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nitrous backfire

This is a discussion on nitrous backfire within the Nitrous forums, part of the LSx Technical Help Section category; so i am new to the nitrous world and i was wondering what causes a nitrous backfire and how do ...

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    nitrous backfire

    so i am new to the nitrous world and i was wondering what causes a nitrous backfire and how do u prevent one

    thanks
    Bruce

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    Grand Imperial Wizard Sarge's Avatar
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    I think your thinking about fuel puddling in your intake.....which is mainly and almost exclusive to carb motors as a fuel injected motor makes this almost impossible.....it usually happens on a carb car when a guy is spraying between shifts...and that's a no no....

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    Senior Member mrr23's Avatar
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    a nitrous backfire occurs when the motor's ability to rpm upward is too slow or stops. the intake manifolds fills with nitrous and fuel, but has nowhere to go. at some point, one of the intake valves open and unburned combustion enters the intake (called reversion) and ignites the mixture inside the intake.

    how to prevent this: some say don't engage the nitrous below certain rpms. but, that's really not the case. even the big boys have nitrous backfires. and they don't launch at 2000 rpms. they launch in the 4000+ rpm range most of the time.

    having a window switch is the best defense against this. that way, you set when the nitrous comes on. now, if the rpms go back below this starting point, the system shuts back off.

    oh, and nitrous backfires aren't exclusive to wet systems. i had a 94 z28 with a 125 dry shot. was having the flames blown out due to weak ignition. so, the mixture was getting burned too late inside the chamber. again, when the intake valve opened before most of the mixture got out the exhaust, it went into the intake. thank goodness it was an LT1. aluminum intake.

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    Quote Originally Posted by mrr23 View Post
    a nitrous backfire occurs when the motor's ability to rpm upward is too slow or stops. the intake manifolds fills with nitrous and fuel, but has nowhere to go. at some point, one of the intake valves open and unburned combustion enters the intake (called reversion) and ignites the mixture inside the intake.

    how to prevent this: some say don't engage the nitrous below certain rpms. but, that's really not the case. even the big boys have nitrous backfires. and they don't launch at 2000 rpms. they launch in the 4000+ rpm range most of the time.

    having a window switch is the best defense against this. that way, you set when the nitrous comes on. now, if the rpms go back below this starting point, the system shuts back off.

    oh, and nitrous backfires aren't exclusive to wet systems. i had a 94 z28 with a 125 dry shot. was having the flames blown out due to weak ignition. so, the mixture was getting burned too late inside the chamber. again, when the intake valve opened before most of the mixture got out the exhaust, it went into the intake. thank goodness it was an LT1. aluminum intake.
    very well put man thanks alot

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    most of the times i have seen a nitrous explosion,it has been from one of three things....
    1) flat out lean on the tuneup
    2) timing retarded too far,usually happens from someone trying to be overly conservative trying not to hurt a motor
    3) spraying a large shot at a low rpm

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    Nitrous Tuner LS2Tuner's Avatar
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    Well I can say that I've personally sprayed 300 shot from a idle for 10 monthes now with not a Single backfire and the car is still running 10's with a NX wet set-up. So it doesn't have anything to do with the rpm but the tune and if the driver is a idiot or a experianced driver!

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    Quote Originally Posted by LS2Tuner View Post
    Well I can say that I've personally sprayed 300 shot from a idle for 10 monthes now with not a Single backfire and the car is still running 10's with a NX wet set-up. So it doesn't have anything to do with the rpm but the tune and if the driver is a idiot or a experianced driver!
    well i am about to be spraying a nitrous works 100 wet shot and i already have a tr230/224 cam with a ls6 intake and my injectors are maxed out almost.....do u think i need a tune and what could the driver do to avoid the backfire
    TR230/224 .575/.563 111 LSA 4.10's, built tranny and now some spray

    and i am still slow...can u say driver mod

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    Senior Member mrr23's Avatar
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    well, i'll assume you had a tune with that cam. so, you might need to go back in and remove some timing. a window switch will be very helpful in the prevention of a backfire.

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