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Cam profiles and supercharging... what's good?

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    #1

    Cam profiles and supercharging... what's good?

    I know cams with as little overlap as possible are best for turbo. Is this true also with superchargers? Or can a good NA cam be useful with a supercharged setup?

    I suppose I should understand the reason WHY wild cams don't sit well with turbos...

    Is it due to the need for a powerful exhaust flow (since a wild cam for our high-revving engines would make power up high, meaning the turbo won't spool as well...)

    Or is it due to the need for the compressed intake charge to remain in the combustion chamber as much as possible (meaning high overlap cams would contaminate the dense charge).



    I know my reasoning is simplistic... I don't mean to get into extreme detail without knowing more than I know. Both of those reasons are strictly from my own understanding, and not based on any sort of hard fact (which is why I'm asking )


    I'm seriously considering supercharging. I NEED a timing belt change before I even consider doing it, and I wouldn't mind getting some Crower Stage 2 cams while I'm at it. However, it would be worthless if the cams didn't work well with the supercharger.






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    #2
    Well for turbos, minimized overlap benefits the pressurization of the intake charge, as well as keeping it in the combustion chamber. Too much overlap would make for blowby...which is when the intake charge goes right through the chamber w/o being burned. Also, I'm pretty sure the giant backpressure of the turbo would make the exhaust want to go back to the lower pressure of the combustion chamber. So on one hand, you have the issue of keeping the intake charge within the chamber...and on the other hand, you have the turbo keeping the exhaust from leaving.

    On a supercharged motor though the exhaust backpressure isn't there, so the rules are different. Blowby is probably more of an issue as the exhaust is free-flowing, which would make the pressurized intake charge want to leave through that conduit even more, but at the same time, you might be able to utilize scavenging a little bit to help with flow, but from what I gather basically the same rules as a turbo cam apply.

    You have DOHC though...just advance the retard the intake cam and advance the exhaust...


    Originally posted by lordoja
    im with you on that one bro! aint nothing beat free food and drinks any day of the week, even if its at a funeral

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      #3
      I wonder what the Crower stage 1.5 (or whatever it's called) would do... Stock small lobes with larger VTEC lobes...






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        #4
        exhaust velocity.

        you want higher exhaust velocity with a turbo car, so it drives the wheel faster. a cam with high overlap would have both valves open more, and therefore would result in greater exhaust scavenging (good for N/A cars) but low exhaust velocity.

        also, blowby is an issue, since the air is pressurized, it will just blow right through the combustion chamber if both valves are open too long.
        -Mark-
        CB7
        CD5


        And if i could swim I'd swim out to you in the ocean
        Swim out to where you were floating in the dark.

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          #5
          evans tuning pwns

          http://forums.evans-tuning.com//view...ght=turbo+cams

          CrzyTuning now offering port services

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