newcomer from france,with loads of questions!

Discussion in 'PSI Superchargers Tech Questions' started by noiraude, Nov 13, 2010.

  1. noiraude

    noiraude Member

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    hello everybody!
    i m cyril,from france.
    i ve been wisely advised to go to this forum to learn about the use of alcohol in drag racing applications and find answers to the many questions i ask myself about the build of my engine.from what i ve read until now,it seems i m in the right place!
    i am currently gathering parts to modify an engine based on a production 383 dodge block with block filler,not cooled,with deburred,lightened and polished stock rods and crank,forged domed pistons(12.27 static compression)all matched and externally balanced,ally edelbrock heads,roller rockers and mechanical flat tappet cam.
    from there,i bought a mechanical injection (nostalgia style 3 ribs bugcatcher with k valve,set up for alky)
    a 8.71 high helix kuhl blower,set up for alky
    a bds blower intake.
    a cam driven fuel pump
    ignition is a mallory supermag 3 magneto and coil
    all those parts were purchased from the same shop,as a matching system
    the questions i ask myself are:
    -will the stock main caps be up to the task,even with a studs and guirdle kit to stiffen it?
    -should i lower the static compression to 11.5?(been told not to touch it,and been told 12 is max for a blown alky application)
    -should i go for copper head gaskets?O ring the block?(been told to stick with the current headgaskets,being extra thick mopar performance gaskets,others tell me it won t handle the compression)
    -also been told to switch to stock lengh aluminum rods,to "make it easier" on the stock main caps,when others say the stock rotating assembly will handle it as is.
    the engine will go in a 100 in wheelbase funny car chassis with front and rear suspension(ladder bars) and a 33 willys body.
    transmission is an upgraded 727 torqueflite,do not know about the converter specs yet.goal is to run high 8s.
    -i was first targetting 1000hp,but i ve been told they ll be more than enough to achieve this ET with this combo.
    finally,does anybody have "general" infos on the boost/rpm input of the aforementioned blower?
    i know i m asking a lot of questions for a first time...but i really can t afford to make any mistakes,especially if they are obvious to you.
    i thank you in advance
    cyril
     
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  2. rb0804

    rb0804 Active Member

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    make sure you put a balistic blanket and or a scatter shield on that torque flight. Some of the nastiest tranny explosions that I have even seen where the ole Torque Flights. Some of them not even blown.
     
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  3. noiraude

    noiraude Member

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    thanks for the advice!
    from what i ve read,those 727 explosions happen mainly from a 1st gear burnout...
    but i m far away from there!
     
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  4. wildride boy

    wildride boy Top Sportsman Racer

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    see your PM
     
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  5. secondwindracing

    secondwindracing top alcohol

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    o-ring it...dave
     
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  6. Money Shot

    Money Shot Member

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    rods and pins

    Use a good alum rod if you can. Heavy wall pins are a plus. Agree about the O-Ring. Its a must.
     
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  7. Money Shot

    Money Shot Member

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    Sorry.....That sounded kinda Dr. Seuss.
     
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  8. noiraude

    noiraude Member

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    thank you very,very much everybody!
    i know where i m headed now!
    one last question:does a mechanical cam with these specs seem good with the new combo:
    -advertised duration:296/296
    -@0.050":252/252
    -0-lap:76
    -center line:110
    -lift:0.557"/0.557"
    -basic rpm:3000/6700
    it s a mopar perf cam that is currently on the engine,with 0.600" max lift springs on the heads.
    i will change all that if necessary...
     
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  9. Money Shot

    Money Shot Member

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    I would lean towards a cam with a wider center....say 114....If you didnt want to spend the money the 110 would work though. Make sure you have good seat pressure on your springs.
     
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  10. 23T Hemmee

    23T Hemmee Member

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    will the stock main caps be up to the task,even with a studs and guirdle kit to stiffen it?
    -should i lower the static compression to 11.5?(been told not to touch it,and been told 12 is max for a blown alky application)


    Stock caps are pretty marginal even normally aspirated once you get above 600-650Hp. They may hold, or may not, but I can guarantee you'll get cap walk at that hp level. Anything above will only make it worse. Its worse if you're running a stroker thats putting out a lot of bottom end torque. You didn't say but I got the impression you might be running a 383 crank, which the shorter stroke will put a little less strain on the bottom end. I've only see one girdle assembly I was really impressed with and that was the BCR unit, 1/2" thick with aluminum caps, a really well thought out setup, unfortunatley he closed shop about 8 months ago. I think the girdle system that 440Source sells is pretty decent, know there are a few others, can't remember much about them though. Given the strengths/weaknesses of an iron block, believe I would cut compression down, maybe as low as 10.75 to 11-1, just to give yourself a little tuning window cushion, and as already mentioned aluminum rods would be money well spent. No matter how much work has been done on the stock rods, you've got to consider they are 40+ years old and no telling how many miles they've seen before they were turned into race rods and again aluminum rods have a cushioning effect on an already stiff and somewhat brittle block. Given your ET and speed goals I think its definitley doable without leaning on it that much, just be patient, start out with a good safe tuneup and just take small steps in blower and timing changes, should be a lot of fun. Good luck with it. :)
     
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  11. noiraude

    noiraude Member

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    to all of you answering my questions:a big,big thank you!
    ...thank you again!
     
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  12. john348

    john348 Top Alcohol

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    ok where do i begin
    35 years ago i did pretty much the same thing you are going to try
    exception i used a 440 block
    get rid of the steel rods they are going to bend
    we was able to use the steel shim head gasket and laying in a copper wire with gasga cinch to hold it in place to work ok
    lower your CR, bit to much, take it down to 11-11.5-1 max lower if possible easy to do if you do a rod change, does it have a cast crank or a forged one you didnt say
    i dont think you mentioned rpms but you wil need good springs as your valves are heavy
    use studs on your main caps, they ARE going to walk, YOU WILL crack the block from the mains up thru the cyl wall.
    727 are nasty
    absolutely without question have some one pin the rear sprag, if you dont know how find someone that does so you dont eat it, this is why a torqueflight explodes

    hopefully i scared you enough you abandoned this and you will start to gather older alum hemi stuff, you will be money ahead
     
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    Last edited: Nov 16, 2010
  13. rb0804

    rb0804 Active Member

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    I don't think that I would o-ring the block or heads. I would much rather push out a head gasket then crack a block or blow a rod. Seems that you are already treading on thin ice with your current engine combo. Adding aluminum rods will help you 'cushin' things a bit and might help with the longevity of your other parts (crank, block). A good crank is a must. I would also cut your compression down a bit some where between 10 to 11:1. Make sure you keep ontop of checking your spring pressure and your valve adjustments. A 'rev kit' may be beneficial in your situation.
     
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  14. rb0804

    rb0804 Active Member

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    Why would you go with a wider LSA?
     
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  15. Moparious Maximus

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    Blower motors tend to like the wider lobe seperations, 112-114 is pretty normal, in your case you shouldn't be too worried about making more power, spend your money keeping the bottom end happy, worry about the power later.
     
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