Ordering pistons what compression?

Discussion in 'Stage II Tech' started by norbs, Jul 11, 2012.

  1. Dusty Bradford Well-Known Member

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    Nowhere was it said this motor would be ran on pump gas and 22 psi. The thread was derailed. If on pump gas it will be ran along with alky and lower boost. 9.5 is fine for that.
  2. Alky V6 Let's go racing, boyz!

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    Sorry. I was mistaken. The plan was maybe 23 psi boost on pump gas and alky as quoted from the first posting by the OP. I thought all this time it was 22 psi. Again, I'm sorry for the misunderstanding.

    Ooops. :rolleyes: Some of you aren't sounding too sure about that 9.5 and 22-23 psi boost on pump gas and alky.
  3. norbs doing more with less

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    Guy's I am going with a alky kit for the street and C16 for the track, I should be fine for 22-23 psi and 30-32 psi respectively. I really wan;t to feel what a 9.5 to 1 motor is going to feel response wise, and Bison is dead on with his calcs.
  4. bison Moderator

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    That would be no problem either. The converter would not flash high enough at 22psi if it was built for 30psi though. Still over 80lbs/minute at 22psi.
  5. Alky V6 Let's go racing, boyz!

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    I know you seem pretty sure that 9.5 will be 'plenty safe'. It sounded like some others weren't as sure.
    Take it from me, bison, sometimes you can't trust calculations, or sims. These engines can surprise you, sometimes.
  6. bison Moderator

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    9.5:1 with a cam like I described and 20* will be brutal with 93/alky.
  7. norbs doing more with less

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    Does this mean 20* boost will be risky on alky or the car will be brutal fast?:)
  8. bison Moderator

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    At 22psi it should be about the fastest 93/alky build out there. The converter won't work well at both power levels though
  9. norbs doing more with less

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    Or it could be bunch of scrap metal..........either way its going to be interesting.
  10. bison Moderator

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    It's going to be really quick
  11. Alky V6 Let's go racing, boyz!

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    norbs. Which turbo are you using again?
  12. norbs doing more with less

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    Garrett GTXR4202............


    GTX4202R-Compressor-Map.jpg 451888-11turb.jpg
  13. Reggie West Active Member

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    Is that as big a turbo I think it is?

    I don't know if I would run anything but C16 with that monster. Damn.
  14. norbs doing more with less

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    Its not a big turbo at all, nothing compared to a gt47 or pt88......
  15. bison Moderator

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    It more than covers your needs and you won't be working it hard at all with your intended pressures. You will be right in the center island with the 93 alky tune and still in the mid 70's islands with the 30psi tune. Even in crap air it will still do well if the intercooler is doing it job
  16. bison Moderator

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    There are plenty of fuels that will cover norbs' goals at the highest pressure ratio he will run. C16 is fine, q16 is fine, Maximal is fine. anything with a research octane of 118+ will be fine as far as detonation tolerance. C16 is way overpriced IMO and there are other cheaper fuels that are very consistent and readily available.
  17. norbs doing more with less

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    I'm Lil worried I won't make my goals the S2 heads I am using won;t even be ported and have 2.02 valves only...
  18. Alky V6 Let's go racing, boyz!

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    I'm not worried about when it's on the race gas.
    I believe norbs will be in a much lower eff zone than the mid 70s at 30 psi. I'm seeing more like around 60%.
    Mid 70s? You're only expecting 950 bhp at 30 psi?

    What a/r turbine housing will you be using, and by what rpm are you expecting to see 22-23 psi by with the pump gas?
  19. norbs doing more with less

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    Probably the 1.15 housing, I could see that amount of boost by 4500 rpm I am estimating, but I could be wrong on that.
  20. Alky V6 Let's go racing, boyz!

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    Here's an interesting comparison of the 9.5:1 and 8:1 CRs. This was done with 93 octane, blower rich a/f ratio, and 23 psi boost. No alcohol injection.
    Notice that it looks like the 8:1 spools faster. Not sure why that would be. Maybe the program is trying to tell you that there's no way you want to be at 23 psi boost below 4,300 rpm with a 9.5:1 CR. Blow up city.
    Notice that the knock index is almost double at 9.5:1 compared to 8:1.
    That alcohol injection will need to do quite a job there with the 9.5:1. Like I stated before, it's your wallet, norbs.

    95 vs 80 CRrs.JPG

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