New personal best and a nitrous question

Discussion in 'High Performance Modifications' started by Damon, Nov 21, 2018.

  1. Damon

    Damon Veteran Member

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    Hey, guys, been a while since I was here! Hope everyone has been well and, of course, Happy Thanksgiving to everyone.

    So, made it to the track with a buddy of mine who has been trying to get his turbo blow-through Chevelle into the 9s. He said I should bring my Malibu and take a few runs, too, so I did.

    With the new, shorter blower belt on the itty-bitty Weiand 142 my belt slip issue is gone and I picked up just a smidge of boost on the top end. Good enough to run 11.8 @ 116 on a dead-hook launch with NO other changes to the combo- same as it's been for the last ~6 years. (My friend in the Chevelle was the next car down the track after me and he got his nine: 9.95 @ 137. I was on the return road getting my slip so I didn't get to see it, sadly.)

    So, with that little issue fixed the quest for the 10s is now on for me. All my friends have turbo cars and I'd rather not be the slowest of our crew. At least not by a full second!

    I don't have the time or money to do much, so the old plate nitrous kit I've got on the shelf is getting dusted off and installed over the winter.

    My question relates to ignition advance. I've done blowers. I've done nitrous. But never together before (at least not on my own car). The motor is 8:1 compression and I run it with 28* of timing advance because these little 142 blowers are known detonation-makers if you get too greedy with cylinder pressure. Pump gas, obviously.

    Now, if I throw a mild 100-125HP shot on top of the blower I'm wondering how much timing I should pull out. Normally a shot that small wouldn't require much if any but I'm a little concerned how it's going to interact with the boost. Anybody done something similar could get me in the ballpark with a recommendation?

    Thanks in advance, guys.
     
  2. biker

    biker Veteran Member

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    I'm of no help, but nice to see you back and congrats on an awesome time and trap speed.

    Brent.
     
  3. John Wright

    John Wright Veteran Member Lifetime Gold Member

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    From what I've seen, when adding NO² to boost, it basically doubles the shot. ie. 50 shot turns into 75-100hp
     
  4. 1980RS

    1980RS Veteran Member

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    I see no need to add NOS with a blower, run one or the other. What's your combo, engine specs on the car inc. the drivetrain?
     
  5. Damon

    Damon Veteran Member

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    Well, there is a very good reason to run nitrous on top of a blower. Because the blower is one pulley from being maxed out and I need more power than that last pulley is going to give me. I'm fresh out of turbos, fresh out of bigger blowers, so nitrous it will be.

    Important specs are in the post and my signature, but for clarity, it's a low compression (8:1) 383, ancient set of AFR 190cc heads, Summit house brand cam (214/224* on a 112* LSA), the afore mentioned Weiand 142 underhood roots blower with a home brewed QJet on top. Makes about 6 PSI of boost. Headers, dual exhaust, etc. TH350 trans with a 2800 stall, 3.42 gears, drag radials.

    Like I said, even with the low compression and modest boost I only run 28* of timing right now, blower only.
     
  6. jeff swisher

    jeff swisher Veteran Member

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    Nitrous and Blowers are like peanut butter and jelly.
    You will cool the intake charge with the Nitrous .. you may see more boost when running nitrous as it takes up space.
    I would pull 4 degrees with the 100-125 shot and read the plugs after a run sneak up on the tune with timing.
    If the 6 psi of boost is a struggle for the little blower you may back it off a bit and run the Nitrous and not notice any difference in ET with blower and nitrous // saying 4 or 5 psi with Nitrous may run the same as your 6 psi with nitrous.
    Something to try anyway.

    Some like to run a race gas when going there.. some like it in the main tank and some just run a separate tank for nitrous fuel.
    That is up to you to decide.
    Usually BBC at 9 psi and 200+ hit of nitrous gets the race gas.. yours may not be such an animal.

    And you are not the last Q jet tuner I love those carbs.
    :)
     
  7. 1980RS

    1980RS Veteran Member

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    I remember racing a guy in a Camaro that had a 350 with a B&M blower and I beat him with a 396 and he just could not believe it. I asked what carb was on it, he told me a Holley 650, I told him to try an 850 to make some more boost. He put one on it went to the track and his car picked up a bunch.
     
  8. Mwilson

    Mwilson Veteran Member

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    congrats on the new best
     
  9. C4Racer

    C4Racer Veteran Member

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    My car has a plate NOS system. I could probably be talked out of it since I doubt I will ever use it.
    If you are looking for something used. This was installed but I don’t think ever used.
     
  10. SRGN

    SRGN Veteran Member

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    What ring gap are you running?
     

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