm trying to find a turbo to match it without blowing up my engine. I slept through physics class sadly
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Old 02-02-2020, 11:58 AM
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So as a person who has built 2 compound miata setups, and one of them is my current psuedo DD... please don't take this the wrong way.

If you need to ask questions at this level, you are probably not ready for a compound setup. I suggest you do some research, buy a few books, start putting together some spreadsheets and such. There are only a few of us around with experience on this subject.
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Old 02-02-2020, 12:43 PM
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