Beginner low boost compression questions.

Discussion in 'Forced Induction Mopar' started by 340Duster247, Oct 21, 2018.

  1. 340Duster247

    340Duster247 Well-Known Member

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    So I'm thinking from switching from Nitrous on my small block to centrifugal supercharger.
    I'm only looking for low 6-8lbs of boost with this set up but here's my dilemma.
    My aluminum headed, fordged 408 makes 11.5:1 compression. Now I known thats not ideal. I was thinking of putting a thicker cometic .080 head gasket to get the compression down a bit and running a snow meth injection kit . It would be blown threw with a Holley sniper. 94 octane.
    Is this doable?
     
  2. Garry in AZ

    Garry in AZ Building a 9 second Valiant FABO Gold Member

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    Yes, it is. Lots of modern cars come from the factory with 11:1 CR and a supercharger. The key is to use the right camshaft. Generally speaking you'll want more lift (if you have the clearance) and less overlap. (wider lobe separation angle) Most cam specialists recommend no less than a 115 degree LSA to reduce cylinder pressures. Also, a roller cam will allow steeper ramps, and still maintain wide LSA and high lift. I'd also make sure your valve spring seat pressures will handle another 9psi of boost trying to open the valve.
     
  3. 340Duster247

    340Duster247 Well-Known Member

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    Thanks .my current cam unfortunately is 110 LSA, 600 lift with 1.6s. 242/252@50.
     
  4. Garry in AZ

    Garry in AZ Building a 9 second Valiant FABO Gold Member

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    Yeah, that's not gonna work very well for a street car. If you add the blower, change the cam.