HYP piston question

Discussion in 'High Performance Modifications' started by 80z28phil, Nov 25, 2008.

  1. BIGBADBOWTIE

    BIGBADBOWTIE Veteran Member

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    Ditto....The requirements for nitrous on a KB hyper is very different than nitrous on a forged piston. I have run as much as 175 on KB's with no issues but the tune was spot on.
     
  2. 80z28phil

    80z28phil Veteran Member

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    Now you guys got me scared of spraying lol...
     
  3. pdq67

    pdq67 BANNED

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    And rightly so b/c WE don't want you grenading a fresh motor!

    It can happen in a NY minute!

    pdq67
     
  4. 80z28phil

    80z28phil Veteran Member

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    The thing is, in order for me to make the kinda power range i want just to get this heavy ass camaro rolling would be either boost or nitrous. Boost means id have to get rid of my current flat tops to put a nice blower on there meaning removal of the engine once again... I hate taking out engines casue it takes me months with the time scedule i have to get it back in. So the next best thing was a nice shot of spray. But now i just dont know what to do. Im estimating 350hp currently and need around 450 to get where i want to be. that or spend thousands on heads and crap money i dont have. you know?

    And of course its all about the setup or w/e but... Down here the only ppl who go to the track are fully built n shtuff... Not the street cars like mine. And what basicly wins is power to weight. Not gears, suspension etc etc...
     
    Last edited by a moderator: Dec 6, 2008
  5. 74RAT

    74RAT Veteran Member

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    it's all of those,, including gears suspension, tires, weight, power. someone with "slightly" lower hp can win if the car is geared and tired correctly (vs one that's not) with a good suspension setup,,,,,,, but 150hp difference can be more than what can be corrected for in this case!! lol. power to weight has always been the glory,, but you "do" have to hook it up.
    andy
     
  6. ProStreet383

    ProStreet383 Veteran Member

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    A frind of mine has been running 200+ shot on his CAST piston 355 for 2 years now. He runs it fat and very retarded. He also doesnt care if he blows it up. Its in an older RX7 and it is a street race car that he makes money with. The engine is almost stock with a mild cam.

    I dont recommend doing this but it has worked for him.
     
  7. 80z28phil

    80z28phil Veteran Member

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    Like i said its rarely raced on the track. When I race its Rolling from 40 atleast... Of course the track is safer ect ect. But half the racers down here are on boost and always have excuses of why there crap cant run on the track so i do it on there grounds.
     
  8. AJ_72

    AJ_72 Veteran Member

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    Most of the problems I've seen with KB hyper pistons is they break around the ring lands. I'd attribute that to improper ring gap. I've read a lot of incidents, particularly from the Mustang crowd, who love centrifugal superchargers.

    Basically, the increased silicon content in the aluminum ("hyper"-eutectic) decreases the ductility. But because the silicon, past a 12% blend ratio, doesn't fully "mix" with the aluminum alloy, the casting is more brittle. That's why they're more prone to crack under detonation.

    They also resist heat well, which increases the heat in the combustion chamber during the compression cycle. Because of the added heat the rings expand a little more than they would on a cast piston. If the gap is insufficient they'll bind in the cylinder and put added stress on the piston on the power stroke, possibly breaking the top ring land.

    They were originally designed to help aid in reducing the amount of fuel allowed to escape past the pistons when the engine is "cold". Because they're more dimensionally stable than cast pistons, tighter cylinder wall clearances can be used. Plus they increase efficiency in the combustion process. They're not really a "high performance" piston.
     
  9. pdq67

    pdq67 BANNED

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    Probably not what you want to hear, but please think about switching heads from your -186's at 64 cc's to a -441 at 76 cc and then install a 144 or a 177 blower. You will get away from filling bottles too.

    Or any heavy casting 76 cc chamber head. Install at least 1.60" exhaust valves and go!

    pdq67

    PS., try

    http://www.chevytech.com/

    and hunt up a 400 head off a P/U that has almost 80 cc chambers and stock 1.94"/1.60" valves to lower your CR even further so boost can become your friend.
     
    Last edited: Dec 13, 2008
  10. 74RAT

    74RAT Veteran Member

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    good info there. for the OP,, think of the increased silicon content like pouring sugar into a glass of cold water and stirring as you go. once you pass a certain point,, the sugar won't dilute any more and you'll see it floating arround in the water then settle to the bottom. the increased silicon content in the hypers is right at that dilution point for the most part. pretty soon you have mostly silicon/glass and no aluminum,, so to speak. the glass is brittle when you "strike" it with detonation(uncontrolled burn/pressure spike) vs a controlled burn(push on the piston). hope that helps to see what's happening with the manufacturing process of the hypers.
    andy
     

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