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Thread: nos first time

  1. #1
    Junior Member APPRENTICE
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    nos first time

    Engine runs rich, should i tune carb first ,thinking rich good lean bad.
    currant plug ngk 9. I know its too cold engine loads up after 4 to 5 min of idle, plugs are black .I am just leaning about reading plugs and tuneing. plug I intend on useing autolight ar 3932 ,2 colder than what it should have as a starting point
    what I have
    598 street engine street driven mud bogger 13'' billet converter
    92 octane in one tank c16 in fule cell a bit much but i want to be safe
    msd 6 + digital ,book says 2 deg retard, should i start 3 or 4 deg
    big shot nos 225 hp and never intend on going to a higher setting till i change the je flat top pistons
    nos already instaled I would like to take every safty measure poss
    nos will only be used in the pitt for 6 sec or under , fastest run with out nos 4.56 sec 125 foot in 2.5 foot of mud

  2. #2
    Senior Member MASTER BUILDER
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    You've got to get the engine running sweet on just the carb before looking at the nos. Run some 8 plugs without the nos and tune the carb. You probably won't need colder than 9's even with the nos. You will want to retard about 7 degrees with that much nitrous. Rule of thumb is about 1.5* for every 50 hp nos. Whats your initial timing at, 32? 34?

    I run a 632 with two speedtech systems. Initial timing is 32*. 1st stage nitrous is 400hp and I pull 11* Second stage is 300 hp and I pull another 5*. Thats a little on the sharp edge. Retard is recommended at 12* and 6*
    I was running 10 plugs but now run 9's. They're easier to read and work fine. 10's will give you a rich reading when the car isn't rich... you lean it out and BANGGGG! If you can't read the plugs, pull off the headers and look inside at the manifold end. The colour there will help.

    Read this article by Mike Canter. It is excellent. You will learn to read the plugs to tell if timing, mixture and plug heat range are correct.
    http://www.dragstuff.com/techarticle...ark-plugs.html
    It Ain't Over Til Its NOVA - 634ci of S*#t Your Pants!

  3. #3
    Senior Member RACING JUNKIE
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    I talked to NGK last week about the what spark plugs to run on a b/blk chevy with 200 shot, they told me donot go colder than 9's. he told me that top fuelers run 11's. Also we're running 36 degrees inital, with 8 degrees retard down to 28* on the bottle and that's on a pump gas 468" motor 10.2 comp. I certainly would not run the 598 more than 34*'s inital.

    JMO

    Zip.

  4. #4
    Junior Member APPRENTICE
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    I will try to get the truck to the local seed shop this week to get the carb rejeted and get back here . thanks for the input

  5. #5
    Senior Member EXPERT BUILDER
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    THX FOR THE INFO FIREBALL NOVA DUDE THAT LINK IS VERY INFORMATIVE!!!

  6. #6

    Re: nos first time

    Quote Originally Posted by johnpedamoe
    Engine runs rich, should i tune carb first ,thinking rich good lean bad.
    currant plug ngk 9. I know its too cold engine loads up after 4 to 5 min of idle, plugs are black .I am just leaning about reading plugs and tuneing. plug I intend on useing autolight ar 3932 ,2 colder than what it should have as a starting point
    what I have
    598 street engine street driven mud bogger 13'' billet converter
    92 octane in one tank c16 in fule cell a bit much but i want to be safe
    msd 6 + digital ,book says 2 deg retard, should i start 3 or 4 deg
    big shot nos 225 hp and never intend on going to a higher setting till i change the je flat top pistons
    nos already instaled I would like to take every safty measure poss
    nos will only be used in the pitt for 6 sec or under , fastest run with out nos 4.56 sec 125 foot in 2.5 foot of mud



    make sure your fuel system is capable of supporting the nitrious. Also watch your fuel pressure if it is too high the car will run too rich. If it goes too low it will get very expensive. I run a low fuel pressure switch as a safety percaution. they are very cheap insurance.

  7. #7
    Senior Member RACING JUNKIE oldandtired's Avatar
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    Sugar Hill, GA
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    1,368

    Re: nos first time

    [/quote]make sure your fuel system is capable of supporting the nitrious. Also watch your fuel pressure if it is too high the car will run too rich. If it goes too low it will get very expensive. I run a low fuel pressure switch as a safety percaution. they are very cheap insurance.[/quote]

    x2 Fuel pressure switch to cut off NOS and plumb in an oil pressure switch to cut off ignition. Better to lose one round than an engine.

    Dave
    Dave
    http://www.racingjunk.com/profile/343797
    "All that is necessary for the triumph of evil is for good men to do nothing" Edmund Burke

  8. #8
    Junior Member APPRENTICE
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    spray

    ok heres from a ultra conservative cant afford to break stuff street racer so take it for what its worth i used to run a 454 stock btm end with cast factory piston motor with 396 closed chamber heads on a 2stage 2cheaters plumbed into a 4spray bar plate id set the timing around 34 locked out and run it fat at roughly 7lbs of fuel pressure hit it with 125-175 on the hit and another 125-200 down track never had a problem nor broke a part in a 3800 lb car and ran consistant 680s in the 1/8th on small pills 125-125 n hit it harder on the street so fat and timing is the key so saving parts with your je pistons you should be fine start small work your way up as you are comfortable i used #51 autolites on spray and 52s off keep checkn the plugs if u burn electrodes start backin the timing out by 2deg increments till a good color is achieved and no plug damage youl be fine SPRAY IT MAN

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