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high comp pistons boosted?

Discussion in 'Engine Building' started by Ignorant import guy, Aug 22, 2006.

  1. Ignorant import guy

    Ignorant import guy Senior Member

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    Are putting high compression pistons along with an 8 psi supercharcharger a good idea or will it damage the engine unless the engine is completly built (cam(s), valves, valve springs, rods, crank
     
  2. 1Twin1

    1Twin1 Junior Member

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    whats the compression ratio before u put iut on. if they are pushing about 10.9:1 or higher usual thats not a good idea but you can put on a thiocker head gasket to lower it but the best compresion to boost is 8.5:1 or 9.1
     
  3. reikoshea

    reikoshea HS Troll...And Mod Moderator VIP

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    i tend to agree, but ive seen people who have done it with good results. i cant give you an estimate on engine life though.
     
  4. MikeBergy

    MikeBergy Blah blah blah....

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    High CR + Boost + 100 octane gas + good tune = One happy, fast mamma jamma.
    High CR + Boost + crap gas + any tune = preignition = bye bye bottom end.
    The end.
    Both high compression and boost push the upper limits of normal pump gas' resistance to preignition, or 'knock'. This not only means that the gas is more likely to autoignite before the spark, but the increased cylinder pressure will also increase flame temps and flame speed. You really don't want to mess with high compression and boost unless you are using race fuel. Not to mention a good set of sleeves is NOT optional. But, and a big BUT, if you have a bit of knowledge about the properties of the gas you are intending to use, and can work out the thermodynamic cycle of what you propose to design, you CAN build a safe, reliable, high compression, super/turbo charged engine. And it WILL be fast. Have fun, that's what I'm doing for my next build, not super high compression though, probably close to 11:1.
     
  5. reikoshea

    reikoshea HS Troll...And Mod Moderator VIP

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    high compression FI to me is 10:1+. I know a guy that had a jrsc b16a3 del sol that did really well for over a year.
     
  6. alterdcreations

    alterdcreations Member

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    Turbo integra Type r's & gsr turbo kits are able to run all day at 10 psi. Make sure you change your fuel pump and injectors and run it a little rich (safe) and you should be ok
     
  7. MikeBergy

    MikeBergy Blah blah blah....

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    That may be true with a small turbo, but anything bigger than a .50-.60 A/R T4 cold side is gonna need to be monitored pretty carefully at 10psi. It'll push more air than the t3 compressors that come with a lot of the kits out there.

    Reiko: Yeah, most amateur turbo guys stay away from boosting anything higher than a 10:1 CR. I see boosted stock B16s all the time, they seem to do pretty well, but then again it's all how you tune it, and how much power you are adding with the turbo.

    Personally. I'd like to build an 11:1 bottom end with a gt30, and run it at around 5 psi on the street, and tune for around 8-10 psi on 100 octane.

    That said, I'm shooting for around 300whp including the build and turbo parts. Look for a future thread entitled : "Getting 300whp for a G" :)
    I just paid $12 shipped for an sti bypass valve, and will be sourcing my parts over the next few months. I will be using a stock b18a or b16a bottom end, depending on which I feel like building at the time, and a diy ported and polished pr3 head. We'll see how it goes. I'm hoping CCfab on here will help me out on a DP/MiniRam combo... hehe...
     
  8. alterdcreations

    alterdcreations Member

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    good luck. i am in the process of stroking a h22 with factory parts and made boosting factory 11:1.1 compression and i will be try the ames later on. is you are responsble it should last a long time.
    rmusa cams should be fum
     
  9. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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