Camshaft specs for low 9 to mid 9 second 1/4 mile

Discussion in 'Engine Tech' started by it's just a six, Jan 6, 2009.

  1. it's just a six

    it's just a six Member

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    The cylinder heads flow 320 CFM @ .600 lift. Intake

    I am a little concerned if the 240 degrees duration @ .050 is too much for a street/track car.
     
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  2. quickt

    quickt Well-Known Member

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    the 116 it will idle like a stocker. Your power will come in slow and hit like a hammer up top.
     
    #22
  3. jpwalt1987

    jpwalt1987 Devils in Baggy Pants

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    Is that a stage 2 head?? Impressive flow numbers to say the least!
     
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  4. it's just a six

    it's just a six Member

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    Sorry did not answer old question.

    The head is an aftermarket inline Chevy 6 cyl.
    here r a few pics.

    Thanks for the input guys. There is no forum that can answer the q's I have , that's why I ask for your knowledge here.

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    [​IMG]
     
    #24
  5. yullose

    yullose Certified Gun Nut

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    Inline 6 ??? :confused:

    You must be lost... I think you were looking for the Supra forums. :D
     
    #25
  6. charlief1

    charlief1 Just another kinky six Staff Member

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    Take a look at inliners.org. They should be able to help you some
     
    #26
  7. bison

    bison Moderator Staff Member

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    I like all these recs and no one even knew the ex to int flow ratio, compression ratio, or octane. LMAO! All i will say is if you run a lot of back pressure like the above mentioned guys that went really fast in heads up racing close the ex valve sooner. If you dont run excessive backpressure you can run a lot more overlap and not hurt it. Big difference between the two.
     
    #27
  8. turbobitt

    turbobitt Well-Known Member

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    I went 9.86 @ 19 lbs boost and an old T-76 turbo with a cam very similar to yours. It was definetly a 7500+ rpm cam. I will still run it for my new 8 second goal.
    Allan G.
     
    #28
  9. it's just a six

    it's just a six Member

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    The exhaust to int flow ratio is 74%.

    Compression is not set yet,but between 8.5:1 - 9.0:1.

    octane,only have 91 -100 octane no lead. Will use methanol injection. Will also use race gas Q16.

    What do you think?:cool:
     
    #29
  10. charlief1

    charlief1 Just another kinky six Staff Member

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    Go with the 8.5 as a precaution. It will keep you out of trouble and you should be able to turn up the boost some that way.
     
    #30
  11. it's just a six

    it's just a six Member

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    Thanks,
    & what is Bisons reply/thoughts?
     
    #31
  12. it's just a six

    it's just a six Member

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    Thanks,
    & what is Bisons reply/thoughts?
     
    #32
  13. it's just a six

    it's just a six Member

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    "The exhaust to int flow ratio is 74%.

    Compression is not set yet,but between 8.5:1 - 9.0:1.

    octane,only have 91 -100 octane no lead. Will use methanol injection. Will also use race gas Q16.

    What do you think"


    So,,, what is Bisons reply/thoughts? :cool:
     
    #33
  14. Jerryl

    Jerryl Doing MORE with LESS!

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    I am FAR from an expert, so please don’t take this the wrong way, but I see 2 main challenges with your question, and there are no real answers to your original question. :eek:

    If you build a purpose build motor to run low 9’s, the fuel needs to be consistent and on right on the $$.
    I know you already know this, but there is a BIG difference between low 9 second advice for 91 pump and Q16.
    The operating parameters are just too wide for any and all advice to run low 9’s.
    “I” think, one should start with a single fuel, boost level and rpm level, and go from there. :wink:

    Secondly, since this is not a Turbo Buick, there will not be much low 9 sec advice.
    That advice needs to be from a cam MFG or another individual with direct experience with the application.
    Now if you want “opinions”, sure, but I don’t think that is what you are asking. ;)

    I have noticed over the years that Bison and some of the other true experts will not give opinions on such a question.
    Reason? - Their advice is based on experience, data, and results. :cool:
     
    #34
  15. it's just a six

    it's just a six Member

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    The main topic question is what do you guys have as far as camshaft specs & are running low to mid 9's. Pretty basic & in general.

    Bison made a comment saying you guys should not give any advise if you dont know the cyl head int to exhaust ratio, what fuel, etc,etc of my engine combo & specs.

    So I posted what compression I will run, cyl head flow ratio & fuel, so I would like to hear now that he knows some of the specs on my engine maybe he can give me better advise than what was posted here.

    The engine is 6 cylinders, 250 ci, close to same size as the Buick engines.

    As far as fuel is conern, I posted what range of fuels I will use.

    For the street use,most likely just 91 octane & alky injection. I will tune it this way this first.

    Here is my friends Chevy Opala in Brazil with the same cylinder head I posted here. His car is the yellow one & this is his 2nd time only @ the track w/this car. The Black Opala wagon just set the record in the 1/4 of 7.8 seconds & my friend is going to try & beat that.
    http://www.youtube.com/watch?v=jBMHJ-O4lTU

    I think my car should be a little lighter than a T-Type or GN, about 2800 lbs.:cool:

    Is he on vacation?:D
     
    #35
  16. sdteb

    sdteb trying to get it like you

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    9.70 with an off the shelf hyd 215/220
     
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  17. it's just a six

    it's just a six Member

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    #37
  18. bison

    bison Moderator Staff Member

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    My thoughts are to run A T4 flange BB turbo with a HPS exhaust wheel .81 for street/.96 for strip and run a single pattern solid cam in the 225-230*@.050 range and what ever lift you need to maximize the head flow that will not overwork the springs. Looks like you can get a lot of flow if the valve is opened further. For Q16 id run 9.3-9.5:1 and no alky. If you build it to run alky/91 you will leave a lot on the table vs higher CR and Q16. Shifting around 6500 with the boost cranked up. Higher CR will not only increase the cyl pressure during the intake stroke but will help clean out the cylinder during the ex stroke. Close the ex valve at or near TDC.
     
    #38
  19. it's just a six

    it's just a six Member

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    #39
  20. John Wilde

    John Wilde RIP ChavoLC2 Staff Member

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    Shandy, that is good to know!
    Are you running iron or aluminum heads.
     
    #40

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